JPH0678499B2 - Painting method - Google Patents

Description

The present invention relates to a coating finishing method.

More specifically, the present invention is obtained by polymerizing a specific amount of a vinyl-based monomer having a polymerizable unsaturated group and at least one siloxy group in one molecule and a copolymerizable other vinyl-based monomer. A base metallurgical coating composition and a topcoat coating composition, which use a coating resin composition composed of a vinyl polymer, a curing agent (crosslinking agent) reactive with a hydroxyl group formed by the polymer, and a dissociation accelerating catalyst, are so-called 2 The present invention relates to a coating method of coating and one-baking finish.

In recent years, in metallurgical coating for automobile topcoats, instead of so-called 1-coat metallic finish in which a thermosetting coating compounded with metallic powder is coated and baked as it is, a thermosetting coating (base coat) containing metallic powder is coated, Then, a so-called two-coat / one-bake finish metallizing method in which a thermosetting clear paint (top coat) containing no coloring pigment is applied on the base coat and the base coat and the top coat are baked at the same time has become popular. This 2 coat 1 bake finish has an excellent finished appearance, and with the conventional 1 coat 1 bake finish, the metallic powder is easy to be soaked in the acid, so that coating film defects such as stains often occur. The 2-coat 1-bake finish has the advantage that almost no coating film defects occur.

Conventional solid color paints containing vinyl polymer as a main component have a remarkable drawback in weather resistance. However, by adopting the two-coat, one-bake coating method, a coating film excellent in weather resistance can be obtained. There are advantages.

For such a two-coat and one-bake finish, as a base coat paint, an aminoalkyd resin paint, a thermosetting acrylic resin paint or the like is generally applied, and after the base coat is applied, the solvent is volatilized to some extent for 2 to 5 minutes. rear,
Immediately apply the same type of top coat paint and then bake for 20 to 30 minutes in an atmosphere of a hot air drying oven at a temperature of 140 ° C to 150 ° C to cure.

Here, heavy oil, propane gas, butane gas, city gas or electric power is generally used as a source of hot air, but two coats using a conventional thermosetting paint that is heated and hardened in a hot air drying oven or an electric oven. The one-bake metallurgical finishing method has a drawback in that energy costs increase due to fuel consumption, electric power, and the like.

On the other hand, in the automobile industry, plasticization of outer panels and parts is rapidly being promoted. When the material is a steel plate, so-called baking one-pack type paints such as the above-mentioned amino alkyd resin paints and thermosetting acrylic resin paints are usually used as the paint resin system. However, when the material is plasticized, the heat resistant temperature of the material is low in some cases, and it is inappropriate to use a normal baking one-pack type paint for plastics. Therefore, for plastics, room temperature curing type and low temperature curing type coatings have been studied or partially used.
Examples of these paint resins include a combination of a polyol type resin and an isocyanate prepolymer, a combination of an acrylic resin having a tertiary amino group and a polyfunctional epoxy resin, and a curing system by aminoplast using a low temperature curing catalyst.
However, among such paint systems, the polyol type resin-isocyanate prepolymer system and the tertiary amino-epoxy resin curing system are both two-part type and have a major drawback in workability such as pot life.

In addition, although the aminoplast system using a low temperature curing catalyst is a one-pack type as a form, it has the drawback that the functional groups involved in the reaction are not blocked and are highly active, and the storage stability over a long period is extremely poor. Moreover, it is impossible to cure at a temperature around room temperature.

Separately, if an isocyanate prepared by blocking an isocyanate prepolymer with an appropriate blocking agent is used, a one-pack type polyol type resin-isocyanate prepolymer curing system can be obtained, but at present, the dissociation temperature of the blocking agent is high and the room temperature or low temperature curing type resin system is used. It is hard to say.

As described above, in the metallic finish for automobile top coating, from the viewpoint of energy saving and material conversion, a one-part room temperature or low temperature curable resin having excellent coating workability, various physical properties, weather resistance and storage stability was used. The reality is that there is an urgent need for the rapid development of coatings for coat 1 bake.

However, as a result of intensive investigations by the present inventors to obtain a two-coat one-bake finishing paint that meets the above-mentioned various requirements, as a top-coat paint and a base-coat paint, at least one polymerizable unsaturated group and at least one polymerizable unsaturated group are contained in one molecule. The inventors have found that a vinyl-based polymer using a vinyl-based monomer having a single siloxy group can surprisingly improve such required performance, and have completed the present invention.

