JP2003128958A - Coating composition and method for coating finish using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both a quick-curing one-part coating composition having a composite curing mechanism of a curing system containing hydroxy group protected in the form of siloxy group and an isocyanate group and a photocuring system with a polymerizable unsaturated group and a method for coating finish using the coating composition as a top clear. SOLUTION: This coating composition comprises (a) a resin containing at least one or more kinds of functional groups selected from the siloxy group and isocyanate group, (b) a compound containing at least one or more kinds of functional groups selected from the siloxy group and isocyanate group and reactive with the functional groups contained in the resin (a), (c) a polymerizable unsaturated group-containing compound, (d) a siloxy group-dissociating catalyst and (e) a photopolymerization initiator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-pack type coating composition having a composite curing mechanism of a curing system containing a hydroxyl group protected in the form of a siloxy group and an isocyanate group and a photocuring system based on a polymerizable unsaturated group. The present invention relates to a composition and a coating finishing method using the composition as a top clear. The compositions and methods of the present invention are particularly suitable for use in automotive repairs.

[0002]

2. Description of the Related Art At present, in the field of automobile repair, acrylic lacquer is used for workability and room temperature curing is also used.
From the viewpoint of finishability, weather resistance and the like, a two-pack type coating material comprising a combination of an acrylic polyol and a polyfunctional isocyanate curing agent is widely used. However, the acrylic lacquer has problems such as inferior finish compared to the two-pack type, and the two-pack type is inferior in workability because the main agent and the curing agent must be blended at the painting site. There is a problem that the excess or deficiency of the above influences the coating performance, and that the viscosity of the base resin is high due to the hydrogen bond of the hydroxyl group, so that a large amount of the diluting solvent must be used. In order to solve these problems, by using a siloxy group-containing vinyl polymer instead of the conventional hydroxyl group-containing vinyl polymer,
Techniques such as a one-pack type resin composition comprising this and a polyfunctional isocyanate curing agent have been proposed (for example,
JP-A-3-250016 and JP-A-5-5057). However, coatings using these resin compositions require drying for 20 minutes to 1 hour in a 60 ° C. atmosphere for curing after coating, and development of coatings that cure in a short time has been desired.

On the other hand, in recent years, a composition utilizing photo-curing having a fast curing property has also been proposed (Japanese Patent Laid-Open No. 9-10030).
No. 6, JP-A 2000-344856, etc.). According to this composition, curing progresses rapidly and a coating film excellent in hardness and adhesiveness can be formed, but there is a problem that the adhesiveness is insufficient depending on the coated surface.

An object of the present invention is to provide a one-pack type coating composition which is fast-curing and does not impair coating properties such as adhesion and weather resistance.

[0005]

The present invention includes: (A) a resin containing at least one functional group selected from a siloxy group and an isocyanate group, (b)
A compound containing at least one functional group selected from a siloxy group and an isocyanate group and capable of reacting with the functional group contained in the resin (a), (c) a compound containing a polymerizable unsaturated group, (d) 1. A coating composition comprising a siloxy group dissociation catalyst and (e) a photopolymerization initiator. 2. The coating composition according to item 1, wherein the component (a) is a resin containing two or more siloxy groups in one molecule, and the component (b) is a polyisocyanate compound. Hydroxyl groups formed from isocyanate groups and siloxy groups in the composition have an equivalent ratio of NCO / OH = 0.5 to 2.0.
3. The coating composition according to item 1, which is within the range of 4. 4. The coating composition according to item 1, wherein the component (c) is a monomer or oligomer having at least one acryloyl group or methacryloyl group in one molecule. The amount of component (c) used is such that the total resin solid content in the paint is 10
5. The coating composition according to claim 1, which is in the range of 5 to 90 parts by weight relative to 0 parts by weight. A coating finish method in which a base coat paint is applied to the surface to be coated, then a clear coat paint is applied to the coating surface, and light is irradiated to simultaneously cross-link and cure both coating films,
The present invention relates to a coating finishing method using the coating composition according to any one of items 1 to 5 as the clear coat coating material.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a resin (a) containing at least one functional group selected from a siloxy group and an isocyanate group is usually a vinyl-based resin having each of these reactive functional groups. It can be obtained by appropriately selecting monomers and copolymerizing them with other vinylic monomers copolymerizable with them in the presence of a radical polymerization initiator by a conventional method such as a solution polymerization method. Specifically, a monomer mixture containing one or both of a siloxy group-containing vinyl monomer and an isocyanate group-containing vinyl monomer is copolymerized.

In the present invention, the siloxy group is represented by the following formula (I)

[0008]

[Chemical 1]

(In the formula, 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).

