JPH01225675A - Finishing by coating - Google Patents

Abstract

PURPOSE:To give a finish coat excellent in appearance and low-temperature curability to a substrate, by coating the substrate with a paint comprising a curable resin containing a metallic powder or a coloring pigment, further coating it with a clear paint comprising a specified curable resin and curing this resin. CONSTITUTION:A process for finishing a substrate comprises coating the substrate with a paint (base coat) based on a curable resin containing a metallic powder and/or a coloring pigment and curing this resin, wherein the composite cured film is formed from a resin composition formed by mixing a vinyl polymer (A) having at least one cyclocarbonate group in the molecule with a polyketimine compound (B) as the resin component of said base coat paint and using a resin composition prepared by mixing a polyisocyanate with a vinyl polymer-polyol and/or a polyester-polyol as the resin component of the top coat paint.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a painting finishing method, and particularly to a so-called two-coat, one-bake painting finishing method.

[Prior Art and Problems to be Solved by the Invention] In recent years, in the top coating of automobiles, not only metallic paint finishing methods are used in which paints containing metallic powder are applied, but also coatings are entirely coated with paints containing all colored pigments. Even in the so-called solid color painting finishing method, the effectiveness of a two-coat, one-bake painting finishing method in which a base coat paint is applied and then a top coat paint is applied has been recognized.

In other words, the paint film obtained by this 2-coat, 1-bake finish has excellent finished appearance and texture, and is particularly effective because it has a gold-based component that is a vinyl polymer that has previously had remarkable weather resistance. The solid color paint has various advantages, such as improved weather resistance and a nine-coat finish by applying a two-coat, one-bake finish.

Generally, 2-coat, 1-bake finishing method is to apply all the materials such as amino alkyd resin paint or thermosetting acrylic resin paint as a pace coat paint, leave it for 2 to 5 minutes to volatilize a certain amount of solvent, and then The same type of top coat paint is applied to the surface, and then the temperature inside the hot air drying oven is 140-15
It is baked at 0° C. for 20 to 30 minutes to harden it.

Heavy oil, glopan gas, city gas, or f''ii electric power is used as the hot air source, but 2 coats and 1 coats using conventional thermosetting paints that are heated and cured at 140 to 150°C are used.
The bake painting finishing method has the drawback of increasing costs due to the fuel and electricity consumed.

On the other hand, in the automobile industry, the use of glass for exterior panels, parts, etc. is rapidly progressing. With the shift to glass,
It is necessary to select all paints that match the heat resistance temperature of the material, and should we choose room-temperature curing or low-temperature curing paints for general-purpose glass? It is necessary to use it.

As mentioned above, from the viewpoint of energy saving and material conversion, in the automotive top coating finishing method, two-coat and one-coat coatings using low-temperature curing resin are used, which are superior in coating workability, various physical properties, finished appearance, etc. The current situation is that there is a strong need for the immediate development of paints for this purpose.

[Means to solve all problems]

In line with the above-mentioned requirements, the present inventors created a 7t2 coat,
As a result of intensive studies to obtain a curable paint for a one-bake finish, we found that a resin composition containing a vinyl polymer containing a cyclocarbonate group and a polyketiban compound as main components was used as a resin for a pacecoat paint. Vinyl polymer polyol and/or polyester polyol and polyinsyanate as resins for Totubu Coat paints? By using a resin composition as the main component, we have discovered that all of these required performances can be surprisingly improved, and have completed the present invention.

That is, in the present invention, a paint (pace coat) containing metallic powder and/or colored pigment as a main component and an FC curable resin as a main component (pace coat) is applied, and then a clear paint (pace coat) containing a curable resin as a main component is applied to the painted surface. top coat) fully painted,
In the coating finishing method, which is then cured, a polyketimine compound (B) is blended with [I] a vinyl polymer (A) having at least one cyclocarbonate group in one molecule as a resin component of the paste coat paint. Also, using a resin composition made of As resin for top coat paint [II] Vinyl polymer polyol and/or
Alternatively, it is a painting finishing method characterized by forming the entire composite cured coating film using a resin composition formed by blending polyisocyanate gold with polyester paint.