That is, the present invention is a two-coat one-bake finish coating composition for top coating and coating composition for base coating, which comprises a vinyl polymer (I) component, a curing (crosslinking) agent (II) and a dissociation promoting catalyst component (III). The vinyl polymer (I) is 1 to 100% by weight of the vinyl monomer (A) containing a polymerizable unsaturated group and at least one siloxy group in one molecule, and the above (A) It is obtained by polymerizing such a mixture in the presence of a radical generator using 99 to 0% by weight of vinyl monomers (B) other than the above. In the composition of the present invention, the siloxy group in the vinyl-based monomer (A) reacts with moisture in the air to form a hydroxyl group in the vinyl-based polymer (I), and a curing (crosslinking) agent component reactive with the hydroxyl group. (II) reacts to form a strong coating film, and the coating composition using the resin composition of the present invention has excellent storage stability as a one-pack type coating composition and can be cured at room temperature or low temperature. To provide a top coat coating composition and a base coating composition.

Here, the vinyl-based monomer (A) is 1
A vinyl-based monomer having a polymerizable unsaturated group and at least one siloxy group bonded to a carbon atom represented by the following formula in the molecule.

(However, R ₁ , R ₂ and R ₃ represent an alkyl group consisting of C _{1 to} C ₁₈ , a phenyl group, an aryl group or H, and may be the same or different.) These vinyl-based monomers (A) are, for example, In the presence of a hydrochloric acid scavenger such as triethylamine or pyridine,
A compound obtained by reacting trialkylchlorosilane or triphenylchlorosilane, triarylchlorosilane, dialkylchlorosilane, etc. with a hydroxyl group-containing vinyl-based monomer (b) as described below is designated, and representative of them Examples include trimethylsiloxyethyl (meth) acrylate, trimethylsiloxypropyl (meth) acrylate, trimethylsiloxybutyl (meth) acrylate, triethylsiloxyethyl (meth)
Examples thereof include acrylate, tributylsiloxypropyl (meth) acrylate and triphenylsiloxyalkyl (meth) acrylate. These can be used alone or as a mixture of two or more kinds.

Moreover, as the hydroxyl group-containing vinyl-based monomer (b), β-hydroxyethyl (meth) acrylate, β-
Hydroxypropyl (meth) acrylate or β-
Hydroxyalkyl (meth) acrylates such as hydroxybutyl (meth) acrylate or N-methylolated (meth) acrylamide; β-hydroxyethyl (meth) acrylate to which ε-caprolactone is added [eg Praxel FM, FA series ( DAICEL CHEMICAL INDUSTRIES CO., LTD. And TONE ^TM M-100 (manufactured by Union Carbide Co.)]; BLEMMER PP-1000 represented by generic name polypropylene glycol monomethacrylate and BLEMMER PE series represented by generic name polyethylene glycol monomethacrylate (both Kyo Nippon Oil & Fat Co., Ltd.);
Unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid or itaconic acid, and "Cajyura E" (Glycidyl ester of branched fatty acid manufactured by Ciel Chemical Co., Ltd.), glycidyl octylate or coconut oil Typical examples are monoglycidyl esters of monovalent carboxylic acids such as fatty acid glycidyl esters or adducts with monoepoxy compounds represented by monoglycidyl ethers such as butyl glycidyl ether; and the like. The amount of the vinyl monomer (A) used is preferably 1 to 100% by weight, and more preferably 5 to 90% by weight. If it is less than 1% by weight, the effect of the monomer cannot be expected.

Typical examples of the vinyl-based monomer (B) include an alkyl (meth) acrylate having an alkyl group having 1 to 22 carbon atoms in the side chain, styrene, vinyltoluene,
t-butyl styrene, α-methyl styrene, glycidyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, (meth) acrylonitrile, cyclohexyl (meth) acrylate, maleic acid or fumaric acid and C _{1 to} C ₁₈ monovalent Diesters with alcohols,
(Meth) acrylamides such as (meth) acrylamide or N-alkoxymethylated (meth) acrylamides, N, N dialkylaminoalkyl (meth) acrylates, phosphoric acid group-containing (meth) acrylates, vinyl acetate and hexafluoropropylene , Fluorine-containing vinyl monomers such as tetrafluoroethylene, and the like.

