JPH08302285A - Coating method - Google Patents

Abstract

PURPOSE: To prepare an excellent coating film exhibiting high hardness, high density, etc., by coating a substrate with a composition consisting mainly of a specified organopolysiloxane, tetraalkoxyzirconium, an inorganic filler and an organic solvent followed by curing either at normal temperature or under heating at relatively low temperatures. CONSTITUTION: This coating method is carried out by coating a substrate with a composition consisting mainly of a total 100wt.% of (A) 2.5 to 50wt.% of an organopolysiloxane made from an organosiloxane of the formula, R<1> n SiO(4-n)/2 (R<1> is H or a 1-8C organic group; (n) is 1 or 2), (B) 1 to 15wt.% of at least one kind selected from tetraalkoxyzirconiums of the formula, Zr(OR<2> )4 (R<2> is a 1-5C hydrocarbon residue), its hydrolyzate and its partial polycondensate, (C) 3.5 to 60wt.% of an inorganic filler having an average particle diameter of 0.01 to 10μm, and (D) 7 to 93wt.% of an organic solvent, and then curing the resultant coating film at normal temperature or by low-temperature heating. This low-temperature heating is carried out at a temperature exceeding 30 deg.C but not higher than 250 deg.C, preferably, 50 to 250 deg.C, more preferably, 100 to 180 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a coating method. More specifically, a specific coating composition is applied to the surface of iron, aluminum, stainless steel or other metals and products such as cement, glass, ceramics, resins, and wood, and is cured at room temperature or at low temperature to obtain a Hardness, high density, non-combustibility, heat resistance, weather resistance,
The present invention relates to a coating method capable of forming a film having excellent volatility, stain resistance, inorganic / organic chemical resistance, corrosion resistance, abrasion resistance, and insulation.

[0002]

2. Description of the Related Art Conventionally, heat resistance, weather resistance, and
Various coating methods or coating compositions for forming a coating film have been proposed for the purpose of improving chemical resistance, water repellency, corrosion resistance, insulation, stain resistance, abrasion resistance and the like. For example, a silicone resin composition, an organoalkoxysilane composition, a silane zirconium composition, a fluororesin composition, etc. are disclosed.

However, the silicone resin composition has a low hardness even if it is sufficiently heat-treated, and has problems in weather resistance, stain resistance, damage resistance, abrasion resistance and the like. Also,
Organoalkoxysilane compositions have problems in alkali resistance and boiling water resistance when fired at low temperatures. Furthermore, the silane-zirconium-based composition has a low coating density, and has problems in corrosion resistance, stain resistance, insulation, hardness, and the like. Further, the fluorine-based resin composition has low hardness and has problems in damage resistance, stain resistance, workability, and the like.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and has a high hardness, a high coating density, and weather resistance, stain resistance, damage resistance, To provide a coating method which can obtain a coating film having excellent wear resistance, corrosion resistance, stain resistance, and insulation properties, can be cured by heating at low temperature for a short time, and is excellent in workability and economy. With the goal.

[0005]

The present invention provides (a) the general formula R ¹ _n SiO _{(4-n) / 2} (wherein R ¹ is a hydrogen atom, an organic group having 1 to 8 carbon atoms, and n is 2.5 to 50% by weight of an organopolysiloxane composed of an organosiloxane represented by the formula (1 or 2), (b) the general formula Zr (OR
R ² ₄ (wherein, R ² is the hydrocarbon residue shown a C1-5) at least selected from tetraalkoxy zirconium represented by, and the hydrolyzate of tetraalkoxy zirconium or its partial polycondensate 1 to 1
5% by weight, (c) 3.5 to 60% by weight of an inorganic filler having an average particle size of 0.01 to 10 μm, and (d) 7 to 93% by weight of an organic solvent (however, (a) + (b) + (C) +
(D) = 100% by weight] is applied to a base material and the composition is cured at room temperature or at low temperature by heating.

