JP2007099992A - Room temperature drying type solvent-based top coating material, paint and coating film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material for an ordinary-temperature-drying solvent-based topcoating that exhibits excellent scratch resistance and chipping resistance and forms a coating film hardly suffering from cracks or the like, a coating obtained using the same and a coating film. <P>SOLUTION: The material for the ordinary-temperature-drying solvent-based topcoating comprises a lipophilic polyrotaxane that comprises a ring molecule, a linear molecule and blocking groups, where the linear molecule and the ring molecule are hydrophobic. The amount of the included ring molecule is 0.06-0.61. The molecular weight of the linear molecule is 1,000-70,000. The ordinary-temperature-drying solvent-based topcoating is obtained by using the material for the ordinary-temperature-drying solvent-based topcoating. The solvent-based topcoating film is obtained by solidifying the ordinary-temperature-drying solvent-based topcoating. A laminated coating film is obtained by sequentially forming a basecoat coating film using the solvent-based topcoating and a clear coating film on an item to be coated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a room temperature drying type solvent-based top coating material, a coating material and a coating film using the material, and more specifically, a product used in a field requiring particularly scratch resistance, mainly an automobile body; Resin molded products indoors and outdoors; woodwork products such as stairs, floors, furniture; room temperature drying type solvent-based topcoat materials that can be applied to aluminum wheels and door mirrors that have been subjected to plating, vapor deposition, sputtering, etc. It relates to the paint and coating film used.

Conventionally, resin molded products such as polycarbonate and acrylic plates lack various physical properties such as hardness, weather resistance, stain resistance, and solvent resistance. Therefore, surface treatment is usually applied to supplement these physical properties.
As such a surface treatment, for example, a curable paint such as a normally dry paint or a two-component urethane paint is employed (see, for example, Patent Document 1).
However, the treatment film using the paint is easily scratched, and the scratch is easily noticeable.
JP 2004-131601 A

Moreover, metal mirror surface treatments such as plating, vapor deposition, and sputtering are employed for design properties (see, for example, Patent Document 2).
However, when the metal mirror surface treatment is performed, the treatment film is easily scratched, and the scratch is easily noticeable. Usually, after the mirror treatment such as vapor deposition and sputtering, the surface treatment as described above is performed. However, the obtained treatment film is easily scratched, and the scratch is easily noticeable.
JP 2003-293146 A

Furthermore, with regard to the top coat for automobiles, in recent years, the trend toward high durability has been strengthened so as to maintain the painted appearance of new cars for a long period of time. For this reason, there is a demand for scratch resistance that is not damaged by car wash machines, dust, stone splashes, or the like.
Conventionally known as scratch-resistant paints are ultraviolet (UV) curable paints, electron beam energy (EB) curable paints, silica-based hard coat agents, two-component acrylic urethane-based soft paints, and the like. (For example, refer to Patent Document 3).
Japanese Patent Publication No. 6-29362

  However, in the UV curable paint, EB curable paint, and silica-based hard coat agent, the use of a hard monomer for increasing the hardness and the increase in strain at the time of curing shrinkage by increasing the crosslink density, Problems such as poor adhesion and cracking are likely to occur.

  On the other hand, the above-mentioned two-component acrylic urethane-based soft paint has no problems of chipping and cracking, but often has a tacky feeling and has a disadvantage that it is inferior in weather resistance and stain resistance.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to provide a coating film that has excellent scratch resistance and chipping resistance and is less prone to cracks. It is an object of the present invention to provide a curable solvent-based topcoat material that can be formed, and a paint and a coating film using the material.

  As a result of intensive studies to solve the above object, the present inventors have found that the above object can be achieved by using a lipophilic polyrotaxane in which a linear molecule or a cyclic molecule is hydrophobic. It came to completion.

  That is, the room temperature drying solvent-based top coating material of the present invention comprises a cyclic molecule, a linear molecule that claws the cyclic molecule in a skewered manner, and the cyclic molecule disposed at both ends of the linear molecule. It has a blocking group for preventing elimination, and at least one of the linear molecule and the cyclic molecule is composed of a lipophilic polyrotaxane having hydrophobicity.

