KR100510042B1 - Photodegradation-resistant electrodepositable coating compositions and processes related thereto - Google Patents

Abstract

The present invention includes the steps of electrodepositing the electrodepositable composition on a substrate; Heating the coated substrate to cure the coating thereon; A substrate comprising applying at least one pigment containing coating composition and / or at least one pigment member coating composition onto the cured and electrodeposited coating to form a top coat thereon and heating the coated substrate to cure the top coat. Provided are methods for coating. The electrodepositable composition is formed from a cationic salt group-containing resin in the ungelled state, wherein the salt group is formed from pendant and / or terminal amino groups and at least partially blocked aliphatic polyisocyanate curing agents. There is also provided an anti-degradation multilayer composite coating of the undercoat layer formed from the electrodepositable composition and the top coat, wherein the composite coat is substantially free of delamination upon exposure to intensive daylight irradiation, which corresponds to two years of outdoor weathering. Did not occur as. The present invention also provides an improved method for electrophoretic coating of a substrate.

Description

Anti-degradation electrodepositable coating composition and related method {PHOTODEGRADATION-RESISTANT ELECTRODEPOSITABLE COATING COMPOSITIONS AND PROCESSES RELATED THERETO}

This application claims priority to US Provisional Application No. 60 / 266,577 and US Provisional Application No. 60 / 266,576, filed February 5, 2001.

The present invention relates to an electrodepositable primer composition and a method for coating a conductive substrate using the composition. More specifically, the present invention relates to a multilayer composite coating comprising an anti-degradable electrodepositable undercoat composition and a top coat thereon, and a method of forming a composite coated on a substrate.

Electrodeposition, a coating method, involves depositing a film-forming composition on a conductive substrate under the influence of applied power. Compared with coating means other than electrophoresis, electrodeposition is becoming more important in the coating industry because it provides increased paint efficiency, improved corrosion protection, and lower environmental pollution.

Initially, electrodeposition was carried out with the material to be coated which acts as an anode. This is commonly referred to as anionic electrodeposition. However, in 1972, cationic electrodeposition was introduced commercially and became increasingly popular. At present, cationic electrodeposition has become the main method of electrodeposition. For example, a cationic undercoat is applied by electrodeposition to over 80% of all automobiles produced worldwide.

Electrodepositable undercoat compositions especially used in the automotive industry are typically corrosion resistant epoxy based compositions crosslinked with aromatic isocyanates. When exposed to ultraviolet energy, such as sunlight, such compositions can be photodegraded. In some applications, prior to the application of the one or more top coats, one subsurface surfer is hardened and spray-coated to the electrodeposited coat. Subsurface-surfacers can provide the coating system with a variety of properties, such as the ability of the electrodeposition coating to protect against photodegradation. Optionally, one or more of the top coats may be applied directly to the cured and electrodeposited coatings, in which case the top coat is formulated to provide sufficient protection to prevent photodegradation of the coats under electrodeposition. If the top coat does not provide sufficient protection, the photodegradation of the undercoat can lead to delamination of the cured and subsequently applied topcoat from the electrodeposited undercoat, which can suddenly damage the cured coating system. .

For example, if one or more of the top coats are sufficiently opaque to ultraviolet light, a small amount of ultraviolet light passing through the top coat from the electrodeposited coat, which causes photodegradation, is caused by a high concentration of pigments and / or light-absorbing compounds. Or not permeable at all. However, when the thin film top coat and / or the top coat which is not absorbed by the ultraviolet light is applied to the cured and electrodeposited undercoat, the ultraviolet light may cause light deterioration of the undercoat which is cured and electrodeposited through the top coat. The above problem is likely to occur when the top coat is weakly colored by a metal fragment pigment that tends to transmit visible light and / or ultraviolet rays to the precoated, cured and electrodeposited undercoat.

Various approaches are known to suppress photodegradation of cured and electrodeposited coatings. As mentioned above, the top coat can be formulated to have a high concentration of pigment that provides ultraviolet transparency. In addition, the top coat formulations can be used in combination with antioxidants such as phenolic antioxidants to suppress or reduce the transmission of ultraviolet light, such as ultraviolet light absorbers ("UVAS") and / or steric hindrance. Additives such as amine light stabilizers (“HALS”).

Other factors may deteriorate the photosensitivity of the epoxy based primer, thereby contributing to the delamination of the top coat subsequently applied from the undercoat. Such factors include, but are not limited to, the use of aromatic isocyanate crosslinkers and excessive baking of the coating under excessive time and / or temperature deposition.

U. S. Patent No. 4,755, 418 discloses a method for inhibiting yellowing of the outermost coating of a multicoat coating system. The method comprises the steps of initially depositing an undercoat of at least one layer of an amine-epoxy resin additive and a crosslinker on a conductive substrate by cationic electrodeposition; Curing the primer until it is a hard durable film; Depositing a second coating on the undercoat layer comprising one or more layers of colored base coat; Depositing a second coating on the third outermost coating, the second coating comprising one or more layers of transparent top coat; And simultaneously curing the basecoat and the transparent top coat. The electrodepositable undercoat composition is a blocking polyisocyanate selected from aliphatic polyisocyanates having 6 or more carbon atoms, isocyanurates of aliphatic polyisocyanates, aromatic polyisocyanates with a molecular weight greater than 174, and isocyanurates of aromatic diisocyanates with a molecular weight greater than 174. It contains a crosslinking agent.

U. S. Patent No. 5,205, 916 discloses electrodepositable undercoat compositions containing an aqueous dispersion of epoxy based ionic resins and antioxidant additives comprising a mixture of phenolic and sulfur-containing antioxidants. Such additives disclose that yellowing due to excessive baking of the subsequently applied top coat can be reduced and the intercalation of the top coat can be suppressed after external exposure.

U. S. Patent No. 5,260, 135 discloses an anti-degradation electrodeposition composition comprising an epoxy ionic resin, a hindered amine light stabilizer present in an amount of about 1%, and a phenolic antioxidant. Although effective in improving the anti-degradation properties of the electrodeposition coating, the effect may vary due to the volatilization of HALS present on the surface after thermal curing of the composition. In some cases, the introduction of HALS in the electrodepositable coating composition can provide insufficient improvement for preventing photodegradation of the cured and electrodeposited coating since the HALS can subsequently migrate to the applied top coat layer. In addition, due to environmental and toxicological relationships, it is desirable to avoid the use of phenolic compounds such as the phenolic antioxidants described above.

While the foregoing references provide anti-degradation coating systems that can provide a number of advantages, each individual coating system disclosed herein may possess one or more defects, including excessive cost, toxicity issues, or insufficient effects. have. Accordingly, there is a need in the coatings industry for cost-effective electrodepositable undercoat compositions that retard the photodegradation and delamination of subsequently applied top coats irrespective of the top coat compositions.

In one embodiment, the present invention is directed to an improved method for coating a conductive substrate. The method includes the steps of (a) electrophoretic deposition of a curable electrodepositable coating composition on a conductive substrate to form a film deposited on at least a portion of the substrate; (b) heating the coated substrate to a sufficient temperature for a time sufficient to allow the coating deposited on the substrate to cure; (c) directly applying one or more pigment containing coating compositions and / or one or more pigment member coating compositions to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature sufficient for a time sufficient to cure the top coat, wherein the cured top coat has a light transmittance of at least 0.1% when measured at 400 nm. do. The electrodepositable coating composition comprises a resinous phase dispersed in an aqueous medium, (1) at least one ungelled active hydrogen containing cationic amine salt group containing resin, which can be electrodeposited on the cathode, and (2) one or more at least partially blocked aliphatic polyisocyanate curing agents. An improvement is the presence of at least one cationic amine salt group containing resin in the curable electrodepositable coating composition, wherein the amine salt group is derived from pendant and / or terminal amino groups of Formula I or Formula II:

-NHR

Where

R is H or C ₁ to C ₁₈ alkyl;

R ¹ , R ² , R ³ and R ⁴ are the same or different and each independently H or C ₁ to C ₄ alkyl;

X and Y may be the same or different and each independently represent a hydroxy group or an amino group.

The present invention further relates to a method of forming a light deterioration prevention multilayer coating covering a conductive substrate. The method comprises the steps of (a) electrophoretic deposition of a curable electrodepositable coating composition on a conductive substrate to form a coating electrodeposited on at least a portion of the substrate; (b) heating the coated substrate in an atmosphere containing NO ₂ in an amount of 5 ppm or less at a sufficient temperature for a time sufficient to allow the coating deposited on the substrate to cure; (c) directly applying one or more pigment containing coating compositions and / or one or more pigment member coating compositions to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature sufficient for a time sufficient to cure the top coat, wherein the cured top coat has a light transmittance of at least 0.1% when measured at 400 nm. do. The electrodepositable coating composition comprises a dendritic phase dispersed in an aqueous medium, the dendritic phase comprising (1) at least one polymer capable of adhering onto the cathode, and (2) at least one partially blocked aliphatic polyisocyanate curing agent. .

In another embodiment, the present invention provides a method of forming an anti-deterioration multilayer film on a conductive substrate, the method comprising (a) electrophoretic deposition of an aqueous curable electrodeposition coating composition as described above on a conductive substrate to Forming a film electrodeposited on at least a portion, the substrate functioning as a cathode in an electrical circuit comprising a cathode and an anode, the cathode and anode being immersed in an electrodepositable coating aqueous solution, between the cathode and the anode Passing an electric current to deposit the coating on at least a portion of the substrate; (b) heating the coated substrate at a sufficient temperature for a time sufficient to allow the coating deposited on the substrate to cure; (c) directly applying one or more pigment containing coating compositions and / or one or more pigment member coating compositions to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature sufficient for a time sufficient to cure the top coat, wherein the cured top coat has a light transmittance of at least 0.1% when measured at 400 nm. do. Improvements include introducing an anode other than ferrous into the circuit.

In a further embodiment, the present invention relates to an improved method for coating a conductive substrate, the method comprising (a) electrophoretic deposition of a curable electrodepositable coating composition onto a conductive substrate to form a coating deposited on at least a portion of the substrate. Forming; (b) heating the coated substrate to a temperature of 250 ° F. to 400 ° F. (121.1 ° C. to 204.4 ° C.) for a time sufficient to allow the electrodeposited coating to cure on the substrate; (c) directly applying one or more pigment-containing coating compositions and / or one or more pigment member coating compositions to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature sufficient for a time sufficient to cure the top coat, wherein the cured top coat has a light transmittance of 0.1 to 50% when measured at 400 nm. It includes. The electrodepositable coating composition comprises a dendritic phase dispersed in an aqueous medium, wherein the dendritic phase is (1) can be electrodeposited on a cathode and is selected from acrylic polymers, polyethoxide polymers, and mixtures thereof, and at least one active hydrogen-containing cation. At least one aliphatic polyisocyanate curing agent partially blocked by at least one based amine salt group-containing resin and (2) at least one blocking agent selected from 1,2-alkane diols having at least 3 carbon atoms, benzyl alcohols and mixtures thereof do. Improvements include cationic systems derived from one or more pendant and / or terminal amino groups of formula II described above, wherein R ¹ , R ² , R ³ , R ⁴ , X, and Y are as described above in the curable electrodepositable composition. Resins with amine salt groups are present. The present method is that when the electrodepositable coating composition is electrodeposited and cured, two or more electron-withdrawing groups are bonded at beta positions for substantially all amine nitrogen atoms.

The present invention also relates to an anti-degradation multilayer composite coating comprising a cured top coat layer on at least a portion of the conductive substrate, and a cured top coat layer positioned on at least a portion of the cured bottom coat layer. The undercoat layer is formed from a curable electrodepositable coating composition comprising a resinous phase dispersed in an aqueous medium, the resinous phase comprising (1) one or more active hydrogen containing cationic amine salt group containing resins that can be electrodeposited on the cathode, and (2 ) One or more at least partially blocked aliphatic polyisocyanate curing agents. The cationic salt group of the resin (1) may comprise at least one pendant of formula (I) or formula (II), wherein R, R ¹ , R ² , R ³ , R ⁴ , X and Y are each as defined above; and / Or a terminal amino group. The top coat layer is formed from at least one pigment containing coating composition and / or at least one pigment member coating composition. Multilayer composite coatings, when the top coat layer has a light transmittance of 80% or more as measured at 400 nm, are intercalated between the hardened and electrodeposited bottom coat layer and the hardened top coat layer upon focused daylight spectrum irradiation equivalent to two years of outdoor climate. Is substantially not generated.

In one embodiment, the present invention provides an anti-degradation multilayer composite coating comprising a cured top coat layer on at least some conductive substrate, and a cured top coat of at least some cured bottom layer. The undercoat layer is formed from a curable electrodepositable coating composition comprising a resinous phase dispersed in an aqueous medium, wherein the resinous phase is (1) electrodepositable on the cathode and contains a resin selected from acrylic polymers, polyepoxide polymers, and mixtures thereof One or more active hydrogen-containing cationic amine salt group containing resins; And (2) at least one aliphatic polyisocyanate curing agent at least partially blocked by a blocking agent selected from 1,2-alkane diols having at least 3 carbon atoms, benzyl alcohols, and mixtures thereof. Resin (1) comprises at least one pendant and / or terminal amino having the structure of Formula I or Formula II, wherein R, R ¹ , R ² , R ³ , R ⁴ , X and Y are as described above. Cationic amine salt groups derived from the group. The top coat layer is formed from at least one pigment containing coating composition and / or at least one pigment member coating composition. Multi-layered composite coatings, when the top coat layer has a light transmittance of 80% or more as measured at 400 nm, substantially exfoliation between the cured undercoat layer and the cured top coat layer during concentrated sunlight irradiation equivalent to outdoor climate for two years. It is characterized by not.

In an alternative embodiment, the invention relates to a method of coating a metal substrate, the method comprising the steps of: (a) electrophoretic deposition of a curable electrodepositable coating composition on a substrate; (b) heating the substrate to a temperature of 250 ° F. to 400 ° F. (121.1 ° C. to 204.4 ° C.) for a time sufficient to cure the electrodepositable coating on the substrate; (c) directly applying at least one pigment containing coating composition and / or at least one pigment member top coat coating composition to the cured and electrodeposited composition to form a top coat directly on the cured and electrodeposited coating; And (d) heating the coated substrate at a sufficient temperature for a time sufficient to cure one or more pigment containing coating compositions and / or one or more pigment free coating compositions.

In addition, active hydrogen, which can be electrodeposited on the cathode, is derived from polyglycidyl ethers of polyhydric phenols which are essentially free of aliphatic carbon atoms to which more than one aromatic group is bonded, as used in the above-mentioned methods. -Containing cationic salt group-containing resins; And (2) an at least partially blocked polyisocyanate curing agent that is essentially free of isocyanato groups or blocking isocyanato groups to which aromatic groups are bonded. The composition is applied to a substrate, cured appropriately, and then applied to a corrosion test piece, such as the standard ASTM B117 salt spray test, or to a cyclic test method, such as GM Engineering Standard 9540P Method B, such a composition may contain aromatic isocyanates and / or It will not retain more corrosion than scribe compared to that indicated by a suitable control containing a bisphenol A based aromatic polyepoxide. If the top is covered with a transparent base coating and / or a transparent coating composition having a light transmittance of greater than 50% at a wavelength of 400 nm, it will withstand no substantial degradation in xenon arcs for more than 1500 hours, which is accelerated weathering conditions as in SAE J1960. .

It is understood that all numbers expressing quantities of ingredients, reaction conditions, and the like used in the specification and claims are capable of being changed by the term “about” unless otherwise stated or otherwise stated. Accordingly, unless expressly stated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties obtainable by the present invention. Since there is little intention to limit the present application to the views corresponding to the claims, each numerical parameter should be interpreted by applying ordinary approximation methods, at least in view of the reported major Arabic numerals.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. However, any numerical value includes certain errors necessarily resulting from the standard deviation found in each individual test measurement.

In addition, any numerical range recited herein is intended to include all sub-regions included herein. For example, the range “1 to 10” is intended to include all subranges therebetween, including the minimum 1 cited and the maximum cited 10, ie all subregions greater than or equal to 10 and less than or equal to 10.

As noted above, in one embodiment, the present invention is directed to an improved method of coating a conductive substrate. The method includes the steps of (a) electrophoretic deposition of a curable electrodepositable coating composition on a substrate to form a coating deposited on at least a portion of the substrate; (b) heating the coated substrate to a sufficient temperature for a time sufficient to allow the coating deposited on the substrate to cure; (c) directly applying one or more pigment containing coating compositions and / or one or more pigment member coating compositions to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature sufficient for a time sufficient to cure the top coat, wherein the cured top coat has a light transmittance of at least 0.1% when measured at 400 nm. do. The electrodepositable coating composition comprises a dendritic phase dispersed in an aqueous medium, the dendritic phase comprising (1) one or more ungelled active hydrogen containing cationic amine salt group containing resins that can be electrodeposited at the cathode, and (2) one At least partially blocked aliphatic polyisocyanate curing agent. The amine salt groups of the cationic resin (1) are derived from pendant and / or terminal amine groups of the general formula (I) or (II):

Formula I

-NHR

Formula II

Where

R is H or C ₁ to C ₁₈ alkyl;

R ¹ , R ² , R ³ and R ⁴ are the same or different and each independently H or C ₁ to C ₄ alkyl;

X and Y are the same or different and each independently a hydroxy group or an amino group.

In the method of the invention, the curable electrodepositable coating composition may be electrophoretically deposited on one or more portions of various conductive substrates, including various metal substrates. Suitable metal substrates may include ferrous and metals other than ferrous. Suitable ferrous metals include iron, steel, and alloys thereof. Non-limiting examples of useful steel materials include cold rolled steel, galvanized (i.e. galvanized) steel, electrogalvanized steel, stainless steel, pickling steel, GALVANNEAL®, GALVALUME, registered Trademarks), and galvan (GALVAN®), zinc-aluminum alloys coated on steel, and mixtures thereof. Useful non-ferrous metals include conductive carbon coated materials, aluminum, copper, zinc, magnesium and alloys thereof. Cold rolled steel is also suitable when pretreated with a metal phosphate solution, an aqueous solution containing at least one Group IIIB or IVB metal, an organophosphate solution, an organophosphonate solution and a mixture of the foregoing solutions. Mixtures of composites of ferrous metals and metals other than ferrous metals may also be used.

The electrodepositable coating composition of the present invention may be applied to bare metal or pretreated metal substrates. By "untreated metal" is meant a circular metal substrate that has not been treated with a pretreatment composition, such as conventional phosphate solutions, heavy metal washes, and the like. In addition, for the purposes of the present invention, a "untreated metal" substrate may alternatively comprise a cut edge of the substrate treated and / or coated on a surface other than the edge of the substrate.

Prior to the treatment or application of any coating composition, the substrate may optionally be formed into a production object. Combinations of one or more metal substrates may be assembled together to form a manufacturing object.

Also, as used herein, an electrodepositable composition or coating formed on at least a portion of a “substrate” means a composition formed directly on at least a portion of the substrate surface and any coating or pretreatment material previously applied to at least a portion of the substrate. Refers to the formed composition or coating.

That is, the “substrate” to which the coating composition is electrodeposited may include any conductive substrate, including those previously described, in which one or more pretreatment and / or undercoats have been previously applied. For example, a “substrate” can include a weldable undercoat and a metallic substrate coated on at least a portion of the substrate surface. The electrodepositable coating composition described above is then electrodeposited and cured at least in part. One or more top coating compositions, described below, are subsequently applied to at least a portion of the subsequently cured and electrodeposited coating.

For example, the substrate can include any of the conductive substrates described above and a pre-treatment composition applied to at least a portion of the substrate, wherein the pretreatment composition can include one or more Group IIIB or IVB element-containing compounds or mixtures thereof. And a solution containing is dissolved or dispersed in a carrier medium, typically an aqueous medium. Group IIIB and IVB atoms are as defined in the CAS Periodic Table of Elements, as shown, for example, in Handbook of Chemistry and Physics (60th Ed. 1980). Transition metal compounds and rare earth metal compounds are typically zirconium, titanium, hafnium, yttrium, cerium and mixtures thereof. Typical zirconium compounds include hexafluorozirconic acid, alkali metal and ammonium salts thereof, ammonium zirconium carbonate, zirconyl nitrate, zirconium carboxylate and zirconium hydroxy carboxylate, for example hydrofluorozirconium acid, zirconium acetate, zirconium It may be selected from oxalate, ammonium zirconium glycolate, ammonium zirconium lactate, ammonium zirconium citrate and mixtures thereof.

The pretreatment composition carrier may also contain a film-forming resin, for example an epoxy functional material containing two or more epoxy groups and one or more reaction products of alkanolamines, as disclosed in US Pat. No. 5,653,823. Other suitable resins include water soluble and water dispersible polyacrylic acids as disclosed in US Pat. No. 3,912,548 and US Pat. No. 5,328,525; Phenol-formaldehyde resins as described in US Pat. No. 5,662,746, which is incorporated herein by reference; Water-soluble polyamides as disclosed in WO 95/33869; Copolymers of allyl ether with maleic or acrylic acid as described in Canadian Patent Application No. 2,087,352; And water-soluble and water-soluble resins, including epoxy resins, aminoplasts, phenol-formaldehyde resins, tannins, and polyvinyl phenols as disclosed in US Pat. No. 5,449,415.

Additionally, substrates other than ferrous or ferrous substrates may be pretreated with a non-insulating layer of organophosphate or organophosphonate as described in US Pat. No. 5,294,265 and US Pat. No. 5,306,526. Such organophosphate or organophosphonate pretreatment is commercially available from PPG Industries as a trademark of NUPAL®. Application of a non-conductive coating, such as NewPal, to a substrate typically includes washing the substrate with deionized water and then incorporating the coating thereafter. This ensures that the non-conductive coating is thin enough to be non-insulating, that is to say that the non-conductive coating is thin enough to allow subsequent electrodeposition of the electrodepositable coating composition without affecting the electrical conductivity of the substrate. The pretreatment coating composition may further comprise a surfactant that acts as an aid to improve the wettability of the substrate. Generally, the surfactant material is present in an amount of less than about 2 weight percent based on the weight of the pretreatment coating composition. Other optional materials of the carrier medium include antifoams and substrate wetting agents.

With regard to environmental issues, the pretreatment coating composition may be free of chromium-containing materials. That is, the composition contains less than about 2 weight percent, less than about 0.05 weight percent chromium containing material (expressed as CrO ₃ ).

In a typical pretreated process, it is useful to remove alien material from the metal surface by sufficiently washing and degreasing the surface before applying the pretreatment composition on the surface of the metal substrate. The surface of the metal substrate may be subjected to physical or chemical means, such as mechanically wear or clean / degrease the surface with commercially available alkali or acidic cleaners such as sodium metasilicate and sodium hydroxide, which are already known to those skilled in the art. It can be cleaned by. A non-limiting example of a suitable cleaner is CHEMKLEEN® 163, an alkaline-based cleaner commercially available from PPG Pretreatment and Specialty Products, Troy, Mich. In addition, acidic cleaners may be used. Following the cleaning step, the metal substrate is generally washed with water to remove any residue. Metal substrates can be air dried using an air knife, shortly exposing the substrate to high temperatures to remove water, or to pass the substrate through rubber rolls. The pretreatment coating composition may be deposited on at least a portion of the outer surface of the metal substrate. Preferably, the entire outer surface of the metal substrate is treated with the pretreatment composition. The thickness of the pretreatment film can vary, but is generally less than about 1 μm, preferably from about 1 to about 500 nm, more preferably from about 10 to about 300 nm.