The organopolysiloxane (a) used in the present invention has the general formula R ¹ _n SiO _{(4-n) / 2} (wherein R ¹ is a hydrogen atom, an organic group having 1 to 8 carbon atoms, and n is It is composed of an organosiloxane represented by 1 or 2) and has a molecular weight of 1,000 to 100,000. R in such an organopolysiloxane
¹ is a hydrogen atom, an organic group having 1 to 8 carbon atoms, an alkyl group, a phenyl group, an allyl group, a vinyl group,
Specific examples thereof include a hydroxyl group and the like. Specific examples include an alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an i-propyl group, and a γ-chloropropyl group, a vinyl group, 3,3,3-tri Fluoropropyl group, γ-glycidoxypropyl group, γ-methacryloxypropyl group, γ-mercaptopropyl group, phenyl group, methylphenyl group, 3,4-epoxycyclohexylethyl group,
γ-aminopropyl group and the like. When R ¹ is a methyl group or a methylphenyl group, heat resistance and water repellency are the best.

As such an organopolysiloxane, a commercially available pure silicone varnish obtained by dehydration-condensing a hydrolyzate of a halogenated alkylsilane or an alkoxysilane and dissolving it in a solvent can be used. Pure silicone varnish is a silicone polymer having a siloxane (-Si-O-Si-) bond as a main chain and having a methyl group, a phenyl group, etc. as a side chain. Monomethyl or monophenyltrichlorosilane and a small amount of dimethyl, diethyldiene are used. An initial condensate prepared by mixing chlorosilanes is dissolved in a solvent to further bond the hydroxyl groups remaining in the polysiloxane to form a three-dimensional network structure.

In the present invention, the organopolysiloxane (a) functions as a binder and forms a film having weather resistance, heat resistance, water repellency, chemical resistance and insulation. The organopolysiloxane (a) is contained in the coating composition in an amount of 2.5 to 50% by weight, preferably 10 to 30% by weight. If it is less than 2.5% by weight, the bonding strength is insufficient, while if it exceeds 50% by weight, the coating film hardness is insufficient and the drying becomes insufficient.

The (b) tetraalkoxyzirconium used in the present invention is represented by the general formula Zr (OR ² ) ₄ (wherein R
² represents a hydrocarbon residue having 1 to 5 carbon atoms). R in such zirconium tetraalkoxide
² is an alkyl group having 1 to 5 carbon atoms, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-
A butyl group, a sec-butyl group, a tert-butyl group and the like.

Specific examples of these zirconium tetraalkoxides include zirconium tetramethoxide, zirconium tetraethoxide, zirconium tetra-n-propoxide, zirconium tetra-i-propoxide, zirconium tetra-n-butoxide and zirconium tetraoxide. -Sec-butoxide, zirconium tetra-tert-butoxide and the like can be mentioned. These zirconium tetraalkoxides may be used alone or in combination of two or more. Of these zirconium tetraalkoxides, zirconium tetra-n-butoxide is particularly preferable.

The zirconium tetraalkoxide is rapidly hydrolyzed to liberate an alcohol to produce a corresponding zirconium tetrahydroxide, and the polycondensation of the hydroxyl substituent is carried out by the formation of the hydroxide. A partial polycondensate of hydroxide is produced and further polycondensed to produce a zirconia component which is a complete polycondensate. Therefore, the zirconium tetraalkoxide in the present invention includes not only the zirconium tetraalkoxide represented by the above general formula but also a hydrolyzate thereof or a partial polycondensate of the hydrolyzate. Such a hydrolyzate and / or partial polycondensate may be formed from the zirconium tetraalkoxide in the coating composition, or may be pre-blended during preparation of the coating composition.

The zirconium tetraalkoxide is contained in the coating composition in an amount of 1 to 15% by weight, preferably 2 to 8% by weight. If it is less than 1% by weight, curing may not proceed sufficiently or a sticky feeling may be produced.
On the other hand, if it exceeds 15% by weight, the curing proceeds too much and the coating film is cracked or peeled off.