These vinyl-based monomers (B) can be used alone or as a mixture of two or more types depending on the desired coating film performance. It is also possible to use the above hydroxyl group-containing vinyl-based monomer (b) as the vinyl-based monomer (B) component. However, when the functional group is not blocked and an isocyanate prepolymer is used as a curing agent, the one-component type coating composition has poor storage stability, and it is not preferable to use the hydroxyl group-containing vinyl monomer (b). On the other hand, when aminoplast is used as a curing agent, the hydroxyl group-containing vinyl monomer (b) can be used. However, it is necessary to consider the addition of a curing catalyst in order to impart low-temperature curability, and the amount used should be less than 5% by weight, which does not adversely affect the storage stability as a one-pack type.

In order to obtain the vinyl polymer (I) constituting the composition of the present invention, a known and conventional method using the monomers described above, for example, a solution polymerization method using a radical generator is used. Can be done.

As the radical generator, any of those usually used for the polymerization of vinyl-based monomers may be used, but among them, representative ones include azobisisobutyronitrile and di-tert-butyl. Peroxide or benzoyl peroxide, etc., and as the solvent, aromatic hydrocarbons such as toluene or xylene; acetic acid ester type such as ethyl acetate, butyl acetate or cellosolve acetate; ketone type such as methyl ethyl ketone or methyl isobutyl ketone A solvent such as can be used.

Further, if necessary, a commonly used chain transfer agent such as mercaptans, α-methylstyrene and “dipentene T” (manufactured by Nippon Terpene Chemical Co., Ltd.) can be used.

The vinyl polymer (I) thus obtained preferably has a number average molecular weight (n) of 500 to 50,000.

When n of the copolymer (I) is less than 500,
The physical properties of the coating film cannot be sufficient, and the hydroxyl value generated after the trialkylsiloxy groups and the like of the polymer (I) are liberated in an attempt to bring out the physical properties of the coating film (hereinafter referred to as "OH value" If the value exceeds 50,000, on the contrary, the appearance of the coating film,
It is not preferable because defects are likely to appear in gloss, feeling of flesh, workability in painting, and the like.

Next, as the cross-linking agent (II), which is another component constituting the composition of the present invention, when only the hydroxyl group generated from the vinyl-based monomer (A) is a functional group, the cross-linking agent (II ), Polyisocyanates and aminoplasts are used.

Typical polyisocyanates are aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate or xylylene diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate or trimethylhexane diisocyanate;
Isophorone diisocyanate, methylcyclohexane-
2,4- (or 2,6-) diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate or 1,4
Alicyclic diisocyanates such as 3-di (isocyanatomethyl) -cyclohexane, and each of these diisocyanates, and polyhydric alcohols such as ethylene glycol, propylene glycol, neopentyl glycol or trimethylolpropane; functional groups reactive with isocyanate groups An extremely low molecular weight polyester resin (including oil-modified type) having: or an adduct with water, a biuret form, or a polymer of the above-mentioned diisocyanates (including an oligomer). . The compounding ratio of these polyisocyanates and the vinyl polymer (I) is OH groups produced.
The range of / NCO group = 1 / 0.5 to 1/3 (equivalent ratio) is preferable from the viewpoint of coating film performance. In this case, either a one-pack type in which polyisocyanates are mixed in advance or a two-pack type in which polyisocyanates are mixed immediately before coating can be used.

On the other hand, in the case of using the hydroxyl group-containing vinyl monomer (b) in the vinyl polymer (I), aminoplast is preferable as the curing (crosslinking) agent (II) in consideration of storage stability.

However, it is also possible to mix and use polyisocyanates immediately before coating. A typical aminoplast which is etherified with a monohydric alcohol is usually used. However, the presence of alcohol in the coating composition of the present invention may cause a reaction with siloxy groups to cause a drawback in long-term stability. Therefore, hexamethoxymethylolmelamine, which does not use alcohol as a resin solvent, is preferable as the aminoplast.

The amount of aminoplast used is preferably 10 to 40% by weight of the vinyl polymer (I). Further, a curing accelerator for aminoplast, for example, an acid catalyst such as paratoluenesulphonic acid may be added to increase the crosslinkability. The amount of the curing accelerator used is 0 based on the resin solid content.
1 to 10% by weight is preferred. When long-term storage stability is not required, aminoplast etherified with a monohydric alcohol containing alcohol may be used as the resin solvent.

