JPH11131015A - Coating material composition and coating finish using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating material composition which is a curing system containing hydroxy groups protected in the form of siloxy groups and isocyanate group and useful especially as a base coating material for repairing automobiles. SOLUTION: This coating material composition is obtained by adding (II) a diluting solvent prepared by including a siloxy group-dissociating catalyst therein to (I) a base coating material containing a resin composition prepared by compounding (a) a resin containing at least two siloxy groups in one molecule, (b) a cellulosic derivative and (c) a polyisocyanate compound so as to provide 5-40 wt.% cellulosic derivative (b) in the total resin solid content and the ratio NCO/OH of the isocyanate groups in the compound (c) to hydroxyl groups produced from the siloxy groups in the resin (a) within the range of 0.5-2.0 expressed in terms of equiv. ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hardening type coating composition containing a hydroxyl group and an isocyanate group protected in the form of a siloxy group, and is particularly useful as a base coating for automotive repair. The present invention relates to a coating composition and a paint finishing method using the same.

[0002]

2. Description of the Related Art At present, in the field of automobile repair,
Acrylic lacquers are widely used from the viewpoint of workability, and two-pack paints composed of a combination of acrylic polyol and polyisocyanate are widely used in terms of room temperature curability, finishability, weather resistance and the like. As a base coat paint of 2-coat 1-bake coating, a lacquer obtained by blending cellulose acetate, nitrocellulose, a plasticizer, and melamine with acrylic polyol. A two-pack base coat prepared by blending a base coat paint, a main agent containing acrylic polyol, cellulose acetate butyrate or nitrocellulose, and a curing agent containing polyisocyanate at the time of use. Paint.

[0003] However, a coating film made of a lacquer-based base paint has poor adhesion and water resistance, and when re-repaired, it is re-dissolved by the solvent of the re-repair paint to cause scum. In a two-pack basecoat paint, the main agent and the curing agent must be blended at the painting site, resulting in poor workability. Excessive or insufficient blending amount of the curing agent affects the performance of the coating film. There is a problem that a large amount of a diluting solvent must be used because the viscosity of the base resin is high due to hydrogen bonding.

In order to solve these problems, a one-pack type resin comprising a siloxy group-containing vinyl polymer instead of a conventional hydroxyl group-containing vinyl polymer and a polyfunctional isocyanate curing agent is used. There have been proposed techniques such as a composition (for example, JP-A-3-250016 and JP-A-5-5057).
There has also been proposed a coating finishing method (Japanese Patent Application Laid-Open No. 62-254876) which is used for a base coat of coat one-bake coating.

[0005] However, in the case of a coating film made of the basecoat paint, the drying property and finish property are insufficient, and the storage stability is lowered depending on the type of a siloxy group dissociation catalyst contained in the paint. was there.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, have found that a siloxy group-containing resin,
Base containing cellulose derivative and polyisocyanate compound
By blending a diluting solvent containing a siloxy group dissociation catalyst immediately before coating with a coating viscosity while adjusting the coating viscosity, it is a one-pack type with no excess or deficiency of the curing agent, and excellent storage stability. It has been found that a coating composition having excellent drying properties and finish properties can be formed by using this as a base coating composition for two-coat one-bake coating. Reached.

That is, the present invention comprises (a) a resin containing at least two siloxy groups in one molecule, (b) a cellulose derivative, and (c) a polyisocyanate compound, and b) is 5 to 40% by weight based on the total resin solid content, and the polyisocyanate compound (c) has a hydroxyl group formed from an isocyanate group in the compound (c) and a siloxy group in the resin (a). NCO / OH = 0.
A coating composition characterized by adding a diluting solvent (II) containing a siloxy group dissociation catalyst to a base coating (I) containing a resin composition compounded in the range of 5 to 2.0. And a paint composition comprising a base paint containing a metallic pigment and / or a color pigment, and then a clear coat paint on the base paint. The present invention also provides a method of finishing a coating composition which is used as a coating composition, and the present invention further provides a base coating composition containing a metallic pigment and / or a coloring pigment, and then a clear coating composition. In a coating finishing method comprising applying a coating material, the base coating material comprises: (a) a resin containing at least two siloxy groups in one molecule; (b) a cellulose derivative; and (c) Polyisocyanate compound Is intended to include a resin composition having, and the clear - co - DOO paint is to provide a paint finishing method, characterized in that those comprising a siloxy group dissociating catalyst.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a siloxy group has the following formula:

[0009]

Embedded image

(Wherein, R ₁ , R ₂ and R ₃ may be the same or different and each represents an alkyl group having 1 to 18 carbon atoms, a phenyl group or an allyl group).