The pretreatment coating composition is applied to the surface of the metal substrate by any conventional application technique, for example by spraying, dipping or roll coating in a batch or continuous manner. The temperature of the pretreatment coating composition at the time of application is typically about 10 ° C to about 85 ° C, preferably about 15 ° C to about 60 ° C. The pH of the pretreatment coating composition at the time of application is generally from 2.0 to 5.5, typically from 3.5 to 5.5. The pH of the medium may be selected from inorganic acids such as hydrofluoric acid, fluoroboric acid, phosphoric acid and the like, including mixtures thereof; Organic acids such as lactic acid, acetic acid, citric acid, sulfamic acid or mixtures thereof; And water-soluble or water-dispersible bases such as sodium hydroxide, ammonium hydroxide, ammonia, or amines such as triethylamine, methylethyl amine or mixtures thereof.

Continuous processes are typically used in the coil coating industry and also in wheat applications. The pretreatment coating composition may be applied by any such conventional process. For example in the coil industry, substrates are typically cleaned and cleaned and then contacted with the pretreatment coating composition by a roll coating method with a chemical applicator. The treated strip is then heated to dry, colored and baked by conventional coil coating processes.

Mill application of the pretreatment composition may be applied to the newly produced metal strip by dipping, spraying or roll coating. Excess pretreatment composition is typically removed by impeller rolls. After the pretreatment composition is applied to the metal surface, the metal can be washed with deionized water, dried at room temperature or elevated temperature to remove excess moisture from the treated substrate surface and to cure any curable coating components to form a pretreatment coating. have. Optionally, the treated substrate can be heated at a temperature of 65 ° C. to 125 ° C. for 2 to 30 seconds to produce a coated substrate having dried residues of the pretreatment coating composition. If the substrate has already been heated from the hot melt production process, no post-applied heating of any treated substrate is required to facilitate drying. The temperature and time for drying the coating will depend on changes such as the content of solids in the coating, the components of the coating composition and the type of substrate.

The film coverage of the residue of the pretreatment composition is generally from 1 to 10,000 mg / m ² , generally from 10 to 400 mg / m ² .

The weldable undercoat layer may be applied to the substrate whether or not the substrate is pretreated. A typical weldability coat is BONAZINC®, a zinc rich wheat coated organic metal forming composition commercially available from PPG Industries Inc., Pittsburgh, Pa. Bonazink can be applied at a thickness of at least 1 μm, typically 3 to 4 μm. Other weldable primers, such as iron-phosphide rich primers, are also commercially available.

The electrodeposition process of the present invention typically immerses a conductive substrate in an electrodeposition bath of an aqueous composition for electrodeposition, where the substrate acts as a cathode in an electrical circuit comprising a cathode and an anode. Sufficient electrical circuitry is applied between the electrodes to deposit a substantially continuous and adhesive film on at least a portion of the surface of the conductive substrate. Electrodeposition is generally performed at constant bolts between 1 volt and thousands of volts, typically between 50 and 500 volts. Current densities range from 1.0 amps to 15 amps per square foot (10.8 to 161.5 amps per square meter) and tend to decrease rapidly during the electrodeposition process, which means that a continuous self-insulating film is formed.

Any of a variety of electrodepositable coating compositions can be used in the process of the present invention. In a specific embodiment of the invention, the electrodepositable coating composition comprises a dendritic phase dispersed in an aqueous medium, the dendritic phase being capable of adhering on (1) a cathode, cationic resin or polymer in a gelled state, typically active hydrogen And at least one cationic amine salt group containing polymer containing (2) and at least one partially blocked aliphatic polyisocyanate curing agent.

In electrodepositable coating compositions, cationic polymers that are typically suitable for use as the main film forming polymer include, as many cations known in the art as long as the polymer can be "water dispersible", ie, dissolved, dispersed or emulsified in water. It may be one of the sex polymers. Such polymers contain cationic functional groups that confer positive charges.

The term "gelling" refers to the intrinsic viscosity when the resin is substantially free of crosslinks when dissolved in a suitable solvent, as measured, for example, according to ASTM-D1795 or ASTM-D4243. It means to hold. The intrinsic viscosity of the reaction product is an indicator of molecular weight. On the other hand, the gelling reaction product, since it has an infinite molecular weight, the intrinsic viscosity will be too high to be measured. As used herein, “substantially free of crosslinking” reaction product refers to a reaction product having a weight average molecular weight (Mw) of less than 1,000,000 as measured by gel permeation chromatography.

Also, as used herein, the term "polymer" refers to both oligomers and homopolymers and copolymers. Unless stated otherwise, when used in the specification and claims, the number average molecular weight of polymeric material obtained by gel permeation chromatography using polystyrene standards as a method known in the art when indicated by "Mn" to be.

Suitable examples of such cationic film-forming resins are selected from one or more polyepoxide polymers, acrylic polymers, polyurethane polymers, polyester polymers, mixtures thereof, and polymers thereof, such as polyester-polyurethane polymers. Cationic polymers containing active hydrogen. Typically, the resin (1) comprises a polyepoxide polymer or a mixture of polyepoxide and acrylic polymer. As described above, polymers suitable for use as the cationic resin (1) include active hydrogen as the curing reaction site. The term "active hydrogen" is described in Journal of the american chemical society, Vol. 49, page 3181 (1927), refers to a reactive group having an isocyanate as determined by the Zerewithoff test method as described. In one embodiment of the invention, active hydrogens are derived from hydroxy groups, primary amine groups and / or secondary amine groups.

Various polyepoxides known in the art can be used in the form of cationic resin (1). Examples of suitable polyepoxides for this purpose include those having one or more, typically two, 1,2-epoxy equivalents, ie, polyepoxides having an average of two epoxide groups per molecule. Include. Such polyepoxide polymers include polyglycidyl ethers of cyclic polyols such as polyhydric phenols such as bisphenol A. Such polyepoxides can be prepared by etherification of epihalohydrin or dihalohydrin such as epichlorohydrin or dichlorohydrin and polyhydric phenol in the presence of alkali. Non-limiting examples of suitable polyhydric phenols include 2,2-bis- (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) ethane, 2-methyl-1,1-bis (4 -Hydroxyphenyl) propane, 2,2- (4-hydroxy-3-tert-butylphenyl) propane, and bis- (2-hydroxynaphthyl) methane.

In addition to polyhydric phenols, other cyclic polyols can be used to prepare polyglycidyl ethers of cyclic polyol derivatives. Examples of such cyclic polyols are alicyclic polyols such as cycloaliphatic polyols such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-bis (hydroxymethyl) cyclohexane, 1 And 3-bis (hydroxymethyl) cyclohexane and hydrogenated bisphenol A.

Polyepoxides may be chain extended with polyether or polyester polyols. Examples of suitable polyether polyols and chain extension conditions are disclosed in US Pat. No. 4,468,307. Examples of polyester polyols for chain extension are disclosed in US Pat. No. 4,148,772.

Other suitable polyepoxides can be similarly prepared from novolak resins or similar polyphenols. Such polyepoxide resins are described in US Pat. No. 3,663,389, US Pat. No. 3,984,299, US Pat. No. 3,947,338 and US Pat. No. 3,947,339. Additional polyepoxide resins suitable for use in forming the cationic resin 1 include those described in US Pat. No. 4,755,418, US Pat. No. 5,948,229, and US Pat. No. 6,017,432.

Suitable acrylic polymers from which the active hydrogen-containing, cationic salt group-containing polymers can be derived may include one or more alkyl esters of acrylic or methacrylic acid and optionally one or more copolymers of other polymerizable ethylenically unsaturated monomers. have. Suitable alkyl esters of acrylic acid or methacrylic acid include methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethyl acrylate, butyl acrylate, and 2-ethyl hexyl acrylate. Suitable other copolymerizable ethylenically unsaturated monomers include nitriles such as acrylonitrile and methacrylonitrile; Vinyl and vinylidene halides such as vinyl chloride and vinylidene fluoride; And vinyl esters such as vinyl acetate. Acid and anhydride functional ethylenically unsaturated monomers can be used, for example acrylic acid, methacrylic acid, or anhydrides, itaconic acid, maleic acid or anhydrides, fumaric acid. Amide functional monomers are also suitable, including acrylamide, methacrylamide and N-alkyl substituted (meth) acrylamides. Vinyl aromatic compounds such as styrene and vinyl toluene can be used as long as the prevention of photodegradation of the polymer and the resulting electrodeposition coating are not compromised.

Functional groups such as hydroxy groups and amino groups can be introduced into the acrylic polymer by using functional monomers such as hydroxyalkyl acrylates and methacrylates or aminoalkyl acrylates and methacrylates. Epoxide functional groups (for conversion to cationic salt groups) include glycidyl acrylate and methacrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 2- (3,4-epoxycyclohexyl Functional monomers such as) ethyl (meth) acrylate or allyl glycidyl ether can be used to introduce acrylic polymers. Optionally, the epoxide functional group can be introduced into the acrylic polymer by reacting an epihalohydrin or dihalohydrin such as epichlorohydrin or dichlorohydrin with a carboxyl group on the acrylic polymer. Acrylic polymers are conventional free radical initiators, as known in the art, using suitable catalysts that optionally include peroxides and azo compounds and optionally chain transfer agents such as alpha-methyl styrene dimers and tertiary dodecyl mercaptans. It can be prepared by polymerization techniques, for example by solution or emulsion polymerization. Additional acrylic polymers suitable for forming the active hydrogen-containing, cationic amine salt group-containing resin (1) used in the electrodeposition composition of the present invention include those described in US Pat. No. 3,455,806 and US Pat. No. 3,928,157. Can be mentioned.

Except for the polyepoxides and acrylic polymers described above, the active hydrogen-containing cationic salt group-containing polymers can be derived from polyesters. Such polyesters can be prepared by condensation of polyhydric alcohols and polycarboxylic acids by known methods. Suitable polyhydric alcohols include, for example, ethylene glycol, propylene glycol, butylene glycol, 1,6-hexylene glycol, neopentyl glycol, diethylene glycol, glycerol, trimethylol propane, and petaerythritol. Examples of suitable polycarboxylic acids used to prepare the polyesters include succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and trimellitic acid. In addition to the polycarboxylic acids described above, when functional equivalents of anhydrides and acids are present, functional equivalents of acids such as anhydrides or lower alkyl esters of acids such as methyl esters can be used.

The polyester contains some free hydroxy groups useful for the curing reaction (due to the use of excess polyhydric alcohols and / or higher polyols during the preparation of the polyester). Epoxide functional groups can be introduced into the polyester by reaction of epihalohydrin or dihalohydrin such as epichlorohydrin or dichlorohydrin with carboxyl groups on the polyester.

Amino groups can be introduced into the polyester polymer by reacting the epoxy functional groups of the polymer with hydroxy containing tertiary amines such as N, N-dialkylalkanolamines and N-alkyldialkanolamines. Specific examples of suitable tertiary amines include the N-alkyl dialkanolamines disclosed in US Pat. No. 5,483,012, paragraphs 49-63. Suitable polyesters for use in the process of the invention include those disclosed in US Pat. No. 3,928,157.

Polyurethanes can be used as polymers from which active hydrogen-containing, cationic salt group-containing resins can be derived. Among the polyurethanes that can be used, polymeric polyols prepared by reacting polyester polyols or acrylic polyols as described above with polyisocyanates, wherein the OH / NCO equivalence ratio is greater than 1: 1 such that free hydroxy groups are present in the product to be. Small amounts of polyhydric alcohols as described above for use in the preparation of the polyester can be used in place of or in combination with the polymeric polyols.

Additional examples of polyurethane polymers suitable for forming active hydrogen-containing, cationic amine salt group containing resins (1) include the reaction of polyurethanes, polyureas, and polyether polyols and / or polyether polyamines with polyisocyanates. Poly (urethane-urea) polymers prepared. Such polyurethane polymers are described in US Pat. No. 6,248,225.

Amidoxy functional tertiary amines such as N, N-dialkylalkanolamines and N-dialkyl dialkanolamines can be used in combination with other polyols in the preparation of polyurethanes. Examples of suitable tertiary amines include the N-alkyl dialkanolamines disclosed in lines 49 to 63 of page 3 of US Pat. No. 5,483,012.

Epoxide functional groups can be introduced into the polyurethane by methods known in the art. For example, epoxides can be introduced by reacting hydroxy groups on polyurethane with epihalohydrin or dihalohydrin, such as epichlorohydrin or dichlorohydrin, in the presence of alkalis.

Mixtures of the foregoing polymers may also be used preferably. In one embodiment of the invention, the cationic resin (1) comprises a mixture of cationic polyepoxide polymer and cationic acrylic polymer. When such a mixture is used, the polyepoxide polymer may be present in the electrodepositable coating composition in an amount of 10 to 90% by weight, typically 20 to 80% by weight, based on the total weight of resin solids present in the composition.

The polymers used in the electrodepositable coating compositions of the invention have a number average molecular weight (Mn) of 1000 to 20,000, often 1000 to 8000, typically depending on the type of resin used when measured by gel permeation chromatography using polystyrene standards. As 1000 to 5000.

The active hydrogen-containing resin (1) comprises cationic amine salt groups derived from pendant and / or terminal amino groups. The term "terminus and / or pendant" means that primary and / or secondary amino groups are present as substituents suspended on or at the ends of the polymer backbone, or optionally suspended and / or suspended from the polymer backbone and end of the polymer backbone It means a terminal group substituent of the group located in. On the other hand, the amino group from which the cationic amine salt group is derived is not present in the polymeric backbone.

Pendant and / or terminal amino groups have the structure of Formula I or Formula II:

Formula I

-NHR

Formula II

Where

R is H or C ₁ to C ₁₈ alkyl;

R ¹ , R ² , R ³ and R ⁴ are the same or different and each independently H or C ₁ to C ₄ alkyl;

X and Y are the same or different and each independently a hydroxy group or an amino group.

"Alkyl" is an alkyl and aralkyl, cyclic or acyclic, linear or branched monovalent hydrocarbon group. The alkyl group may be unsubstituted or substituted with one or more heteroatoms, ie atoms other than carbon and hydrogen, such as one or more oxygen, nitrogen or sulfur atoms.

The pendant and / or terminal amino groups represented by the formulas (I) and (II) above are selected from ammonia, methylamine, diethanolamine, diisopropanolamine, N-hydroxyethyl ethylene diamine, diethylenetriamine and mixtures thereof Can be derived from. One or more of these compounds react with one or more of the aforementioned polymers, such as, for example, polyepoxide polymers, wherein the epoxy groups are ring-opened by reaction with polyamines, thereby providing terminal amino groups and secondary hydroxy groups. do.

In one particular embodiment of the invention, when the electrodepositable coating composition is electrodeposited and cured, at least two electron withdrawing groups (described in detail below) are applied to substantially all of the nitrogen atoms present in the cured and electrodeposited coating. To be bound at the beta position, the cationic salt group containing polymer contains amine salt groups derived from one or more pendant and / or amino groups having the structure of Formula II above. In a further embodiment of the present invention, when the electrodepositable coating composition is electrodeposited and cured, three electron withdrawing groups are bonded at beta positions to substantially all nitrogen atoms present in the cured and electrodeposited coating. At least 65% of all nitrogen atoms present in the cured and electrodeposited coatings derived from amines used to form "substantially all" cationic amine salt groups at substantially all nitrogen atoms present in the cured and electrodeposited coatings, Typically 90%.

As described below, the electron withdrawing groups used herein for reference are the pendant and / or terminal hydroxyl and / or amino groups represented by the polyisocyanate curing agent (2) represented by X and Y in the structure of formula (II). Bound to the beta position relative to the nitrogen atom in the structure of formula (II). The amount of free or unbound amine nitrogen present in the cured glass film of the electrodepositable composition can be determined as follows. The cured glass coating film may be cryogenically ground and dissolved using acetic acid and then potentiometric titrated with acetic acid perchloric acid to determine the total substrate content of the sample. The primary amine content of the sample can be determined by reacting the primary amine with salicyaldehyde to form inadequate azomethine. Any unreacted secondary and tertiary amines can then be determined by potentiometric titration using perchloric acid. The difference between the total basicity and the titer means the primary amine. The content of tertiary amines in the sample can be determined by potentiometric titration using perchloric acid after reacting the primary and secondary amines with acetic anhydride to form the corresponding amides.

In one embodiment of the invention, the terminal amino group has the structure of Formula II wherein both X and Y are amino groups derived from primary amino groups, for example diethylenetriamine. It should be understood that primary amino groups may be blocked, for example, by reacting with ketones such as methyl ethyl ketone to form diketamine before reacting with the polymer. Such ketamines are described in column 23, line 23 to column 7, line 23 of US Pat. No. 4,104,147. Ketamine groups can decompose upon dispersing the amine-epoxy reaction product in water to provide the free primary amine group as the curing reaction site.

Small amounts of amines, such as mono, di and trialkylamines that do not contain hydroxyl groups, and mixed aryl-alkyl amines, or amines substituted with groups other than hydroxyl (e.g., those present in the composition Amounts of up to 5% of amine nitrogen), provided that including such amines does not adversely affect the photodegradability of the cured and electrodeposited coating. Specific examples include monoethanolamine, N-methylethanolamine, ethylamine, methylethylamine, triethylamine, N-benzyldimethylamine, dicocoamine and N, N-dimethylcyclohexylamine.

The above-mentioned reaction of the amine with the epoxide group of the polymer occurs upon mixing of the amine and the polymer. An amine may be added to the polymer or the polymer may be added to the amine. The reaction can be carried out in the presence of a suitable solvent such as methyl isobutyl ketone, xylene or 1-methoxy-2-propanol or in a pure state. This reaction is generally exothermic, so cooling may be desired. However, the reaction can be promoted by heating to an intermediate temperature of about 50-150 ° C.

The active hydrogen containing cationic salt group containing polymer used in the electrodepositable composition is prepared from components selected to maximize photodegradability of the polymer and the resulting cured electrodeposition composition. Without wishing to be bound by any theory, the photodegradation resistance (ie, resistance to visible and ultraviolet degradation) of the cured and electrodeposited coating is determined by the nitrogen-containing cations used in the dispersion of cationic amine salt group-containing resins containing active hydrogen. It may be related to the location and nature of sex groups.

For the purposes of the present invention, the amines leading to pendant and / or terminal amino groups comprise primary and / or secondary amine groups such that the active hydrogens of the amines are at least partially blocked with an aliphatic polyisocyanate curing agent (2) React with to form urea groups or bonds during the curing reaction, allowing them to be consumed. The urea groups formed during the curing reaction do not have a significant adverse effect on the photodegradation resistance of the cured and electrodeposited coating, and the subsequently applied top coat has a light transmittance of 0.1% or more when measured at 400 nm.

In one embodiment of the invention, the polyepoxide polymer may be “defunctionalized” with excess ammonia to produce a polymer comprising one or more structural units of formula III. Subsequently, cationic salt groups can be formed by admixing the polymer with a suitable soluble acid to facilitate dispersion in water.

In an optional embodiment of the invention, the cationic polymer (1) may comprise a polyepoxide polymer having pendant and / or terminal amino groups comprising primary amine groups capable of forming cationic amine salts. have. Such polymers can be prepared, for example, by reacting diethylene triamine bis-ketamine with an epoxy group containing polymer and then hydrolyzing to break down ketamine. Such polymers may comprise one or more structural units of formula (IV).

Surprisingly, it has been found that electrodeposition compositions comprising such polymers exhibit improved photodegradation resistance despite the presence of tertiary nitrogen in these structural units. Without being bound by theory, it is believed that this phenomenon is due to the formation of two strong electron withdrawing groups (in this case, urea groups) bonded to the beta position to the tertiary nitrogen during the curing reaction by the polyisocyanate curing agent.

Likewise, it has been found that polymers comprising other structural units having isocyanate reactive groups in the beta position relative to the nitrogen atom may also exhibit similar photodegradation resistance. Such polymers may include, for example, structural units of the following formulas (V) and (VI).

When reacting a polymer having at least one structural unit of formula (VI) with a polyisocyanate curing agent (2), electron withdrawing urethane groups are formed at the beta position relative to tertiary nitrogen atoms derived from pendant and / or terminal amino groups. Likewise, when reacting a polymer having at least one structural unit of formula V with a polyisocyanate curing agent (2), the electron withdrawing urethane and urea groups are in beta position relative to tertiary nitrogen atoms derived from pendant and / or terminal amino groups. Is formed.

As used in the description and claims of the present invention, an "electron attracting group" refers to a group that makes the amine nitrogen less basic by having a tendency to attract electron or electronegative charges from amine nitrogen atoms (e.g., urethane Or urea groups). Such electron withdrawing groups are derived from the reaction of a polyisocyanate curing agent (2) with hydroxyl and / or amino groups represented by X and Y in the structure of formula (II), which are pendant and / or terminal from resin (1). Can be induced. Moreover, for the purposes of the present invention, urethane groups derived from the reaction of hydroxyl groups along polyisocyanate curing agents and polymer backbones, and / or secondary hydroxyl groups formed upon ring opening of epoxy groups are referred to as "electron attracting groups". It should be understood that it is not intended to be included within the meaning of the term.

Polymers comprising primarily structural units, such as the structural units of formula VII and / or formula VIII, wherein R is an unsubstituted alkyl group, exhibit substantially detrimental photodegradability compared to the polymers just described. Revealed. Without wishing to be bound by theory, the adverse photodegradation resistance of polymers primarily comprising structural units of formula VII and / or formula VIII is that basic nitrogen is present in the backbone of the polymer (not pendant and / or terminal to the polymer backbone). And / or do not react with the polyisocyanate curing agent to produce two electron withdrawing groups at the beta position relative to the basic amine group.

In view of the generally disadvantageous cure of cationic epoxy containing structural units of formula (VII) and formula (VIII), the hydroxy, which is in beta position relative to the phenoxy group on the backbone of the structural unit of formula (VII) and near the end of the structural unit of formula (VIII) It can be inferred by those skilled in the art that the hydroxyl group does not participate effectively in curing (ie the hydroxyl group is not fully converted to the electron withdrawing urethane group during the curing step). It should also be noted that the extent to which basic nitrogen is consumed by reaction with the polyisocyanate curing agent can be measured by titration of the cryogenically polished electrodepositable composition after the curing step as described above.

In some cases, small amounts of polymers having structural units of Formula (VII) and / or Formula (VIII) may be included in the electrodepositable coating composition of the present invention, provided that such polymers are detrimental to the photodegradability of the cured and electrodeposited coating. It does not exist in quantity.

Terminal amino group containing polymers containing active hydrogens become cationic and water dispersible by at least partial neutralization with an acid. Suitable acids include organic and inorganic acids such as formic acid, acetic acid, lactic acid, phosphoric acid, dimethylpropionic acid and sulfamic acid. Mixtures of acids can be used. The range of neutralization varies depending on the particular reaction product involved. However, sufficient acid must be used to disperse the electrodepositable composition in water. Typically, the amount of acid used is at least 30% of the total theoretical neutralization. In addition, excess acid may be used in excess of the amount required for 100% total theoretical neutralization.

The cationic salt group formation range should be such that a stable dispersion of the electrodepositable composition is formed when the polymer is mixed with the aqueous medium and other components. "Stable dispersion" means a dispersion that can be easily redispersed if no precipitation occurs or if some precipitate is formed. Moreover, the dispersion should have sufficient cationic properties such that the dispersed particles move in the cathode direction and are deposited thereon when the potential is set between the anode and the cathode immersed in the aqueous dispersion.

Generally, cationic polymers are gelled and contain from about 0.1 to 3.0 milliequivalents, preferably from about 0.1 to 0.7 milliequivalents of cationic salt groups per gram of polymer solid.

Active hydrogens associated with cationic polymers include any active hydrogens that are reactive with isocyanates within a temperature range of about 93-204 ° C., preferably about 121-177 ° C. Typically, active hydrogens are selected from the group consisting of hydroxyl and primary and secondary aminos, including mixed groups such as hydroxyl and primary amino. Preferably, the polymer has from about 1.7 to 10 milliequivalents (me / g), more preferably about 2.0 to 5 milliequivalents (me / g) of active hydrogen per gram of polymer solid.

The cationic salt group containing polymer is present in an amount of 20 to 80 wt%, often 30 to 75 wt%, typically 50 to 70 wt%, based on the total combined weight of the resin solid of the cationic salt group containing polymer and the curing agent. It may be present in the electrodepositable composition used in the process of the invention.

