JPS62252473A - Coating method - Google Patents

Abstract

PURPOSE:To obtain a composite cured film having excellent voluminousness, gloss and film performance, by carrying out wet-on-wet coating by using base metallic paint contg. a specified resin compsn. and topcoating paint. CONSTITUTION:A vinyl polymer having a number-average MW of 500-50,000, obtd. by polymerizing 1-100wt% vinyl monomer having a polymerizable unsaturated group and at least one siloxy group per molecule [e.g., trimethylsiloxyethyl (meth)acrylate] with 99-0wt% vinyl monomer copolymerizable therewith [e.g., an alkyl (meth)acrylate] in the presence of a radical generating agent is blended with a curing agent reactive with hydroxyl groups generated from said polymer (e.g., a polyisocyanate) and a catalyst for promoting the dissociation of siloxy group (e.g., phosphoric acid) to obtain a resin compsn. A base coat mainly composed of a resin compsn. obtd. by blending said resin compsn. with metallic powder and/or a color pigment is applied, and a topcoat mainly composed of said resin compsn. is then applied thereon.

Description

[Detailed description of the invention] The present invention relates to a painting finishing method.

More specifically, the present invention is obtained by polymerizing a mixture of a specific amount of a vinyl monomer having a polymerizable unsaturated group and at least one siloxy group in one molecule and another copolymerizable vinyl monomer. Pace metallic paints and dog coat paints are coated in layers using a coating resin composition consisting of a vinyl polymer, a curing agent (crosslinking agent) that is reactive with the hydroxyl groups produced by the polymer, and a dissociation promoting catalyst. This relates to a two-coat, one-bake finishing method.

In recent years, in metallic paint for automobiles, instead of the so-called one-coat metallic finish in which a thermosetting paint containing metallic powder is applied and then baked, a thermosetting paint (base coat) containing metallic powder is being applied. A so-called two-coat, one-bake metallic finishing method has become common, in which a thermosetting clear paint (top coat) that does not contain colored pigments is then applied on top of the base coat, and the base coat and top coat are baked at the same time. This 2-coat, 1-bake finish has an excellent finished appearance, and in the conventional 1-coat, 1-bake finish, the metallic powder is easily attacked by acid, which often causes coating defects such as stains. A two-coat, one-bake finish has the advantage that almost no coating film defects occur.

In addition, conventional solid color paints, especially those mainly composed of vinyl polymers, have significant drawbacks in weather resistance, but by using this two-coat, one-bake coating method, a coating film with excellent weather resistance can be obtained. There are various advantages.

In such a two-coat, one-bake finish, the base coat paint is generally an amino alkyd resin paint, a thermosetting acrylic resin paint, etc., and after the base coat is applied, it is left for 2 to 5 minutes to volatilize a certain amount of the solvent. rear,
Immediately apply the same type of top coat paint, then dry in an atmosphere with a hot air drying oven temperature of 140°C to 150°C for 20 to 20 minutes.
Bake for 30 minutes to harden.

Here, sources of hot air include heavy oil, gro-gun gas,
Butane gas, city gas, or electricity is generally used, but the conventional two-coat, one-bake metallic finish method, which uses a thermosetting paint that is heated and cured in a hot air drying oven or electric oven, consumes a lot of fuel and electricity. This has the disadvantage of increasing energy costs due to

On the other hand, in the automobile industry, the use of plastic for outer panels, parts, etc. is rapidly progressing. When the material is a steel plate, the so-called bake-liquid type casing, such as the above-mentioned amino alkyd resin paint or thermosetting acrylic resin paint, is usually employed as the paint resin system. However, when the material is made into plastic, the heat resistance of some materials is low, so it is inappropriate to use ordinary baking-wave type paints for plastics. Therefore, room temperature curing type and low temperature curing type paints are being considered or partially used for plastics. These coating resins include combinations of polyol-type resins and incyanate prepolymers, combinations of acrylic resins having tertiary amino groups and polyfunctional epoxy resins, and curing systems using aminoplasts using low-temperature curing catalysts. However, among such paint systems, d? Polyol type resin isocyanate prepolymer type and tertiary amino acid d? Both of the xylene resin curing systems are two-component types and have major drawbacks in terms of workability such as pot life.

Furthermore, although the aminoplast system that uses a low-temperature curing catalyst is a one-component type, it has the disadvantage that the functional groups involved in the reaction are unblocked and are highly active, resulting in extremely poor long-term storage stability. Moreover, it is impossible to cure it at a temperature near room temperature.