In the present invention, the resin (a) containing at least two siloxy groups per molecule generally contains a vinyl monomer having the siloxy group and another vinyl copolymer copolymerizable therewith. It can be obtained by copolymerizing a monomer with a conventional method such as a solution polymerization method in the presence of a radical polymerization initiator.

Typical examples of the siloxy group-containing vinyl monomer include, for example, trimethylsiloxyethyl (meth) acrylate, trimethylsiloxypropyl (meth) acrylate, trimethylsiloxybutyl (meth) acrylate, and triethylsiloxyethyl (meth) acrylate. )
Examples include trialkylsiloxyalkyl (meth) acrylates such as acrylate, triethylsiloxypropyl (meth) acrylate, and triethylsiloxybutyl (meth) acrylate. However, the present invention is not limited to this. Any compound can be used as long as it is converted into a siloxy group with the silylating agent. That is, hydroxyethyl (meth) acrylate with ε-caprolactone added thereto, compounds obtained by converting polyoxyalkylene glycol (meth) acrylates into siloxy groups with silylating agents such as trimethylchlorosilane and t-butyldimethylchlorosilane, etc. Can also be used.

Representative examples of the above-mentioned other vinyl monomers include, for example, vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene and α-chlorostyrene; methyl (meth) acrylate and ethyl (meth). ) Acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (n-, i-, t-)
Butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n
-Carbon number of acrylic acid or methacrylic acid such as octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and cyclohexyl (meth) acrylate;
4 alkyl esters or cycloalkyl esters; methoxybutyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxybutyl (meth) acrylate, and other acrylic or methacrylic acid having 2 to 1 carbon atoms
8 perfluoroalkylethyl (meth) acrylate, perfluoroalkyl (meth) acrylate such as perfluoroisononylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; CF2 = CF2, CHF = CF
2, a general formula CX such as CH2 = CF2, CCIF = CF2
2 = CX2 (where X is the same or different and H, C
l, Br, F, an alkyl group or a haloalkyl group. However, the formula contains at least one F. )
And a so-called macromonomer which is a polymer of one and / or more of these monomers and has a copolymerizable double bond at one end. Examples thereof include monomers copolymerizable with the group-containing vinyl monomer. From the viewpoint of improving low-temperature curability, for example, vinyl trimethoxysilane,
Vinyltriethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyldimethoxymethylsilane, γ-
Alkoxysilyl group-containing vinyl monomers such as (meth) acryloyloxypropyltriethoxysilane, styrylethyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltriacetooxysilane, and siloxy group-containing vinyl monomers And copolymerizable monomers. These can be appropriately selected and used according to desired physical properties.

Solvents used in the solution polymerization of the monomer mixture include, for example, alkylbenzene derivatives such as benzene, toluene and xylene; ethyl acetate, propyl acetate, amyl acetate, methoxybutyl acetate, methyl acetoacetate, methyl acetoacetate, Acetate solvents such as methyl cellosolve acetate, cellosolve acetate, diethylene glycol monomethyl ether acetate, carbitol acetate;
Ether solvents such as dioxane, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether; acetone,
Examples thereof include ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and these can be used alone or as a mixture of two or more.

Examples of the radical polymerization initiator include benzoyl peroxide, di-t-butyl hydroperoxide, t-butyl hydroperoxide, cumyl peroxide,
Peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, t-butylperoxybenzoate, lauryl peroxide, acetyl peroxide, t-butylperoxy-2-ethylhexanoate; α, α'-azo Examples include azo compounds such as bisisobutyronitrile, α, α'-azobis-2-methylbutyronitrile, azobisdimethylvaleronitrile, and azobiscyclohexanecarbonitrile.