As mentioned above, the dendritic phase of the electrodepositable coating composition further comprises a curing agent 2 which is adjusted to react with the active hydrogen groups of the cationic electrodepositable resin 1 described above. In one embodiment of the invention, the curing agent 2 comprises at least one aliphatic polyisocyanate at least partially blocked. In this embodiment, the aromatic polyisocyanate may be included in small amounts (ie, less than 10%, preferably less than 5%, by weight of the total resin solids of the curing agent present in the composition), provided that the aromatic polyisocyanate It is not present in an amount that adversely affects photodegradation resistance.

Curing agents used in the cationic electrodeposition compositions of the invention are typically blocked aliphatic polyisocyanates. Aliphatic polyisocyanates may be fully blocked, as described in rows 1 to 68 of the first side of US Pat. No. 3,984,299, lines 1 to 15 of the second and third sides, or of US Pat. No. 3,947,338. Partially blocked as described in rows 65 to 68 of column 2, rows 1 to 30 of column 3 and column 4 can be reacted with the polymer backbone. By “blocked” it is meant that the blocked isocyanate groups produced by reacting isocyanate groups with a compound are stable to active hydrogen at ambient temperature but are generally reactive with active hydrogen in the film forming polymer at elevated temperatures of 90-200 ° C. . In one embodiment of the invention, the polyisocyanate curing agent is a fully blocked polyisocyanate that is substantially free of free isocyanate groups.

Typically diisocyanates are used, but higher polyisocyanates may be used in place of or in combination with diisocyanates. Examples of aliphatic polyisocyanates suitable for use as curing agents include cycloaliphatic and aliphatic polyisocyanates such as 1,6-hexamethylene diisocyanate, isophorone diisocyanate, bis- (isocyanatocyclohexyl) methane, polymers Soluble 1,6-hexamethylene diisocyanate, trimerized isophorone diisocyanate, norbornane diisocyanate and mixtures thereof. In certain embodiments of the invention, the curing agent (2) comprises a fully blocked polyisocyanate selected from 1,6-hexamethylene diisocyanate, isophorone diisocyanate and mixtures thereof. In another embodiment of the present invention, the polyisocyanate curing agent comprises a fully blocked trimer of hexamethylene diisocyanate commercially available from Bayer Corporation as Desmodur N3300®.

In one embodiment of the invention, the polyisocyanate curing agent (2) comprises 1,2-alkane diols (eg 1,2-propanediol), 1,3-alkane diols (eg 1,3-butanediol), At least one blocking agent selected from benzyl alcohol (eg benzyl alcohol), allyl alcohol (eg allyl alcohol), caprolactam, dialkylamine (eg dibutylamine) and mixtures thereof Partially blocked. In a further aspect of the invention, the polyisocyanate hardener (2) is at least partially blocked with at least one 1,2 alkane diol (eg, 1,2-butanediol) having three or more carbon atoms.

If desired, the blocking agent may further comprise other well known blocking agents such as lower aliphatic alcohols such as methanol, ethanol and n-butanol; Cycloaliphatic alcohols such as cyclohexanol; Aromatic-alkyl alcohols such as phenyl carbinol and methylphenyl carbinol; And aliphatic, cycloaliphatic or aromatic alkyl monoalcohols or phenolic compounds, including phenolic compounds such as phenol itself, and substituted phenols such as cresols and nitrophenols, wherein the substituents do not affect the coating operation It may comprise a small amount of the compound. Glycol ethers and glycol amines can also be used as blocking agents. Suitable glycol ethers include ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol methyl ether and propylene glycol methyl ether. Other suitable blocking agents include oximes such as methyl ethyl ketoxime, acetone oxime and cyclohexanone oxime. As mentioned above, such conventional blocking agents may be present in small amounts, but are not present in an amount that adversely affects the anti-photolysis resistance of the cured and electrodeposited coating.

The at least partially blocked polyisocyanate curing agent (2) is 80 to 20% by weight, often 75 to 30% by weight, based on the total combined weight of the resin solids of the cationic salt group containing polymer (1) and the curing agent (2) And typically in an amount of from 70 to 50% by weight in the electrodepositable composition used in the process of the present invention.

As noted above, the present invention also provides a method of electrophoretic deposition of (a) depositing a curable electrodepositable coating composition described below on at least a portion of a substrate; (b) heating the substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for a time sufficient to cure the electrodepositable composition; (c) directly applying at least one pigment containing coating composition and / or at least one pigment member coating composition to the electrodepositable composition to form a top coat; And (d) heating the coated substrate to a temperature sufficient for a time sufficient to cure the topcoat composition to “selective method” for coating any of the metal substrates detailed above.

“Optional method” may include one or more optional steps as follows: (a) optionally, forming a metal object from the substrate; (b) optionally carrying a substrate using an alkaline and / or acidic cleaner, among the foregoing; (c) optionally, an aqueous solution containing at least one metal phosphate solution, Group IIIB and / or Group IVB metals, organophosphate solution, organophosphonate solution and combinations thereof, suitable examples of which are as described above. Pretreating the substrate with a solution selected from the group consisting of: (d) optionally, cleaning the substrate with water; (e) electrophoretically depositing the curable electrodepositable coating composition described below on a substrate; (f) heating the substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for a time sufficient to cure the electrodepositable composition; (g) directly applying at least one pigment containing coating composition and / or at least one pigment member coating composition to the electrodepositable composition to form a top coat; And (h) heating the coated substrate to a time and temperature sufficient to cure the top coat composition.

Note that changing the order of steps (a) to (h) of the optional method can yield the same results without departing from the scope of the present invention. In addition, additional water washing steps may be added as needed.

Also provided is a curable electrodepositable coating composition for use in an “optional method”. The composition is (1) derived from polyglycidyl ethers of polyhydric phenols which are essentially free of aliphatic carbon atoms bonded to more than one aromatic group and are cationic salt groups containing active hydrogens that can be electrodeposited on the cathode Containing resins; And (2) at least partially blocked polyisocyanate curing agents in which essentially no isocyanate groups or blocked isocyanato groups to which aromatic groups are bound are present.

Curable electrodepositable coating compositions for use in the "optional method" of the present invention typically comprise an amine salt group containing resin (1) with at least partially blocked polyisocyanate curing agent (2). In certain embodiments, such compositions comprise a cationic polyepoxide comprising a chain extended polyglycidyl ether of a polyhydric phenol having an aliphatic hydroxyl and an active hydrogen group and a cationic salt group selected from primary and secondary amino groups. Resin.

These chain extended polyepoxides react together with only polyepoxides and polyhydroxyl or polycarboxyl group-containing materials, or inert organic solvents such as toluene and ketones including methyl isobutyl ketone and methyl amyl ketone. It can be prepared by reacting together in the presence of an aromatic solvent such as xylene and a glycol ether such as dimethyl ether of diethylene glycol. The reaction is typically carried out for 30 to 180 minutes at a temperature of 80 to 160 ° C. until an epoxy group containing resinous reaction product is obtained. In general, the epoxide equivalent weight of the polyepoxide is between 100 and 2000, typically between 180 and 500. The epoxy compound may be saturated or unsaturated, cyclic or acyl, aliphatic, cycloaliphatic, aromatic or heterocyclic. These may contain substituents such as hydrogen, hydroxyl and ether groups.

Examples of suitable polyepoxides for use in the optional compositions are more than one, preferably about two, 1,2-epoxy equivalents, ie polyepoxides having an average of two epoxide groups per molecule. Suitable polyepoxides are polyglycidyl ethers of polyhydric phenols which are essentially free of aliphatic carbon atoms bonded to more than one aromatic group. In one optional embodiment, such polyepoxides comprise polyglycidyl ethers of polyhydric phenols selected from the group consisting of resorcinol, hydroquinone, catechol and mixtures thereof. In alternative embodiments, such polyepoxides comprise polyglycidyl ethers of polyhydric phenols selected from resorcinol, catechol, and mixtures thereof. Polyglycidyl ethers of such polyhydric phenols can be prepared by etherifying polyhydric phenols with epihalohydrin or dihalohydrin such as epichlorohydrin or dichlorohydrin in the presence of alkalis.

In electrodepositable compositions for use in the optional methods of the invention, the cationic salt group containing resin comprises at least 16%, typically at least 30%, by weight of the functional groups of the formulas based on the total weight of the resin solids: .

Examples of polyhydroxyl group containing materials used to chain extend the polyepoxide or increase its molecular weight (ie, via a hydroxyl-epoxy reaction) include any of the polyhydric phenols described above. Other polyols may also be used for chain extension. Examples of cyclic polyols are alicyclic polyols, in particular cycloaliphatic polyols such as 1,2-cyclohexane diol, 1,4-cyclohexane diol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1-bis (4-hydroxycyclohexyl) ethane, 2-methyl-1,1-bis (4-hydroxycyclohexyl) propane, 2,2-bis (4-hydroxy-3-tertiaryarylbutylcyclo Hexyl) propane, 1,3-bis (hydroxymethyl) cyclohexane and 1,2-bis (hydroxymethyl) cyclohexane. Examples of aliphatic polyols include trimethylpentanediol and neopentyl glycol in particular. Suitable polymeric polyols for chain extension include polyester polyols as described in US Pat. No. 4,148,772; And urethane diols as described in US Pat. No. 4,931,157, provided that the polyols described in this patent document are essentially free of aliphatic carbon atoms bonded to more than one aromatic group. Mixtures of alcoholic hydroxyl group containing materials and phenolic hydroxyl group containing materials may also be used.

The equivalent ratio of reactants, ie, the equivalent ratio of the epoxy: polyhydroxyl group containing material in the chain extension, is typically between 1.00: 0.75 and 1.00: 2.00. Chain extension of such polyepoxides can be carried out using polycarboxylic acid materials, in most cases dicarboxylic acids. Useful dicarboxylic acids include acids of the formula HOOC-R-COOH, wherein R is a divalent moiety that does not substantially react with the polyepoxide. R may typically be a straight or branched alkylene or alkylidene residue having 2 to 42 carbon atoms. Some examples of suitable dicarboxylic acids include cyclohexanedicarboxylic acid and include adipic acid, 3,3-dimethylpentanedioic acid, benzenedicarboxylic acid, phenylenediethanic acid, naphthalenedicarboxylic acid, pimelic acid, suberic acid, azela Acid, sebacic acid, etc. are preferable. Dicarboxylic acids of the formula HOOC-R-COOH, wherein R is a residue having less than 4 carbon atoms, may include, for example, oxalic acid, malonic acid, succinic acid and glutaric acid, but these acids are less preferred. Further suitable dicarboxylic acids include substantially unsaturated acyl aliphatic dimer acids formed by the dimerization reaction of fatty acids having 4 to 22 carbon atoms with terminal carboxyl groups (forming dimer acids having 8 to 44 carbon atoms). Dimer acids are well known in the art and are commercially available from Emery Industries under the trade name EMPOL. Dicarboxylic acids may be formed as reaction products of anhydrides and diols or diamines by reaction conditions and techniques known to those skilled in the art for particular reactants. Diols may include polytetramethylene glycol, polycaprolactone, polypropylene glycol, polyethylene glycol, and the like. Suitable anhydrides include maleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride and the like. In addition, dicarboxylic acids formed by the reaction of anhydrides with diamines can be used. Dicarboxylic acids formed by the reaction of polyoxyalkylenediamines with the aforementioned anhydrides, such as polyoxypropylenediamines available under the trademark KEFFAMINE® from Huntsman Chemical Company, can be used. have.

Typically, the amount of dicarboxylic acid used to chain extend the polyepoxide is sufficient to provide an acid group of 0.05 to 0.6, often 0.2 to 0.4 per epoxide group. This reaction is usually carried out at 80 to 175 ° C.

Materials having mixed hydroxyl and carboxyl functionality, such as 2-hydroxypivalic acid, are also suitable for use as chain extenders. In addition, materials with mixed hydroxyl / amino and amino / carboxyl functionality can be used, some of which are further described below.

The chain extended polyepoxide may have a number average molecular weight of 1000 to 3000, typically 1700 to 2600. Epoxy group containing acrylic polymers may also be used. One particularly suitable polyepoxide is EPON X1510® from Shell Oil and Chemical Company, which is chain extended with materials selected from resorcinol, catechol and mixtures thereof. Commercially available cycloaliphatic diepoxides.

In addition, any of the aforementioned acrylics, polyesters, polyurethanes, and polyepoxide resins may be used with the polyepoxides (ie, those used in the optional compositions) just described.

As mentioned above, the compositions used in the optional methods of the present invention comprise resins having cationic salt groups, for example the polyepoxides just described above. Cationic salt groups can be incorporated into the resin by reacting an epoxy group containing resinous reaction product prepared as described above with a material capable of forming cationic salt groups. Such materials are reactive with epoxy groups and may be acidified prior to, during or after the reaction with the epoxy groups to form cationic salt groups. Examples of suitable materials are primary or secondary amines which can be acidified after reaction with epoxy groups to form amine salt groups, or quaternary ammonium salt groups which can be acidified prior to reaction with epoxy groups and after reaction with epoxy groups Amines such as tertiary amines which can form Examples of other suitable materials include sulfides which can be mixed with acid prior to reaction with the epoxy groups and form ternary sulfonium salt groups upon subsequent reaction with the epoxy groups.

When amines are used to form cationic salt groups, monoamines, typically hydroxyl containing amines, are used. Polyamines may be used but are not recommended due to the tendency to gel the resin.

In one embodiment of the invention, the cationic salt group containing resin (used in the optional electrodepositable composition) contains a nitrogen atom bonded to one or more, preferably two alkyl groups having a hetero atom in the beta position relative to the nitrogen atom. It contains amine salt groups derived from amines. Heteroatoms are non-carbon or non-hydrogen atoms, typically oxygen, nitrogen or sulfur.

When used for this purpose, the hydroxyl containing amine can provide a resin having an amine group comprising a nitrogen atom bonded to at least one alkyl group having a hetero atom at the beta position relative to the nitrogen atom. Examples of hydroxyl containing amines include alkanolamines, dialkanolamines, alkyl alkanolamines and aralkyl alkanolamines having 1 to 18 carbon atoms, typically aralkyls having 1 to 6 carbon atoms in each of the alkanol, alkyl and aryl groups Alkanolamines. Specific examples include ethanolamine, N-methylethanolamine, diethanolamine, N-phenylethanolamine, N, N-dimethylethanolamine, N-methyldiethanolamine and N- (2-hydroxyethyl) -piperazine. Include. In one particular optional embodiment of the invention, the amine is diethylenetriamine, diethylenetriamine bisketamine, aminopropyl diethanolamine, aminopropylmorpholine, N- (2-aminoethyl) -morpholine and It is selected from the group consisting of a mixture thereof.

Also substituted with amines such as mono, di and trialkylamines containing no hydroxyl groups and mixed aryl-alkyl amines, or groups other than hydroxyls that do not adversely affect the reaction between the amine and the epoxy. Amines can be used in small amounts. Specific examples include ethylamine, methylethylamine, triethylamine, N-benzyldimethylamine, dicocoamine and N, N-dimethylcyclohexylamine.

Mixtures of the foregoing amines may also be used. For the purposes of the optional embodiments of the present invention, all of the aforementioned amines suitable for use as cationic salt group formers can be used to chain extend the polyepoxide prior to salt group formation.

The reaction of primary and / or secondary amines with polyepoxides occurs upon mixing of the amines and polyepoxides. An amine may be added to the polyepoxide or the polyepoxide may be added to the amine. The reaction can be carried out purely or in the presence of a suitable solvent such as methyl isobutyl ketone, xylene or 1-methoxy-2-propanol. Such reactions are generally exothermic and cooling may be desired. However, heating to an intermediate temperature of about 50-150 ° C. may facilitate the reaction.

The reaction products of primary and / or secondary amines and polyepoxides become cationic and water dispersible by at least partially neutralizing with acid. Suitable acids include any of the aforementioned organic and inorganic neutralizing acids. The range of neutralization varies depending on the particular reaction product involved. However, sufficient acid must be used to disperse the electrodepositable composition in water. Typically, the amount of acid used is at least 20% of the total theoretical neutralization. In addition, excess acid in excess of the amount required for 100% total theoretical neutralization may be used.

In the reaction of a tertiary amine with a polyepoxide, the tertiary amine can be prereacted with a neutralizing acid to form an amine salt, and then the amine salt can be reacted with a polyepoxide to form a quaternary salt group containing resin. The reaction is carried out by mixing the amine salt with polyepoxide in water. Typically, water is present in an amount ranging from about 1.75 to about 20 weight percent based on the weight of the total reaction mixture solids.

In the formation of quaternary ammonium salt group containing resins, the reaction temperature may vary (at atmospheric pressure) from the lowest temperature at which the reaction is generally at room temperature or slightly higher at room temperature to a maximum temperature of about 100 ° C. At higher pressures, higher reaction temperatures may be used. Preferably, the reaction temperature is about 60-100 ° C. Solvents such as hindered esters, ethers or hindered ketones may be used, but their use is not necessary.

Some of the amines that react with the polyepoxide, including the primary, secondary, and tertiary amines described above, may be ketimines of the polyamines described above.

Cationic resins containing ternary sulfonium groups can be used in the formation of cationic polyepoxides used in optional embodiments, including resins containing amine salts and quaternary ammonium salt groups. Examples of such resins and methods for their preparation are described in US Pat. No. 3,793,278 to DeBona and US Pat. No. 3,959,106 to Bosso et al., Which are incorporated herein by reference.

Generally, cationic resins are gelled and contain from about 0.1 to 3.0 milliequivalents, preferably from about 0.1 to 0.7 milliliters of cationic salt group per gram of resin solid. Typically, polyepoxides have from 1.7 to 10 milliliter equivalents, often from 2.0 to 5 milliliter equivalents of active resin per gram of resin solid.

The cationic salt group containing resin is 20 to 80% by weight, often 30 to 75% by weight, typically 40 to 40% by weight, based on the total combined weight of the resin solids of the cationic salt group containing resin (1) and the curing agent (2). It may be present in the optional compositions of the present invention in an amount of 70% by weight.

Polyisocyanate curing agents used in the optional compositions of the present invention may be at least partially blocked and are typically fully blocked polyisocyanates that are substantially free of free isocyanate groups. However, although the polyisocyanate may be an aliphatic or aromatic polyisocyanate, or a mixture thereof, the curing agent is essentially free of isocyanate groups or blocked isocyanato groups to which aromatic groups are bound. That is, for the purpose of the optional composition, the aromatic groups present in the curing agent are not directly bonded to the isocyanato groups. Although diisocyanates are used in most cases, higher polyisocyanates can be used instead of or in combination with diisocyanates.

Examples of suitable aliphatic diisocyanates include any of the aliphatic polyisocyanates described above. Examples of suitable aralkyl diisocyanates are meta-xylene diisocyanate and α, α, α ', α'-tetramethylmeth-xylene diisocyanate. Preferred polyisocyanates are fully blocked trimers of hexamethylene diisocyanate available under the trade name Desmodur N3300 from Bayer Corporation.

Isocyanate prepolymers, for example polyols such as neopentyl glycol and trimethylol propane or reaction products of polyisocyanates with polymeric polyols such as polycaprolactone diols and triols (NCO / OH equivalence ratio greater than 1) may also be used. .

For the purposes of optional embodiments of the invention, for example, lower aliphatic alcohols such as methanol, ethanol and n-butanol; Cycloaliphatic alcohols such as cyclohexanol; Aromatic-alkyl alcohols such as phenyl carbinol and methylphenyl carbinol; And any suitable aliphatic, cycloaliphatic or aromatic alkyl monoalcohol or phenolic system, including phenol itself and substituted phenols such as cresols and nitrophenols, wherein the substituents do not adversely affect coating operations. Compounds can be used as capping agents for polyisocyanates. Glycol ethers may also be used as capping agents. Suitable glycol ethers include ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol methyl ether and propylene glycol methyl ether. Diethylene glycol butyl ether is preferred among the glycol ethers.

Other suitable capping agents include oximes such as methyl ethyl ketoxime, acetone oxime and cyclohexanone oxime, lactams such as epsilon-caprolactam and secondary amines such as dibutyl amine.

Polyisocyanate curing agent is about 20 to 80% by weight, typically 30 to 75% by weight, typically 50 to 70% by weight, based on the total combined weight of the resin solids of the cationic salt group containing resin (1) and the curing agent (2) It may be present in an optional composition of the present invention in an amount of%.

In an optional embodiment of the present invention, such a composition is applied to a substrate to appropriately cure and then subjected to a periodic test such as a corrosion test such as standard ASTM B117 salt spray test or GM Engineering Standard 9540P Method B. When performed, there will be no corrosion portions beyond the scribe compared to that indicated by a suitable control containing aromatic isocyanates and / or bisphenol A based aromatic polyepoxides. When the top is coated with a clear coating composition and / or a transparent substrate coating having a light transmittance of greater than 50% as measured at a wavelength of 400 nm, it withstands no substantial degradation in xenon arcs for more than 1500 hours, which is accelerated weathering conditions as in SAE J1960. Serve Any of the foregoing electrodepositable coating compositions may further comprise one or more metal sources selected from rare earth metals, yttrium, bismuth, zirconium, tungsten and mixtures thereof. One or more metal sources are present in the electrodepositable composition in which the metal is typically in an amount of 0.005 to 5% by weight, based on the total weight of the resin solids in the coating composition. Typically yttrium is used.

Both soluble and insoluble yttrium compounds can act as yttrium sources in the electrodepositable compositions used in the process of the present invention. Examples of yttrium sources suitable for use in the electrodepositable composition are soluble organic and inorganic yttrium salts such as yttrium acetate, yttrium chloride, yttrium formate, yttrium carbonate, yttrium sulfamate, yttrium lactate and yttrium nitrate. When yttrium is added to the composition as an aqueous solution, yttrium nitrate, a readily available compound, is the preferred yttrium source. Other suitable yttrium compounds are organic and inorganic yttrium compounds such as yttrium oxide, yttrium bromide, yttrium hydroxide, yttrium molybdate, yttrium sulfate, yttrium silicate and yttrium oxalate. Organotium complexes and yttrium metal may also be used. If yttrium is incorporated as a component of the pigment paste, yttrium oxide is the preferred yttrium source.

Suitable rare earth metal compounds include soluble, insoluble, organic and inorganic salts of rare earth metals such as acetates, oxalates, formates, lactates, oxides, hydroxides and molybdates of rare earth metals, and the like.

There are various ways in which yttrium, bismuth, zirconium, tungsten or rare earth metal compounds can be incorporated into any electrodepositable composition used in any of the processes of the present invention. Soluble compounds may be added directly to the composition "pure", ie without premixing or reaction with other ingredients. Alternatively, the soluble compound may be added to a predispersed transparent polymer feed that may include cationic polymers, curing agents and / or any other non-colored components. Preferably, the soluble compound is added "pure". On the other hand, it is preferable that the insoluble compound and / or metal pigment is preliminarily blended with the pigment paste component and then the paste is incorporated into the electrodepositable composition.

The optional electrodepositable composition used in any of the processes of the present invention contains yttrium, bismuth, zirconium, tungsten or rare earth metals as the only corrosion inhibiting inorganic component, or incidentally contains other corrosion inhibiting inorganic or organic components such as calcium. You can add In one embodiment of the present invention, the electrodepositable coating composition used in the process and in the anti-photodegradation coating and multilayer composite coating of the present invention is substantially free of heavy metals such as lead.

 Any of the electrodepositable compositions of the invention described above may further comprise, but not necessarily require, a hindered amine light stabilizer for further UV deterioration protection. Such hindered amine light stabilizers include compounds disclosed in US Pat. No. 5,260,135. The materials, when used, may be present in amounts of 0.1 to 2 percent by weight based on the total weight of polymer solids in the electrodepositable composition.

The composition used as the electrodeposition bath in any of the aforementioned processes of the invention generally contains about 5 to 25% by weight of polymer solids, based on the total weight of the electrodeposition bath.