The (b) zirconium compound Zr (OR ² ) ₄ used in the present invention is hydrolyzed in the presence of a trace amount of water to give a hydrolyzate (zirconium tetrahydroxide).
Since the hydrolyzate undergoes polycondensation to form a partial polycondensate, and further has a higher molecular weight to form a thin film or a block-like cured product over time, in the present invention, the curing of the (a) organopolysiloxane is promoted. It functions as a binder. Such a zirconium compound undergoes a very rapid hydrolysis and polycondensation reaction, and therefore, when mixed with the organopolysiloxane (a), it cures in a short time even at low temperature heating. Then, as the bonding strength increases, the film becomes a high hardness, and the weather resistance, heat resistance, abrasion resistance, stain resistance, water repellency, etc. are further improved.

In the present invention, the inorganic filler (c) has an average particle size of 0.01 to 10 μm, preferably 0.1.
Those having a diameter of 01 to 1 μm are used. Average particle size is 0.0
If it is less than 1 μm, the functionality of the inorganic filler cannot be expressed, or the manufacturing cost is too high. On the other hand, if it exceeds 10 μm, the coating film becomes rough and the adhesion is lowered. As such an inorganic filler, a water-insoluble one is preferable, and an inorganic extender pigment, a functional pigment, an inorganic pigment, a metal powder, an antibacterial silica gel or zeolite, an organometal oxide sol, and the like can be used. 1 or 2 or more types selected from the group of.

Specific examples of the inorganic extender pigment and the functional pigment include commercially available silica, alumina, kaolin, zircon, tin oxide, mullite, silicon carbide, silicon nitride, and the like. Commercially available oxides of titanium, iron, manganese, cobalt, chromium, nickel, etc., carbon or cobattle and aluminum, two kinds of synthetic oxides such as iron and manganese, or three kinds of synthetic oxides such as iron, copper and chromium. Can be mentioned. Further, nickel, silver, metal powders such as silver plated copper and silver, silica gel or zeolite supporting copper, copper and alcoholic colloidal silica, titania, cerium oxide, etc. can be mentioned, but are not limited to these. Absent.

The amount of such inorganic filler is 3.5 to 60% by weight, preferably 10 to 10% by weight in the coating composition.
It is 50% by weight. If it is less than 3.5% by weight, the functionality of the inorganic filler cannot be exhibited, while if it exceeds 60% by weight, the adhesion and hardness are lowered and the viscosity is increased, which is not preferable. Such an inorganic filler is necessary for making a thick film, and further coloring of the coating film, imparting various functionalities to the coating film, for example, thermal emissivity, ultraviolet absorbing property, heat insulating property of the coating film,
It imparts conductivity, rust prevention, antibacterial properties, deodorization properties, and the like.

In the present invention, the organic solvent (d) is a concentration adjusting agent for the above-mentioned (a) organopolysiloxane and (b) tetraalkoxyzirconium, and a curing rate adjusting agent for these components (a) and (b). And (c) is used as a dispersion medium for the inorganic filler.
As such an organic solvent, low boiling point organic solvents, glycol derivatives, alcohols, etc. are suitable. Examples of the low boiling point organic solvent include xylene, toluene, benzene, acetone, methyl ethyl ketone, cyclohexane, and tetrahydrofuran. Examples of glycol derivatives include ethyl glycol, diethylene glycol monobutyl ether, and ethylene glycol monoethyl ether acetate. Examples of alcohols include n-butyl alcohol, i-butyl alcohol, methanol and ethanol.

Among these organic solvents, preferred are xylene, toluene, diethylene glycol monobutyl ether and n-butyl alcohol. These organic solvents may be used alone or in combination of two or more. The proportion of the (d) organic solvent in the coating composition used in the method of the present invention is 7 to 93% by weight, preferably 12 to 60% by weight in the composition. If the amount used is less than 7% by weight, the viscosity is excessively increased, the dispersibility of the pigment is deteriorated, and gelation tends to occur. On the other hand, if it exceeds 93% by weight, a thin film is formed and the performance cannot be exhibited.

In the present invention, (e) other additives, for example, an acid, as a fluidity modifier for the coating composition, as a leveling improver when the composition is applied, and (b) tetraalkoxy. It can be used as a hydrolysis catalyst of zirconium and a curing catalyst of a coating film. As such an acid, both an organic acid and an inorganic acid can be used, for example, acetic acid, acetic anhydride, chloroacetic acid,
Examples thereof include hydrochloric acid, formic acid, propionic acid, maleic acid, citric acid, glycolic acid and the like. Among them, acetic acid or acetic anhydride is preferable.