  The room temperature drying solvent-based top coating composition of the present invention is characterized in that the coating material of the present invention, that is, the lipophilic polyrotaxane is contained in an amount of preferably 1 to 30% with respect to the coating film forming component. And

  Furthermore, the top coat film of the present invention is characterized by solidifying the above-mentioned room temperature dry solvent-based top coat paint of the present invention.

  Furthermore, the laminated coating film of the present invention can be formed by sequentially forming a base coat film and a clear coating film using a room temperature drying solvent-based top coating material on the object to be coated, or a room temperature drying solvent system top coating on the object to be coated. It is characterized by forming an enamel coating film using a paint.

  According to the present invention, the use of a lipophilic polyrotaxane in which linear molecules and cyclic molecules are hydrophobic has excellent scratch resistance, chipping resistance, adhesion, etc. As for the performance, it has the same performance as a conventional room temperature dry lacquer.

  Hereinafter, the room temperature dry solvent-based top coating material of the present invention, the coating material using the same, and the coating film will be described in detail. In the present specification, “%” represents mass percentage unless otherwise specified.

As described above, the room temperature drying solvent-based top coating material of the present invention comprises a lipophilic polyrotaxane modified to a room temperature drying type that dissolves in a solvent.
The room temperature drying solvent-based top coating composition of the present invention contains the above material, that is, a lipophilic polyrotaxane.

FIG. 1 is a schematic diagram conceptually showing a hydrophobic modified polyrotaxane.
In this figure, this hydrophobic modified polyrotaxane 1 has a linear molecule 2, a cyclodextrin 3 that is a cyclic molecule, and a blocking group 4 disposed at both ends of the linear molecule 2. The molecule 2 penetrates the opening of the cyclic molecule 3 and includes the cyclic molecule 3.
And cyclodextrin 3 has the hydrophobic modification group 3a.

In the present invention, one or both of the cyclic molecule 2 and the linear molecule 3 have hydrophobicity, and the lipophilic polyrotaxane showing lipophilicity as a whole, typically the cyclic molecule 2 has a hydroxyl group, A lipophilic polyrotaxane in which all or part of the hydroxyl groups of the cyclic molecule are modified with a hydrophobic modifying group is used, and the polyrotaxane becomes soluble in the solvent described later, and is used as a component of the solvent-based paint. It becomes possible to mix.
In addition, when the topcoat material of the present invention comprising such a lipophilic polyrotaxane is mixed with another polymer, pseudo-crosslinking is caused by van der Waals force, and both are considered to behave as a composition or a compound. It is done. In this case, it is considered that at least the polyrotaxane exhibits the pulley effect described above.

In the present invention, the modifying group exhibiting hydrophobicity has a hydrophobic group or a hydrophobic group and a hydrophilic group, and may be hydrophobic as a whole.
Examples of the hydrophobic group include an alkyl group, a benzyl group (benzene ring) and a benzene derivative-containing group, an acyl group, a silyl group, a trityl group, a nitrate ester group, and a tosyl group.
Examples of the hydrophilic group include a carboxyl group, a sulfonic acid group, a sulfate ester group, a phosphate ester group, an amino group (primary to tertiary), a quaternary ammonium base, and a hydroxyalkyl group.

The cyclic molecule in the lipophilic polyrotaxane is not particularly limited as long as it is included in the linear molecule as described above and exhibits a pulley effect, and various cyclic substances can be exemplified. Many cyclic molecules have a hydroxyl group.
In addition, it is sufficient that the cyclic molecule is substantially cyclic, and it is not necessarily required to be completely closed like “C” shape.

Furthermore, as the cyclic molecule, those having a reactive group are preferable, and this facilitates the binding with the above-described hydrophobic modifying group.
Examples of such a reactive group include, but are not limited to, a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an isocyanate group, a thiol group, and an aldehyde group. In addition, as a reactive group, when forming the blocking group mentioned later (blocking reaction), the group which does not react with this blocking group is preferable.