In the present invention, after coating the paint composition CI for pacecoat and then overcoating the topcoat paint (Il"l), in the pacecoat, the vinyl polymer (cyclocarbonate group in Al Ban compound (B) reacts with moisture in the air to liberate all the ketone compounds, and the amino groups react to form a coating film.On the other hand, in TOG COAT, the hydroxyl groups in the polyol and the isocyanate groups in the polyisocyanate The purpose of this invention is to provide a coating resin composition that forms a strong composite coating film by reacting with the resin composition and has excellent coating film appearance and low-temperature curability.

Resin composition for pace coat used in the method of the present invention (Ill
The vinyl polymer (A) having at least one cyclocarbonate group in one molecule, which is one component, is a vinyl polymer having at least one, preferably one or two cyclocarbonate groups in one molecule. It refers to a polymer.

Such a vinyl polymer (A) is composed of (1) 5 to 40% by weight of a vinyl monomer containing at least one polymerizable unsaturated group and a cyclocarbonate group in one molecule, and (2) copolymerizable with the monomer. It can be obtained by copolymerizing 60 to 95% by weight of other vinyl monomers.

Examples of monomers (1) containing the above-mentioned polymerizable unsaturated group and cyclocarbonate group include 2,3-carsanatoglopyl (meth)acrylate, 3,4-cargenatobutyl (meth)acrylate, and 4,5-cargenatoglopyl (meth)acrylate. (Meth)acrylates such as natebentyl (meth)acrylate, 6,7-cargenate hexyl (meth)acrylate; 2,3-cargenate clopylaryl ether, methyl-2,3-cargenate clobyl maleate , methyl-2,
Vinyl monomers such as 3-cargenate globyl crotonate can be mentioned. Another vinyl monomer (2) that can be copolymerized with these vinyl monomers (1) is (meth)acrylic acid.

maleic acid, fumaric acid, or itaconic acid, or an esterified product of an unsaturated dicargenic acid such as maleic acid, fumaric acid, or itaconic acid with a C5-04 monohydric alcohol, or a hydroxyl group-containing vinyl compound with phthalic anhydride. Cal&-p obtained by total addition of acid anhydrides such as
Syl group-containing monomer; alkyl (meth)acrylate having 1 to 22 carbon atoms, styrene, vinyltoluene, t
-7” Tylstyrene, α-methylstyrene, glycidyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, (meth)acrylonitrile, cyclohexyl (meth)acrylate, (meth)acrylamide or N-alkoxymethylated (meth)acrylamide (Meth)acrylamides such as: N-N sialylaminoalkyl (meth)acrylates; or (meth)acrylates containing phosphoric acid groups; There are vinyl monomers, etc.''Also, hydroxyl group-containing vinyl monomers can be used as other functional group monomers.

These vinyl monomers (1) can be used alone or in a mixture of two or more, depending on the desired coating performance. The above-mentioned vinyl-based monomer (vinyl monomer) completely improves the compatibility and storage stability of the resin composition (1), so it is recommended to use it in the range of 0.1 to 10% by weight. .

To prepare the vinyl polymer (A) from the various monomers constituting the vinyl polymer (A) component of the present invention described above, any conventionally known method such as a solution polymerization method or a non-aqueous dispersion polymerization method can be used. Although the following polymerization methods can be applied, solution radical polymerization is the simplest method. The number average molecular weight of the vinyl polymer is preferably in the range of 2.000 to 50,000.

If the number average molecular weight is less than 1000, the desired performance cannot be obtained, while if it exceeds 50,000 i, the workability will be adversely affected.

Note that typical solvents used in the solution radical polymerization method described above include toluene and -? Hydrocarbon solvents such as sylene, cyclohexane, n-hexane, octane: methyl acetate, ethyl acetate.

Ester solvents such as n-butyl acetate and amyl acetate; acetone methyl ethyl ketone, methyl in butyl ketone,
Examples include keto/based bath agents such as methyl abalketone and cyclohexenone, and it goes without saying that any mixture of these may also be used.

Solution radical polymerization is carried out using the solvents and various radical polymerization initiators such as an azo type represented by azobisisobutyronitrile or a peroxide type represented by benzoic/4'-oxide. The entire polymerization may be carried out by a conventional method, and if necessary, lauryl mercagutan, octyl mercagutan, 2-mercagutoethanol, or octyl thioglycolate may be added as a molecular weight regulator.