In addition, if you use isocyanate made by separately blocking incyanate prepolymer with a suitable blocking agent, it will become a one-component polyol type resin-isocyanate prepolymer/polymer curing system, but at present, the dissociation temperature of the blocking agent is high and it cures at room temperature or low temperature. It is hard to say that it is a mold resin type.

As mentioned above, from the viewpoints of energy saving and material conversion, metallic finishing for automobiles uses one-component, room-temperature or low-temperature curing resins that have excellent physical properties, weather resistance, and storage stability. The current situation is that there is an urgent need for the development of a one-coat bake paint.

However, as a result of intensive study to obtain a two-coat, one-bake finishing paint that meets the above-mentioned requirements, the present inventors have found that a dog coat paint and a base coat paint that contains at least a polymerizable unsaturated group in one molecule. It was discovered that a vinyl polymer using a vinyl monomer having one siloxy group surprisingly improves these required performances, and the present invention was completed.

That is, the present invention provides a two-coat, one-bake dog coat paint and a base coat paint consisting of a vinyl polymer (1) component, a curing (crosslinking) agent (2), and a dissociation promoting catalyst component me. This vinyl polymer (I) contains a vinyl monomer (A) containing a polymerizable unsaturated group and at least one siloxy group in one molecule.
) and 99 to 0% by weight of the vinyl monomer (B) other than (A) above, and polymerize the mixture in the presence of a rough cal generator. It is. The composition of the present invention has a vinyl monomer (
The siloxy groups in A) react with moisture in the air to generate hydroxyl groups in the vinyl polymer (I), and react with the curing (crosslinking) creation component (2) that is reactive with the hydroxyl groups to form a strong The paint using the resin composition of the present invention has excellent storage stability as a one-component paint, and can be cured at room temperature or low temperature, and can be used as a top coat paint or base coat paint with a two-coat, one-bake finish. It provides:

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

R.

-0-5i-R.

(However, R1, R1 and R3 represent an alkyl group of C1 to CIa, a phenyl group, an aryl group, or H, and may be the same or different types.) These vinyl monomers (A), for example triethylamine or pyrinone. Those obtained by reacting trialkylchlorosilane, triphenylchlorosilane, triarylchlorosilane, methylkylchlorosilane, etc. with a hydroxyl group-containing vinyl monomer (6) as shown below in the presence of a hydrochloric acid scavenger such as The representative ones are trimethylsiloxyethyl (meth)acrylate, triethylsiloxyethyl (meth)acrylate, and trimethylsiloxybutyl (meth)acrylate.
Examples include acrylate, triethylsiloxyethyl (meth)acrylate, tributylsiloxypropyl (meth)acrylate, or triphenylsiloxyalkyl (meth)acrylate. These can be used alone or as a mixture of two or more.

Further, as the hydroxyl group-containing vinyl monomer (b), hydroxyalkyl (meth)acrylates such as β-hydroxyethyl (meth)acrylate, β-hydroxyglobil (meth)acrylate, or β-hydroxybutyl (meth)acrylate are used. or N-methylolated (meth)acrylamide; β-hydroxyethyl (meth)acrylate with ε-caglolactone added [e.g. Glaxel FM, FA series (Daicel Chemical Industries, Ltd.), TONE M-100 (Union) (manufactured by Carbide Co., Ltd.); general name propylene glycol monomethacrylate
1000 and the Premar PE series represented by the common name polyethylene glycol monomethacrylate (both manufactured by NOF Corporation!!!1).

unsaturated carboxylic acids such as (meth)acrylic acid, maleic acid, fumaric acid or itaconic acid; Typical examples include adducts of monovalent carboxylic acids with monoglycyl esters such as oil fatty acid glycytyl esters or monoepoxy compounds typified by monoglycyl sol ethers such as butyl glycytyl ether; etc. The amount of these vinyl monomers (,f) used is preferably 1% to 100% by weight, preferably 5 to 90% by weight.
Weight j"4: , %. 1% by weight of sea urchin; no effect of the monomer can be expected on the back of sea urchin.