In addition, the degree of modification by the hydrophobic modifying group of the cyclic molecule in the lipophilic polyrotaxane used in the present invention may be 0.02 or more when the maximum number of hydroxyl groups that the cyclic molecule can be modified is 1. Preferably, it is 0.04 or more, more preferably 0.06 or more.
That is, when the modification degree is less than 0.02, the solubility in a solvent is not sufficient, and insoluble bumps may be generated.

  The maximum number of hydroxyl groups that can be modified in the cyclic molecule means the total number of hydroxyl groups that the cyclic molecule had before modification. The degree of modification is, in other words, the ratio of the number of modified hydroxyl groups to the total number of hydroxyl groups.

  Furthermore, when the polyrotaxane has a large number of cyclic molecules, it is not necessary that all or a part of the hydroxyl groups of each cyclic molecule is modified with a hydrophobic modifying group. In other words, as long as the entire polyrotaxane exhibits lipophilicity, there may be no problem even if a cyclic molecule having a hydroxyl group that is not modified with a hydrophobic modifying group is partially present.

As a method for introducing the hydrophobic modifying group, the following method can be employed.
For example, cyclodextrin is used as a cyclic molecule of polyrotaxane, and an isocyanated PEG-monostearate composed of hexamethylene diisocyanate and PEG-monostearate is reacted with the hydroxyl group of the cyclodextrin. The modification rate can be arbitrarily controlled by changing the addition amount of the isocyanated PEG-monostearate at this time.

In the lipophilic polyrotaxane, the number (inclusion amount) of the cyclic molecule included in the linear molecule is 0 when the maximum inclusion amount that the linear molecule can include the cyclic molecule is 1. 06-0.61 are preferable, 0.11-0.48 are still more preferable, and 0.24-0.41 are still more preferable.
That is, if this ratio is less than 0.06, the pulley effect is insufficient and the elongation percentage of the coating film may decrease. If it exceeds 0.61, the cyclic molecules are arranged too densely, the mobility of the cyclic molecules is lowered, and similarly, the elongation rate of the coating film is insufficient and the scratch resistance tends to deteriorate.

Further, the amount of inclusion of the cyclic molecule can be controlled as follows.
For example, to DMF (dimethylformamide), a BOP reagent (benzotriazol-1-yl-oxy-tris (dimethylamino) phosphonium hexafluorophosphate), HOBt, adamantaneamine, and diisopropylethylamine are added in this order. To do. On the other hand, a solution is obtained in which a clathrate complex in which a cyclic molecule is skewered into a linear molecule is dispersed in a DMF / DMSO (dimethyl sulfoxide) mixed solvent. By mixing these two and changing the mixing ratio of DMF / DMSO at this time, the inclusion amount of the cyclic molecule can be arbitrarily controlled. In addition, the higher the DMF / DMSO ratio, the greater the amount of inclusion of the cyclic molecule.

  Specific examples of the cyclic molecule include various cyclodextrins such as α-cyclodextrin (glucose number: 6), β-cyclodextrin (glucose number: 7), and γ-cyclodextrin (glucose number: 8). ), Dimethylcyclodextrin, glucosylcyclodextrin and derivatives or modified products thereof, and crown ethers, benzocrowns, dibenzocrowns, dicyclohexanocrowns and derivatives or modified products thereof.

The above-mentioned cyclic molecules such as cyclodextrin can be used alone or in combination of two or more.
Of the various cyclic molecules described above, α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin are particularly preferable, and in particular, α-cyclodextrin is used from the viewpoint of inclusion. Is preferred.

On the other hand, the linear molecule may be substantially linear, and may have a branched chain as long as the cyclic molecule that is a rotor can be included so that it can rotate and exert a pulley effect. .
Further, although it is affected by the size of the cyclic molecule, its length is not particularly limited as long as the cyclic molecule can exert a pulley effect.