The proportion of each monomer used is 5 to 99% by weight, preferably 10 to 6% by weight, of a siloxy group-containing vinyl monomer.
It is suitable that the content is 0% by weight, and 1 to 95% by weight, preferably 40 to 90% by weight of other vinyl monomers.

The resin (a) obtained by a usual radical solution polymerization method using the above-mentioned vinyl monomer, solvent and polymerization initiator has a weight average molecular weight of 1,000 to 200,000.
0, more preferably in the range of 2,000 to 100,000. When the weight average molecular weight is less than 1,000, satisfactory drying properties are hardly obtained, and the weather resistance and durability of the obtained coating film tend to decrease. On the other hand, 20
If it is larger than 000, the finished appearance is deteriorated, which is not preferable.

In the present invention, the cellulose derivative (b) is blended for improving the drying property. Examples thereof include nitrocellulose, cellulose acetate butyrate, cellulose acetate butyrate 5 and the like. 75% by weight and polymerizable unsaturated monomer 25 as listed in the description of resin (a)
A graft copolymer obtained by copolymerizing about 95% by weight can be used.

The amount of the cellulose derivative (b) is 5 to 40% by weight, preferably 10 to 30% by weight, based on the total resin solids.
It is. If the amount is less than 5% by weight, the arrangement of flake-like metallic pigments such as aluminum powder and pearl powder is deteriorated, which tends to cause unevenness. It is not preferable because it lowers.

In the present invention, the polyisocyanate compound (c) includes, for example, tetramethylene diisocyanate
Aliphatic diisocyanates such as hexamethylene diisocyanate and trimethyl hexamethylene diisocyanate
Alicyclic diisocyanates such as hydrogenated xylylene diisocyanate, 1,4-diisocyanate cyclohexane and isophorone diisocyanate; tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate Ne
And organic diisocyanates such as aromatic diisocyanates, and adducts of these organic diisocyanates with polyhydric alcohols, low molecular weight polyesters or water, or the above-mentioned organic diisocyanates. Cyclic polymers, further, isocyanate burettes and the like can be mentioned.

In the polyisocyanate compound (c), an isocyanate group in the compound (c) and a hydroxyl group generated from a siloxy group in the resin (a) are equivalent in NCO / OH equivalent ratio.
= 0.5 to 2.0.

In the present invention, the resin composition in the base paint (I) contains the above resin (a), cellulose derivative (b) and polyisocyanate compound (c) as essential components. Further, an acrylic resin (d) containing no hydroxyl group can be contained from the viewpoint of drying properties.

The acrylic resin (d) is the same as the resin (a)
One or two or more vinyl monomers appropriately selected from the other vinyl monomers listed in the description of the above are used in a solution polymerization method in the presence of a radical polymerization initiator similarly to the resin (a). It can be obtained by copolymerization according to a conventional method such as The amount of the acrylic resin (d) used is suitably not more than 30% by weight, preferably not more than about 20% by weight, based on the total resin solids.

In the present invention, if necessary, pigments (for example, metallic pigments such as aluminum paste, pearl powder, graphite, MIO, titanium white, carbon black) may be added to the base paint (I). Organic and inorganic coloring pigments, extenders, etc.), organic solvents, ultraviolet absorbers, antioxidants, dispersants, and other paint additives.

The base paint (I) includes a water binder for trapping water in the paint from the viewpoint of storage stability, and a urethane which promotes a reaction between a hydroxyl group generated from a siloxy group and an isocyanate group. A catalyst may be added.

Examples of the water binder include trialkyl orthoformates such as trimethyl orthoformate, triethyl orthoformate and tributyl orthoformate; and trialkyl orthoacetates such as trimethyl orthoacetate, triethyl orthoacetate and tributyl orthoacetate. Phenyl isocyanate, p-chlorophenyl isocyanate, p-
Monoisocyanate compounds such as toluenesulfonyl isocyanate can be used. As the urethanization catalyst, for example, an organotin compound such as dibutyltin dilaurate can be used.