Representative examples of the vinyl monomer (II) include alkyl (meth)acrylates having an alkyl group having 1 to 22 carbon atoms in the side chain, styrene, vinyltoluene, t-butylstyrene, α-methylstyrene, Glycitur (meth)acrylate, 2-ethoxyethyl (meth)acrylate, (meth)acrylonitrile, cyclohexyl (meth)acrylate, diesters of maleic acid or fumaric acid and monohydric alcohols of 01 to C1, (meth)acrylamide or (meth)acrylamide such as N-alkoxymethylated (meth)acrylamide, N,N-soalkylaminoalkyl (meth)
Examples include acrylates, phosphoric acid group-containing (meth)acrylates, and fluorine-containing vinyl monomers such as vinyl acetate, hexafluoropropylene, and tetrafluoroethylene.

These vinyl monomers (B) can be used alone or in a mixture of two or more depending on the desired coating performance. It is also possible to use the aforementioned hydroxyl group-containing vinyl monomer (b) as the vinyl monomer (B) component. However, when incyanate sol polymer is used as a curing agent because the functional groups are not blocked, the storage stability as a one-component paint is poor, and it is not preferable to use a hydroxyl group-containing vinyl monomer (BL). When used as a hardening agent, hydroxyl group-containing vinyl
' type monomer (b) can be used. However, if necessary, a curing catalyst may be added to impart low-temperature curing properties, and the amount used must be less than 51% so as not to adversely affect storage stability as a one-component type.

In order to obtain the vinyl polymer (I) constituting the composition of the present invention, the above-mentioned monomers are used in a known and commonly used method, such as a solution polymerization method using a radical generator. Can be done.

5') As the cal generator, any of those commonly used in the polymerization of vinyl monomers can be used, but representative examples include azopeisobutyronitrile, Sortert-butylnog-oxide or penzoylno-J? Examples of solvents include aromatic hydrocarbons such as toluene or xylene; acetate-based solvents such as ethyl acetate, butyl acetate, or cellosolve acetate; and ketone-based solvents such as methyl ethyl ketone or methyl isobutyl ketone. Can be used.

If necessary, commonly used chain transfer agents such as mercaptans, α-methylstyrene, and "Diintene T" (manufactured by Nippon Terpene Kagaku Co., Ltd.) can also be used.

The vinyl polymer (I) thus obtained has a number average molecule @
(Also, n) is preferably in the range of 500 to so, ooo.

The physical properties of the coating film may not be sufficient for the electrolyte (1) whose λn is 500, and it may be necessary to try to obtain the physical properties of the electrolyte (I). The hydroxyl value (hereinafter referred to as "OH value") generated after alkylnoloxy groups etc. are migrated is not desirable because it makes the coating film brittle, and on the contrary, it is 50.0OOtl- If it exceeds the range, defects are likely to appear in the appearance, gloss, texture, paint workability, etc. of the coating film, which is not preferable.

Next, +- MiJ which is another component constituting the invention composition.
The vinyl monomer (2) mentioned above is the vinyl monomer (2).
When only the hydroxyl groups generated from , () are to be used as a public agent, polyisocyanates or aminosilasts are used as the crosslinking agent.

Narrow examples of polyisocyanates include aromatic twinocyanates such as tolylene twinocyanate, sophenylmethane soinocyanate or xylylene twinocyanate; tetramethylene twinocyanate, hexamethylene twinocyanate or trimethylhegysanzoisocyanate. Aliphatic zoisocyanates such as; isophorone soisocyanate, methylcyclohexane-2
Alicyclic diincyanates such as 4-(or 2,1s-) diisocyanate, 44'-methylenebis(cyclohexyl isocyanate or 1,3-)(isocyanatomethyl)-cyclohexane, and each of these diisocyanates and ethylene glycol. , polyhydric alcohols such as propylene glycol, neopentyl glycol, trimethylolpronocene; very low molecular weight ester resins (including oil-modified types) having a functional group that reacts with isocyanate groups; or water. It is an adduct of the above-mentioned diincyanates, a billet form, or a polymer (including oligomers) of the above-mentioned diincyanates. The blending ratio of these polyisocyanates and the vinyl polymer (I) should be within the range of generated OE groups/NCO groups = 1/0.5 to 1/3 (equivalent ratio). Preferable from the viewpoint of performance. In this case, either one method can be used, in which the polyisocyanate is blended in advance, or the polyisocyanate is blended immediately before painting.

On the other hand, when the hydroxyl group-containing vinyl monomer (b) is used as the vinyl polymer (I), aminosilast is preferable as the curing (crosslinking) agent (6) in consideration of storage stability.

However, it is also possible to mix and use polyisocyanates before coating. A typical aminogellast that 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 the siloxy groups, resulting in shortcomings in long-term stability. Therefore, as the aminoplast, hexamethoxymethylolmelamine, which does not use alcohol as a resin solvent, is preferable.