Chain transfer agents such as 3-mercaptopropionic acid or α-methylstyrene dimer can also be used.

In addition to the preparation method described above, an acid anhydride group-containing vinyl monomer such as maleic anhydride is polymerized with other vinyl monomers that can be copolymerized with it to obtain an anhydride group-containing vinyl polymer. The vinyl polymer (A) can also be obtained by an addition reaction with an alcohol having 3 to 6 carbon atoms and having a cyclocargenate group, such as 2,3-cyclocargonate clobyl alcohol.

By the way, this is one component of the base coat resin composition (1).j? IJ ketimine compound (
In B), the ketimine group site in the molecule (the specific site where the oxygen of the cargenyl group of the ketone group is substituted with an imino group) reacts with moisture in the air to regenerate the polyamine compound. Then, this regenerated abano group reacts with the cyclocarbonate group in the vinyl polymer (A) component. Therefore, any compound (B) may be used as long as the active hydrogen of the polyamine compound can be temporarily protected in the form of a ketimine group. Examples of the ketone compound or aldehyde compound used to obtain this type of compound by reaction with a polyamine compound include acetaldehyde and glopionaldehyde.

n-butyraldehyde, 1-butyraldehyde.

Trimethylacetaldehyde, paleoaldehyde.

Acrolein, crotonaldehyde, acetone.

Methyl ethyl ketone, methyl imbutyl ketone.

Examples include diethyl ketone, diisobutyl ketone, methylhegutinone, -/chlorhexanone, isophorone, and acetophenone. The reaction between the polyamine and the above ketone compound or aldehyde compound may be carried out under conventionally known reaction conditions.

The coating performance of the base coat resin composition CI) of the present invention is largely influenced by the polyamine compound, but the polyamine compound is preferably an aliphatic polyamine or an alicyclic polyamine having two or more primary amine groups. For example, ethyleneamine, globylenediamine, propylenediamine, trimethylenediamine, diethylenetriamine, tetramethylenecyabane, hexamethylenediamine, NN
'-Aliphatic polyamines such as dibutylhexamethylene diamine; cyclohexylcyaine, ebome) BO
O2, Epomate S-602 (Yuka Shell Ekishi (#
91. )); aliphatic trifunctional amines such as trisanoethylammonium and abutymethylnoaminooctane; acrylics obtained by reacting acid group-containing acrylic resin with ethyleneimine or glopyreneimine gold. Polyamines and the like are used. and,
It is also possible to use two or more of these tetra-amino compounds in combination.

The above-mentioned cyclocargonate group-containing vinyl polymer (A
) and ketimine compound (B), the ratio of the amount of cyclocarbonate groups to the amount of ketimine groups is 0.8:1.0
~1.0: The O35 range is preferable because it provides good coating film performance.

te vinyl polymer (A) and polyketimine compound (B)
The system does not react unless it is exposed to the atmosphere, so
Base coat resin composition (1) used in the method of the present invention
) is a liquid 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-binding agent that is reactive with moisture. Examples of water-binding agents that are reactive with water include trimethyl orthoformates such as trimethyl orthoformate, triethyl orthoformate, and tributyl orthoformate; Alkyl; trialkyl orthoborate such as tributyl orthoborate, triethyl orthoborate; tetramethyl silicate.

Tetra (substituted) such as tetraethyl silicate, tetrabutyl silicate, tetra (2-methoxyethyl) silicates or tetra (2-chloroethyl) silicate
Single alkyl silicates; the above tetra (substituted) such as tetraphenyl silicate and tetrabenzyl silicate
Substances with the same effect as alkyl silicates (hereinafter abbreviated as the same effect simple substance); Mata includes tetraethyl silicate dimer, trimer, tetramer, hexamer, [ethyl silicate 40J (Kolko 1' (ff) product, tetraethyl silicate tetramer, -1) Hydrolyzable ester compounds such as individual tetra(substituted) alkyl silicates listed above, such as mixtures of silicates and hexamers, and condensates of the same silicates, may be mentioned. Or P-
Long-term stability can also be ensured by using acidic additives such as toluenesulfonic acid.

The amount of these used is 0.1 to 30% by weight, preferably 0.5 to 20% by weight based on the vinyl polymer (A).
The person in charge of T is angry.