In addition, as a linear molecule, what has a reactive group in the both ends is preferable, and it becomes possible to react this with the said blocking group easily by this.
Such a reactive group can be appropriately changed according to the type of blocking group employed, and examples thereof include a hydroxyl group, an amino group, a carboxyl group, and a thiol group.

Such a linear molecule is not particularly limited, and is a polyester having a polyalkylene, polycaprolactone, or the like, a polyether such as polyethylene glycol, a polyamide, a polyacryl, or a linear chain having a benzene ring. Can be mentioned.
Among these linear molecules, polyethylene glycol and polycaprolactone are particularly preferable, and polyethylene glycol is preferably used from the viewpoint of solubility in water or a solvent.

The molecular weight of the linear molecule is preferably 1,000 to 70,000, preferably 10,000 to 50,000, and more preferably 35,000 to 50,000. preferable.
That is, if the molecular weight of the linear molecule is less than 1,000, the pulley effect due to the cyclic molecule cannot be sufficiently obtained, the elongation rate of the coating film is lowered, and the scratch resistance is deteriorated. When the molecular weight exceeds 70,000, the paintability when used as a paint is lowered, and the appearance such as smoothness and gloss as a top coat tends to deteriorate.

On the other hand, the blocking group may be any group as long as it is arranged at both ends of the linear molecule as described above and can keep the cyclic molecule pierced by the linear molecule. It can be a group.
Examples of such a group include a group having “bulkiness” or a group having “ionicity”. Here, the “group” means various groups including a molecular group and a polymer group.

Examples of the group having “bulkyness” include a spherical shape and a side wall-shaped group.
In addition, the ionicity of the group having “ionicity” and the ionicity of the cyclic molecule interact with each other, for example, repelling each other, so that the cyclic molecule is skewed into a linear molecule. Can be held.

  Specific examples of such blocking groups include dinitrophenyl groups such as 2,4-dinitrophenyl group and 3,5-dinitrophenyl group, cyclodextrins, adamantane groups, trityl groups, fluoresceins and pyrenes. And derivatives or modified products thereof.

Here, the manufacturing method of the lipophilic polyrotaxane used for this invention is demonstrated.
As mentioned above, the lipophilic polyrotaxane is
(1) mixing a cyclic molecule and a linear molecule, penetrating the opening of the cyclic molecule in a skewered manner with the linear molecule, and including the cyclic molecule in the linear molecule;
(2) a step of preparing both the ends of the obtained pseudopolyrotaxane (both ends of the linear molecule) with a blocking group so that the cyclic molecule is not detached from the skewered state;
(3) a step of modifying the hydroxyl group of the cyclic molecule of the obtained polyrotaxane with a hydrophobic modifying group,
Is obtained by processing.

  In the step (1), the lipophilic polyrotaxane can also be obtained by using a hydroxyl group of the cyclic molecule that has been modified with a hydrophobic modifying group in advance. In that case, the step (3) is performed. Can be omitted.

By the above production method, a lipophilic polyrotaxane excellent in solubility in various solvents can be obtained.
Such a solvent is not particularly limited, but alcohols such as isopropyl alcohol and butyl alcohol, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, diethyl ether and dioxane, and the like. Examples include ethers, hydrocarbon solvents such as toluene and xylene, and the lipophilic polyrotaxane exhibits good solubility in a solvent in which two or more of these are mixed.

In the present invention, the lipophilic polyrotaxane may be pseudo-crosslinked or crosslinked as long as it is soluble in an organic solvent, and the lipophilic crosslinked polyrotaxane is used instead of the non-crosslinked lipophilic polyrotaxane. Or a mixture thereof.
Examples of such a lipophilic crosslinked polyrotaxane include a lipophilic polyrotaxane crosslinked with a polymer having a relatively low molecular weight, typically a polymer having a molecular weight of about several thousand.