The composition of the present invention, when exposed to the atmosphere, is hydrolyzed by a reaction with moisture in the air to generate a hydroxyl group capable of reacting with a curing agent. To accelerate this hydrolysis, a catalyst (II
I) must be used. As the catalyst, an acidic catalyst such as phosphoric acid, phosphoric acid ester, phosphite ester, p-toluene, sulfonic acid and its amine salt, benzoic acid, trichloroacetic acid, trifluoroacetic acid, naphthalene disulfonic acid and its amine salt, Amines such as ethylenediamine, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, butylamine, dibutylamine, t-butylamine, hexylamine and triethylamine, alkali catalysts such as potassium hydroxide, lithium hydroxide and sodium hydroxide A metal salt of a carboxylic acid such as an alkyl titanate, an octylate, dibutyltin dilaurate, and lead octylate, a monobutyltin sulfide, a sulfide type such as dioctyltin mercapite, a mercaptide type organic tin compound, tetraethylammonium fluorite, Compounds which generate fluorine ions such as cesium fluoride are effective.
The amount of catalyst (III) added is based on the vinyl polymer (I).
It is recommended to use 0.001 to 10% by weight, preferably 0.005 to 8% by weight.

Further, since the composition of the present invention does not form a hydroxyl group capable of reacting with the curing agent unless it is exposed to the atmosphere, the composition of the present invention is a one-pack type composition having good stability. However, in order to ensure long-term storage stability, it is only necessary to capture a small amount of water that enters for some reason.
That is, long-term stability is ensured by adding a water-binding agent having reactivity with water. Further, this water binder may be used by mixing it in the initial stage in the production of the vinyl polymer (I). Examples of the water-binding agent having reactivity with water include trialkyl orthoformates such as trimethyl orthoformate, triethyl orthoformate and tributyl orthoformate; trialkyl orthoacetate such as trimethyl orthoacetate, triethyl orthoacetate and tributyl orthoacetate. Trialkyl orthoborates such as tributyl orthoborate and triethyl orthoborate; tetra (substituted) such as tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, tetra (2-methoxyethyl) silicate or tetra (2-chloroethyl) silicate Alkyl silicates alone; Tetraphenyl silicates, tetrabenzyl silicates, and similar substances of the above tetra (substituted) alkyl silicates (hereinafter abbreviated as synonyms); or tetraethyl Each of the above listed tetra (substituted) alkyl silicates, such as silicate dimer, trimer, tetramer, hexamer "ethyl silicate 40" (a product of Colcoat Co., Ltd., a tetramer of tetraethyl silicate, a mixture of pentamer and hexamer), and the silicate alone. Hydrolyzable ester compounds such as condensates of simple substances having the same effect, phenyl isocyanate, p-chlorophenyl isocyanate, benzenesulphonyl isocyanate, p-trienesulphonyl isocyanate, isocyanate ethyl methacrylate (Dow Chemical Company ( Manufactured by NCO group-containing monomer) and other compounds having an isocyanate group.

The amount used is 0.1 to 3 with respect to the vinyl polymer (I).
0% by weight, preferably 0.5 to 20% by weight is good.

The composition of the present invention thus obtained is used as a top coat paint and a base coat paint having a two-coat, one-bake finish.

When it is used as a top coat paint, it can be used as it is as a clear paint, but if necessary, a coloring pigment or dye can be appropriately added.

When used as a base coat paint, the composition of the present invention may be mixed with an inorganic or organic color pigment, a dye, a metallic powder or the like to prepare a paint by a conventional coating method.

Here, as the coloring pigment, for example, titanium white, red iron oxide,
Inorganic compounds such as oxide yellow, organic compounds such as toluidine red, phthalocyanine blue, and benzidine yellow.Metallic powders include aluminum powder, copper powder, mica powder, mica powder coated with titanium oxide, MIO (mica). Iron oxide) can be used.

If necessary, various conventional additives such as a leveling agent, an ultraviolet absorber and a pigment dispersant can be mixed with the top coat coating composition and the base coating composition.

The base coat paint thus blended is used as the first layer,
After allowing this coating film to reach a touch-dry or semi-cured dry state, a top coat paint is applied as a second layer, and the top coat paint is contained in the base coat paint and the top coat paint by heating at normal temperature or low temperature. The siloxy group produces a hydroxyl group due to the moisture in the air, and the reaction proceeds with the curing (crosslinking) agent component that is reactive with this hydroxyl group to proceed with curing, resulting in a metalic composite cured coating film with excellent flatness and smoothness. Is formed.