In order to use the obtained composition [■] as a base coat paint, inorganic or organic coloring pigments, dyes, metallic powders, etc. are blended with the composition and the paint is prepared using a conventional paint method. do it.

Here, as a coloring pigment, for example, titanium white, Bengara,
Inorganic powders such as Oxide Yellow, organic powders such as toluidine red, phthalocyanine blue, and benzidine yellow, and metallic powders such as aluminum powder, copper powder, mica powder, and titanium oxide fully coated ± mica-like powder and MTO (mica powder) are available. iron oxide) can be used.

Next, the resin composition [II] of the top coat paint, which is completely overcoated on the above-mentioned pace coat paint, will be explained.

The vinyl polymer polyol constituting the top coat resin composition [ll] of the present invention contains a hydroxyl group-containing vinyl monomer as an essential component, and if necessary, other copolymerizable vinyl monomers are used. It can be obtained by a known and commonly used method, for example, a solution polymerization method using a radical generator. Typical examples of hydroxyl group-containing vinyl monomers include hydroxyalkyl (meth)acrylate, β-hydroxyglobil (meth)acrylate, and β-hydroxybutyl (meth)acrylate. ) Acrylates are listed.

- In addition, other typical copolymerizable vinyl monomers include a kill group t at 7 having 1 to 22 carbon atoms.
- Alkyl (meth)acrylate in the side chain, styrene, vinyltoluene, t-butylstyrene, α-methylstyrene, glycidyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, (meth)acrylonitrile, cyclohexane (meth)acrylate , diesters of maleic acid or fumaric acid and C1 to C18 monohydric alcohols, and fluorine-containing vinyl monomers such as vinyl acetate, hexafluoroglobylene, and tetrafluoroethylene.

These vinyl monomers can be used alone or in a mixture of two or more depending on the desired coating performance.

On the other hand? Reester polyol has acid components such as isophthalic acid, phthalic anhydride, succinic anhydride, adipic acid,
Polybasic acids such as trimellitic anhydride, benzoic acid, para-t
-monobasic acid such as butylbenzoic acid, 7A/l-'' components include neointyl alcohol, trimethylolethane, trimethylolpro/yne, 1.6-hexandiol,
1.5-(It is synthesized as appropriate using ntandiol, intererythritol, glycerin, ethylene glycol, etc.).

Also, polyester? Liol may be oil-modified, and usually has an oil length of 30% or less, and in terms of compatibility with resins and weather resistance, it is made of non-drying oils, especially coconut oil and its fatty acids, synthetic fatty acids such as octylic acid, It can be obtained by using in combination a monoglycidyl ester of a synthetic fatty acid such as E.

Typical examples of polyisocyanates that are curing agents include aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and ri-fusylylene diisocyanate; tetramethylene diisocyanate, hesomethylene diisocyanate, and trimethylhexane diisocyanate. aliphatic diisocyanates such as isophorone twinocyanate, methylcyclohexane-2,4-(or 2,6-) diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate) or 1,3-di(incyanatemethyl)-cyclohexane; alicyclic diisocyanates, and polyhydric alcohols such as each of these diisocyanates, ethylene glycol, globylene glycol, neointhyl glycol, or trimethylolethane; Polyester resin (including oil-modified type) or inocyanate (including oil-modified type) or an adduct such as water, which is a vinylet body or contains an incyanur term obtained by combining 3i of the above diisocyanates.
(including oligomers).

Also. Incyanate ethyl (meth)acrylate, isocyanate globil (meth)acrylate, incyanate butyl (meth)acrylate, methacryloyl isocyanate. and an incyanate group.
A copolymer of one or more of the above-mentioned hydroxyl group-containing vinyl monomers can also be used as the polyisocyanate compound. .

The blending ratio of these I-lysocyanate compounds and the vinyl polymer polyol and/or RI polyester polyol is OH/NCO-110,
A range of 2 to 1/3 (equivalent ratio) is preferable from the viewpoint of coating film performance. Further, in order to promote the entire reaction, known and commonly used catalysts can also be used.