In addition, the amount of aminoplast used is vinyl polymer (
A proportion of 10 to 40% by weight of I) is preferred.

Further, in order to increase the crosslinkability, a curing accelerator for aminoplasts, for example, an acid catalyst such as .9radluenesulfonic acid may be added. The amount of curing accelerator used is preferably 0.1 to 10% by weight based on the solid content of the resin. If long-term storage stability is not required, an aminoplast etherified with a monohydric alcohol using alcohol as the resin solvent may be used.

When the composition of the present invention is exposed to the atmosphere, it is hydrolyzed by reaction with moisture in the air to generate hydroxyl groups that react with the curing agent. Catalyst 01 to promote this hydrolysis
11 must be used. As a catalyst, acidic catalysts such as phosphoric acid, phosphoric acid ester, phosphite, p-toluene, sulfonic acid and its amine salt, benzoic acid, trichloroacetic acid, trifluoroacetic acid, naphthalinosulfonic acid and its amine salt, Amines such as ethylenesoamine, N-β-aminoethyl-r-aminoglopyltrimethoxysilane, butylamine, sibutylamine, t-butylamine, hexylamine, triethylamine, potassium hydroxide, lithium hydroxide, sodium hydroxide, etc. alkaline catalysts, metal salts of carboxylic acids such as alkyl titanate, octylate, subbutyltin zolaurate, and lead octylate, sulfide-type and mercaptide-type organotin compounds such as motubutyltin sulfide and dioctyltin mercaptite, tetraethylammonium fluoride, etc. Compounds that produce heptadonium ions, such as cesium fluoride and cesium fluoride, are effective.

The amount of catalyst (e) added is 0 relative to the vinyl polymer (I).
．． It is preferable to use 0.001 to 10%, preferably 0.005 to 8%.

Furthermore, since the composition of the present invention does not react with a curing agent to produce hydroxyl groups unless exposed to the atmosphere, the composition of the present invention can be used as a one-component coating composition with good stability. However, in order to ensure long-term storage stability, it is sufficient to trap trace amounts of moisture that enter for some reason.

That is, long-term stability is ensured by adding a water binder that is reactive with moisture. Further, when producing the vinyl polymer (I), this water binder may be mixed and used at the initial stage of S caulking. Examples of water binding agents reactive with moisture include trialkyl orthoformates such as trimethyl orthoformate, triethyl orthoformate, and tributyl orthoformate; trialkyl orthoacetates such as trimethyl orthoacetate, triethyl orthoacetate, and tributyl orthoacetate Trialkyl orthoborates such as tributyl orthoborate and triethyl orthoborate;
Tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, tetra(2-methoxyethyl)
Single silicates or tetra(substituted)alkyl silicates such as tetra(2-chloroethyl)silicate;
Equivalent substances of the above-mentioned tetra (substituted) alkyl silicates such as tetraphenyl silicate and tetrapentyl silicate (hereinafter abbreviated as the same effect substance); or tetraethyl silicate dimer, trimer, tetramer, hexamer "Ethyl silicate 40J ( Each of the above-mentioned tetras (substituted), such as (mixtures of tetramers, pentamers, and hexamers of tetraethyl silicate) manufactured by Colco Co., Ltd.
Hydrolyzable ester compounds such as simple alkyl silicates and condensates of the same effective simple substances of the same silicates, phenyl isocyanate, p-chlorophenylisocyanate, benzenesulfonyl isocyanate, p-trienesulfonylinocyanate, incyanate ethyl methacrylate ( Compounds having incyanate groups such as NCO group-containing monomers manufactured by Dow Chemical Company, etc.

As for usability, 0.1 for vinyl polymer (I)
~30 weight f1''9, preferably α5 to 20% by weight.

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

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

When used as a base coat paint, a paint may be prepared by blending the composition of the present invention with inorganic or organic coloring pigments, dyes, metallic powders, etc. by a conventional paint preparation method.

Examples of coloring pigments include titanium white, Bengara,
Inorganic powders such as Oxide Yellow, organic powders such as Toluison Red, Phthalocyanine Blue, and Penduzone Yellow, and metallic powders include aluminum powder, copper powder, mica powder, mica-like powder coated with titanium oxide, and MIO (mica-like powder). iron oxide) etc. can be used.

Furthermore, various conventional additives such as a leveling agent, an ultraviolet absorber, and a pigment dispersant can be mixed into the top coat paint and the base coat paint, if necessary.