The amount of such acid in the coating composition is preferably 0.3 to 10% by weight, preferably 1 to 3%.
% By weight. If it is less than 0.3% by weight, the effect of using an acid may be reduced, while if it exceeds 10% by weight, the odor becomes strong, and addition of more than that does not change the effect.

In the method of the present invention, the above (a) to
Other known additives (e) such as a coupling agent, a chelating agent, a metal soap, and a surfactant may be added to the coating composition comprising the component (d). Further, the hydrolyzate and / or partial condensate of tetraalkoxytitanium represented by the general formula Ti (OR) ₄ (wherein R represents a hydrocarbon residue having 1 to 5 carbon atoms) is dried and It can also be added as a curing accelerator.

To prepare the coating composition used in the method of the present invention, for example, (a) an organopolysiloxane component, (d) an organic solvent is added and mixed, and then (b) a tetraalkoxyzirconium component and (c). A method in which an inorganic filler component is added and mixed or dispersed, or after the components (a) and (b) are added to the component (d) and mixed,
A method such as a method of adding the component (c) and mixing and dispersing can be used. The coating composition used in the method of the present invention can be dispersed with a high-speed stirrer, a ball mill, or another disperser and filtered to obtain a uniform and stable dispersion liquid.

The base material to which the above coating composition is applied includes various metals such as iron, aluminum and stainless steel, inorganic materials such as cement materials, ceramics, glass and stone materials, products such as plastics, wood and paper. Examples thereof include, but are not limited to, the surface or the surface of an organic coating film. On the surface of the substrate, spray,
1 by applying means such as roll, brush and dipping
It is possible to apply 10 to 300 g of the coating composition per 1 m ^{2 at a} time, and apply this to 6 to 2 at 10 to 30 ° C.
Allow to cure at room temperature for 4 hours, or exceed 30 ° C for 2 hours
The coating film can be easily cured by heating at a temperature of 50 ° C. or lower, preferably 50 to 250 ° C., more preferably 100 to 180 ° C. for 20 to 60 minutes, preferably 20 to 40 minutes to easily cure the coating film.

In the method of the present invention, the coating composition can be formed into a thick film by overcoating,
An anticorrosion film, an electric insulating film, a heat insulating film, etc. can be produced.

The coating film obtained by the method of the present invention is a coating film having good adhesion and high hardness and high density. At the same time, it has excellent heat resistance, weather resistance, waterproofness, water repellency, stain resistance, chemical resistance, damage resistance, electrical insulation, impact resistance, wear resistance, etc., and can be used for various purposes. You can For example, metal weather resistance, stain resistance, corrosion resistant decorative film, non-combustible, heat radiation decorative film, heat resistant electrical insulation film, weather resistance of cement-based building materials,
Contamination-resistant, alkali-resistant decorative film, water-repellent waterproof film, or water-repellent waterproof film for wood or paper, flame-retardant film, thermal radiation non-stick film on the inner surface of the cooker, heat absorbing film on the outer surface, etc. Can be used for

Specifically, when it is used for metal or cement-based building materials (inner and outer wall materials, etc.),
By heating for about 30 minutes, it is possible to obtain a high hardness, nonflammable, maintenance-free film having excellent weather resistance, damage resistance, stain resistance, and chemical resistance. In addition, when used on the inside and outside of the cooker, it can withstand continuous use at 500 ° C or higher,
A coating film with excellent damage resistance, stain resistance, and corrosion resistance can be obtained.
Further, when used for protective makeup of automobiles, a wax-free coating film having excellent weather resistance, corrosion resistance, stain resistance, and damage resistance can be obtained. As described above, the method of the present invention makes it possible to produce a coating film that can be used for various applications which have hitherto been insufficient.