The obtained resin composition [II] is used for a top coat paint, so it can be used as a clear paint as it is, but if necessary, a coloring pigment or dye can be added as appropriate to an extent that does not impair the transparency. . Various conventional additives such as a leveling agent, an ultraviolet absorber, a pigment dispersant, etc. can be mixed into the prepared paste coat paint and top coat paint, if necessary.

For painting base coat paints and top coat paints using the composition of the present invention, air gray painting and electrostatic spraying are suitable for achieving a sufficient cosmetic effect, and the film of the base coat paint is suitable. The thickness (as dry film thickness, the same applies hereinafter) is in the range of 5 to 50, preferably 10 to 2011.
All ranges of m are appropriate.

The film thickness of the top coat paint is applied in a range of V'ilo to 100 μm, preferably in a range of 10 to 604 m.

The drying conditions for the Couette paint film for pacecoat and the coating interval for pacecoat and top coat are approximately 20℃ and 1 to 4 degrees.
5 minutes, preferably 2 to 20 minutes, and if the entire coating film of the pacecoat is forcibly dried, heating with hot air at 60 to 80°C for 0.5 to 5 minutes is sufficient. That is, after the base coat film is completely dry to the touch or semi-cured dry under the above drying conditions, the top coat is applied. Dry the top coat with warm air at 60-100℃ for 30~
Forced drying for about 60 minutes is preferable from the viewpoint of curability and productivity, but drying may be carried out as appropriate depending on the type and properties of the paint for pace coat Totog coat.

There is no problem even if the curing conditions are completely changed.

〔Effect of the invention〕

As described above, by carrying out the two-coat, one-bake coating method using the gold composition of the present invention, it is possible to improve gloss, texture, and paint quality by drying at room temperature or at a low temperature below the heat resistance temperature of ordinary glass materials. This composition can be used to form a composite cured coating with excellent film performance, and provides a finish comparable to that of conventional thermosetting acrylic resin paints or amino alkyd resin paints. The system is extremely effective in saving heat sources and improving coating workability using the metal/glass integrated coating method.Furthermore, the composition of the present invention has excellent low-temperature curability and greatly contributes to improving productivity. It is.

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

Production Example 1 [Preparation of cyclocarbonate group-containing vinyl polymer] 200 parts of 2,3-carbonate propyl methacrylate and methyl methacrylate were placed in a four-necked flask equipped with a thermometer, cooling tube, stirrer, and N2 gas inlet tube. 300 copies,
200 parts of styrene, 270 parts of n-butyl acrylate,
20 of a mono-1 mixture consisting of 30 parts of methacrylic acid
0 parts and 500 parts of toluene, 200 parts of isobutyl acetate,
10 parts of tart-butyl peroctate (TBPO) and 5 parts of azobisin butyronitrile (ATBN) were charged and kept at 90°C for 1 hour, then for 30 minutes. The temperature was then raised to 115°C, and at the same temperature, the remaining monomer mixture was heated to 80°C.
A mixture of 0 parts and 300 parts of isobutyl acetate, 10 parts of TBPo and 5 parts of AIBN was added dropwise over a period of 3 hours.

Furthermore, when kept at the same temperature for 10 hours, the non-volatile content was 49.8%.
, viscosity (Gardner viscosity at 25°C; below.

Same) 2-2. A resin solution (+-1) having a number average molecular weight of 130,000 was obtained.

Production example 2 [same as above] 2.3-cargonate clopylaryl ether 200
parts, 510 parts of methyl methacrylate, 200 parts of n-butyl methacrylate, acrylic fi? ! Production Example 1 except that 15 parts and 75 parts of methyl acrylate were used instead.
A resin was obtained in the same manner as above. Nonvolatile content 50.7%,
A resin solution with a viscosity of Z3 and a number average molecular weight of 18.000 (1
-2).

Production Example 3 [Same as above] Same as Production Example 1 except that 300 parts of 4-cargenetoptyl acrylate, 250 parts of styrene, 250 parts of butyl acrylate, 180 parts of methyl methacrylate, and 20 parts of methacrylate were used instead. A resin was obtained by the operation. Non-volatile content 50.8, viscosity Y, number average molecule fj
The resin solution (1-3) was 18,000 yen.