For the coating of the base coat coating composition and the top coat coating composition using the composition of the present invention, air spray coating, electrostatic spray coating, etc. are suitable for sufficiently exhibiting cosmetic curing, and the film thickness of the base coating composition ( As the dry film thickness, the same applies hereinafter) in the range of 5 to 50 μm, preferably 10 to 20 μm, and the film pressure of the top coat coating is 10 to 100 μm.
m, preferably 10-60 μm.

The drying conditions for the wet coating film of the base coat paint and the coating interval between the base coat and top coat are about 20 ° C. for 1 to 45 minutes, preferably 2 to 20 minutes, and when the base coat coating film is forcibly dried, it is 60 to 80 minutes. All you need to do is warm it with warm air at ℃ for 0.5 to 5 minutes. That is, the top coat is applied after the coating film of the base coat has reached the touch-dry or semi-cured dry state under the above drying conditions. It is preferable to dry the top coat by hot air at 60 ° C to 100 ° C for about 30 to 60 minutes from the viewpoint of curability and productivity, but it is necessary to dry it depending on the types and properties of the base coat paint and top coat paint. It does not matter if the curing conditions are changed.

As described above, by performing the two-coat one-bake coating method using the composition of the present invention, gloss can be obtained by drying at room temperature or low temperature which is lower than the heat resistant temperature of ordinary plastic materials,
It is possible to form a composite cured coating film with excellent feeling of flesh and coating performance, and a coating finish comparable to that of conventional thermosetting acrylic resin paints and aminoalkyd resin paints can be obtained. The coating system using the composition is remarkably effective in saving the heat source and improving the coating workability by the metal / plastic integral coating method, and the composition of the present invention is a one-pack type and excellent in storage stability. It greatly contributes to the improvement of productivity.

Next, the present invention will be specifically described with reference to Production Examples, Examples and Comparative Examples, and all parts below are based on weight unless otherwise specified.

Production Example 1 [Preparation of vinyl polymer (I)] Toluene (500 parts) and isobutyl acetate (50 parts) were placed in a four-necked flask equipped with a stirrer, an inert gas inlet, a thermometer and a condenser, and heated to 110 ° C. Hold and then from a monomer mixture consisting of 260 parts of trimethylsiloxyethyl methacrylate, 390 parts of n-butyl methacrylate, 150 parts of n-butyl acrylate and 200 parts of styrene, and 50 parts of azobisisobutyronitrile and 450 parts of isobutyl acetate. The resulting mixture was added dropwise over 6 hours and kept at the same temperature for 10 hours to give a nonvolatile content of 50.9%, viscosity (Gardner viscosity, 25 ° C, the same applies below) CD, number average molecular weight of 10,000 and
A resin solution having an OH number of 36 was obtained. Hereinafter, this vinyl polymer solution is abbreviated as (I-1).

Production Example 2 [Preparation of vinyl polymer (I)] 230 parts of trimethylsiloxyethyl methacrylate, β-
Hydroxyethyl methacrylate 20 parts, styrene 200
Parts, n-butyl methacrylate 400 parts and n-butyl acrylate 150 parts are used in the same manner as in Production Example 1, except that a nonvolatile matter 49.1%, viscosity GH, number average molecular weight 15,000 and OH number 36 are used. A solution was obtained. Hereinafter, this vinyl polymer is abbreviated as (I-2).

Production Example 3 [Preparation of comparative vinyl polymer] 170 parts of β-hydroxyethyl methacrylate, styrene 2
Using the same procedure as in Production Example 1 except that 00 parts, 477 parts of n-butyl methacrylate, 150 parts of n-butyl acrylate, and 3 parts of methacrylic acid were used instead, a nonvolatile content of 50.3
%, Viscosity KL, number average molecular weight 14,000 and OH number 36 were obtained. Hereinafter, this vinyl-based polymer is referred to as (I-
It is abbreviated as 3).

Production Example 4 [Preparation of vinyl-based polymer (I)] 500 parts of toluene and 50 parts of isobutyl acetate were placed in a four-necked flask equipped with a stirrer, an inert gas inlet, a thermometer and a condenser, and heated to 105 ° C. Hold, then a mixture of 200 parts of trimethylsiloxyethyl methacrylate, 400 parts of methyl methacrylate, 300 parts of ethyl acrylate and 100 parts of n-butyl acrylate, and 7 parts of azobisisobutyronitrile and 393 parts of isobutyl acetate. It took 4 hours to add the solution dropwise, and to the same temperature 10
After holding for a period of time, a resin solution having a nonvolatile content of 49.1%, a viscosity G-H, a number average molecular weight of 13000 and an OH value of 28 was obtained. Less than,
This vinyl polymer is abbreviated as (I-4).