[0027]

In the method of the present invention, as a coating composition, a silicone resin having extremely fast reactivity and a cured product thereof having tetraalkoxyzirconium excellent in weather resistance and corrosion resistance is used. When such a composition is coated on a substrate and heated, (a) the organopolysiloxane component is hydrolyzed by a solvent condensation reaction, and (b) the tetraalkoxyzirconium component is instantly hydrolyzed by a small amount of water, At the same time, the condensation reaction that occurs simultaneously cures with the inorganic filler component (c).

At this time, in the present invention, the polycondensation / curing reaction of the component (b) is very fast, and therefore, by mixing it with the organopolysiloxane (a), it is cured at room temperature or at low temperature in a short time. To do. Furthermore, since the polycondensation / curing reactivity of the component (b) is high, the hardness of the coating film can be greatly improved, resulting in a coating film of high hardness and high density. With it, weather resistance, damage resistance, stain resistance, wear resistance,
The stain resistance is improved.

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the scope of the claims. In the examples, parts and% are based on weight unless otherwise specified.

Examples 1 to 8 Eight types of coating compositions A to H shown in Table 1 were prepared. Of the above compositions, A, B, C and E, F, H
Was prepared by putting components (a), (b), (d) and (e) in a stirring tank, stirring lightly, then adding component (c) and stirring at high speed (13,000 rpm) for 30 minutes. did. Compositions D and G are (a), (b),
After the components (d) and (e) were mixed, the component (c) was added and lightly stirred, and this mixed liquid was dispersed by a roll mill to prepare.

The symbols in the table represent the following. (A) -1: Methylphenyl silicone varnish [TSR-108 manufactured by Toshiba Silicone Co., Ltd.] (a) -2: Methyl silicone varnish [TSR-1291 manufactured by Toshiba Silicone] (b): Tetra -N-Butoxyzirconium (c) -1: Titanium oxide (average particle size 0.5 μm) (c) -2: Iron oxide / manganese oxide (average particle size 0.6 μm)
m) (c) -3: Kaolin (average particle size 1 μm) (c) -4: Nickel (average particle size 3 μm) (c) -5: Colloidal silica (isopropanol as mixed solvent, solid content concentration 20%, average) Particle size 0.02μ
m)

(D) -1: xylene (d) -2: toluene (d) -3: n-butyl alcohol (d) -4: diethylene glycol monobutyl ether (e) other (e) -1: glacial acetic acid (e) ) -2: Polybutyl titanate (e) -3: Cobalt naphthenate (e) -4: Nonionic surfactant

Comparative Examples 1 and 2 As Comparative Examples 1 and 2, two kinds of coating compositions I and J shown in Table 1 were prepared. The above composition was placed in a stirring tank, composition I was composed of components (a) and (d), composition J
Is prepared by adding (a), (b) and (d) components, adding (e) component to the mixture and gently stirring, then adding (c) component and stirring at high speed (13,000 rpm) for 30 minutes. did.

[0034]

[Table 1]

The coating composition thus prepared was applied to various base materials shown in Table 2 and subjected to a curing treatment,
Evaluation test pieces TP1 to TP21 were prepared. Among the base materials, a steel plate, an aluminum plate, a stainless plate, and a glass plate were subjected to alkaline degreasing treatment, and others were subjected to cleaning treatment as a base treatment before coating with the coating composition. An air spray gun was used for applying the coating composition, and an electric oven was used for heating. Tables 3 and 4 show the number of times the coating composition was applied and the curing conditions.

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

The composition J of Comparative Example 2 was applied to a steel plate and a cement slate plate, but both of them had cracks and were peeled off, so the production of the test piece was stopped.

[Evaluation Test] After the test piece prepared as described above was kept indoors for 7 days, the following evaluation test was carried out. Adhesion Adherence to JIS K-5400-6.15 cross cut test. Adhesiveness A test piece (used) having a thermal cycleability described later was used, and it was in conformity with the JIS K-5400-6.15 cross-cut test.

Hardness This was based on the JIS K-5400-6.14 pencil scratch test. Impact resistance Based on JIS K-5400-6.13.2 (1 /
2 inches, 500 g x 20 cm).