The room temperature drying type solvent-based top coating composition of the present invention contains the above-mentioned room temperature drying type solvent-based top coating material, that is, the above-described lipophilic polyrotaxane. It is preferable that 1-40% in terms of mass is contained with respect to the resin solid content. More preferably, it is 10 to 40%, and particularly preferably 20 to 30%.
That is, when the content of the lipophilic polyrotaxane relative to the coating film forming component is less than 1%, the pulley effect of the polyrotaxane cannot be sufficiently obtained, and the elongation percentage of the coating film is lowered to obtain a desired scratch resistance. It may not be possible. If it exceeds 40%, the coating film may have a sticky feeling.

The room temperature drying type solvent-based top coating composition of the present invention is prepared by applying the above-described lipophilic polyrotaxane to an existing room temperature drying type solvent-based top coating composition, for example, acrylic lacquer, cellulose lacquer, urethane resin paint, and the like. It is obtained by blending as follows.
In other words, the room temperature drying solvent-based top coating material of the present invention, that is, a lipophilic polyrotaxane, a resin component, an additive, a pigment, a brightening agent or a solvent, and any combination thereof, based on a conventional method Can be blended and mixed.

The resin component is not particularly limited, but the main chain or side chain is a hydroxyl group, amino group, carboxyl group, epoxy group, vinyl group, thiol group or photocrosslinking group, and any combination thereof. Those having a group are preferred.
Examples of the photocrosslinking group include cinnamic acid, coumarin, chalcone, anthracene, styrylpyridine, styrylpyridinium salt, and styrylquinoline salt.

Two or more kinds of resin components may be mixed and used. In this case, it is preferable that at least one kind of resin component is bonded to the polyrotaxane via a cyclic molecule.
Further, the resin component may be a homopolymer or a copolymer. In the case of a copolymer, it may be composed of two or more monomers, and may be a block copolymer, an alternating copolymer, a random copolymer or a graft copolymer.

Specific examples include polyvinyl alcohol, polyvinyl pyrrolidone, poly (meth) acrylic acid, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and other cellulose resins, polyacrylamide, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyvinyl acetal resins, Polyolefin resins such as polyvinyl methyl ether, polyamine, polyethyleneimine, casein, gelatin, starch and copolymers thereof, copolymer resins with polyethylene, polypropylene and other olefinic monomers, polyester resins, polyvinyl chloride resins , Polystyrene resins such as polystyrene and acrylonitrile-styrene copolymer resin, polymethyl methacrylate and (meth) acrylic Acrylic resins such as acid ester copolymers, acrylonitrile-methyl acrylate copolymers, polycarbonate resins, polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins and derivatives or modified products thereof, polyisobutylene, polytetrahydrofuran , Polyaniline, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyamides such as nylon (registered trademark), polyimides, polydienes such as polyisoprene and polybutadiene, polysiloxanes such as polydimethylsiloxane, polysulfones, List polyimines, polyacetic anhydrides, polyureas, polysulfides, polyphosphazenes, polyketones, polyphenylenes, polyhaloolefins, and their derivatives It can be.
As the derivatives, those having the above-mentioned hydroxyl group, amino group, carboxyl group, epoxy group, vinyl group, thiol group, photocrosslinking group, and groups related to these combinations are preferable.

  Specific examples of the additive include a dispersant, an ultraviolet absorber, a light stabilizer, a surface conditioner, and a crack inhibitor.

  Specific examples of the pigment include organic color pigments such as azo pigments, phthalocyanine pigments, and perylene pigments, and inorganic color pigments such as carbon black, titanium dioxide, and bengara.

  Specific examples of the brightening agent include aluminum pigments and mica pigments.

  Specific examples of the solvent include esters such as ethyl acetate, butyl acetate and isobutyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethers such as diethyl ether and dioxane, toluene and xylene, Hydrocarbon solvents such as Solvesso or long-chain alcohols with high hydrophobicity can be used. Two or more of these may be mixed as appropriate. Moreover, even if some aqueous solvents, such as water and a butyl cellosolve acetate, are contained, it should just be considered as an organic solvent as a whole.