In addition to water, the aqueous medium of the electrodeposition bath may contain coalescing solvents. Useful coalescing solvents include hydrocarbons, alcohols, esters, ethers and ketones. Preferred coalescing solvents include alcohols, polyols and ketones. Specific coalescing solvents include isopropanol, butanol, 2-ethylhexanol, isophorone, 2-methoxypentanone, ethylene and propylene glycol, and monoethyl, monobutyl and monohexyl ethers of ethylene glycol. The amount of coalescing solvent is generally from about 0.01 to 25% by weight, preferably from about 0.05 to about 5% by weight, based on the total weight of the aqueous medium.

As mentioned above, the electrodeposition bath may comprise a pigment composition and any other additives such as surfactants, wetting agents or catalysts. The pigment composition may be of a conventional type, including inorganic pigments such as iron oxide, china clay, carbon black, coal, titanium dioxide, talc, barium sulfate, and organic color pigments such as phthalocyanine green and the like. have. The pigment content in the dispersion is generally expressed as the ratio of pigment to polymer. In the examples of the present invention, when using pigments, the ratio of pigment to polymer is generally about 0.02 to 1: 1. The other additives described above are generally present in amounts of about 0.01 to 3 weight percent in the dispersion, based on the weight of the polymer solids.

All electrodepositable coating compositions of the invention are in the form of aqueous dispersions. The term "dispersion" refers to a two-phase transparent, translucent or opaque dendritic system in which the resin is in a dispersed phase and water is present in the continuous phase. The average particle diameter of the dendritic phase is generally less than 1.0 μm, typically less than 0.5 μm, typically less than 0.15 μm.

The concentration of the dendritic phase in the aqueous medium is at least 1% by weight, typically 2 to 60% by weight, based on the total weight of the aqueous dispersion. When the composition of the present invention is in the form of a resin concentrate, it generally has a resin solids content of 20 to 60% by weight, based on the weight of the aqueous dispersion.

The curable electrodepositable coating composition of the present invention described above typically comprises two components: (1) generally active hydrogen containing cationic polymer, ie the main film-forming polymer, at least partially blocked polyisocyanate curing agent, and any additional A transparent resin feed comprising a water dispersible non-colored component; And (2) a pigment paste (described above), generally comprising at least one pigment, a water dispersible milling resin which may be the same or different from the main film-forming polymer, and optionally additives such as catalysts and wetting or dispersing aids. Is applied. The electrodeposition bath is prepared by dispersing components (1) and (2) in an aqueous medium comprising water and generally coalescing solvent. Alternatively, the electrodepositable composition of the present invention can be supplied as one component composition.

As mentioned above, in the electrodeposition process, the metal substrate to be coated and the conductive anode, which generally act as cathodes, are placed in contact with the cationic electrodepositable composition. When a current passes between the cathode and the anode during contact with the electrodepositable composition, an adhesive film of the electrodepositable composition will be deposited on the conductive substrate in a substantially continuous manner.

In one embodiment, the present invention provides a method of (a) electrophoretic deposition of any of the aforementioned aqueous, curable electrodepositable coating compositions onto a substrate to form a coating electrodeposited on at least a portion of the substrate, the substrate comprising a cathode and Acting as a cathode in an electrical circuit comprising an anode, wherein the cathode and anode are immersed in an aqueous electrodepositable coating composition and an electric current is passed through the cathode and the anode to at least a portion of the substrate: (b) Heating the coated substrate for a sufficient time at a temperature sufficient to allow the coating deposited on the substrate to cure; (c) applying at least one pigment containing coating composition and / or at least one pigment member coating composition directly to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) at a temperature sufficient for the topcoat to cure for a sufficient time, wherein the cured topcoat has a light transmittance of at least 0.1% when measured at 400 nm. An improved process for forming anti-degradation multilayer coatings on conductive substrates is presented. The improvement includes the inclusion of an anode other than ferrous, for example, an anode consisting of ruthenium oxide and a carbon rod in the circuit.

In most conventional cationic electrodeposition systems, the anode (s) consists of ferrous material, for example stainless steel. Typical cationic electrodeposition baths have an acidic pH of 4.0 to 7.0, often 5.0 to 6.0. However, in a typical electrodeposition bath system, the anolyte (ie, electrodeposition bath solution in the near zone of the anode) may exhibit a low pH of less than 3.0 due to the concentration of the anode or near the anode. In the pH range of this strong acid, the ferrous anode may deteriorate, thereby releasing soluble iron into the electrodeposition bath. The term "soluble iron" means Fe ⁺² or F ⁺³ ions derived from iron salts that are at least partially soluble in water. During the electrodeposition process, soluble iron is deposited with the dendritic binder and present in the cured and electrodeposited coating. It has been found that the presence of soluble forms of iron may contribute to the delamination of the top coat layer subsequently applied from the cured and electrodeposited coat layer upon exposure to outdoor weathering. In this respect, the electrodepositable coating composition of the present invention, when used in the form of an electrodeposition bath, preferably contains less than 10 ppm, typically less than 1 ppm of soluble iron. This can be done by including an anode other than ferrous in the circuit.

The electrodepositable coating composition described above is electrodeposited on at least a portion of the conductive substrate and then the coated substrate is heated for a sufficient time at a temperature sufficient to cure the electrodeposited coating on the substrate. The coated substrate is subjected to a temperature of 250 ° F. to 450 ° F. (121.1 ° C. to 232.2 ° C.), often 250 ° F. to 400 ° F. (121.1 ° C. to 204.4 ° C.), typically 300 ° F. to 360 ° F. (148.9 ° C. to 180 ° C.). Can be heated. The curing time may depend on the curing temperature and other variables such as the film thickness of the electrodeposited coating, the level and type of catalyst present in the composition, and the like. For the purposes of the present invention, sufficient time is necessary to influence the curing of the electrodeposited coating on the substrate. For example, the curing time is 10 minutes to 60 minutes, typically 10 minutes to 30 minutes. In one embodiment of the present invention, the coated substrate is heated to a temperature of 360 ° F. (180 ° C.) or less for a time sufficient to affect the curing of the electrodeposited coating on the substrate. The thickness of the resultant cured electrodeposited film is generally 15 to 50 mu m.

The term "curing" as used in reference to a composition (eg "curing composition") means that any crosslinkable component of the composition is at least partially crosslinked. In a particular embodiment of the invention, the crosslinking density, ie the degree of crosslinking, of the crosslinkable component is between 5% and 100% of full crosslinking. In other embodiments, the crosslinking density is between 35% and 85% of full crosslinking. In other embodiments, the crosslinking density is between 50% and 85% of full crosslinking. Those skilled in the art can determine the presence and degree of crosslinking (ie crosslink density) of crosslinking by various methods such as dynamic mechanical thermal analysis (DMTA) using an analyzer using a TA instrument DMA 2980 DMTA performed under nitrogen. I will understand that. The method measures the glass transition temperature and the crosslink density of the glass film of the film or polymer. The physical properties of the cured material are related to the crosslinked network structure. For the purposes of the present invention, the cured composition should be rubbed 100 times or more until a detectable deterioration portion occurs in the coating when rubbed twice with a cloth moistened with acetone.

In another embodiment, the present invention provides an electrophoretic coating of any of the electrodepositable coating compositions to a conductive substrate as in step (a), and at a temperature sufficient to cure the electrodeposited coating on the substrate as described above. A process capable of heating in an environment with nitrogen oxides (NOx) of less than 5 ppm, typically less than 1 ppm, over time is presented. The presence of NOx in the curing oven can result in an oxidizing environment that can result in delamination between the cured and electrodeposited coating and any applied topcoat coating upon outdoor weathering exposure.

Nitrogen oxides can be formed during the combustion of hydrocarbon fuels, for example natural gas used in fuel gas fired ovens. Nitrogen oxides have two oxidation mechanisms: (1) the reaction of excess oxygen with nitrogen in the combustor air (called thermal NOx) and (2) the reaction of nitrogen chemically bound in the fuel (called fuel NOx). Is formed as a result. In addition, small amounts of NOx are formed through the complex interaction of hydrocarbons with molecular nitrogen in the initial phase of the flame front. The amount of NOx produced when a fuel burns depends mainly on temperature, time and alternating current variables. That is, the flame temperature and residence time of the fuel / air mixture together with the nitrogen content of the fuel and the amount of excess air used for combustion determine the extent of NOx present in the curing oven environment. The delay of fuel and air mixing results in low NOx combustion, reducing combustion temperatures, minimizing initial flow, and delaying the formation of NOx in the curing oven to NOx levels below 5 ppm.

The electrodeposited coating is cured on a substrate according to any of the processes of the present invention, and then one or more pigment containing coating compositions and / or one or more pigment member coating compositions are applied directly to the cured and electrodeposited coating.

Due to the improved anti-degradation provided by the various compositions used in any of the processes of the present invention, the use of undercoat or undercoat-surface is unnecessary. Suitable top coats (including base coats, clear coats, colored single coats, and colored and transparent composite compositions) include various top coats known in the art, each independently in the form of solid particles, ie, powder coating compositions or It may be aqueous or solvent-based in the form of a powder slurry. The top coat typically contains a film-forming polymer, a crosslinking material, and one or more pigments when the colored base coat or a single coat.

Non-limiting examples of suitable base coating compositions include US Pat. No. 4,403,003; No. 4,147,679; And aqueous base coatings such as those disclosed in US Pat. No. 5,071,904. Suitable transparent coating compositions are described in US Pat. No. 4,650,718; 5,814,410; 5,814,410; And materials disclosed in US Pat. No. 5,891,981 and WO 98/14379.

The top coat composition may be applied by conventional means, including brushing, dipping, flow coating, spraying, and the like, but is most often applied by spraying. Conventional spraying techniques and equipment in air spraying and electrostatic spraying, and manual or automatic methods can be used.

After each top coat is applied to the substrate, the film is formed on the surface of the substrate by dehydrating the film by a heating or air drying period. Typically, the thickness of the colored base coat is about 0.1 to about 5 mils (about 2.54 to about 127 μm), preferably about 0.4 to about 1.5 mils (about 10.16 to about 38.1 μm). The thickness of the transparent coating is generally about 0.5 to about 5 mils (about 12.7 to about 127 μm), preferably about 1.0 to about 3 mils (about 25.4 to about 76.2 μm).

The heating is preferably done for a short time and should be sufficient to ensure that any phase coating can be subsequently applied without causing any decomposition to the coating interface. Appropriate drying conditions will depend on the particular topcoat composition and ambient humidity (if the topcoat composition is water-based), but generally about 1-5 minutes of drying at a temperature of about 80 ° F to 250 ° F (20 ° C to 121 ° C) Time is used. In general, between coatings, flash the previously applied coating. That is, exposed to ambient conditions for about 1 to 20 minutes.

After applying the top coat composition, the coated substrate is heated for a temperature and time sufficient to cure the coat layer. In the curing operation, the solvent is removed and the film-forming materials of the top coat are each crosslinked. Heating or curing operations are generally carried out at temperatures of 160 ° F. to 350 ° F. (71 ° C. to 177 ° C.), and lower or higher temperatures necessary to activate the crosslinking mechanism may be used if necessary. Curing is defined as described above.

For the purposes of the present invention, a film thickness of 1.9 to 2.2 mils (48.26 to 55.88 μm) using a Perkin-Elmer Lambda 9 scanning spectrophotometer with a 150 mm Lap Sphere integrating sphere The percentage light transmittance is determined by measuring the light transmittance of the free cured top coat with Results are collected using Perkin-Elmer UV WinLab software according to ASTM E903, standard test method, solar absorption, reflection and permeability of the material using the integrating sphere.

In one embodiment, the present invention is directed to an anti-degradation multilayer composite coating comprising a cured undercoat layer on at least a portion of a conductive substrate, and a top coat layer cured on at least a portion of the cured undercoat layer. The undercoat layer is formed from any of the curable electrodepositable coating compositions described above in detail.

The top coat layer may be formed from one or more pigment containing coating compositions and / or one or more pigment member coating compositions, as described above, and two-year outdoor climate when the top coat layer has a light transmittance of 80% or more as measured at 400 nm. When the concentrated sunlight spectrum equivalent to the above, the delamination between the cured undercoat layer and the cured top coat layer in the multilayer composite coating is substantially absent. Any of the topcoat compositions described above can be used to form a topcoat layer of a photodegradable multilayer composite coating, and when cured, the topcoat layer has a light transmittance of 80% or greater as measured at 400 nm wavelength. In addition, only when the cured and electrodeposited undercoat has satisfactory initial adhesion to the substrate, the improved anti-degradation can be observed upon the intense sunlight irradiation and the cured multilayer composite coating is satisfactory initial It is evident that the interlayer adhesion is exhibited. This is because the adhesive damage in such a case is apparently caused by factors other than photodegradation of the cured and electrodeposited film. As used in the specification and claims herein, the term "intensive daylight exposure" corresponding to a focused daylight spectrum irradiation equivalent to two years of outdoor climate uses ASTM G90-98, intensive natural daylight, three cycles. Means an accelerated exposure test performed in accordance with SAE J1961, which is embodied in the Standard Practice for Performing Accelerated Outdoor Weathering of Non metallic Materials Using Concentrated Natural Sunlight (Cycle 3). This is done using the EMMAQUA-NTW (Equatorial Mount with Mirrors for Acceleration, with Water-nighttime wetting) test, which is commercially available at the DSET Laboratory in Pohenics, Arizona, USA. Use a solar concentrator. The accelerated exposure test is conducted for a period of time under conditions associated with two years of outdoor weathering exposure (described in detail below). The method involves the use of a Fresnel-reflective system that focuses natural daylight onto a coated test panel surface mounted on a target board using ten flat first side mirrors. The high performance first side mirror uniformly concentrates daylight onto the test panel surface at an intensity of about 8 times the solar radiation and about 5 times the amount of earth radiation. The test panel is sprayed with deionized water at regular intervals measured in advance.

ISO 877, Plastics-Directed Weathering Exposure, Exposure to Weathering Using Glass-Filled Insolation, and Plastics-Method of Exposure to Direct Weathering, to Weathering Using Glass-filtered Test parameters were adjusted by Daylight, and to Intensified Weathering by Daylight Using Fresnel Mirrors) and ASTM G90. EMMAQUA exposure corresponds to the "year" of total UV actual time exposure in the common desert (Central Arizona) or subtropics (South Florida). (See the correlation table below.) See, eg, Bauer, D. R, "Chemical Approaches for Evaluating Automotive Materials and Test Methods" by Advanced Symposium on Automotive Materials Testing, Scottsdale, AZ, 1993; Journal of Coatings Technology, Dec. 1987, Vol. 59, No. 755, Pg. Bauer, DR, Paputa Peck, MC, And Carter, RO, "Evaluation of Accelerated Weathering Tests for a Polyester-Urethane Coating Using Photoacoustic Infrared Spectroscopy", 103-109; Metal Architecture, Sep. 1991, Vol. 7, No. 9, pg 56-60 (figure 2) of Higgins, Dr. Richard L., "Powder Coatings, Focus on Usage Trends"; Keller, DM of Advanced Coatings Technology Conference, Chicago, IL, 1992, pg 133-144, "Testing to Failure of Paint on Plastics"; Wineburg, JP, "Automotive Coatings and Stabilizers", Advanced symposium on Automotive Materials Testing, Scottsdale, AZ, 1993; Advanced Coatings Technology Seminar, Detroit, MI. See Zwelaut, GA, and Robbins, JS, "Accelerated Outdoor Exposure Testing of Coil Coating by the EMMAQUA ^R Test Method," 1991 (Table 4).

For the purposes of the present invention, intensive daylight exposure is associated with Southern Florida for two years upon 45 ° outdoor exposure.

As discussed above, transmission of visible and / or ultraviolet light through the cured top coat layer (s) into the cured and electrodeposited coating causes photodegradation of the electrodeposited coating at the electrodeposition / top coat interface, This may cause delamination of the top coat layer from the electrodeposition layer. Thus, to ensure that the top coat layer has a light transmittance of at least 80% when measured at 400 nm wavelength, two transparent (ie, uncolored) top coat layers are typically formed over the electrodeposited undercoat. For testing purposes, the two transparent top coat layers are formed in a first coat layer or base coat layer that is substantially free of pigment, and then likewise subsequently applied to a second coat or transparent layer that is substantially free of pigment.

Metal substrates coated by the process of the present invention exhibit excellent corrosion resistance and excellent photodegradation resistance when measuring salt sprays and / or other cyclic corrosion resistance tests. When top coated with a base coating and / or transparent coating system having a light transmittance of 0.1% or more as measured at 400 nm wavelength, the resulting multilayer composite coating is subsequently applied with a cured and electrodeposited coating according to ASTM-3359-97, Method B. Delamination or adhesion damage between the coated top coat layers is measured to be substantially absent. In addition, in the multilayer composite coating of the present invention, in the case of having a top coat layer having a light transmittance of 80% or more as measured at 400 nm, the cured and electrodeposited film and the subsequent coating under concentrated daylight exposure corresponding to two years of outdoor weathering Delamination or adhesion damage between the applied top coat layers is virtually absent.

The description of the invention and the following examples are not intended to limit the invention to these details. All parts and percentages in the following examples and throughout the specification are by weight unless otherwise indicated.

Example A

This example describes the preparation of cationic amine salt group containing acrylic resins with a blocked aliphatic polyisocyanate curing agent mixed with a polymer. The resin was used as a component of the electrodepositable coating composition of Example 1 below. The cationic acrylic polymer was prepared as described below with the following components:

ingredient Parts by weight DOWANOL PNB ¹ 84.48 Dawanol PM ² 108.58 Methylisobutyl ketone 27.60 Tinuvin ^R 1130 ³ 20.40 Ethyl acrylate 456.00 Styrene 84.00 Hydroxypropyl methacrylate 180.00 Methyl methacrylate 336.00 Glycidyl methacrylate 144.00 t-dodecyl mercaptan 12.00 VAZO (Bazo) -67 ⁴ 30.01 Dawanole PNB 38.40 Dawanoll PM 19.20 Methylisobutyl ketone 15.36 LUPERSOL-75M ⁵ 24.00 Dawanole PNB 19.20 Dawanoll PM 9.60 Methylisobutyl ketone 113.30 Diethanolamine 80.64 Ketamine ⁶ 72.00 Crosslinker ⁷ 787.34 Sulfamic acid 77.28 Deionized water 5537.58 ¹ N-butoxypropanol solvent commercially available from Dow Chemical ² Propylene glycol monoethyl ether solvent commercially available from Dow Chemical ³ UV light stabilizer commercially available from CIBA-GEIGY Corp ⁴ DuPont Specialty Chemicals Reaction of the radical initiator ⁵ diethylenetriamine and methylisobutyl ketone (72.69% solids in methylisobutene ketone) commercially available from DuPont Specialty Chemicals. ⁶ US Pat. No. 4,576,979, Preparation of Component (B), described in Table 1. Prepared by reacting 1 equivalent of isocyanurated hexamethylene diisocyanate with 1 mole of dibutylamine according to the conventional method.

As measured by titration with perchloric acid, the epoxy equivalent of the monomer mixture was found to be 1212. The first four components were charged to a suitably equipped reaction vessel under a nitrogen atmosphere and heated to 100 ° C. to add the second ten components to the vessel over 2.5 hours. Once the addition was complete, the reaction mixture was held at a temperature of 115-120 ° C. for an additional 30 minutes. The reaction mixture was then maintained at 120 ° C. and the temperature maintained for 30 minutes while the next three components were added over 10-15 minutes. The reaction mixture was then cooled to room temperature diluted with the final charge of methylisobutyl ketone. Samples diluted with dawanol PM such that the ratio of polymer to solvent was 2: 1 showed Gardner-Holt bubble viscosity of T-U.

The reaction mixture was heated to 90 ° C. to add diethanolamine under a nitrogen blanket and the mixture was kept at 90 ° C. for 1 hour. The ketamine was then added and the resulting reaction mixture was held at 90 ° C. for an additional hour. The crosslinker was added and the reaction mixture was maintained at 90 ° C. for 20 minutes. The polymer sample was found to exhibit a Gardner-Hold bubble viscosity of R. The last two components were mixed separately and heated to a temperature of 50 ° C. To this, 94% of the polymer was added with stirring to prepare a dispersion of organic polymer in an aqueous medium having a solid weight of 25%. Final distillation removed the methylisobutyl ketone to give a dispersion with 30.88% by weight of solids.

Example B

This example describes the preparation of a cationic amine salt group containing polyepoxide resin with a blocked aliphatic polyisocyanate curing agent mixed with a polymer. The resin was used as a component of the electrodepositable coating composition of Example 2 below. The cationic polyepoxide resin was prepared as described below with the following components:

ingredient Parts by weight EPON 880 ¹ 614.68 Bisphenol A-ethylene oxide adduct ² 125.00 Bisphenol A 265.42 Methylisobutyl ketone 20.51 Ethyltriphenylphosphonium iodide 0.6 Bisphenol A-ethylene oxide adduct 125.00 Methylisobutyl ketone 21.11 Crosslinker ³ 891.13 Diketamine ⁴ 57.01 Methylethanolamine 48.68 ¹ Reaction product of bisphenol A with ethylene oxide in a molar ratio of diglycidyl ether ² of bisphenol A of 188 bisphenol A, commercially available from Resolution Performance Products. ³ DESMODUR ) 3 equivalents of N 3300 (multifunctional hexamethylene diisocyanate) commercially available from Bayer Corporation and 3 equivalents of caprolactam and reacted with dibutyltin dilaurate (85% solids in methylisobutyl ketone) as catalyst Manufactured by ⁴ Reaction product of diethylenetriamine with methylisobutyl ketone (73% replacement in methylisobutyl ketone)

The first four components were added to a suitably equipped reaction vessel and heated to a temperature of 125 ° C. under a nitrogen atmosphere. Ethyltriphenylphosphonium iodide was added and the reaction mixture was exothermic to a temperature of 145 ° C. The temperature was maintained for 2 hours and a second charge of bisphenol A-ethylene oxide adduct was added to give an epoxy equivalent. The second charge, methylisobutyl ketone, crosslinker, diketamine and methylethanolamine were added in order. The resulting reaction mixture was exothermic and kept at a temperature of 122 ° C. and maintained for 1 hour. An aqueous dispersion was prepared by adding 1900 parts by weight of the reaction mixture to a mixture of 39.44 parts by weight of sulfamic acid and 1255 parts by weight of deionized water. To the mixture was added 17.1 parts by weight of a 30% solution of rosin acid in butylcarbitol foam. The dispersion was diluted with 1437 parts by weight of deionized water (added over two steps) and then removed in vacuo to remove organic solvents. The solids content of the resulting product was 38.84% (1 hour at 110 ° C.).

Example C

This example describes the preparation of a cationic amine salt group containing polyepoxide resin with a blocked aliphatic polyisocyanate curing agent mixed with a polymer. The resin was used in the electrodepositable coating composition of Example 3 below. The cationic polyepoxide resin was prepared as described below from the following components.

ingredient Parts by weight EPON 880 614.68 Bisphenol A-Ethylene Oxide Adduct of Example B 125.00 Bisphenol A 265.42 Methylisobutyl ketone 20.51 Ethyltriphenylphosphonium iodide 0.6 Bisphenol A-Ethylene Oxide Adduct of Example B 125.00 Methylisobutyl ketone 22.46 Crosslinker of Example B 905.58 Diethanolamine 68.05 Diketamine of Example B 57.01

The first four components were charged to a suitably equipped reaction vessel and heated to a temperature of 125 ° C. under a nitrogen atmosphere. Ethyltriphenylsoxonium iodide was then added and the reaction mixture was exothermic to a temperature of 145 ° C. The mixture was kept at this temperature for 2 hours and a second charge of bisphenol A-ethylene oxide adduct was added to give an epoxy equivalent. The second charge, methylisobutyl ketone, crosslinker and diethanolamine, were added in order. The resulting reaction mixture was exothermic to a temperature of 122 ° C. The reaction mixture was kept at this temperature for 30 minutes and diketamine was added and the resulting reaction mixture was held at 122 ° C. for an additional 30 minutes. An aqueous dispersion was prepared by adding 1900 parts by weight of the reaction mixture to a mixture of 38.81 parts by weight of sulfamic acid and 1255 parts by weight of deionized water. To the mixture was added 17.1 parts by weight of a 30% solution of rosin acid in butylcarbitol foam. The mixture was diluted with 1437 parts by weight of deionized water (added over two steps) and then removed in vacuo to remove organic solvents. The solids content of the resulting product was 37.3% (1 hour at 110 ° C.).