Heat resistance The test piece was kept at 500 ° C. for 8 hours in an electric furnace and then naturally cooled, and the appearance of the coating film was observed. Boiling resistant water Hold the test piece in boiling water for 8 hours and allow it to cool.
After repeating 0 times, the appearance of the coating film was observed.

Hot water resistance After the test piece was kept in hot water of 60 ° C. for 20 days, the appearance of the coating film was observed. Cooling / Heat Cycle Property The test piece was kept at 500 ° C. for 30 minutes in an electric furnace and then naturally cooled. Salt spray resistance 5% salt solution was continuously sprayed on the test piece for 960 hours, and then the appearance of the coating film was observed.

Alkali resistance A 10% aqueous solution of caustic soda was dropped onto the test piece, and after holding for 8 hours, the appearance of the coating film was observed. A 20% hydrochloric acid aqueous solution was dropped on the acid-resistant test piece, and after holding for 8 hours, the appearance of the coating film was observed. Solvent resistance After immersing the test piece for 20 days in a mixed solvent of acetone / cellosolve / ethyl acetate / hydrous alcohol for industrial use / toluene = 3/2/2/1/2 (weight ratio), the appearance of the coating film was observed.

Abrasion resistance After the test piece was strongly rubbed with # 0000 steel wool, the appearance of the coating film was observed to determine the presence or absence of scratches. Contamination resistance It was drawn with black and red magic ink, wiped with a compress (water), and the trace state was observed. Contamination resistance 0.1% carbon-dispersed water was applied, heated at 60 ° C. for 1 hour and then wiped off with a compress, and the trace state was observed.

Weather resistance The test piece was exposed for 4000 hours by a sunshine carbon arc lamp weather resistance tester according to JIS K-5701, and then the appearance of the coating film was observed. Water repellency The contact angle (°) was measured using ion-exchanged water. Water Absorption It was immersed in ion-exchanged water and the water absorption rate (%) after 24 hours was measured.

Water permeability The water permeability after 72 hours was measured using ion-exchanged water by the funnel method (mg / cm ² ). The evaluation of the appearance observation result of the coating film was as follows. ◯: No peeling of the coating film was observed and the appearance was not changed. X: Peeling, cracking or melting damage is observed in part or all of the coating film. /: No evaluation The results of the above evaluation tests are shown in Tables 5 to 7.

[0048]

[Table 5]

[0049]

[Table 6]

[0050]

[Table 7]

[0051]

According to the method of the present invention, a coating having good adhesion, high hardness and high density can be obtained. In addition, this coating film has excellent heat resistance, weather resistance, waterproofness, water repellency, stain resistance, chemical resistance, damage resistance, electrical insulation, impact resistance, abrasion resistance, etc. Can be used for. For example, metal weather resistance, stain resistance, corrosion resistant decorative film, non-combustible, heat radiation decorative film, heat resistant electrical insulation film, weather resistance of cement-based building materials,
Anti-staining, alkali-resistant decorative film, water-repellent waterproof film, or water-repellent waterproof film of wood or paper, flame-retardant film, heat radiation non-stick film on the inner surface of cooking container, heat absorption film on the outer surface, and other wide range of applications Can be used for

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Claims (1)

[Claims] (A) General formula R ¹ _n SiO _{(4-n) / 2} (wherein R ¹ represents a hydrogen atom, an organic group having 1 to 8 carbon atoms, and n represents a number of 1 or 2) 2.5 to 50% by weight of an organopolysiloxane composed of an organosiloxane represented by: (b) General formula Zr (OR ² ) ₄ (wherein R ² represents a hydrocarbon residue having 1 to 5 carbon atoms). 1) to 15% by weight of at least one selected from the group consisting of tetraalkoxyzirconium represented by the formula 1), a hydrolyzate of the tetraalkoxyzirconium and a partial polycondensate thereof, and (c) the average particle size is 0.1.
3.5 to 60% by weight of an inorganic filler of 01 to 10 μm, and (d) an organic solvent of 7 to 93% by weight (however, (a) +
(B) + (c) + (d) = 100% by weight] as a main component, and the composition is applied to a base material and cured at room temperature or at low temperature.