Furthermore, the above-mentioned top coat paint can form a base coat paint film or an enamel paint film as a general base coat paint or enamel paint.
Specifically, an acrylic paint, a melamine paint, a urethane paint, a polyester paint or the like may be prepared.
Moreover, these may be a one-pack type or a two-pack type (for example, urethane resin paint).

Although it does not specifically limit as a film thickness of the said enamel coating film, About 20-40 micrometers is preferable.
The thickness of the base coat is not particularly limited, but is preferably about 10 to 15 μm.

  The room temperature drying type solvent-based topcoat paint of the present invention is a metal material such as iron, steel, and aluminum, a resin material, a woody material, with various work equipment such as a spray gun, under the same workability as a conventional paint. It can be applied to various objects to be coated consisting of materials, stone materials such as stones, bricks, blocks, leather materials, etc., and a top coat film can be formed by drying and solidifying at room temperature. Although it does not specifically limit as a coating-film thickness at this time, It is desirable to apply so that it may become about 20-40 micrometers.

Next, the laminated coating film of the present invention will be described in detail.
The laminated coating film of the present invention is formed by sequentially forming a base coating film and a clear coating film using the above-mentioned solvent-based top coating material on an object to be coated.

  This improves the scratch resistance and chipping resistance of the laminated coating film. Moreover, since the smoothness of a base coat film becomes favorable, a clear film can be formed uniformly.

The clear coating film can be formed from a general clear coating material, and is typically a hydrophilic liquid such as an oleophilic liquid such as an acrylic paint, a melamine paint, or a urethane paint. Clear paints such as polyester paints and acrylic paints that are powders such as acrylic paints, urethane paints, and melamine paints can be used alone or in combination.
The lipophilic liquid may be a one-pack type, a two-pack type (for example, urethane resin paint) or the like, or a lacquer or photo-curing resin.

Examples of the article to be coated typically include various metal materials such as iron, aluminum and copper, various organic materials such as polypropylene and polycarbonate, and various inorganic materials such as quartz and ceramics (calcium carbide, etc.).
In addition, as a method for coating these with a solvent-based top coat, known and commonly used methods can be employed. For example, a brush coating method, a spraying method, an electrostatic coating method, an electrodeposition coating method, a powder coating, and a sputtering method can be used.
Furthermore, the solvent-based top coating composition can be formed into a coating film by room temperature drying treatment, but may be formed by heat drying treatment.
In addition, the said solvent-type top coat can coat | cover the whole to-be-coated article or a part. Moreover, generally the said basecoat coating film contains a clear layer and an enamel coating film does not contain a clear layer.

  Moreover, in the laminated coating film of the present invention, it is preferable to further form an undercoat coating film between the article to be coated and the base coat coating film. At this time, the scratch resistance and chipping resistance of the laminated coating film can be further improved. Further, since the smoothness of the base coat film can be further improved, a clear paint film can be formed uniformly. Furthermore, the adhesion at the interface can be further improved.

  On the other hand, another laminated coating film of the present invention is formed by forming an enamel coating film using the above-described solvent-based top coating material on an object to be coated.

  This improves the scratch resistance and chipping resistance of the laminated coating film. Moreover, the smoothness of the surface of a laminated coating film becomes favorable.

  Moreover, it is preferable to further form an undercoat coating film between the article to be coated and the enamel coating film. At this time, the scratch resistance and chipping resistance of the laminated coating film can be further improved. Further, since the smoothness of the base coat film can be further improved, a clear paint film can be formed uniformly. Furthermore, the adhesion at the interface can be further improved.

An example (schematic cross section) of the laminated coating film of the present invention described above is shown in FIG.
In this laminated coating film, an undercoat coating film layer 10 and an enamel coating film 11 are sequentially provided.
In addition, for convenience of explanation, the “laminated coating” includes a coating formed by coating only the solvent-based top coating on the object to be coated, but this coating is not limited to a single layer and is formed from a plurality of layers. May be.