Example D

This example describes the preparation of a cationic amine salt group containing polyepoxide resin with a blocked aliphatic polyisocyanate curing agent mixed with a polymer. The cationic resin was used as a component of the electrodepositable coating composition of Example 4 below. The cationic resin was prepared in the following two steps.

Example D-1

This example describes the preparation of blocked aliphatic polyisocyanate curing agents used in the electrodepositable coating composition of the present invention. The blocked polyisocyanate was prepared as follows.

ingredient Parts by weight Death Mode ^R N-3300 ¹ 1600.0 Methylisobutyl ketone 137.3 Dibutyltin dilaurate 3.0 Caprolactam 340.2 Caprolactam 340.2 Caprolactam 340.2 Methylisobutyl ketone 873.2 Hexamethylene diisocyanate trimers having an NCO equivalent of 194, commercially available from ¹ Bayer Corporation.

The first three ingredients were charged in a properly equipped vessel under a nitrogen atmosphere. The mixture was heated to 105 ° C. Upon reaching this temperature, a first portion of caprolactam was added. After initial exotherm, the reaction mixture was cooled to 105 ° C. and a second portion was added. The reaction mixture was then exothermic and the temperature was adjusted back to 105 ° C. Upon reaching this temperature, a third portion of caprolactam was added and the reaction mixture was exothermic again. The temperature was then adjusted back to 105 ° C. and the reaction mixture was kept at this temperature for 3 hours. Subsequently, NCO disappearance of the reaction mixture was monitored by infrared spectroscopy. Upon disappearance of the NCO peak, methylisobutyl ketone was added slowly and the reaction mixture was mixed until uniform. The solids content of the final reaction product was 69.8% (1 hour at 110 ° C.).

Example D-2

The following examples describe the preparation of cationic amine salt group containing polyepoxide resins having the blocked polyisocyanate crosslinker of Example D-1 mixed with the resin. The cationic resin was prepared as follows:

ingredient Parts by weight EPON 880 973.1 Bisphenol A 375.3 MAZON ^R 1651 ¹ 104.7 TETRONIC ^R 150R1 ² 0.5 Diethanolamine 56.3 1-amino-3-N, N-di (2-hydroxyethyl) amino propane ³ 153.8 Crosslinker of Example D-1 2036.5 Deionized water 851.7 Sulfamic acid 28.6 30% gum with rosin solution in Marzon ^R 1651 13.6 Deionized water 950.6 Deionized water 1600 ¹ Foam of 2- (2-butoxyethoxy) ethanol commercially available from BASF Corporation. ² Alkoxylated diamine surfactants commercially available from BASF Surfactant. ³ Available from Air Products and Chemicals, Inc.

The first ingredients were charged to a properly equipped container, heated to 70 ° C. under a nitrogen atmosphere and held at the temperature for 15 minutes. Then two amines were added. The reaction mixture was exothermic and then the temperature was adjusted to 140 ° C. The reaction mixture was kept at this temperature for 2 hours, a crosslinker was added and the reaction mixture was adjusted to 120 ° C. An aqueous dispersion was prepared by dispersing 1600 g of the resulting reaction mixture in a solution prepared with the eighth and ninth components. Gum rosin solution was added to the dispersion and deionized water was added. The resulting dispersion was diluted with additional deionized water and heated to a temperature of 60-65 ° C. The organic solvent was removed under reduced pressure to give an aqueous dispersion with a nonvolatile solids content of 26.8% (1 hour at 110 ° C.).

Example E

This example describes the preparation of cationic amine salt group containing acrylic resins with a blocked aliphatic polyisocyanate curing agent mixed with a polymer. The resin was used as a component of the electrodepositable coating composition of Example 5 below. The cationic acrylic resin was prepared from the following components:

ingredient Parts by weight Dawanole PNB 122.5 Dawanol ^R PM 157.44 Methylisobutyl ketone 40.02 Tinuvin ^R 1130 29.58 Ethyl acrylate 661.20 Styrene 121.80 Hydroxypropyl methacrylate 261.00 Methyl methacrylate 487.20 Glycidyl methacrylate 208.80 t-dodecyl mercaptan 17.40 Bajo-67 43.51 Dawanole PNB 55.68 Dawanoll PM 27.84 Methylisobutyl ketone 22.27 Looper-75M 34.80 Dawano-PNB 27.84 Dawanoll PM 13.92 Methylisobutyl ketone 164.29 Diethanolamine 116.93 Ketamine of Example A 104.40 A crosslinking agent of A 1141.64 Sulfamic acid 112.06 Deionized water 8029.49

Upon titration with perchloric acid the epoxy equivalent of the monomer mixture was found to be 1212, which satisfies a specific range of 1195-1263. The first four components were charged under nitrogen atmosphere into a suitably equipped reaction vessel and heated to 100 ° C. Ten components were then added to the vessel over 2.5 hours and at the end of the addition the reaction mixture was held at a temperature of 115 ° C. to 120 ° C. for 30 minutes. The reaction mixture was heated to 120 ° C. and the next three components were added over 10-15 minutes and then held at this temperature for 30 minutes. The mixture was then cooled to room temperature and the viscosity sample was taken out. The mixture was then diluted with a final charge of methylisobutyl ketone. The viscosity sample was diluted with dawanol PM such that the ratio of resin to solvent was 2: 1. The sample was found to have a Gardner-Hold bubble viscosity of T-U.

The mixture was then heated to a temperature of 90 ° C. under a blanket of nitrogen, diethanolamine was added and the resulting reaction mixture was maintained at a temperature of 90 ° C. for 1 hour. Ketamine was then added and the reaction temperature was again maintained at 90 ° C. for 1 hour. The crosslinker was then added in a holding period of 20 minutes. The viscosity sample was found to have a Gardner Holt bubble viscosity of Q +. The last two components were separately mixed and heated to 52 ° C. and 94% of the reaction mixture prepared as described above was stirred with addition to prepare a dispersion of organic resin in an aqueous medium having a solids content of 25% ( 1 hour at 110 ° C). The dispersion was distilled off under vacuum to remove the organic solvent to give a final product having a solids content of 32.23% (1 hour at 110 ° C.).

Example F

This example describes the preparation of a cationic amine salt group containing polyepoxide resin with a blocked aliphatic polyisocyanate curing agent mixed with a polymer. The cationic polyepoxide was used as a component of the electrodepositable coating composition of Example 5 below. The cationic polyepoxide was prepared from the following components:

ingredient Parts by weight EPON 880 614.68 Bisphenol A-Ethylene Oxide Adduct of Example B 125 Bisphenol A 265.42 Methylisobutyl ketone 20.51 Ethyltriphenylphosphonium iodide 0.6 Bisphenol A-Ethylene Oxide Adduct of Example B 125 Methylisobutyl ketone 1.64 Crosslinker ¹ 877.11 Diketamine of Example B 57.01 Methylethanolamine 48.68 ¹ DESMODUR N 3300 (commercially available from Bayer Corporation multifunctional hexamethylene diisocyanate) with one equivalent of the catalyst as prepared by using dibutyl tin dilaurate and 1,2-butanediol by reacting 1 equivalent of blocking the polyisocyanate (methylisobutyl 80% solids in butyl ketone)

The first four components were added to a suitably equipped reaction vessel and heated to a temperature of 125 ° C. under a nitrogen atmosphere. Ethyltriphenylphosphonium iodide was added and the reaction mixture was exothermic to 145 ° C. The reaction mixture was kept at this temperature for 2 hours, at which time a second charge of bisphenol A-ethylene oxide was added and an epoxy equivalent was obtained. A second charge of methylisobutyl ketone, crosslinker, diketamine and methylethanolamine was added sequentially to the reaction mixture. The reaction mixture was exothermic and brought to 122 ° C. and maintained for 1 hour. 1900 parts by weight of the reaction mixture thus prepared was added to a mixture of 47.69 parts of sulfamic acid and 1220 parts of deionized water to prepare an aqueous dispersion. To this mixture was added 16.87 parts of a 30% solution of rosin acid in butylcarbitol formal. The dispersion was further diluted with 1425 parts by weight of deionized water (added in two steps). The dispersion was vacuum stripped to remove organic solvent to give a final product of solid content 45.72% (1 hour at 110 ° C.).

Example G

This example describes a process for the preparation of such polymers with blocked aliphatic polyisocyanate curing agents mixed with cationic amine salt group-containing acrylic resins. The cationic acrylic resin was used as a component in the electrodepositable coating composition of Example 6 below. Cationic acrylic resins were prepared from the following components as described below.

ingredient Parts by weight Methylpropyl ketone 274.78 TINUVIN® 1130 27.85 Ethyl acrylate 605.23 Styrene 463.25 Hydroxypropyl methacrylate 149.45 Methyl methacrylate 52.30 Glycidyl methacrylate 224.18 t-dodecyl mercaptan 14.93 VAZO-67 37.34 DOWANOL PNB 47.83 DOWANOL PM 23.90 Methylisobutyl ketone 19.38 LUPERSOI-75M 29.95 DOWANOL PNB 23.90 Methylisobutyl ketone 11.95 Diethanolamine 134.16 Ketamine of Example A 109.68 Crosslinker ¹ 1973.42 Sulfamic acid 89.45 Deionized water 9033.12 ^First trimethylolpropane 1 10 equivalents of isophorone diisocyanate having an equivalent weight of bisphenol A- ethylene oxide polyol (a bisphenol A to ethylene oxide molar ratio of 1: 6 (prepared in a ratio of 100% solids)) from 3 equivalents and 1-butylene glycol Blocked polyisocyanate curing agent prepared by reacting a 6-hydroxy equivalent

The first two components were added to a suitably equipped reaction vessel under a nitrogen atmosphere and heated to a temperature of 101 ° C. The next ten components were added to the reaction vessel over 2.5 hours. After all additions, the reaction mixture was held at 103-108 ° C. for 30 minutes. The reaction mixture was heated to 120 ° C. at which time the next three components were added over 10-15 minutes and held at 120 ° C. for 30 minutes. The reaction mixture was then cooled to room temperature and a viscosity sample was taken. The sample was diluted with DOWANOL PM in a 2: 1 resin to solvent ratio and found to have a Gardner-Holt bubble viscosity of K-L. The reaction mixture was then heated to a temperature of 110 ° C. using a nitrogen blanket, at which time diethanolamine was added and the reaction mixture was kept at 110 ° C. for 1 hour. It was then held for an additional hour after the addition of ketamine and for an additional 20 minutes after the addition of the crosslinker. The viscosity sample was then taken and measured to have a Gardner-Holt bubble viscosity of T-U. The last two components were mixed separately and heated to 50 ° C. An aqueous dispersion was prepared by adding 95% of the resin prepared as described above with stirring. This dispersion had a solids content of 25% by weight. The organic solvent was removed by distillation to give a final product having a solids content of 28.6% by weight (1 hour at 110 ° C.).

Example H

This example describes a process for preparing the polymer having a blocked aliphatic polyisocyanate curing agent mixed with a cationic amine salt group-containing polyepoxide resin. The cationic polyepoxide resin was used as a component in the electrodepositable coating composition of Example 6 below. Cationic polyepoxide resins were prepared from the following components as described below.

ingredient Parts by weight EPON 880 448.71 Bisphenol A-Ethylene Oxide Adduct of Example B 91.25 Bisphenol A 193.76 Methylisobutyl ketone 6.95 Ethyltriphenylphosphonium iodide 0.44 Bisphenol A-Ethylene Oxide Adduct of Example B 91.25 Methylisobutyl ketone 4.55 Crosslinker ¹ 833.59 Methylisobutyl ketone 18.33 Diethanolamine 42.99 Diketamine of Example B 65.71 EPON 880 (85% solution in methylisobutyl ketone) 18.96 TINUVIN (registered trademark) 123 ² 16.12 ¹ DESMODUR N 3300 (5 equivalents of 1,2-butanediol and 5 equivalents of benzyl alcohol, using dibutyltin dilaurate as catalyst based on 10 equivalents of a polyfunctional aliphatic isocyanate resin based on hexamethylene diisocyanate commercially available from Bayer Corporation) Blocked polyisocyanate curing agent (87% solids in methylisobutyl ketone) ² hindered amine light stabilizer commercially available from Ciba-Geigy Corp. prepared by addition to the mixture

The first four components were added to a suitably equipped reaction vessel and heated to a temperature of 125 ° C. under a nitrogen atmosphere. Ethyltriphenylphosphonium iodide was added and the reaction mixture was exothermic to 145 ° C. The reaction mixture was kept at this temperature for 2 hours, at which time a second charge of bisphenol A-ethylene oxide adduct was added and an epoxy equivalent was obtained. A second charge of methylisobutyl ketone, crosslinker, methylisobutyl ketone and diethanolamine was added sequentially to the reaction mixture. The reaction mixture was exothermic and made up to 122 ° C. The reaction mixture was kept at this temperature for 30 minutes at which time diketamine was added and the reaction mixture was kept at 122 ° C. for an additional hour. EPON 880 (85% solution in methylisobutyl ketone) was added to the mixture and the reaction mixture was kept at 122 ° C. for 30 minutes. TINUVIN 123 was then added and held at 122 ° C. for 30 minutes. An aqueous dispersion was prepared by adding 1500 parts by weight of the reaction mixture thus prepared to a mixture of 29.71 parts of sulfamic acid and 971 parts of deionized water. The dispersion was diluted with 1119 parts by weight of deionized water (added in two steps) and the resulting dispersion was vacuum stripped to remove the organic solvent. The final product had a content of 39.58% (1 hour at 110 ° C).

Example I

This example describes a process for the preparation of cationic polyepoxide resins with blocked aliphatic crosslinkers mixed with polyepoxide polymers. Polyepoxide resin was used as a component in the electrodepositable coating composition of Example 7 below. Cationic polyepoxide resins were prepared according to the methods described below from the following components.

ingredient Parts by weight EPON 880 89.7 Ball-resin ¹ 18.3 Bisphenol A 38.7 Methylisobutyl ketone 1.4 Ethyltriphenylphosphonium iodide 0.088 Ball-resin ¹ 18.3 Methylisobutyl ketone 2 Crosslinker ² 139 Methylisobutyl ketone 4.5 Diethanolamine 10 Diketamine ³ 8.3 EPON 880 (85% solution in methylisobutyl ketone) 3.48 TINUVIN® 123 2.95 ¹ part of commercially available bisphenol A- ethylene oxide from BASF Corp. water (1/6 molar ratio) ² hexamethylene as a polyfunctional aliphatic isocyanate resin based on 10 times the amount of polyisocyanate; as a (DESMODUR N 3300 commercially available from Bayer Corporation), the catalyst dibutyl Prepared by addition to a mixture of 5 equivalents of 1,2-butanediol and 5 equivalents of benzyl alcohol using tin dilaurate (87% solids in methyl isobutyl ketone) derived from ³ diethylenetriamine and methyl isobutyl ketone ( 73% solids in methyl isobutyl ketone)

EPON 828, an initial charge of bisphenol A-ethylene oxide additive, an initial charge of bisphenol A and methylisobutyl ketone were charged into a suitably equipped reaction vessel and heated to a temperature of 125 ° C. under a nitrogen atmosphere. Ethyl triphenyl phosphonium iodide was then added and the reaction mixture was exothermic to about 145 ° C. The reaction was maintained at 145 ° C. for 2 hours and a second charge of bisphenol A-ethylene oxide additive was added to give an epoxy equivalent. A second charge of methyl isobutyl ketone, crosslinker, methyl isobutyl ketone and diethanolamine was added sequentially. The mixture was exothermic to make 122 ° C. The reaction mixture was kept at 122 ° C. for 30 minutes and diketetimine was added. The reaction mixture was kept at 122 ° C. for 1 hour, at which point EPON 880 in methyl isobutyl ketone was added and the mixture was kept at 122 ° C. for 30 minutes. TINUVIN 123 was then added and held at 122 ° C. for 30 minutes. The reaction mixture (330 parts) was dispersed in an aqueous medium by addition to a mixture of 9.2 parts of sulfamic acid and 225.7 parts of deionized water. These include 50/50 of N-hydroxyethyl imidazoline of coconut fatty acids neutralized to 75% total theoretical neutrality with the commercially available surfactants (SURFYNOL 104 and acetic acid from Air Products and Chemicals, Inc.). Mixture) 4.7 parts and 2.95 parts of a 30% solution of rosin acid in butylcarbitol formal were added. The dispersion was diluted by adding 117.8 parts of deionized water and 127.1 parts of deionized water separately. The resulting dispersion was vacuum stripped and the organic solvent removed and a dispersion with a solids content of 40.62% was obtained.

Example J

This example describes the preparation of the cationic acrylic resin used in the electrodepositable coating composition of Example 7 below. Acrylic resin was prepared from the following components as described below.

ingredient Parts by weight Methylpropyl ketone 274.78 TINUVIN® 1130 27.85 Ethyl acrylate 605.23 Styrene 463.25 Hydroxypropyl methacrylate 149.45 Methyl methacrylate 52.3 Glycidyl methacrylate 224.18 t-dodecyl mercaptan 14.93 VAZO-67 37.34 PROPASOL B 47.83 DOWANOL PM 23.9 Methylisobutyl ketone 19.38 LUPERSOL-75M 29.95 PROPASOL B 23.9 Methylisobutyl ketone 4.78 Diethanolamine 134.16 Ketamine of Example I 109.68 Crosslinker ¹ 1255.88 Sulfamic acid 88.51 Deionized water 7771.22 ¹ Crosslinkers are prepared by reacting 1 equivalent of isocyanurated hexamethylene diisocyanate with 1 mole of dibutylamine according to the method disclosed in US Pat. No. 4,576,979.

The first two components were charged into a suitably equipped reaction vessel under a nitrogen atmosphere and heated to a temperature of 100 ° C. The next 10 ingredients were fed into the container for 2.5 hours. When all was fed, the reaction mixture was held at 115-120 ° C. for an additional 30 minutes. At the end of the holding period, the reaction vessel was heated to 120 ° C. and the next three components were added for 10 to 15 minutes and then held for 30 minutes. The reaction mixture was cooled to room temperature and then sampled for bubble viscosity measurement. Samples were diluted with Dowanol PM in a 2: 1 ratio of resin: Dowanol PM and had a viscosity of K. The next day, the reaction mixture was added under a blanket of nitrogen to 110 ° C. To this, diethanolamine was added and then maintained at 110 ° C. for 1 hour. It was maintained for an additional hour after the addition of diketamine. Finally, the crosslinker was added and held for 20 minutes. Samples were taken after holding for viscosity measurements and the samples were found to have a Gardner-Holt bubble viscosity of Z. After the last two components were mixed and heated to 52 ° C., 94% of the resin was added under stirring to give a dispersion of organic resin in a 25% by weight aqueous medium. Finally distillation to remove methyl isobutyl ketone gave a dispersion of 23.9% solids (1 h at 110 ° C.).

Electrodepositable coating composition:

Example 1

In the present Example, the manufacturing method of the electrodepositable coating composition of this invention based on the cationic acrylic resin of Example A is demonstrated. The coating composition was prepared from a mixture of the following components.

The electrodepositable coating composition in the form of electrodeposition bath was prepared by adding 300 parts of deionized water to the cationic resin under stirring. The pigment paste and the catalyst paste were added separately under stirring and diluted with 300 parts of deionized water. The paste mixture was then mixed with the diluted resin under stirring. Then the remainder of the deionized water was added under stirring. The final electrodeposition solid was 22% by weight and the pigment to resin ratio was 0.15: 1.0. The electrodeposition bath was mixed under gentle stirring for about 2 hours. 20% of the total paint weight was removed by superfiltration and replaced with deionized water.

Example 2

In the present Example, the manufacturing method of the electrodepositable coating composition of this invention based on the cationic polyepoxy resin of Example B is demonstrated. The coating composition was prepared from a mixture of the following components.

The electrodepositable coating composition in the form of electrodeposition bath was prepared by first diluting the co-resin with 300 parts of deionized water under stirring. Cationic resin was then added under stirring. The pigment paste and catalyst paste were separately mixed under stirring and diluted with 300 parts of deionized water. The paste mixture was then mixed with the diluted resin mixture under stirring. Then the remainder of the deionized water was added under stirring. The final electrodeposition solid was 18% by weight and the pigment to resin was 0.15: 1.0. The electrodeposition bath was mixed under gentle stirring for about 2 hours. 30% of the total paint weight was removed by ultrafiltration and replaced with deionized water.

Example 3

In the present Example, the manufacturing method of the electrodepositable coating composition of this invention based on the cationic polyepoxy resin of Example C is demonstrated. The coating composition was prepared from a mixture of the following components.

ingredient Parts by weight Cationic Resin of Example C 1451.3 Ball-resin ¹ 115.2 Pigment Paste ² of Example ² 140.8 Catalyst Paste ³ of Example 2 18.0 Deionized water 2074.7 ¹ Prepared as follows: 639.65 g DER 732, 156.27 g bisphenol A and 10.97 g ethylene glycol monobutyl ether were charged to a suitable reaction vessel and heated to 103 ° C. Add 1.5 g of benzyldimethylamine and hold at 135 ° C. until the epoxy equivalent of the reaction mixture reaches 1250, at which time 52.7 g of ethylene glycol monobutyl ether is added and the reaction mixture is cooled to 100 ° C., at 164.92 g of JEFFAMINE D400 Was added. The mixture was kept at 95 ° C. for 4 hours at which time the sample diluted with methoxy propanol (10 g of resin and 8.7 g of methoxy propanol) had a Gardner-Hold bubble viscosity of K. A mixture of 19.38 g of EPON 828 and 3.07 g of ethylene glycol monobutyl ether was added and the mixture was kept at a temperature of 95 ° C. for 80 minutes, at which time samples diluted with methoxy propanol (10 g of resin and 8.7 g of solvent) were obtained from Gardner- of PQ. Had a Holt bubble viscosity. In the mixture, 889.49 g was poured into a mixture of 29.07 lactic acid (88% solution) and 929.18 g deionized water with stirring to form a viscous aqueous dispersion. After mixing for 30 minutes, 1009.15 g of deionized water was added under stirring. The final aqueous dispersion was determined to have a solids content of 30% (1 hour at 110 ° C.).

The electrodepositable coating composition in the form of electrodeposition bath was prepared by first diluting the co-resin with 300 parts of deionized water under stirring. Cationic resin was then added under stirring. The pigment paste and catalyst paste were separately mixed under stirring and diluted with 300 parts of deionized water. The paste mixture was then mixed with the diluted resin mixture under stirring. The remaining deionized water was added under stirring. The final electrodeposition solid was 18% by weight and the pigment to resin was 0.15: 1.0. The electrodeposition bath was mixed under gentle stirring for about 2 hours. 30% of the total paint weight was removed by ultrafiltration and replaced with deionized water.

Example 4

In the present Example, the manufacturing method of the electrodepositable coating composition of this invention based on the cationic polyepoxy resin of Example D is demonstrated. The coating composition was prepared from a mixture of the following components.

An electrodepositable coating composition in the form of an electrodeposition bath was prepared by adding each of the above components sequentially with stirring. The resulting electrodeposition bath is 20% solids content, pH of 5.54, based on the total weight of the electrodeposition bath, as measured using an ACCUMET pH / conductivity meter commercially available from Fisher Scientific, Inc. It had a conductivity of 1395 micro-Siemans.