In the present invention, the diluting solvent (II) is used to adjust the base paint (I) to a coating viscosity immediately before coating, and contains a siloxy group dissociation catalyst.

The siloxy group dissociation catalyst promotes a reaction in which a siloxy group is hydrolyzed by moisture in the air after coating to form a hydroxyl group. Typical examples thereof include phosphoric acid and its acid ester, and phosphorous acid. Esters; sulfonic acids such as paratoluenesulfonic acid and naphthalenedisulfonic acid and amine salts thereof; and acidic compounds such as carboxylic acids such as trichloroacetic acid and trifluoroacetic acid and amine salts thereof.

The siloxy group dissociation catalyst is used in the base paint (I).
It is suitable to add to the diluting solvent in a ratio of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the resin solid content therein.

Examples of the solvent used include alkylbenzene derivatives such as benzene, toluene and xylene; ethyl acetate, propyl acetate, amyl acetate, methoxybutyl acetate,
Acetate solvents such as methyl acetoacetate, ethyl acetoacetate, methyl cellosolve acetate, cellosolve acetate, diethylene glycol monomethyl ether acetate, carbitol acetate; ether solvents such as dioxane, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether A ketone solvent such as acetone, methyl ethyl ketone and methyl isobutyl ketone; and these can be used alone or as a mixture of two or more.

Since the coating composition of the present invention is prepared as described above, there is no excess or deficiency in the amount of the curing agent, and the composition is excellent in long-term storage properties.

According to the present invention, in a coating finishing method comprising coating a base coat paint containing a metallic pigment and / or a color pigment, and then coating a clear coat paint thereon. -A coating finishing method (1) using the coating composition of the present invention obtained as described above as a coating composition is provided. That is, the base paint is obtained by further adding a metallic pigment and / or a color pigment to the base paint (I) and adding a diluting solvent (II) containing a siloxy group dissociation catalyst. Used.

The clear core applied to the above method (1)
As the paint, conventionally known ones can be used without particular limitation, and specifically, are selected from resins having an active hydrogen-containing functional group such as a hydroxyl group, for example, a hydroxyl group-containing acrylic resin, a fluororesin, a fluorinated acrylic resin, and the like. Examples include urethane-curable paints containing at least one kind and a polyisocyanate compound as main components, and acrylic resin-based lacquer paints containing cellulose derivatives. Further, as the clear coat paint, a paint using a siloxy group-containing acrylic resin instead of the above-mentioned hydroxyl group-containing acrylic resin (for example, see JP-A-8-259887) can be preferably used.

[0034] Additives for paints such as an organic solvent, a surface conditioner, an ultraviolet absorber, a curing catalyst, and a pigment can be added to the clear coat paint, if necessary.

Further, in the present invention, the metallic pigment and / or
Alternatively, in a coating finishing method in which a base paint containing a coloring pigment is applied, and then a clear coat paint is applied thereon, the base paint contains (a) one molecule per molecule. A resin containing at least two siloxy groups, (b)
A resin composition containing a cellulose derivative and (c) a polyisocyanate compound;
A coating finishing method (2) in which the coating composition contains a siloxy group dissociation catalyst.

In the above method (2), the base paint (I) may be one obtained by further adding a metallic pigment and / or a color pigment to the base paint (I).

The clear core applied to the above method (2)
As the paint, any of the paints listed in the above-mentioned method (1) can be appropriately selected and used, and a siloxy group dissociation catalyst is used in an amount of 0.1 to 100 parts by weight of the resin solid content in the clear coat paint. It is contained in an amount of from 0.1 to 10 parts by weight, preferably from 0.1 to 5 parts by weight. At this time, the siloxy group dissociation catalyst may be used by being contained in a diluting solvent of the clear coat paint. By applying a clear coat paint containing the siloxy group dissociation catalyst on the base coat film, it acts on the siloxy groups in the base coat film to form a base coat film. Promotes the curing of

In the present invention, as the method of applying the above-mentioned base coat paint and clear coat paint, any method known in the field of coating such as spray coating, brush coating, and roller coating is used. The base coat usually has a dry film thickness of 5
６０60 μm, preferably about 10-50 μm, clear
The coating has a dry film thickness of 10 to 80 μm, preferably 20 to 80 μm.
Painted about 50 μm.