  Hereinafter, the present invention will be described more specifically based on examples. The present invention is not limited to these examples.

Example 1
1. Synthesis of Modified Polyrotaxane After binding 6 g of hexamethylene diisocyanate to 20 g of PEG-monostearate (manufactured by TCI) in toluene, purification was performed by recrystallization with ether.
15 g of the obtained isocyanate-modified PEG-monostearate was reacted with polyrotaxane (about 500 mg) dissolved in DMSO overnight at room temperature, and then purified by reprecipitation with ether and dried.

2. Preparation of Topcoat Paint The obtained polyrotaxane was dissolved with toluene so as to be 10%.
On the other hand, 200 g of CMCAB (CMCAB-641-0.5 manufactured by EASTMAN CHEMICAL) was added to 300 g of buticerorubu (ethylene glycol monobutyl ether) with stirring, and a water / amine mixed solution (water 498.09 g / dimethylaminoethanol 1. 91 g) was poured into the CMCAB solution to prepare a resin solution to 20%. In addition, a pigment was dispersed in this resin solution to obtain a top coat.

3. Formation of multi-layer coating film Cathodic electrodeposition paint (trade name “Power Top U600M”, cation-type electrodeposition paint manufactured by Nippon Paint Co., Ltd.) is applied to a 0.8 mm thick, 70 mm × 150 mm thick steel plate treated with zinc phosphate. After electrodeposition coating so that the thickness was 20 μm, baking was performed at 160 ° C. for 30 minutes.
Thereafter, a gray undercoat (trade name: Hyepico No. 500) manufactured by Nippon Oil & Fats Co., Ltd. was applied with 30 μm and baked at 140 ° C. for 30 minutes.
Next, 30 μm of a top coating to which modified polyrotaxane was added was applied.

(Examples 2-11, Comparative Examples 1-3)
A laminated coating film was formed by repeating the same operation as in Example 1 except that the specifications shown in Table 1 were adopted.

  About the obtained laminated coating film, the following (1)-(6) was evaluated.

(1) Solubility The white turbidity when the top coat obtained in Step 2 was applied to a glass plate was visually evaluated.
○: No change △: Slight cloudiness ×: Cloudiness and separation

(2) Smoothness The degree of smoothness of the topcoat film in the laminated coating film obtained in Step 3 was visually evaluated.
◯: Pretty smooth Δ: Slightly uneven ×: Uneven

(3) Abrasion resistance Dustnel (friction cloth) is attached to the slider of the abrasion tester with double-sided tape, and the top coating film in the laminated coating film obtained in step 3 under a load of 0.22 g / cm ^2. Was reciprocated 50 times to evaluate the presence or absence of scratches.
○: There is almost no scratch.
Δ: Slightly scratched
X: There are many scratches so as to be conspicuous.

(4) Abrasion resistance Dustnel (friction cloth) is attached to a slider of an abrasion tester with a double-sided tape, and the top coating film in the laminated coating film obtained in step 3 under a load of 0.22 g / cm ^2. Was reciprocated 50 times to evaluate the presence or absence of scratches.
○: Almost no scratch Δ: Slightly scratch ×: There are many scratches that stand out

(5) Pigment settling property The top coat obtained in step 2 is left in a constant temperature bath at 40 ° C. for 1 month to determine whether or not the precipitate has become a hard cake (in a state that does not recover even when stirred). Judged.
○: Recovered △: Time required but recovered ×: Not recovered

(6) Weather resistance The top coat film in the multilayer coating film obtained in step 3 was tested for 1440 hours with a xenon weather meter (XWM), and the color difference (ΔE) was measured.
○: △ E ≦ 3
Δ: 3 <ΔE ≦ 5
×: ΔE> 5

As is apparent from the results in Table 1, the topcoat film in the laminated film of Examples 1 to 8, which is a preferred embodiment of the present invention, exhibits a pulley effect by the addition of a lipophilic polyrotaxane, and improves scratch resistance. It can be seen that the solubility, smoothness, pigment sedimentation and weather resistance are also good.
Further, as in Example 9, it can be seen that when the molecular weight of the linear molecule is less than 1000, the scratch resistance is lowered. Furthermore, as in Example 10, when it exceeds 70,000, it can be seen that the smoothness, pigment sedimentation, and weather resistance deteriorate.
Furthermore, as shown in Example 11, when the amount of lipophilic polyrotaxane added to the coating exceeds 40%, it is understood that the solubility, smoothness, pigment precipitation, and weather resistance are lowered.