Example 5

In this example, the production method of the three electrodepositable coating compositions of the present invention comprising the cationic acrylic resin of Example E and the cationic polyepoxide resin of Example F will be described. Comparative Example 5A describes a method for producing an electrodeposition bath containing no soluble iron at all, Example 5B describes a method for producing an electrodeposition bath containing 15 ppm of soluble iron, and Example 5C shows 30 ppm of soluble iron. The manufacturing method of the electrodeposition bath containing is demonstrated. Each electrodepositable composition was prepared from a mixture of the following ingredients as described below.

ingredient Example 5A * (Parts by weight) Example 5B (Parts by weight) Example 5C (Parts by weight) Cationic Resin of Example E 1314.8 1314.8 1314.8 Cationic Resin of Example F 580.5 580.5 580.5 Co-resin of Example 2 47.6 47.6 47.6 Pigment Paste of Example 1 170.1 170.1 170.1 Catalyst Paste of Example 1 22.0 22.0 22.0 Deionized water 1665.0 1665.0 1665.0 Iron (II) Acetate ⁴ - 0.187 0.374 Comparative Example

Each of the electrodepositable coating compositions was prepared in the form of an electrodeposition bath as follows. The cationic resin and the co-resin of Example F were mixed with 300 parts of deionized water under stirring as the mixture was slowly added. The mixture was then added to the cationic resin of Example E. The pigment paste and the catalyst paste were mixed separately and diluted with 300 parts of deionized water and then mixed with the resin mixture. The remainder of the deionized water was then added to the mixture under stirring. The composition was mixed under gentle agitation for about 2 hours. The final electrodeposition solid was about 22% by weight and the pigment to resin was 0.15: 1.0. 20% of the total electrodeposition weight was removed by ultrafiltration and replaced with deionized water. Iron (II) acetate was added to the compositions of Examples 5B and 5C with stirring.

Example 6

In this example, the preparation method of the electrodepositable coating composition of the present invention based on the cationic acrylic resin of Example G and the cationic polyepoxide resin of Example H will be described. The coating composition was prepared from a mixture of the following ingredients.

ingredient Parts by weight Cationic Resin of Example G 1447.7 Cationic Resin of Example H 697.3 E6251 ¹ 237.5 Catalyst Paste of Example 1 6.6 Deionized water 1410.9 ¹ Pigment paste commercially available from PPG Industries, Inc.

The electrodepositable coating composition was prepared in the form of an electrodeposition bath as follows. To the cationic resin of Example G was added 300 parts of deionized water with stirring, followed by the cationic resin of Example H. The pigment paste and catalyst paste were separately mixed under stirring and diluted with 300 parts of deionized water. The paste mixture was then added to the resin mixture with stirring followed by the rest of deionized water. The composition was mixed under gentle agitation for about 2 hours. The final electrodeposition solid was about 22% by weight and the pigment to resin was 0.15: 1.0. 20% of the total electrodeposition weight was removed by ultrafiltration and replaced with deionized water.

Test panel manufacturing method

Each of the electrodepositable coating compositions of Examples 1-5 and conventional electrodepositable comparative compositions prepared as disclosed in US Pat. No. 5,389,219, Example 2 was prepared from APR23834 from ACT Laboratories, Inc. (B) (deposited with E60 EZG 60G, C700 C18 phosphate and rinse) were electrodeposited on the commercial 4 " X12 " zinc-phosphated galvanic steel test panel. Each of the compositions was electrodeposited onto the substrate under the conditions necessary to form a substantially continuous film having a film thickness of approximately 1 mil (25.4 μm) on the substrate. The electrodeposited test panels were thermally cured as follows. That is, one set cured at 360 ° C. for 30 minutes in an electric oven, one set cured at 395 ° C. for 60 minutes in an electric oven, and one set cured at 395 ° C. for 60 minutes in a gas-ignition oven.

The test panels were then topcoat with a solvent-based uncolored basecoat / transparent topcoat system designed to allow 80% light transmission measured at 400 nm wavelength. The base film composition is as follows.

ingredient Parts by weight Methyl ethyl ketone 94.1 xylene 280.4 Diisobutyl ketone 490.7 Amyl alcohol 80.7 TINUVIN 328 ¹ 60.5 Microgel ² 458.1 RESIMENE 755 ³ 1008.3 Polyester resin ⁴ 100.8 Acrylic resin ⁵ 1038.1 Methanol 121.1 Catalyst ⁶ 67.2 ¹ UV absorber commercially available from Ciba Specialty Chemicals 2 Prepared as disclosed in US Pat. No. 4,147,688 Example II 3 Melamine-formaldehyde crosslinker commercially available from Solutia, Inc. 4 C ₃₆ dibasic acids (59.1% of reactive solids) ) And condensation reaction products of neopentyl glycol (16.9% of reactive solids), cyclohexane dimethanol (17.5% of reactive solids) and trimethylol propane (6.5% of reactive solids) (100% of total solids) 5 hydroxy action Acrylic resins (18.5% n-butyl methacrylate / 40 hydroxypropyl acrylate / 0.5% methyl methacrylate / 20% styrene / 19% n-butyl acrylate / 2% acrylic acid), acetone, Aromatic 100 and amyl 68.8% solid 6 diisopropylamine neutralized dodecylbenzene sulfonic acid in a mixture of acetate

The basecoat composition was spray applied to each of the electrodeposition test panels to obtain a basecoat dry film thickness of about 0.35 mil (8.89 μm). The applied base coat had a one minute attribute period. A solvent-based transparent coating, DCT 1002B (commercially available from PPG Industries, Inc.), was then spray applied to the base coating to obtain a dry transparent coating thickness of 1.6 to 1.8 mils (40.64 to 15.72 μm). The test panel was then thermally cured at a temperature of 250 ° F. (121.1 ° C.) for 30 minutes.

Using a cured glass film applied to the precursor film thickness described above using a Perkin-Elmer Lambda 9 scanning spectrophtometer with a 150 mm Lab Sphere integrating sphere, The light transmittance of the base film / transparent film system was measured. Data was collected with Perkin-Elmer UV WinLab software according to ASTM E903.

Photodegradation protection was evaluated as described above according to ASTM G 90-98 using EMMAQUA NTW® (available commercially from DSET Laboratories, Atlas Weather Services, Inc., Fenix, USA). The test panel is cooled by forced air convection to limit the increase in the surface temperature of the specimen to 10 ° C. above the maximum surface temperature when the same fixed specimens are exposed to direct sunlight at 90 ° incidence angle at the same time and location without concentration. It was. The exposure was recorded as such that the total aggregated UV radiation was between 295 and 385 nm wavelength.

Two panel sets (2 "x 5.5" panels) from each of the three curing schemes discussed above were tested using the method. For one panel set ("Set 1"), half of each panel was masked with aluminum foil with an exposure of 145 MJ / m 2. Set 1 test panels were removed from the exposure and evaluated for anti-laminar separation resistance after exposure of 290 MJ / m 2. Half of each panel of the second set (“Set 2”) was masked with aluminum foil with an exposure of 435 MJ / m 2. Set 2 was removed from the exposure for post-exposure evaluation of 580 MJ / m 2. Total UV radiation ranged in wavelength from 295 to 385 nm.

As discussed above, an all-weather exposure test conducted according to this method was associated with South Florida exposure south of 45 °.

The exposure relationship is as follows:

Exposure energy (MJ / ㎡) Florida exposure (40 degrees south) 145 6 months 290 12 months 435 18 months 5880 24 months

The photodegradation resistance of the cured and electrodeposited coating was evaluated by the crosshatch adhesion of the exposure test panel at each of the above exposure energies. Adhesion tests were performed after each test panel was exposed for 16 hours at 100 ° F. with 100% relative humidity. The crosshatch adhesion test was performed according to ASTM D3359-97 using a rating scale of 0 to 10, with 10+ being the best and using a 2mm crosshatch tool (Model PA-2056 available from BYK Gardner).

Adhesion results are reported in Tables 1 and 2 below.

Example K

This example describes a process for preparing the polymer having a blocked polyisocyanate curing agent mixed with a cationic polyepoxide resin. The cationic resin was used as a component in the electrodepositable composition of Example 7 below. Cationic polyepoxide resins were prepared from the following components as described below.

ingredient Parts by weight EPON 880 89.7 Ball-resin ¹ 18.3 Bisphenol A 38.7 Methylisobutyl ketone 1.4 Ethyltriphenylphosphonium iodide 0.088 Ball-resin ¹ 18.3 Methylisobutyl ketone 2 Crosslinker of Example 1 139 Methylisobutyl ketone 4.5 Diethanolamine 10 Diketamine ² 8.3 EPON 880 (85% solution in methylisobutyl ketone) 3.48 TINUVIN 123 2.95 ¹ bisphenol A-ethylene oxide adduct (1/6 molar ratio) ² diketamine is derived from diethylenetriamine and methyl isobutyl ketone (73% solids in methyl isobutyl ketone)

EPON 828, the initial charge of the co-resin, the initial charge of bisphenol A and methyl isobutyl ketone were charged to a suitably equipped reaction vessel and heated to 125 ° C. under a nitrogen atmosphere. Ethyl triphenyl phosphonium iodide was then added and the reaction mixture was exothermic to about 145 ° C. The reaction was maintained at this temperature for 2 hours and a second charge of co-resin was added and an epoxy equivalent was obtained. A second charge of methyl isobutyl ketone, crosslinker, methyl isobutyl ketone and diethanolamine was added sequentially. The reaction mixture was exothermic and made a temperature of 122 ° C. The reaction mixture was kept at 122 ° C. for 30 minutes and diketamine was added and the mixture was kept at 122 ° C. for 1 hour. EPON 880 (85% solution in methyl isobutyl ketone) was added and the mixture was held at 122 ° C. for 30 minutes. TINUVIN 123 was then added and the temperature maintained at 122 ° C. for 30 minutes. The reaction mixture (330 parts) was added to a mixture of 9.2 parts of sulfamic acid and 225.7 parts of deionized water and dispersed in an aqueous medium. Included here are 4.7 parts of a surfactant commercially available from Air Products and Chemicals (50/50 mixture of SURFYNOL 104 and coconut fatty acid N-hydroxyethyl imidazoline neutralized to 75% total theoretical neutrality with acetic acid) and butylcarbitol fort 95 parts of a rosin acid 30% solution was added to the powder. The dispersion was diluted by adding 117.8 parts of deionized water and 127.1 parts of deionized water in two steps. The dispersion was vacuum stripped and the organic solvent removed and a dispersion with a solids content of 40.6% was obtained (1 hour at 110 ° C.).

Example L

This example describes a process for preparing the polymer having a blocked polyisocyanate curing agent mixed with a cationic acrylic resin. The cationic resin was used as a component in the electrodepositable composition of Example 7 below. Acrylic resin was prepared from the following components as described below.

ingredient Parts by weight Methylpropyl ketone 274.78 TINUVIN® 1130 27.85 Ethyl acrylate 605.23 Styrene 463.25 Hydroxypropyl methacrylate 149.45 Methyl methacrylate 52.3 Glycidyl methacrylate 224.18 t-dodecyl mercaptan 14.93 VAZO-67 37.34 PROPASOL B 47.83 DOWANOL PM 23.9 Methylisobutyl ketone 19.38 LUPERSOL-75M 29.95 PROPASOL B 23.9 Methylisobutyl ketone 4.78 Diethanolamine 134.16 Diketamine of Example I 109.68 Crosslinker ¹ 1255.88 Sulfamic acid 88.51 Deionized water 7771.22 ¹ prepared by reacting 1 equivalent of isocyanurated hexamethylene diisocyanate with 1 mol of dibutylamine according to the procedure described in US Pat. No. 4,576,979.

The first two components were added to a suitably equipped reaction vessel under a nitrogen atmosphere and heated to a temperature of 100 ° C. The next ten components were added to the reaction vessel over 2.5 hours. After all additions, the reaction mixture was held at 115-120 ° C. for an additional 30 minutes. The reaction mixture was heated to 120 ° C. at which time the next three components were added over 10-15 minutes and held for 30 minutes. The reaction mixture was then cooled to room temperature and a sample taken for viscosity measurement. The sample was diluted with DOWANOL PM in a 2: 1 resin to solvent ratio and found to have a Gardner-Hold bubble viscosity of K. The reaction mixture was then heated to a temperature of 110 ° C. under a blanket of nitrogen, at which time diethanolamine was added and the reaction mixture was kept at 110 ° C. for 1 hour. Diketimine was then added and held for an additional hour. The crosslinker was added and held for an additional 20 minutes. A sample was then taken for viscosity measurement. This sample was found to have a Gardner-Hold bubble viscosity of Z. The last two components were mixed separately and heated to 52 ° C. and 94% of the resin was added under stirring and a dispersion of organic resin was produced in an aqueous medium having a 25% by weight solids content. Final distillation removed the methyl isobutyl ketone and gave a dispersion having a solids content of 23.7% (1 hour at 110 ° C.).

Example 7

This example describes a method for preparing ten electrodepositable coating compositions in the form of electrodeposition baths, each containing one of a variety of rare earth metals. The electrodeposition bath was prepared as described below.

ingredient Parts by weight Cationic Resin of Example K 3220.25 Cationic Resin of Example L 8205.58 Pigment paste ¹ 1124.88 Catalyst Paste of Example 1 31.18 Deionized water 5418.11 ¹ E6251, commercially available from PPG Industries, Inc.

An electrodepositable coating composition in the form of an electrodeposition bath was prepared while adding 800 parts of deionized water to the cationic resin of Example K under shaking. Next, the cationic resin of Example L was added to the mixture. The pigment paste and catalyst paste were mixed separately with shaking and diluted with 500 parts of deionized water and then mixed with the reduced resin mixture under shaking. Then, the remaining deionized water was added with shaking. The solid of the final electrodeposition bath is about 22% and the ratio of pigment to resin is 0.15: 1.0. The electrodeposition was shaken for 2 hours. 20% of the total electrodeposition weight was filtered off and replaced with deionized water.

Examples 7A-J

Examples 7A to 7I below describe the preparation of an electrodepositable coating composition in the form of an electrodeposition bath containing a rare earth element according to the invention. Comparative Example 7J illustrates the preparation of an electrodeposition bath containing no rare earth elements. The electrodepositable coating composition was prepared from the following components as follows.

Example 7A

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Disprosium Nitrate ¹ 2.0 Deionized water 97.1 ¹ Available from Alfa Aesar

Example 7B

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Erbium Nitrate ¹ 2.0 Deionized water 98.0 ¹ Available from Alfa Aesar

Example 7C

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Europium Nitrate ¹ 2.2 Deionized water 97.8 ¹ Available from Alfa Aesar

Example 7D

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Gadolinium Acetate ¹ 1.6 Deionized water 98.4 ¹ Available from Alfa Aesar

Example 7E

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Holmium Nitrate ¹ 2.0 Deionized water 98.0 ¹ Available from Alfa Aesar

Example 7F

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Lutetium Nitrate ¹ 1.6 Deionized water 98.6 ¹ Available from Alfa Aesar

Example 7G

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Neodymium Acetate ¹ 1.7 Deionized water 98.3 ¹ Available from Aldrich Chemical Company, Inc.

Example 7H

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Praseodymium Nitrate ¹ 2.2 Deionized water 97.8 ¹ Available from Acros Organics

Example 7I

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Samarium Acetate ¹ 1.6 Deionized water 98.4 ¹ Available from Aldrich Chemical Company, Inc.

Comparative Example 7J

ingredient Parts by weight Electrodepositable Composition of Example 7 1600.0 Deionized water 100.0

Each of the electrodepositable coating compositions of Examples 7A-7I was prepared by first diluting each rare earth material with deionized water and then adding the mixture to the composition of Example 7 under stirring. The composition of Comparative Example 7J was prepared by adding deionized water to the electrodepositable composition of Example 7. Each composition was then stirred for at least 2 hours.

Electrocoating Procedure:

Each of the electrodepositable coating compositions of Examples 7A-7J was electrodeposited on a commercially available phosphorylated cold rolled steel sheet from ACT Laboratories. (Deionized water wash after commercially available phosphate treatment from Chem. 700 from PPG Industries, Inc.). ). Cationic electrodeposition conditions were 2 minutes at 90 ° F. at the required voltage and a cured film of 1.0 to 1.1 mil (25.4 μm) thick was obtained. The coated substrate was cured in an electric oven at 360 ° F. for 30 minutes.

Test procedure:

Each coated test steel plate was single-scribed and cut in an "I" pattern through the coating to the metal substrate. The test panel was then introduced to the circular corrosion test in accordance with GM 9511P Standard. Test panels were evaluated for "scribe creep" corrosion and visible appearance. The scribe creep is recorded in corrosion mm as the total scribe width. The test results are reported in Table 3 below.

Example # Rare earths Scribe creep * (mm) 7A Dy 4 7B Er 7 7C Eu 4 7D Gd 3.5 7E Ho 3.5 7F Lu 4.5 7G Nd 6 7H Pr 6 7I Sm 6 7J ^** - 9 * Average scribe creep ** according to 20 cycles GM 9511P

The data shown above in Table 3 illustrate that the inclusion of rare earths in the electrodepositable coating compositions of the present invention provides better scribe creep corrosion resistance than similar compositions containing no rare earths.

Alternative Embodiments of the Invention:

Example M

In this embodiment, a method for preparing a cationic resin according to an alternative embodiment of the present invention will be described. Cationic resins were prepared as described below.

Resorcinol diglycidyl ether having an epoxy equivalent of 122 in a 3000 ml four-necked round bottom flask (commercially available as Erisys RDGE from CVC Specialty Chemicals, Maple Shad, NJ), 576.7 g (4.727 equiv) Charged 188.2 g (3.765 equiv) of sorbinol and 169.5 g of 1-butoxy-2-propanol. The flask was equipped with a stirring paddle with bearings, thermocouple probes, heating mantles, gas fittings and water-cooled agglomerators. Under a nitrogen blanket, the flask contents were heated to 105 ° C. and held at this temperature for 10 minutes, at which time 0.6 g of ethyltriphenylphosphonium iodide was added. The reaction mixture was exothermic and the reaction mixture was adjusted to 160 ° C. and held at this temperature for 105 minutes. The reaction mixture was cooled to 100 ° C. 58.3 g (0.155 mole) of an approximately 71% solution of diketamine (formed from diethylenetriamine and excess methyl isobutyl ketone such that the amine equivalent of diketamine solution is 125) and 49.7 g (0.662 equivalents) of N-methylethanolamine Was added. The reaction mixture was adjusted to 140 ° C. and held at this temperature for at least 1.5 hours before cooling to 80 ° C. Once this temperature was achieved, 745.9 g of crosslinker ^{1 and} 11.0 g of SURFYNOL 104 (surfactant sold from Air Products and Chemicals, Inc.) were added and the reaction mixture was mixed for 15 minutes. [ ¹ Crosslinker It was prepared as follows. A 5000 mL four-necked round bottom flask was charged with 1136.2 g (8.788 equivalents) of dibutylamine and 86.4 g of methyl isobutyl ketone. The flask was equipped with a stirring paddle with bearings, thermocouple probes, gas fittings and water cooled agglomerators, heating mantles and addition funnels. The addition funnel was charged and mixed with 1716.9 g (8.850 equivalents) and 343.4 g of methyl isobutyl ketone (hexamethylene diisocyanate trimer having a NCO equivalent of 194 (commercially available as DESMODUR N-3300 from Bayer Corporation) and mixed to give a homogeneous solution. Formed. The isocyanurate solution was added to the dibutylamine solution under nitrogen blanket starting at ambient temperature and the addition continued at a rate to maintain the reaction temperature below 80 ° C. After all addition, the funnel was washed with 73.8 g of methyl isobutyl ketone and the reaction was maintained at 80 ° C. until the infrared spectrum of the reaction mixture showed no more than negligible NCO peak. At this point the product was cooled. The resulting crosslinker had a solids content of 85.1% (1 hour at 110 ° C.). 1500 g of this mixture was added to a solution of 54.8 g (0.564 equiv) of sulfamic acid in 781.2 g of deionized water. After at least 20 minutes, a total of 1335 g of additional deionized water was added. The resulting dispersion was diluted with 1 kg of deionized water, heated to 60-65 ° C. and the solvent co-distilled under reduced pressure to give a dispersion, which was found to be 46.6% of non-volatile material (1 hour at 110 ° C.).

Example N

In this embodiment, a method for preparing a cationic resin according to an alternative embodiment of the present invention will be described. Cationic resins were prepared as described below.

617.9 g (5.327 equiv) of resorcinol diglycidyl ether (used in Example M) with an epoxy equivalent of 116 in a 3000 ml four-necked round bottom flask, 214.0 g (3.891 equimolar amounts) of resorcinol and 1 184.3 g of butoxy-2-propanol were charged. The flask was equipped with a stirring paddle with bearings, thermocouple probes, heating mantles, gas fittings and water-cooled agglomerators. Under a nitrogen blanket, the reaction mixture was heated to 105 ° C. 0.7 g of ethyltriphenylphosphonium iodide was added to the reaction mixture, and the mixture was maintained at 105 ° C for 10 minutes. The temperature increased to 160 ° C. and the reaction mixture was held at this temperature for 105 minutes, at which time the reaction mixture was cooled to 100 ° C. and sampled to confirm that the epoxy equivalent (“EEW”) was 875 on a solid basis. . 63.4 g (0.169 mole) of diketimine (as described in Example M above) and 54.1 g (0.720 equiv) of N-methylethanolamine were added to the reaction mixture and the temperature was increased to 140 ° C. This temperature was maintained at 140 ° C. for 80 minutes and the epoxy equivalent was found to be 33,000 on a solid basis. The material was cooled to 80 ° C. at which time 653.7 g of crosslinker ¹ and 12.0 g of SURFYNOL 104 were added and the reaction mixture was mixed for 15 minutes. [ ¹ Crosslinker was prepared as follows. A 5000 mL four-necked round bottom flask was charged with 630.3 g (4.886 equivalents) of dibutylamine and 210.1 g of methyl isobutyl ketone. The flask was equipped with a stirring paddle with bearings, thermocouple probes, gas fittings and water cooled agglomerators, heating mantles and addition funnels. The addition funnel was charged with 645.0 g (4.886 equiv) of methylene diphenyl diisocyanate (“MDI”) (commercially available as PAPI® 2940 from Dow Chemical Company) having an NCO equivalent of 132. To the dibutylamine solution stirred under a nitrogen blanket, MDI was added at a rate maintaining this temperature under about 70 ° C. After all additions, the funnel was washed with 14.7 g of methyl isobutyl ketone and the reaction mixture was adjusted to 70 ° C. This temperature was maintained at 70 ° C. until the infrared spectrum of the sample of the reaction mixture showed no negligible above NCO peak. . The reaction mixture was cooled down. The resulting crosslinker was found to have a solids content of 85.9% (1 hour at 110 ° C.)]. 1500 g of this product was poured into a solution of 59.6 g (0.614 equiv) of sulfamic acid in 759.9 g of deionized water and the mixture was mixed for at least 20 minutes, at which time additional 1325 g of deionized water was added. This dispersion was also diluted with 1 kg of deionized water and heated to 60-65 ° C., whereupon the solvent was co-distilled under reduced pressure to give a dispersion with a solid content of 32.7% (1 hour at 110 ° C.).

Example O

In this embodiment, a method for preparing a cationic resin according to an alternative embodiment of the present invention will be described. Cationic resins were prepared as described below.