The base coat paint thus formulated is referred to as the first round,
After this paint film is dry to the touch or semi-hardened, a top coat paint is applied as a second layer and heated at room temperature or low temperature to remove the components contained in the base coat paint and top coat paint. The siloxy groups generated by moisture in the air generate hydroxyl groups, and curing progresses through the reaction of these hydroxyl groups with a reactive curing (crosslinking) agent component, resulting in a metallic composite cured coating with excellent flatness and smoothness. is formed.

For painting base coat paints and top coat paints using the composition of the present invention, air gray painting and electrostatic spraying are suitable in order to fully exhibit the cosmetic effect, and the base coat paint film The thickness (as dry film thickness, the same applies hereinafter) is in the range of 5 to 50 μm, preferably 10 to 20 μm.
The film thickness of the dog coat paint is 10
It is coated in the range of ~100 μm, preferably in the range of 10 to 60 μm.

The drying conditions for the wet film of the base coat paint and the coating interval between the base coat and top coat are approximately 20℃ and 1 to 45℃.
2 to 20 minutes, preferably 2 to 20 minutes, and when forced drying the base coat film, use warm air at 60 to 80°C to dry the base coat.
．． All you need to do is warm it up for 5-5 minutes. After the base coat film is dry to the touch or semi-hardened under the above drying conditions, the dog coat is applied.

Dry the top coat with warm air at 60℃ to 100℃ for 30~
Forced drying for about 60 minutes is preferable in terms of curability and productivity, but the drying and curing conditions may be changed as appropriate depending on the type and properties of the base coat paint and dog coat paint.

As described above, by carrying out the two-coat, one-bake coating method using the composition of the present invention, it is possible to achieve gloss and shine by drying at room temperature or at a low temperature below the heat resistance temperature of ordinary plastic materials.
It is possible to form a composite cured coating film with excellent texture and film performance, and it provides a finish that is comparable to that of conventional thermosetting acrylic resin paints and amino alkyd resin paints. The paint system using the composition is extremely effective in saving heat sources and improving coating properties through the integrated metal/plastic coating method, and furthermore, the composition of the present invention has excellent storage stability as a single component. , which greatly contributes to improving productivity.

Next, the present invention will be specifically explained with reference to production examples, working examples, and comparative examples. In the following, all parts are based on weight unless otherwise specified.

500 parts of toluene and 50 parts of inbutyl acetate were charged into a four-bottle flask equipped with a stirrer, an inert gas inlet, a thermometer, and a condenser and maintained at 110°C, and then 260 parts of trimethylsiloxyethyl methacrylate and n-butyl A monomer mixture consisting of 390 parts of methacrylate, 150 parts of n-butyl acrylate, and 200 parts of styrene and a mixture of 50 parts of azobisisobutyronitrile and 450 parts of isobutyl acetate were added dropwise over 6 hours, and the mixture was further heated at the same temperature. After holding for 10 hours, the non-volatile content was 50.
9%, viscosity (Gardner viscosity, 25°C.

Same below) CD, number average molecule 110000 and 0
A resin solution with a valence of 11 and 36 was obtained. Hereinafter, this vinyl polymer solution will be abbreviated as (I-1).

Production Example 2 [Preparation of vinyl polymer (I)] 230 parts of trimethylsiloxyethyl methacrylate, 20 parts of β-hydroxyethyl methacrylate, 200 parts of styrene, n-
By the same operation as in Production Example 1 except for using 400 parts of butyl methacrylate and 150 parts of n-butyl acrylate, a resin with 49.1% of non-producers, viscosity eG -H, number average molecular fi 15000 and Off@f56 was prepared. A solution was obtained.

Hereinafter, this vinyl polymer will be abbreviated as (T-21).

170 parts of β-hydroxyethyl methacrylate, 200 parts of styrene, 477 parts of n-butyl methacrylate, n-
The procedure was the same as in Production Example 1 except that 150 parts of butyl acrylate and 3 parts of methacrylic acid were used instead.
Resin solutions with 00 and 011 valences of 36 were obtained. Hereinafter, this vinyl polymer will be abbreviated as (I-3).