[0039]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.

Production Example 1 of Resin (a) A reactor was equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a dropping pump, and charged with 60 parts by weight of xylene. 103.5 parts by weight of a mixture of a monomer and a polymerization initiator shown in Table 1 was added to 110
The solution was dropped at a constant rate over 3 hours using a dropping pump while keeping the temperature at ° C. After completion of the dropwise addition, the temperature was maintained at 110 ° C. for 1 hour, and the stirring was continued. Thereafter, a solution prepared by dissolving 0.5 part by weight of an additional polymerization initiator in 5 parts by weight of xylene was added dropwise at a constant rate over 1 hour, and the reaction was terminated at 110 ° C. for 1 hour. The obtained siloxy group-containing resin solution has a nonvolatile content of 6%.
It was a homogeneous and clear solution with 0% by weight, Gardner viscosity LM. The weight average molecular weight of this resin was 14,000.

Production Examples 2 to 4 The same procedures as in Production Example 1 were carried out except that the mixture of the monomer and the polymerization initiator and the additional polymerization initiator were used as shown in Table 1, and that each siloxy group A contained resin solution was obtained. Table 1 shows the property values of the obtained resin and resin solution.

[0042]

[Table 1]

Preparation of Base Coating Paint Example 1 In a 2 liter container, 115 parts by weight of the siloxy group-containing resin solution obtained in Production Example 1, 100 parts by weight of a cellulose derivative (Note 1), and aluminum pigment (Note) 2) 10 parts by weight, 120 parts by weight of a solvent (Note 3), 1.5 parts by weight of a water binder (Note 4), and 5 parts by weight of an anti-settling agent (Note 5) were mixed and stirred with a disper. After the mixture became uniform, 18 parts by weight of polyisocyanate (Note 6) was mixed to prepare a base paint (I-1).

On the other hand, in a separate container, 30 parts by weight of toluene, 30 parts by weight of xylene, 40 parts by weight of butyl acetate, 0.05 parts by weight of dibutyltin dilaurate and 1 part by weight of diisopropyl phosphate as a siloxy group dissociation catalyst were mixed. As a result, a dilution solvent (II-1) was prepared.

The above base paint (I-1) was diluted with 100 parts by weight of the diluting solvent (II-1), and the viscosity was adjusted to about 10 seconds (for a hood cup # 4/25 ° C.) to obtain a base paint. -Paint was prepared and provided for painting.

Examples 2 to 4 and Comparative Examples 1 to 4 In the same manner as in Example 1, except that the base paint had the composition shown in Table 2, each base paint (I-
2) to (I-6) were prepared, and each basecoat paint was prepared in the same manner as in Example 1 except that a diluting solvent was used in the combinations and combinations shown in Table 3.

Each of the obtained basecoat paints was subjected to the following performance tests. The results are shown in Table 3. (Note) in Table 2 is as follows, and the diluting solvent (II-
2) has a composition obtained by removing the siloxy group dissociation catalyst from the diluting solvent (II-1). The performance test methods in Table 3 are as follows.

(Note 1) Cellulose derivative: "CAB551-
0.2 ", a product of Eastman Chemical Company, 30% butyl acetate solution.

(Note 2) Aluminum pigment: “Aluminum paste MC-606”, manufactured by Asahi Kasei Corporation (Note 3) Solvent: Toluene / xylene / butyl acetate = 30
/ 30/40 mixed solvent (Note 4) Water binder: Trimethyl orthoacetate (Note 5) Anti-settling agent: "Tarlen 7200-20", manufactured by Kyoeisha (Note 6) Polyisocyanate: "Duranate TPA" −
90E ", manufactured by Asahi Kasei Kogyo Co., Ltd. (* 1) Storage stability: The paint condition after each paint was left sealed at 40 ° C. for one month was visually evaluated (○: good, ×: cloudy).