  On the other hand, as in Comparative Examples 1 to 3, when no lipophilic polyrotaxane is added, the effect of scratch resistance cannot be obtained.

  As described above, according to the present invention, the desired appearance can be obtained with the same workability as that of ordinary coating without being limited to the narrow coating conditions specified in particular, and the scratch resistance and resistance of the top coating film can be obtained. It is possible to improve scratch resistance such as chipping property.

It is a schematic diagram which shows notionally hydrophobic modification polyrotaxane. It is a schematic sectional drawing which shows the structural example of the laminated coating film of this invention.

Explanation of symbols

1 Hydrophobic modified polyrotaxane 2 Linear molecule 3 Cyclic molecule (cyclodextrin)
3a Hydrophobic modifying group 4 Blocking group 10 Undercoat film 11 Enamel film

Claims (15)

  A cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule to prevent the cyclic molecule from being removed. A room-temperature drying type solvent-based top coating material, wherein at least one of a molecule and a cyclic molecule comprises a lipophilic polyrotaxane having hydrophobicity.   2. The room temperature drying solvent-based top coating material according to claim 1, wherein the cyclic molecule has a hydroxyl group, and all or part of the hydroxyl group is modified with a lipophilic modification group.   The room temperature dry solvent system according to claim 2, wherein when the maximum number of hydroxyl groups of the cyclic molecule that can be modified is 1, the degree of modification of the cyclic molecule with a lipophilic modifying group is 0.02 or more. Material for top coating.   The inclusion amount of the cyclic molecule is 0.06 to 0.61 when the maximum inclusion amount that the linear molecule can include the cyclic molecule is 1. The room-temperature drying solvent-based top coating material described in any one of the items.   5. The room-temperature drying solvent-based top coating material according to claim 1, wherein the linear molecule has a molecular weight of 1,000 to 70,000.   The cyclic molecule is at least one type of cyclodextrin selected from the group consisting of α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. The material for room temperature drying type solvent-based top coating materials as described.   A room-temperature drying solvent-based top coating material, comprising the room-temperature drying solvent-based top coating material according to any one of claims 1 to 6.   8. The room temperature drying solvent-based top coating composition according to claim 7, wherein the content of the room temperature drying solvent-based top coating material with respect to the coating film forming component is 1 to 40% by mass.   9. The material according to claim 7 or 8, wherein the room temperature drying type solvent-based top coating material is mixed with at least one selected from the group consisting of a resin component, an additive, a pigment, a brightening agent and a solvent. The room temperature drying type solvent-based top coating as described.   The room-temperature drying solvent-based top coating composition according to any one of claims 7 to 9, which is a base coat paint or an enamel paint.   A top coat film obtained by solidifying the room temperature dry solvent-based top coat paint according to any one of claims 7 to 10. A laminated coating film using the room temperature drying type solvent-based top coating composition according to any one of claims 7 to 10,
A laminated coating film comprising a base coating film and a clear coating film formed using the coating material in order on an object to be coated.   The laminated coating film according to claim 12, wherein an undercoat coating film is further formed between the article to be coated and the base coat coating film. A laminated coating film using the room temperature drying type solvent-based top coating composition according to any one of claims 7 to 10,
A laminated coating film, wherein an enamel coating film using the coating material is formed on an object to be coated.   The laminated coating film according to claim 14, wherein an undercoat coating film is further formed between the article to be coated and the enamel coating film.

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