500 parts of toluene and 50 parts of isobutyl acetate were charged into a four-bottle flask equipped with a stirrer, an inert gas inlet, a thermometer and a condenser and maintained at 105°C, followed by 200 parts of trimethylsiloxyethyl methacrylate and 400 parts of methyl methacrylate. A monomer mixture consisting of 300 parts of ethyl acrylate and 100 parts of n-butyl acrylate, and a mixture of 7 parts of azobisisobutyronitrile and 593 parts of isobutyl acetate was added dropwise over a period of 4 hours, and the mixture was further heated to the same temperature for 10 minutes. Hold for a long time, non-volatile content: 49
1%, viscosity GH, number average molecular weight 13000 and 08
A resin solution having a value of 28 was obtained.

Hereinafter, this vinyl polymer will be abbreviated as (I-4).

Production Example 5 [Preparation of vinyl polymer (I)] 170 parts of trimethylsiloxyethyl methacrylate, 20 parts of β-hydroxyethyl methacrylate, 4 parts of methyl methacrylate
00 parts, 610 parts of ethyl acrylate, and 100 parts of n-butyl acrylate were used in the same manner as in Production Example 4 to obtain a non-volatile content of 496% and a viscosity of 1-1. A resin solution having a number average molecular weight of 16,000 and a valence of 011 of 28 was obtained. This vinyl polymer is hereinafter abbreviated as (I-5).

β-hydroxyethyl methacrylate 130 parts, methyl methacrylate 407 parts, ethyl acrylate) 3.60
By the same operation as in Production Example 4 except for using 100 parts of n-butyl acrylate and 3 parts of methacrylic acid in place of
A resin solution with a valence of 0 and 08 and 28 was obtained. Hereinafter, this vinyl polymer solution will be abbreviated as (I-6).

Production Example 7 [Preparation of vinyl polymer (■)] Production example except that 400 parts of triphenylsiloxyethyl methacrylate, 320 parts of n-butyl methacrylate, 120 parts of exo-butyl acrylate and 160 parts of styrene were used instead. A resin having a nonvolatile content of 5112%, a viscosity DE, a number average molecular weight 11000, and an OH value S6 was obtained by the same operation as in Example 1. Hereinafter, this vinyl polymer will be abbreviated as (I-7).

Examples 1 to 6 and Comparative Example In order to evaluate the fillability of the coating film by the 2-coat 1-bake coating method for the vinyl polymer solutions obtained in the above production examples, the formulations listed in Table 1 were used. A coating was applied to each coating separately according to a conventional coating method, and then coated and cured using the coating method described below. After that, physical property tests were conducted for each item as shown in the table. The results are summarized in the same table.

[Painting method]

A coating film of intermediate coating surfer is formed on a surface-treated steel plate coated with an epoxy ester resin electrodeposited primer, and a viscosity of 10 to 20 seconds (Ford cup ◆ 4/20°C) is applied.
Each of the base coat paints was coated using an air spray gun so that the dry film thickness was 15 to 20 μm. After leaving this at room temperature for 5 minutes, the viscosity was further increased to 20 to 40.
Using an air spray gun, apply each dog coat paint adjusted to a temperature of 4/20°C to a dry film thickness of 30 to 40μ, and after 10 minutes,
71? Reincyanate prepolymer curing system is 60℃,
The aminoplast curing system was baked and dried at 100° C. for 20 minutes.

The physical properties of the coating film were tested after baking and drying the film and leaving it at room temperature for 3 days.

From the performance evaluation results in Table 1, it was found that 2 coats of the composition of the present invention were applied in 1 coat.
When used in baked finish paints, this 2-coat coating has superior coating workability and low-temperature curing properties compared to conventional amino alkyd resin paints and thermosetting acrylic resin paints, and is corrugated and has excellent long-term storage stability. It can be seen that a one-bake paint is provided, and the resulting paint film has extremely practical physical properties.

Claims (1)

[Claims] Apply a paint (base coat) whose main component is a curable resin containing metallic powder and/or colored pigments,
In a painting finishing method in which a clear paint (top coat) containing a curable resin as a main component is then applied to the painted surface and then cured, the base coat paint and the top coat paint contain, as a resin component, 1 to 100% by weight of a vinyl monomer (A) having a polymerizable unsaturated group and at least one siloxy group in one molecule and 9% of a copolymerizable vinyl monomer (B) other than the above (A)
A vinyl polymer (I) obtained by polymerizing a vinyl monomer mixture consisting of 9 to 0% by weight in the presence of a radical generator has reactivity with the hydroxyl group generated from the polymer (I). A coating method characterized by using a resin composition comprising a curing agent (II) and a catalyst (III) for promoting dissociation of siloxy groups.