Production Example 4 [Same as above] Production example except that 150 parts of 2.3-cargenate globilbutyl maleate, 500 parts of vinyl acetate, 330 parts of methyl methacrylate, and 20 parts of acrylic acid were used, and the entire reaction was carried out at 80°C. A resin was obtained by the same operation as in 1. Non-volatile content 51. A resin solution (1-4) having a viscosity of UV and a number average molecular weight of 13,000 was obtained.

Production Example 5 [Preparation of Ketimine Compound] Hexamethylene diamine was heated to reflux with excess methyl isobutyl ketone, and the resulting water was removed using a gold-water separator, followed by distillation to obtain a ketimine compound (AM-1).

Production Example 6 [Same as above] A ketimine compound (AM-2) was obtained in the same manner as in Production 915 except for using 4-methylcyanooctane and cyclohexanone.

Production Example 7 [Preparation of vinyl polymer polyol] 310 parts of methyl methacrylate, 1 ethyl methacrylate
0 parts, 150 parts of ethyl acrylate, 216i of inbutyl methacrylate, 114 parts of β-hydroxyethyl methacrylate, 100 parts of styrene, 200 parts of a monomer mixture consisting of 10 parts of methacrylic acid, 500 parts of toluene, and 200 parts of isoptyl acetate. , 5 parts of azobisisobutyronitrile (AIBN) and t-
10 parts of butyl perbenzoate (t-BPB) was charged into a flask similar to Kinraizou Example 1 and kept at 90°C for 1 hour.Then, the temperature was raised to 115°C over 30 minutes, and at the same temperature, the remaining A mixture consisting of 800 parts of the monomer mixture, 300 parts of isobutyl acetate, 10 parts of t-BPB, and 5 parts of ATBN was added dropwise over 3 hours, and the temperature was further maintained for 10 hours to determine NV-so, os, and viscosity. (Gardner viscosity at 25°C: same below) Z.

M, = 15000 and hydroxyl value (hereinafter referred to as gold)
OH value". ) 25 was obtained.

Hereinafter, this resin solution will be abbreviated as t(II-x).

Production Example 8 (Preparation of polyester polyol) 2 pieces of isophthalic acid were placed in 9 reaction vessels equipped with a stirrer, thermometer, and water separator.
00 parts of phthalic acid, 200 parts of adipic acid, 365.3 parts of neoantyl glycol, and 124 parts of trimethylol alcohol were added, and the temperature was raised to 180°C while stirring. It took 5 hours to raise the temperature from 180°C to 230°C at a nearly constant rate, and then the temperature was maintained at 230°C. Furthermore,
It was gradually added to 720 parts of Kijirole, and the method was switched to an azeotropic condensation method. The acid value of the resin was monitored while maintaining the reaction temperature at 230°C, and the reaction was completely completed when the acid value reached 4.0. The obtained ester polyol has an OH value of 54 and an NV of about 6.
0%, Mn 3000, and was oil-free.

Hereinafter, this resin solution will be abbreviated as t(n-2).

Examples 1 to 8 Top coat paints and pace coat paints were prepared separately by a conventional paint preparation method using the blending ratios (parts by weight) shown in Table 1, and then 1,000 silenes/toluene/ethyl acetate = 3
Diluted to a spray viscosity with a mixed solvent of 0150/20 (weight ratio), a dry coating of 15 μm each of the pace coat paint and the torag coat paint was applied to a zinc phosphate treated steel plate.
The two types of paint were applied by air spray so that the coating thickness was 30 μm and the interval between coatings was 2 minutes, and the entire cured coating film was formed by heating at 80° C. for 30 minutes. Table 1 shows the results of the evaluation of the physical properties of each coating film obtained in this way.

The physical properties were evaluated after being left at room temperature for 3 days after forced drying.

Evaluation method: ◎Very excellent.

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Claims (1)

[Claims] A paint (base coat) mainly composed of a curable resin containing metallic powder and/or colored pigment is applied, and then a clear paint (top coat) mainly composed of a curable resin is applied to the painted surface. ) is applied and then cured, as the resin component of the base coat paint, [I] a vinyl polymer (A) having at least one cyclocarbonate group in one molecule and a polyketimine compound ( B), and as a resin component of the top coat paint, [II] a resin composition obtained by blending a polyisocyanate with a vinyl polymer polyol and/or a polyester polyol. A painting finishing method characterized by forming a hardened paint film.