Production Example 5 [Preparation of vinyl polymer (I)] 170 parts of trimethylsiloxyethyl methacrylate, β-
Non-volatile content 49.6%, viscosity IJ, number average molecular weight by the same operation as in Production Example 4 except that 20 parts of hydroxyethyl methacrylate, 400 parts of methyl methacrylate, 310 parts of ethyl acrylate and 100 parts of n-butyl acrylate were used instead. A resin solution of 16000 and an OH number of 28 was obtained. Less than,
This vinyl polymer is abbreviated as (I-5).

Production Example 6 [Preparation of comparative vinyl polymer] Production except that 130 parts of β-hydroxyethyl methacrylate, 407 parts of methyl methacrylate, 360 parts of ethyl acrylate, 100 parts of n-butyl acrylate and 3 parts of methacrylic acid were used instead. By the same operation as in Example 4, the nonvolatile content 5
A resin solution having a viscosity of 0.6%, a viscosity W, a number average molecular weight of 15,000 and an OH number of 28 was obtained. Hereinafter, the vinyl polymer solution (I-
It is abbreviated as 6).

Production Example 7 [Preparation of vinyl polymer (I)] 400 parts of triphenylsiloxyethyl methacrylate
By the same operation as in Production Example 1 except that 320 parts of n-butyl methacrylate, 120 parts of n-butyl acrylate and 160 parts of styrene were used instead, a nonvolatile content of 50.2% and a viscosity of D-
A resin having E, a number average molecular weight of 11,000 and an OH number of 36 was obtained.
Hereinafter, this vinyl-based polymer is abbreviated as (I-7).

Examples 1 to 6 and Comparative Examples In order to evaluate the physical properties of coating films by the two-coat one-bake coating method for the vinyl-based polymer solutions obtained in the above-described production examples, the formulations shown in Table 1 were used. Paints were separately prepared according to a conventional paint-making method, and then the paints were applied and cured by the following paint methods, and physical properties tests were conducted on each item as shown in the same table. The results are shown together in the same table.

[Painting method]

An air spray gun was used to form each of the base coat paints with a viscosity of 10 to 20 seconds (Food Cup # 4/20 ° C) on a surface-treated steel sheet coated with an epoxy ester resin-based electrodeposition primer, on which a coating of Surfer was formed. Using,
The coating was applied so that the dry film thickness was 15 to 20 μm. After this is left at room temperature for 5 minutes, each top coat paint whose viscosity is adjusted to 20 to 40 seconds (Food cup # 4/20 ° C) is coated again with an air spray gun to a dry film thickness of 30 to 40μ. After 10 minutes, the polyisocyanate prepolymer curing system was 60 ° C for 30 minutes, and the aminoplast curing system was 100 minutes.
It was baked and dried at ℃ for 20 minutes.

The coating film physical property test was performed after baking and drying and leaving it at room temperature for 3 days.

From the performance evaluation results shown in Table 1, 2 coats of the composition of the present invention were used.
By using it as a bake finish paint, compared to conventional amino alkyd resin paints and thermosetting acrylic resin paints, it is a two-coat that excels in coating workability and low temperature curability, and is a one-pack type and has excellent long-term storage stability. 1 bake paint provided,
It can be seen that the obtained coating film has coating properties of extremely high practicality.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C09D 161/28 PHK 8215-4J

Claims (1)

[Claims] 1. A paint (base coat) whose main component is a curable resin containing a metallic powder and / or a color pigment is applied, and then a clear paint (top coat) whose main component is a curable resin is applied to the coated surface. In the coating finishing method of coating and then curing, the base coat paint and the top coat paint have a vinyl-based monomer having a polymerizable unsaturated group and at least one siloxy group in one molecule as a resin component ( 1) to 100)
A vinyl-based polymer obtained by polymerizing a vinyl-based monomer mixture comprising 100% by weight and 99 to 0% by weight of a copolymerizable vinyl-based monomer (B) other than the above (A) in the presence of a radical generator ( A resin composition obtained by blending I) with a curing agent (II) having reactivity with a hydroxyl group produced from the polymer (I) and a siloxy group dissociation promoting catalyst (III). How to paint.