955.6 g (4.550 equivalent) of saturated epoxy (commercially available as EPONEX 1510 from Shell Oil and Chemical Company) with 210 epoxy equivalents in a 5000 ml four-necked round bottom flask, resorcinol 182.8 g (3.324 equiv) and 157.5 g of 1-butoxy-2-propanol were charged. The flask was equipped with a stirring paddle with bearings, thermocouple probes, gas fittings and water cooled agglomerators and heating mantles. Under a blanket of nitrogen, the reaction mixture was heated to 105 ° C. at which time 0.6 g of ethyltriphenylphosphonium iodide was added and heating continued until 160 ° C. The reaction mixture was maintained at 160 ° C. for 105 minutes and cooled to 100 ° C. Epoxy equivalent was determined to be 1244 on a solid basis. At this point, 54.2 g (0.144 mol) of ketimine (as described in Example M above) and 46.2 g (0.615 equiv) of N-methylethanolamine were added and the temperature was adjusted to 140 ° C. This temperature was maintained for 1.5 hours, at which time the epoxy equivalent was found to be infinite. The reaction mixture was cooled at 80 ° C., 693 g of crosslinker (as described in Example M above) and 10.2 g of SURFYNOL 104 were added and the reaction mixture was mixed uniformly for 15 minutes. Of these materials, 1500 g were poured into a solution of 43.6 g (0.449 equiv) of sulfamic acid in 872.1 g of deionized water. This mixture was mixed under stirring for 20 minutes at which time 1081 g of deionized water was added. This dispersion was diluted with 1 kg of deionized water and heated to 60-65 ° C., exposed to reduced pressure to co-distill the solvent, resulting in a dispersion with a solids content of 43.3% (1 hour at 110 ° C.).

Example P

This example describes a method of making a cationic epoxy resin for use in alternative embodiments of the present invention. Cationic resins were prepared as described below.

920.8 g (4.898 equivalents) of bisphenol A diglycidyl ether resin (commercially available EPON 880 from Shell Oil and Chemical Company), 196.7 g of resorcinol (188 epoxy equivalent) in a 3000 ml four-neck round bottom flask 3.576 equivalents) and 169.5 g of 1-butoxy-2-propanol. The flask was equipped with a stirring paddle with bearings, thermocouple probes, gas fittings and water cooled agglomerators and heating mantles. Under a blanket of nitrogen, the reaction mixture was heated to 105 ° C., 0.6 g of ethyltriphenylphosphonium iodide was added and heating continued until 160 ° C. The temperature was maintained at 160 ° C. for 105 minutes and cooled to 100 ° C. with an epoxy equivalent of 1118 on a solid basis. 58.3 g (0.155 mol) of diketimine (as described in Example M above) and 49.7 g (0.662 equiv) of N-methylethanolamine were added and the reaction mixture was heated to 140 ° C. and held at this temperature for 6 hours. It was. The epoxy equivalent based on solid was determined to be 9757 at this temperature after 2 hours. The reaction mixture was then cooled to 80 ° C. and 745.9 g of crosslinker (as described in Example M above), and 11.0 g of SURFYNOL 104 were added and mixed for 15 minutes. Of these materials, 1500 g were poured into a solution of 45.8 g (0.472 equiv) of sulfamic acid in 854.3 g of deionized water. This reaction mixture was mixed for 20 minutes at which time 1372 g of deionized water was added. This dispersion was further diluted with 1 kg of deionized water, heated to 60-65 ° C., and co-distilled under reduced pressure to remove organic solvents. The final dispersion has a solids content of 37.8% (1 hour at 110 ° C.).

Example Q

This example describes a method of making a cationic epoxy resin for use as a component in an electrodepositable coating composition of an alternative embodiment of the present invention. Cationic resins were prepared as described below.

656.7 g (3.127 equivalents) of saturated epoxy (EPONEX 1510 available from Shell Oil & Chemical Company), 108.2 g (1.967 equivalents) and 1 resorcinol having 210 epoxy equivalents 169.5 g of butoxy-2-propanol were charged. The flask was equipped with a stirring paddle with bearings, thermocouple probes, gas fittings and water cooled agglomerators and heating mantles. Under a blanket of nitrogen, the reaction mixture was heated to 105 ° C., 0.6 g of ethyltriphenylphosphonium iodide was added and heating continued until 160 ° C. The reaction mixture was maintained at 160 ° C. for 105 minutes, cooled to 100 ° C. and the epoxy equivalent was measured at 877 on a solid basis. 58.3 g (0.156 mole) of diketamine (as described in Example M above) and 49.7 g (0.662 equiv) of N-methylethanolamine were added and the temperature was adjusted to 140 ° C. This temperature was maintained for 1.5 hours, at which time the epoxy equivalent was determined to be infinite. The reaction mixture was then cooled to 80 ° C. and 745.9 g of crosslinker (as described in Example M above), and 11 g of SURFYNOL 104 were added and mixed until homogeneous for 15 minutes. Of these materials, 1500 g were poured into a solution of 54.8 g (0.564 equiv) of sulfamic acid in 781.2 g of deionized water. This reaction mixture was mixed for 20 minutes at which time 1045 g of deionized water was added. This dispersion was then diluted with 1 kg of deionized water, heated to 60-65 ° C. and co-distilled under reduced pressure to remove the organic solvent. The final dispersion has a solids content of 48.0% (1 hour at 110 ° C).

Example R

This example describes a method of making a cationic epoxy resin for use as a component in an electrodepositable coating composition of an alternative embodiment of the present invention. Cationic resins were prepared as described below.

642.1 g (3.415 equivalents) of bisphenol A diglycidyl ether resin (EPON 880, commercially available from Shell Oil and Chemical Company), 122.7 g of resorcinol, having an epoxy equivalent of 188 in a 3000 ml four-necked round bottom flask. 2.231 equivalents) and 169.5 g of 1-butoxy-2-propanol. The flask was equipped with a stirring paddle with bearings, thermocouple probes, gas fittings and water cooled agglomerators and heating mantles. Under a blanket of nitrogen, the reaction mixture was heated to 105 ° C., 0.6 g of ethyltriphenylphosphonium iodide was added and heating continued until 160 ° C. The temperature was maintained at 160 ° C. for 105 minutes and cooled to 100 ° C. at which time the epoxy equivalent was determined to be 735 on a solid basis. 58.3 g (0.155 mole) of diketimine (as described in Example M above) and 49.8 g (0.662 equiv) of N-methylethanolamine were added and the reaction mixture was heated to 140 ° C. and held at this temperature for 6 hours. It was. Epoxy equivalent was determined to be 9071 after 1.5 hours on a solid basis. The reaction mixture was then cooled to 80 ° C. and 746.1 g of crosslinker (as described in Example M above), and 11.0 g of SURFYNOL 104 were added and mixed for 15 minutes. Of these materials, 1500 g were poured into a solution of 54.8 g (0.565 equiv) of sulfamic acid in 781.2 g of deionized water. This mixture was mixed for 20 minutes at which time 1335 g of deionized water was added. This dispersion was diluted with 1 kg of deionized water, heated to 60-65 ° C. and co-distilled under reduced pressure to remove organic solvent. The final dispersion has a solids content of 42.0% (1 hour at 110 ° C.).

Example S

This example describes a method of making a cationic epoxy resin for use as a component in an electrodepositable coating composition of an alternative embodiment of the present invention. Cationic resins were prepared as described below.

568.2 g (4.898 equivalents) of resorcinol diglycidyl ether with 116 epoxy equivalents, 196.7 g of catechol (3.576 equivalents) and 169.5 g of 1-butoxy-2-propanol in a 3000 ml four-necked round bottom flask Was charged. The flask was equipped with a stirring paddle with bearings, thermocouple probes, heating mantles, gas fittings and water-cooled agglomerators. Under a nitrogen blanket, the flask contents were heated to 105 ° C. and maintained at this temperature for 10 minutes, at which time 0.6 g of ethyltriphenylphosphonium iodide was added. The reaction mixture was exothermic and the reaction mixture was adjusted to 160 ° C. and held at this temperature for 105 minutes. The reaction mixture was cooled to 100 ° C. at which time the epoxy equivalent weight based on solid was found to be 754. To this was added 58.3 g (0.155 mol) of diketamine (as described in Example M above) and 49.7 g (0.662 equiv) of N-methylethanolamine. After controlling the reaction temperature to 140 ° C. and holding for 1 hour, the epoxy equivalent weight based on solid was found to be 29,750. The reaction mixture was then cooled to 80 ° C. Once this temperature was achieved, 745.9 g of crosslinker (as described in Example M) and 11.0 g of SURFYNOL 104 were added and then the reaction mixture was mixed for 15 minutes. In this mixture, 1500 g was added to a solution of 54.8 g (0.564 equiv) of sulfamic acid in 781.2 g of deionized water. The mixture was stirred for 20 minutes, at which time 1335 g of deionized water was added. The resulting dispersion was diluted with 1 kg of deionized water, heated to 60-65 ° C. and the solvent was co-distilled under reduced pressure to give a dispersion having a solids content of 38.3%. (1 hour at 110 ° C.)

Example T

This example describes a method of making a cationic epoxy resin for use as a component in an electrodepositable coating composition of an alternative embodiment of the present invention. Cationic resins were prepared as described below.

568.2 g (4.898 equivalents) of resorcinol diglycidyl ether having 116 epoxy equivalents, 196.7 g of hydroquinone (3.576 equivalents) and 169.5 g of 1-butoxy-2-propanol in a 3000 ml four-necked round bottom flask Was charged. The flask was equipped with a stirring paddle with bearings, thermocouple probes, heating mantles, gas fittings and water-cooled agglomerators. Under a nitrogen blanket, the flask contents were heated to 105 ° C. and maintained at this temperature for 10 minutes, at which time 0.6 g of ethyltriphenylphosphonium iodide was added. The reaction mixture was exothermic and the reaction mixture was adjusted to 160 ° C. and held at this temperature for 105 minutes. The reaction mixture was cooled to 100 ° C. with an epoxy equivalent weight of 695 based on solids. To the reaction mixture was added 58.3 g (0.155 mol) of diketamine (as described in Example M above) and 49.7 g (0.662 equiv) of N-methylethanolamine. The reaction mixture temperature was adjusted to 140 ° C. and maintained for at least 2.5 hours and then cooled to 80 ° C. At this temperature, 745.9 g of crosslinker (as described in Example M) and 11.0 g of SURFYNOL 104 were added and stirring continued for 15 minutes. In this mixture, 1500 g was added to a solution of 54.8 g (0.564 equiv) of sulfamic acid in 781.2 g of deionized water. The reaction mixture was stirred for 20 minutes, at which time 1335 g of deionized water was added. The resulting dispersion was diluted with 1 kg of deionized water and heated to 60-65 ° C., and the solvent was co-distilled under reduced pressure to give a dispersion having a solids content of 39.9%. (1 hour at 110 ° C.)

Examples 8-15

Examples 8-15 below describe methods for the preparation of electrodepositable coating compositions (in the form of electrodeposition baths) according to alternative embodiments of the present invention. The electrodepositable coating composition comprises the cationic resins of Examples M-T.

Example 8

This example discloses a method of making an electrodepositable coating composition according to an alternative embodiment of the present invention. The electrodeposition bath was prepared as described below from the following components.

The resulting electrodeposition bath solids had a 22% content of each electrodeposition bath and a pigment to binder ratio of 0.15: 1.0. 20% by weight of each electrodeposition composition was removed by filtration and replaced with deionized water.

Examples 9-15

In the electrodepositable coating composition in the form of the electrodeposition bath of Examples 9 to 15, the amount of the cationic resin of Examples N to T was respectively adjusted to produce 705.6 parts of a solid, and the amount of deionized water was 3800 weight of the electrodeposition bath for each Example. Prepared in the same manner as in Example 8, except that it was correspondingly adjusted to produce a portion.

Test procedure:

Each of the electrodepositable coating compositions of an optional embodiment of the invention (Examples 8-15) was electrodeposited under conditions sufficient to provide an electrodeposited film thickness of about 1 mil (25.4 μm) on various test substrates. The various substrates, cure conditions and test methods used to evaluate the corrosion resistance and anti-aging properties are shown in Table 4 below. For the Xenon Arc Weatherometer test, it should be noted that the cured electrocoated test panel was subsequently coated with an uncolored base coating / transparent coating system (providing 80% light transmission at 400 nm). ) (Disclosed above with reference to Examples 1-5).

Examples 8 to 9 are comparisons of aliphatic to aromatic isocyanates. The data in Table 4 demonstrate that aliphatic isocyanates provide improved durability over aromatic isocyanates, but aliphatic isocyanates are inferior to corrosion resistance on steel substrates.

Examples 8 to 10 to 11 show a comparison for aromatic bisphenol A epoxy extended with resorcinol diglycidyl ether to saturated epoxy to the same amount of resorcinol. The data in Table 4 demonstrate that resorcinol diglycidyl ether provides improved durability over saturated epoxy analogs that provide better durability than compositions comprising bisphenol A. However, aromatic bisphenol A epoxies provide the best corrosion resistance compared to steel substrates.

Examples 8 vs 12 vs 13 compare the aromatic bisphenol A epoxy extended with resorcinol diglycidyl ether to saturated epoxy to the same amount of resorcinol, using comparable amounts in equivalent crosslinkers Indicates. The data in Table 4 demonstrate that resorcinol diglycidyl ether provides improved durability over saturated or aromatic bisphenol A epoxies. In addition, resorcinol has the best total corrosion resistance.

Examples 8 vs. 14 to 15 show a comparison of resorcinol diglycidyl ethers extended with resorcinol to catechol and hydroquinone. The data in Table 4 illustrate that each of these compositions provides good durability and corrosion resistance (the catechol version is slightly improved in both categories).

Those skilled in the art will recognize that modifications may be made to the embodiments disclosed above without departing from the broad inventive concept of the invention. Accordingly, it is to be understood that the invention is not limited to the specific embodiments disclosed, but is intended to cover modifications within the spirit and scope of the invention as defined by the appended claims.

Claims (116)