(* 2) Drying property: Each paint was spray-painted on a tin plate to a dry film thickness of about 20 μm, and the time (minutes) until a touch-dry state was obtained was examined.

(* 3) Curability: Each paint was spray-coated on a tin plate to have a dry film thickness of about 20 μm, and the pencil hardness (JIS K 5400) after standing at 20 ° C. for 1 day was examined.

[0052]

[Table 2]

[0053]

[Table 3]

Coating Examples 5 to 10 and Comparative Examples 5 to 7 After degreasing the mild steel sheet, it was polished with a 400 # sandpaper, and then "Magicron TC-71" (manufactured by Kansai Paint Co., Ltd.) on the mild steel sheet. Aminoallyl resin paint) dried film thickness 30
The composition was spray-coated to a thickness of .mu.m, baked at 140.degree. C. for 20 minutes, and the coated surface was treated with a fine polishing compound to prepare a coated plate.

As shown in Table 4, each basecoat paint prepared as described above was spray-coated on the coated plate so as to have a dry film thickness of 20 μm, and after touch-drying, “Rethane PG2K Clear-M” ( A two-part urethane tank (manufactured by Kansai Paint Co., Ltd.) is spray-coated so as to have a dry film thickness of 40 μm by appropriately adjusting the viscosity with a diluting solvent.
For 30 minutes to obtain each coated plate.

In Examples 9 and 10, the diluting solvent (II-
1) was used, and the diluting solvent (II-2) was used in other examples.

Each of the obtained coated plates was subjected to the following performance tests.
The results are shown in Table 4.

(* 4) Curability: Each coated plate was allowed to stand at 20 ° C. for 1 day, and the pencil hardness (JIS K 5400) was examined.

(* 5) Adhesion: After leaving each coated plate at 20 ° C. for 3 days, 100 pieces of 2 mm square gobang were formed on the coated surface with an NT cutter, and a cellophane tape was stuck thereon. The number of remaining stitches left when the film was rapidly removed was examined.

(* 6) Water resistance: Each coated plate was left at 20 ° C. for 3 days, and then immersed in 40 ° C. tap water for one month. Thereafter, the state of the coated surface was visually evaluated (o: good, x: blister, swelling).

[0061]

According to the present invention, there can be obtained a one-pack type coating composition excellent in storage stability without excess or deficiency of the amount of a curing agent, and a two-coat one-bake coating composition. When used as a base coat paint for coating, a coating film having excellent drying properties and finish properties can be formed.

[0062]

[Table 4]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // C08G 18/62 C08G 18/62

Claims (5)

[Claims] 1. A resin containing at least two siloxy groups per molecule, (b) a cellulose derivative, and (c)
A polyisocyanate compound, wherein the cellulose derivative (b) is 5 to 40% by weight based on the total resin solid content, and the polyisocyanate compound (c) is an isocyanate group in the compound (c). And base resin (I) containing a resin composition in which hydroxyl groups generated from siloxy groups in resin (a) are blended in an equivalent ratio of NCO / OH = 0.5 to 2.0. And a diluting solvent (II) containing a siloxy group dissociation catalyst. 2. The resin (a) is a resin obtained by copolymerizing a vinyl monomer containing a siloxy group with another vinyl monomer copolymerizable with the monomer. A composition according to claim 1. 3. The composition according to claim 1, wherein the resin composition in the base paint (I) further contains an acrylic resin (d) containing no hydroxyl group. 4. A coating finishing method comprising coating a base paint containing a metallic pigment and / or a color pigment, and then coating a clear coat paint thereon. A paint finishing method comprising using the paint composition according to any one of claims 1 to 3 as a paint. 5. A coating finishing method comprising applying a base coat paint containing a metallic pigment and / or a color pigment, and then applying a clear coat paint thereon. (A) a resin containing at least two siloxy groups per molecule, (b) a cellulose derivative,
And (c) a resin finishing composition comprising a polyisocyanate compound, and wherein the clear coat paint contains a siloxy group dissociation catalyst.