(a) electrophoretic deposition of a curable electrodepositable coating composition on a conductive substrate to form a coating electrodeposited on at least a portion of the substrate, wherein the electrodepositable coating composition is applied to an aqueous medium. A dispersed resinous phase, the resinous phase comprising (1) a polymer selected from polyepoxide polymers, acrylic polymers, polyurethane polymers, polyester polymers, mixtures thereof and copolymers thereof, (2) at least partially blocked aliphatic polyisocyanate curing agent comprising an active hydrogen containing cationic amine salt group containing resin in a gelling state that can be electrodeposited on the cathode; (b) heating the coated substrate to a temperature of 250 to 450 ° F. for 10 to 60 minutes; (c) directly applying a pigment-containing coating composition, a pigment member coating composition or a mixture thereof to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature of 160 to 350 ° F. for 30 to 60 minutes, wherein the cured topcoat has a light transmittance of at least 0.1% when measured at 400 nm. In the coating method of, A coating of the conductive substrate, wherein the curable electrodepositable coating composition contains a resin containing an amine salt group containing a pendant amido group of formula (I) or formula (II), a terminal amino group, or a cationic amine salt group derived from the two groups. Way: Formula I -NHR Formula II Where R group is H or C ₁ to C ₁₈ alkyl; R ¹ , R ² , R ³ and R ⁴ are the same or different and each independently represent H or C ₁ to C ₄ alkyl; X and Y may be the same or different and each independently represent a hydroxy group or an amino group. The method of claim 1, A method of coating a conductive substrate having a light transmittance of 0.1 to 50% when the cured top coat is measured at 400 nm. The method of claim 1, When the cationic amine salt group of the resin (1) is electrodeposited and cured, the at least two electron withdrawing groups selected from ester groups, urea groups, urethane groups and combinations thereof are substantially all nitrogen. A method of coating a conductive substrate derived from pendant amino groups of formula (II) to bond at the β-position relative to the atom. The method of claim 3, wherein A method for coating a conductive substrate in which at least three electron withdrawing groups are bonded at the β position to substantially all nitrogen atoms. delete delete Claim 7 was abandoned upon payment of a set-up fee. The method of claim 1, The coating method of the conductive substrate in which resin (1) contains a polyepoxide polymer. The method of claim 1, A method for coating a conductive substrate, wherein the resin (1) contains a polyepoxide polymer and an acrylic polymer. The method of claim 8, A method for coating a conductive substrate, wherein the polyepoxide polymer is present in the electrodepositable coating composition in an amount of 10 to 90% by weight based on the total amount of the resin solid present in the electrodepositable coating composition. The method of claim 1, Conductive substrate wherein resin (1) comprises cationic amine salt groups derived from compounds selected from ammonia, methylamine, diethanolamine, diisopropanolamine, N-hydroxyethyl ethylene diamine, diethylenetriamine and mixtures thereof Coating method. The method of claim 1, Resin (1) is present in the electrodepositable coating composition in an amount of 20 to 80% by weight based on the total amount of the weight of the resin solid of the resin (1) and the weight of the curing agent (2) present in the electrodepositable coating composition. A method of coating a conductive substrate. The method of claim 1, The curing agent (2) is 1,6-hexamethylene diisocyanate, isophorone diisocyanate, bis- (isocyanatocyclohexyl) methane, polymeric 1,6-hexamethylene diisocyanate, trimerized isophorone diisocyanate, A method for coating a conductive substrate comprising at least partially blocked polyisocyanate selected from norbornane diisocyanates and mixtures thereof. The method of claim 12, A method for coating a conductive substrate, wherein the curing agent (2) comprises polyisocyanate completely blocked. The method of claim 12, A method for coating a conductive substrate, wherein the curing agent (2) comprises a fully blocked polyisocyanate selected from polymeric 1,6-hexamethylene diisocyanate, isophorone diisocyanate and mixtures thereof. The method of claim 1, Conductive substrate wherein the polyisocyanate curing agent (2) is at least partially blocked with a blocking agent selected from 1,2-alkane diol, 1,3-alkane diol, benzyl alcohol, allyl alcohol, caprolactam, dialkylamine and mixtures thereof Coating method. Claim 16 was abandoned upon payment of a setup registration fee. The method of claim 15, A method for coating a conductive substrate, wherein the polyisocyanate curing agent (2) is at least partially blocked with 1,2-alkane diol having 3 or more carbon atoms. The method of claim 15, A method for coating a conductive substrate, wherein the polyisocyanate curing agent (2) is at least partially blocked with a blocking agent selected from 1,2-alkane diols having more than 3 carbon atoms, benzyl alcohols and mixtures thereof. Claim 18 was abandoned upon payment of a set-up fee. The method of claim 17, A method for coating a conductive substrate, wherein the polyisocyanate curing agent (2) is at least partially blocked with 1,2-butanediol, benzyl alcohol or mixtures thereof. The method of claim 1, The polyisocyanate curing agent (2) is an electrodepositable coating composition in an amount of 20 to 80% by weight based on the total amount of the weight of the resin solid of the resin (1) and the weight of the curing agent (2) present in the electrodepositable coating composition. The coating method of the conductive substrate which exists in the inside. The method of claim 1, A method of coating a conductive substrate, wherein the coated substrate of step (a) is heated to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.). The method of claim 1, A method for coating a conductive substrate in which the electrodepositable coating composition does not contain a lead compound. The method of claim 1, The coated substrate of step (a) is heated to a temperature of 360 ° F. (180 ° C.) or less for 10 to 60 minutes. The method of claim 1, A method of coating a conductive substrate, wherein the coated substrate of step (a) is heated to a temperature of 250 to 450 ° F. for 10 to 60 minutes in an atmosphere containing NO _x in an amount of 5 parts per million or less. The method of claim 23, A method of coating a conductive substrate, wherein the coated substrate of step (a) is heated to a temperature of 250 to 450 ° F. for 10 to 60 minutes in an atmosphere containing NO _x in an amount of 1 ppm or less. The method of claim 1, The electrodepositable coating composition further comprises a source of a metal selected from rare earth metals, yttrium and mixtures thereof, wherein the metal is present in an amount of 0.005 to 5% by weight, based on the total amount of resin solids present in the composition Coating method of conductive substrate. (a) electrophoretic deposition of a curable electrodepositable coating composition on a conductive substrate to form a coating electrodeposited on at least a portion of the substrate, wherein the electrodepositable coating composition comprises a resinous phase dispersed in an aqueous medium, the resinous phase being (1) (2) at least partially ungelled cationic polymers that can be electrodeposited on the cathode, selected from polyepoxide polymers, acrylic polymers, polyurethane polymers, polyester polymers, copolymers thereof and mixtures thereof Including a blocked aliphatic polyisocyanate curing agent; (b) heating the coated substrate to a temperature of 250 to 450 ° F. for 10 to 60 minutes in an atmosphere containing NO _x in an amount up to 5 ppm; (c) directly applying a pigment-containing coating composition, a pigment member coating composition or a mixture thereof to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature of 160 to 350 ° F. for 30 to 60 minutes, wherein the cured topcoat has a light transmittance of at least 0.1% when measured at 400 nm; A method of forming a light deterioration prevention multilayer film on a conductive substrate. The method of claim 26, A method for forming a light deterioration preventing multilayer film wherein the cationic polymer comprises a cationic amine salt group. The method of claim 27, A method of forming a photodegradation preventive multilayer coating wherein a cationic amine salt group is derived from a pendant group, a terminal group of formula (I) or formula (II), or two groups: Formula I -NHR Formula II Where R group is H or C ₁ to C ₁₈ alkyl; R ¹ , R ² , R ³ and R ⁴ are the same or different and each independently represent H or C ₁ to C ₄ alkyl; X and Y may be the same or different and each independently represent a hydroxy group or an amino group. The method of claim 27, When the cationic amine salt group is electrodeposited and cured in the electrodepositable coating composition, at least two electron withdrawing groups selected from ester groups, urea groups, urethane groups and combinations thereof are β-positioned to substantially all nitrogen atoms. A method of forming a light deteriorating multilayer film derived from a pendant amino group of formula (II) to be bonded at delete  The method of claim 26, A method of forming a light deterioration prevention multilayer film having a light transmittance of 0.1 to 50% when the top coat is measured at 400 nm. delete Claim 33 was abandoned upon payment of a registration fee. The method of claim 26, A method for forming a light deterioration prevention multilayer film wherein the polymer (1) comprises a polyepoxide polymer. The method of claim 26, A method for forming a light deterioration prevention multilayer film wherein the polymer (1) comprises a polyepoxide polymer, an acrylic polymer and a mixture thereof. The method of claim 34, wherein The polyepoxide polymer is a method of forming an anti-degradation multilayer coating, wherein the polyepoxide polymer is present in the electrodepositable coating composition in an amount of 10 to 90% by weight based on the total amount of the resin solid present in the electrodepositable coating composition. The method of claim 26, Photodegradation in which polymer (1) comprises cationic amine salt groups derived from compounds selected from ammonia, methylamine, diethanolamine, diisopropanolamine, N-hydroxyethylethylenediamine, diethylenetriamine and mixtures thereof Formation method of anti multilayer film. The method of claim 26, The polymer (1) is present in the electrodepositable coating composition in an amount of 20 to 80% by weight based on the total amount of the weight of the resin solid of the resin (1) and the weight of the curing agent (2) present in the electrodepositable coating composition. A method of forming a light deterioration prevention multilayer coating. The method of claim 26, The curing agent (2) is 1,6-hexamethylene diisocyanate, isophorone diisocyanate, bis- (isocyanatocyclohexyl) methane, polymeric 1,6-hexamethylene diisocyanate, trimerized isophorone diisocyanate, A method for forming a light deterioration preventing multilayer film selected from norbornane diisocyanates and mixtures thereof. The method of claim 26, A method for forming a light deterioration preventing multilayer film comprising a polyisocyanate in which a curing agent (2) is completely blocked. The method of claim 39, A method for forming a light deterioration preventive multilayer coating wherein the curing agent (2) comprises a fully blocked polyisocyanate selected from polymeric 1,6-hexamethylene diisocyanate, isophorone diisocyanate and mixtures thereof. The method of claim 26, Photodegradation wherein the polyisocyanate curing agent (2) is at least partially blocked with a blocking agent selected from 1,2-alkane diol, 1,3-alkane diol, benzyl alcohol, allyl alcohol, caprolactam, dialkylamine and mixtures thereof Formation method of anti multilayer film. Claim 42 was abandoned upon payment of a registration fee. The method of claim 41, wherein The polyisocyanate hardener (2) is a method for forming a light deterioration preventing multilayer film at least partially blocked with 1,2-alkane diol having 3 or more carbon atoms. The method of claim 41, wherein The polyisocyanate curing agent (2) is a method for forming a light deterioration prevention multilayer coating wherein the polyisocyanate curing agent (2) is at least partially blocked with a blocking agent selected from 1,2-alkane diols having more than 3 carbon atoms, benzyl alcohols and mixtures thereof. Claim 44 was abandoned upon payment of a set-up fee. The method of claim 43, The polyisocyanate curing agent (2) is a method for forming an anti-degradation multilayer coating wherein at least partly blocks with a blocking agent selected from 1,2-butanediol, benzyl alcohol and mixtures thereof. The method of claim 26, The polyisocyanate curing agent (2) is an electrodepositable coating composition in an amount of 20 to 80% by weight based on the total amount of the weight of the resin solid of the resin (1) and the weight of the curing agent (2) present in the electrodepositable coating composition. Formation method of the light deterioration prevention multilayer film which exists in the inside. The method of claim 26, A method of forming an antideterioration multilayer film wherein the coated substrate of step (a) is heated to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.). The method of claim 46, A method of forming an anti-degradation multilayer coating wherein the coated substrate of step (a) is heated to a temperature of 360 ° F. (180 ° C.) or less for 10 to 60 minutes. The method of claim 26, A method for forming a light deterioration preventive multilayer coating wherein the electrodepositable coating composition does not contain a lead compound. The method of claim 26, The electrodepositable coating composition further comprises a source of metal selected from rare earth metals, yttrium and mixtures thereof, the metal being present in an amount of 0.005 to 5% by weight, based on the total amount of resin solids present in the electrodepositable composition. A method of forming a light deterioration prevention multilayer coating. (a) electrophoretic deposition of a curable electrodepositable coating composition on a conductive substrate to form an electrodeposited coating on at least a portion of the substrate, the substrate functioning as a cathode in an electrical circuit comprising a cathode and an anode, the cathode And an anode is immersed in the aqueous electrodepositable coating composition, a current is passed between the cathode and the anode to electrodeposit the coating on at least a portion of the substrate, and the electrodepositable coating composition comprises a resinous phase dispersed in an aqueous medium; Comprising (1) an ungelled cationic amine salt group containing polyepoxide resin that can be electrodeposited on the cathode and (2) an at least partially blocked aliphatic polyisocyanate curing agent; (b) heating the coated substrate to a temperature of 250 to 450 ° F. for 10 to 60 minutes; (c) directly applying a pigment-containing coating composition, a pigment member coating composition or a mixture thereof to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature of 160 to 350 ° F. for 30 to 60 minutes, wherein the cured top coat has a light transmittance of at least 0.1% when measured at 400 nm, An anode other than ferrous iron is introduced into the electric circuit. A method of forming a light deterioration prevention multilayer film on a conductive substrate. 51. The method of claim 50 wherein A method for forming an antideterioration multilayer film of the aqueous electrodepositable coating composition in the form of an electrodeposition bath containing less than 10 ppm of soluble iron. 51. The method of claim 50 wherein A method of forming a light deterioration prevention multilayer film wherein the coated substrate of step (a) is heated in an atmosphere containing NO _x in an amount of 5 ppm or less. The method of claim 52, wherein A method of forming a light deterioration prevention multilayer film wherein the coated substrate of step (a) is heated in an atmosphere containing NO _x in an amount of 1 ppm or less. 51. The method of claim 50 wherein A method of forming a anti-deterioration multilayer film wherein the cured and electrodeposited film of step (b) comprises less than 10 ppm of soluble iron. 51. The method of claim 50 wherein A method of forming a light deterioration preventing multilayer coating wherein the curable electrodepositable coating composition further comprises a material selected from hindered amine light stabilizers, antioxidants, ultraviolet absorbers and mixtures thereof. (a) electrophoretic deposition of a curable electrodepositable coating composition on a conductive substrate to form a coating electrodeposited on at least a portion of the substrate, wherein the electrodepositable coating composition comprises a resinous phase dispersed in an aqueous medium, the resinous phase being (1) An active hydrogen-containing cationic amine salt group-containing resin in a gelling state which can be electrodeposited on the cathode and selected from acrylic polymers, polyepoxide polymers, and mixtures thereof; An aliphatic polyisocyanate curing agent at least partially blocked with a blocking agent selected from benzyl alcohols and mixtures thereof; (b) heating the coated substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for 10 to 60 minutes; (c) directly applying a pigment-containing coating composition, a pigment member coating composition or a mixture thereof to the cured and electrodeposited coating to form a top coat on at least a portion of the cured and electrodeposited coating; And (d) heating the coated substrate of step (c) to a temperature of 160 to 350 ° F. for 30 to 60 minutes, wherein the cured topcoat has a light transmittance of 0.1% to 50% when measured at 400 nm wavelength; In the coating method of the conductive substrate, The presence of a pendant amino group, a terminal amino group, or a cationic amine salt group derived from the two groups in the curable electrodepositable coating composition; When the electrodepositable coating composition is electrodeposited and cured, two or more electron withdrawing groups are bonded at the β position for substantially all nitrogen atoms, and the electron withdrawing groups are ester groups, urea groups, urethane groups and combinations thereof Method for coating a conductive substrate, characterized in that selected from: Formula II Where R ¹ , R ² , R ³ and R ⁴ are the same or different and each independently represent H or C ₁ to C ₄ alkyl; X and Y may be the same or different and each independently represent a hydroxy group or an amino group. A cured primer coating layer overlying at least a portion of a conductive substrate, and a cured topcoat layer overlying at least a portion of the cured undercoat layer, comprising: The undercoat layer is formed from a curable electrodepositable coating composition comprising a resin phase dispersed in an aqueous medium, wherein the resin phase is (1) a polyepoxide polymer, an acrylic polymer, a polyurethane polymer, a polyester polymer, or a copolymer thereof. And an active hydrogen containing cationic amine salt group containing resin in a gelling state which can be electrodeposited on the cathode, comprising a polymer selected from mixtures thereof, and (2) at least partially blocked aliphatic polyisocyanate curing agents, The cationic amine salt group is derived from a pendant amino group, a terminal amino group of the formula A top coat layer is formed from a pigment-containing coating composition, a pigment-free coating composition or a mixture thereof, When the top coat layer has a light transmittance of 80% or more when measured at 400 nm, there is virtually no intermediate peeling between the cured undercoat layer and the cured top coat layer upon focused daylight spectrum irradiation comparable to two years of outdoor climate. , Light Degradation Multilayer Composite Coating: Formula I -NHR Formula II Where R group is H or C ₁ to C ₁₈ alkyl; R ¹ , R ² , R ³ and R ⁴ are the same or different and each independently represent H or C ₁ to C ₄ alkyl; X and Y may be the same or different and each independently represent a hydroxy group or an amino group. delete Claim 59 was abandoned upon payment of a setup registration fee. The method of claim 57, Multilayer composite coating wherein the resin (1) comprises a polyepoxide polymer. The method of claim 57, A multilayer composite coating wherein the resin (1) comprises a polymer selected from polyepoxide polymers, acrylic polymers and mixtures thereof. The method of claim 60, Wherein the polyepoxide polymer is present in the electrodepositable coating composition in an amount of 10 to 90% by weight or more based on the total amount of resin solids present in the electrodepositable coating composition. The method of claim 57, Wherein the cured top coat has a light transmittance of 0.1 to 50% when measured at 400 nm. The method of claim 57, When the cationic amine salt group of the resin (1) is electrodeposited and cured, the at least two electron withdrawing groups selected from ester groups, urea groups, urethane groups and combinations thereof are substantially all nitrogen. A multilayer composite coating derived from the pendant amino group of formula (II) to be bonded at the β position relative to the atom. delete The method of claim 57, Resin (1) is a multilayer composite comprising a cationic amine salt group derived from a compound selected from ammonia, methylamine, diethanolamine, diisopropanolamine, N-hydroxyethyl ethylenediamine, diethylenetriamine and mixtures thereof jacket. The method of claim 57, Resin (1) is present in the electrodepositable coating composition in an amount of 20 to 80% by weight based on the total amount of the weight of the resin solid of the resin (1) and the weight of the curing agent (2) present in the electrodepositable coating composition. Multilayer composite coating. The method of claim 66, wherein The curing agent (2) is 1,6-hexamethylene diisocyanate, isophorone diisocyanate, bis- (isocyanatocyclohexyl) methane, polymeric 1,6-hexamethylene diisocyanate, trimerized isophorone diisocyanate, A multilayer composite coating comprising at least partially blocked polyisocyanate selected from norbornane diisocyanates and mixtures thereof. The method of claim 66, wherein A multilayer composite coating wherein the curing agent (2) comprises polyisocyanate completely blocked. The method of claim 68, wherein A multilayer composite coating wherein the curing agent (2) comprises a fully blocked polyisocyanate selected from polymeric 1,6-hexamethylene diisocyanate, isophorone diisocyanate and mixtures thereof. The method of claim 57, A multilayer composite coating wherein the polyisocyanate curing agent (2) is at least partially blocked with a blocking agent selected from 1,2-alkanediols, 1,3-alkanediols, benzyl alcohols, allyl alcohols, dialkylamines and mixtures thereof. Claim 71 was abandoned upon payment of a registration fee. The method of claim 70, Multilayer composite coating wherein the polyisocyanate curing agent (2) is at least partially blocked with 1,2-alkanediols having at least 3 carbon atoms. The method of claim 70, A multilayer composite coating wherein the polyisocyanate curing agent (2) is at least partially blocked with a blocking agent selected from 1,2-alkane diols having more than 3 carbon atoms, benzyl alcohols and mixtures thereof. Claim 73 was abandoned upon payment of a set-up fee. The method of claim 72, A multilayer composite coating wherein the polyisocyanate curing agent (2) is at least partially blocked with a blocking agent selected from 1,2-butanediol, benzyl alcohol and mixtures thereof. The method of claim 57, The polyisocyanate curing agent (2) is an electrodepositable coating composition in an amount of 20 to 80% by weight based on the total amount of the weight of the resin solid of the resin (1) and the weight of the curing agent (2) present in the electrodepositable coating composition. Multilayer composite coating present in the middle. The method of claim 57, A multilayer composite coating in which the electrodepositable coating composition does not contain a lead compound. The method of claim 57, The electrodepositable coating composition further comprises a source of a metal selected from rare earth metals, yttrium and mixtures thereof, wherein the metal is from 0.005 to 5% by weight, based on the total amount of resin solids present in the electrodepositable coating composition Multilayer composite coating present. The method of claim 57, A multilayer composite coating wherein the undercoat layer is cured in an atmosphere containing NO _x in an amount of 5 ppm or less. The method of claim 57, A multilayer composite coating wherein the undercoat layer is cured in an atmosphere containing NO _x in an amount of 1 ppm or less. A cured top coat layer overlying at least a portion of a conductive substrate, and a cured top coat layer over over at least a portion of the cured undercoat layer, The undercoat layer is formed from a curable electrodepositable coating composition comprising a resin phase dispersed in an aqueous medium, the resin phase being (1) electrodeposited on the cathode and selected from acrylic polymers, polyepoxide polymers, and mixtures thereof An active hydrogen-containing cationic amine salt group containing resin and (2) an aliphatic polyisocyanate curing agent at least partially blocked with a blocking agent selected from 1,2-alkane diols having more than 3 carbon atoms, benzyl alcohols and mixtures thereof, The cationic amine salt group of the resin (1) is derived from a pendant amino group, a terminal amino group of the formula (I) A top coat layer is formed from a pigment-containing coating composition, a pigment-free coating composition or a mixture thereof, When the top coat layer has a light transmittance of 80% or more when measured at 400 nm, it is characterized by substantially no interlayer delamination between the cured undercoat layer and the cured top coat layer upon focused daylight spectrum irradiation comparable to two years of outdoor climate. , Light Degradation Multilayer Composite Coating: Formula I -NHR Formula II Where R group is H or C ₁ to C ₁₈ alkyl; R ¹ , R ² , R ³ and R ⁴ are the same or different and each independently represent H or C ₁ to C ₄ alkyl; X and Y may be the same or different and each independently represent a hydroxy group or an amino group. Electrophoretic deposition of a curable electrodepositable coating composition comprising (a) an active hydrogen containing cationic amine salt group containing resin capable of electrodepositing on a cathode, and (2) a partially blocked polyisocyanate curing agent The cationic salt group-containing resin of component (1) is derived from polyglycidyl ether of polyhydric phenol, wherein no aliphatic carbon atom is essentially bound to an aliphatic carbon atom, and The curing agent is essentially free of isocyanate groups or blocked isocyanato groups to which aromatic groups are bonded; (b) heating the substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for 10 to 60 minutes; (c) directly applying the pigment-containing top coat composition, the pigment free top coat composition or mixture thereof to the electrodepositable composition; And (d) heating the coated substrate at a temperature of 160 to 350 ° F. for 30 to 60 minutes, Coating method of metal substrate. 81. The method of claim 80, Steel with a metal substrate coated with a zinc rich or iron phosphide rich organic coating; Stainless steel; Steel surface-treated with zinc metal, zinc compounds or zinc alloys; aluminum; Copper; magnesium; Magnesium alloys; Zinc-aluminum alloys; And a coating method of the metal substrate selected from the combination thereof. Claim 82 was abandoned upon payment of a registration fee. 82. The method of claim 81 wherein A method of coating a metal substrate, wherein the metal substrate comprises more than one metal. delete 81. The method of claim 80, A method for coating a metal substrate, wherein the cationic salt group is derived from an amine containing a nitrogen atom bonded to a substituted alkyl group having a hetero atom at the β-position relative to a nitrogen atom. 87. The method of claim 84, The amine salt groups include diethanolamine, aminopropyl diethanolamine, N-methylethanolamine, aminopropylmorpholine, N- (2-aminoethyl) -morpholine, diethylenetriamine, diethylenetriamine bisketamine, And a method of coating a metal substrate derived from a compound selected from mixtures thereof. 81. The method of claim 80, A method of coating a metal substrate, wherein the amine salt group is derived from a basic nitrogen group neutralized with an acid selected from the group consisting of formic acid, acetic acid, lactic acid, phosphoric acid, sulfamic acid, dimethylolpropionic acid, and mixtures thereof. 81. The method of claim 80, A method for coating a metal substrate, wherein the polyhydric phenol is selected from the group consisting of resorcinol, hydroquinone, catechol, and mixtures thereof. Claim 88 was abandoned upon payment of a registration fee. 88. The method of claim 87, A method for coating a metal substrate, wherein the polyhydric phenol is selected from resorcinol, catechol, and mixtures thereof. 88. The method of claim 87, A method for coating a metal substrate, wherein the resin of component (1) comprises at least 16% by weight of functional groups of the formula: based on the total amount of resin solids: 81. The method of claim 80, The electrodepositable coating composition further comprises a source of a metal selected from rare earth metals, yttrium and mixtures thereof, wherein the metal is from 0.005 to 5% by weight, based on the total amount of resin solids present in the electrodepositable coating composition Coating method of the metal substrate which exists. Claim 91 was abandoned upon payment of a setup registration fee. 92. The method of claim 90, A method for coating a metal substrate, wherein the metal comprises yttrium. 81. The method of claim 80, The electrodepositable coating composition further comprises a sterically hindered amine light stabilizer in an amount of 0.1 to 2% by weight based on the total amount of resin solid in the electrodepositable coating composition. 81. The method of claim 80, A method for coating a metal substrate, wherein the cationic salt group-containing resin of component (1) in the electrodepositable coating composition is present in an amount of 20 to 80% by weight based on the total amount of components (1) and (2). 81. The method of claim 80, A method for coating a metal substrate, wherein the curing agent of component (2) in the electrodepositable coating composition is present in an amount of 20 to 80% by weight based on the total amount of components (1) and (2). 81. The method of claim 80, A method of coating a metal substrate, wherein the electrodepositable coating composition is substantially free of lead. (a) electrophoretic deposition of a curable electrodepositable coating composition comprising (1) an active hydrogen containing cationic amine salt group containing resin that can be electrodeposited on the cathode, and (2) a partially blocked polyisocyanate curing agent. The resin containing the cationic amine salt group of component (1) is derived from polyglycidyl ether of polyhydric phenol, wherein no aliphatic carbon atom is essentially bound to an aliphatic carbon atom. The curing agent is essentially free of isocyanate groups or blocked isocyanato groups bound to aromatic groups; (b) heating the substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for 10 to 60 minutes; (c) directly applying the pigment-containing top coat composition, the pigment free top coat composition or mixture thereof to the electrodepositable composition; And (d) heating the coated substrate to a temperature of 160 to 350 ° F. for 30 to 60 minutes, Coating method of metal substrate. 97. The method of claim 96, And the substrate is cold rolled steel and the substrate is pretreated as in step (c). (a) a cationic amine salt group containing resin that can be electrodeposited on the cathode; And (b) a polyisocyanate curing agent that is at least partially blocked. The cationic amine salt group-containing resin of component (a) is derived from polyglycidyl ethers of polyhydric phenols, wherein no aliphatic carbon atoms are essentially bound to an aliphatic carbon atom, The curing agent of component (b) does not necessarily contain isocyanate groups or blocked isocyanato groups to which aromatic groups are bonded, When the electrodepositable coating composition was applied to a zinc substrate and cured, and then subjected to the corrosion test according to ASTM B117, GM Standard 940P Method B, or both methods, the electrodepositable coating composition was selected from aromatic isocyanates, bisphenol A based aromatic polyepoxides. Or a scribe corrosion lower than that exhibited by the control composition containing the mixture, The electrodepositable coating composition withstands xenon arc promoted weathering according to SAE J1960 for at least 1,500 hours without substantial degradation when the electrodepositable coating composition is top coat with a transparent coating composition having a transmittance of more than 50% for ultraviolet region energy of 400 nm wavelength. Coating composition. delete 99. The method of claim 98, A coating composition wherein the cationic salt group is derived from an amine containing a nitrogen atom bonded to a substituted alkyl group having a hetero atom at the β position relative to the nitrogen atom. 101. The method of claim 100, The amine salt groups include diethanolamine, aminopropyl diethanolamine, N-methylethanolamine, aminopropylmorpholine, N- (2-aminoethyl) -morpholine, diethylenetriamine, diethylenetriamine bisketamine, And coating compositions derived from compounds selected from mixtures thereof. 99. The method of claim 98, A coating composition wherein the amine salt group is derived from a basic nitrogen group neutralized with an acid selected from the group consisting of formic acid, acetic acid, lactic acid, phosphoric acid, sulfamic acid, dimethylolpropionic acid, and mixtures thereof. 99. The method of claim 98, The coating composition wherein the polyhydric phenol is selected from the group consisting of resorcinol, hydroquinone, catechol, and mixtures thereof. Claim 104 was abandoned upon payment of a registration fee. 103. The method of claim 103, The coating composition wherein the polyhydric phenol is selected from resorcinol, catechol, and mixtures thereof. 103. The method of claim 103, The coating composition in which the cationic amine salt group-containing resin of component (a) contains 16% by weight or more of the functional groups of the following formula, based on the total amount of the resin solids: 99. The method of claim 98, And a source of metal selected from the rare earth metals, yttrium, and mixtures thereof, wherein the coating composition is present in an amount of 0.005 to 5% by weight, based on the total amount of resin solids present in the coating composition. Claim 107 was abandoned when the fee for setting registration was paid. 107. The method of claim 106, The coating composition wherein the metal comprises yttrium. 99. The method of claim 98, A coating composition further comprising a sterically hindered amine light stabilizer in an amount of 0.1 to 2% by weight, based on the total amount of resin solid in the electrodepositable coating composition. 99. The method of claim 98, A coating composition in which the cationic amine salt group-containing resin of component (a) is present in an amount of 20 to 80% by weight, based on the total amount of components (a) and (b). 99. The method of claim 98, The coating composition in which the curing agent of component (b) is present in an amount of 20 to 80% by weight, based on the total amount of components (a) and (b). 99. The method of claim 98, A coating composition substantially free of lead. active hydrogen-containing cationic salts derived from a polymer selected from the group consisting of (a) essentially free of heavy metals (1) which can be electrodeposited on the cathode and consist of acrylic polymers, polyester polymers, polyurethane polymers, and mixtures thereof Group-containing polymers; (2) at least partially blocked polyisocyanate curing agents; And (3) a source of metal selected from rare earth metals, yttrium, and mixtures thereof, wherein the metal is a metal present in the amount of 0.005 to 5% by weight, based on the total amount of polymer solids in the electrodepositable coating composition. Electrophoretic deposition of the coating composition on the metal substrate; And (b) heating the substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for 10 to 60 minutes, Coating method of metal substrate. 112. The method of claim 112, A method for coating a metal substrate, wherein the metal of component (3) is yttrium. (a) essentially free of heavy metals, (1) containing an active hydrogen containing cationic salt group derived from a polymer selected from the group consisting of acrylics, polyesters, polyurethanes, and mixtures thereof which can be electrodeposited on the cathode polymer; (2) at least partially capped polyisocyanate curing agent essentially free of isocyanate groups or capped isocyanato groups to which aromatic groups are bound; And (3) a source of metal selected from rare earth metals, yttrium, and mixtures thereof, wherein the metal is a metal present in the amount of 0.005 to 5% by weight, based on the total amount of polymer solids in the electrodepositable coating composition. Electrophoretic deposition of the coating composition on a metal substrate, wherein the polymer does not contain aliphatic carbon atoms bonded with more than one aromatic group; And (b) heating the substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for 10 to 60 minutes, Coating method of metal substrate. (a) forming a metal object from the metal substrate; (b) holding the substrate with an alkaline cleaner, an acid cleaner, or both cleaners; (c) pretreating the substrate with a solution selected from the group consisting of metal phosphate solutions, aqueous solutions containing Group IIIB or IVB metals, organophosphate solutions, organophosphonate solutions and combinations thereof; (d) cleaning the substrate with water; (e) electrophoretically depositing a curable electrodepositable coating composition comprising (1) an active hydrogen-containing cationic salt group-containing resin that can be electrodeposited on the cathode, and (2) a partially blocked polyisocyanate curing agent, The cationic salt group-containing resin of component (1) is derived from polyglycidyl ethers of polyhydric phenols, where no additional aromatic groups are necessarily bound to aliphatic carbon atoms, and the curing agent of component (2) The aromatic group is essentially free of bound isocyanato groups or blocked isocyanato groups; (f) heating the substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for 10 to 60 minutes; (g) directly applying the pigment-containing top coat composition, the pigment free top coat composition or mixture thereof to the electrodepositable composition; And (h) heating the coated substrate to a temperature of 160 to 350 ° F. for 30 to 60 minutes, Coating method of metal substrate. (a) forming a metal body from the metal substrate; (b) holding the substrate with an alkaline cleaner, an acid cleaner, or both cleaners; (c) pretreating the substrate with a solution selected from the group consisting of metal phosphate solutions, aqueous solutions containing Group IIIB or IVB metals, organophosphate solutions, organophosphonate solutions and combinations thereof; (d) cleaning the substrate with water; (e) essentially free of heavy metals (1) can be electrodeposited on the cathode and contain active hydrogen containing cationic salt groups derived from polymers selected from the group consisting of acrylics, polyesters, polyurethanes, and mixtures thereof polymer; (2) at least partially capped polyisocyanate curing agent essentially free of isocyanate groups or capped isocyanato groups to which aromatic groups are bound; And (3) a source of metal selected from rare earth metals, yttrium, and mixtures thereof, wherein the metal is a metal present in the amount of 0.005 to 5% by weight, based on the total amount of polymer solids in the electrodepositable coating composition. Electrophoretic deposition of the coating composition on a metal substrate, wherein the polymer is essentially free of aliphatic carbon atoms bonded with more than one aromatic group; And (f) heating the substrate to a temperature of 250 to 400 ° F. (121.1 to 204.4 ° C.) for 10 to 60 minutes, Coating method of metal substrate.