Typical examples of the siloxy group-containing vinyl monomer are, for example, trimethylsiloxyethyl (meth) acrylate, trimethylsiloxypropyl (meth) acrylate, trimethylsiloxybutyl (meth) acrylate and triethylsiloxyethyl (meth). )
Examples thereof include trialkylsiloxyalkyl (meth) acrylates such as acrylate, triethylsiloxypropyl (meth) acrylate, and triethylsiloxybutyl (meth) acrylate, but not limited to these, the hydroxyl group in the hydroxyl group-containing vinyl monomer is commonly known. Any compound can be used as long as it is a compound converted to a siloxy group with the silylating agent. That is, hydroxyethyl (meth) acrylate to which ε-caprolactone is added, polyoxyalkylene glycol (meth) acrylates converted into siloxy groups with a silylating agent such as trimethylchlorosilane and t-butyldimethylchlorosilane, respectively. Can also be used.

In the present invention, "(meth) acrylate" means "acrylate or methacrylate".

Representative examples of the isocyanate group-containing vinyl monomer include isocyanate ethyl (meth) acrylate, isocyanate propyl (meth) acrylate, and meta-isopropenyl-α, α-dimethylbenzyl isocyanate. However, the present invention is not limited to this, and an adduct of a hydroxyl group-containing vinyl monomer such as hydroxyethyl (meth) acrylate and a polyfunctional isocyanate compound such as isophorone diisocyanate can also be used.

Typical examples of other vinyl monomers copolymerizable with the above-mentioned vinyl monomer having a reactive functional group are, for example, vinyl aromatic compounds such as styrene, α-methylstyrene and vinyltoluene. Group compounds; methyl (meta)
Acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (n-, i-, t-) butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) Carbon number of acrylic acid or methacrylic acid such as acrylate, n-octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate ~ 24 alkyl ester or cycloalkyl ester; methoxybutyl (meth) acrylate,
C2-C18 alkoxyalkyl esters of acrylic acid or methacrylic acid such as methoxyethyl (meth) acrylate and ethoxybutyl (meth) acrylate; (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2 -Carboxyl group-containing polymerizable unsaturated monomer such as carboxyethyl (meth) acrylate; epoxy group-containing polymerizable unsaturated monomer such as glycidyl (meth) acrylate; perfluorobutylethyl (meth)
Acrylate, perfluoroisononylethyl (meth)
Perfluoroalkyl (meth) acrylates such as acrylate and perfluorooctylethyl (meth) acrylate; CF2 = CF2, CHF = CF2, CH2 = CF
2, CClF = CF2 and other general formulas CX2 = CX2 (wherein X is the same or different and represents H, Cl, Br, F, an alkyl group or a haloalkyl group, provided that at least one F is contained in the formula. 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl) -2H-benzotriazole, 4- (meth) acryloyloxy-1,2,2,
UV-absorbing or UV-stable polymerizable unsaturated monomers such as 6,6-pentamethylpiperidine; and polymers of one and / or more of these monomers at one end A so-called macromonomer having a copolymerizable double bond in the above is also mentioned as a monomer copolymerizable with the vinyl-based monomer having a reactive functional group. These can be appropriately selected and used according to the desired physical properties.

Examples of the solvent used in the solution polymerization of the above monomer mixture include alkylbenzene derivatives such as benzene, toluene and xylene; acetic ester solvents such as ethyl acetate, propyl acetate, amyl acetate, methoxybutyl acetate and cellosolve acetate. Ether solvents such as dioxane, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, and diethylene glycol diethyl ether; ketone solvents such as methyl isobutyl ketone. These can be used alone or in admixture of two or more.

Radical polymerization initiators 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 thereof include azo compounds such as bisisobutyronitrile, α, α′-azobis-2-methylbutyronitrile, azobisdimethylvaleronitrile and azobiscyclohexanecarbonitrile.

The resin (a) may further contain an alkoxysilyl group from the viewpoint of improving curability and acid resistance.
In order to contain the alkoxysilyl group, an alkoxysilyl group-containing vinyl monomer is further used as the copolymerization component.

Typical examples of the above-mentioned vinyl monomer containing an alkoxysilyl group include, for example, vinyltrimethoxysilane, vinyltriethoxysilane and γ- (meth).
Acryloyloxypropyltrimethoxysilane, γ-
(Meth) acryloyloxypropyldimethoxymethylsilane, γ- (meth) acryloyloxypropyltriethoxysilane, styrylethyltrimethoxysilane,
Examples thereof include vinyl tris (2-methoxyethoxy) silane and vinyl triacetoxy silane.

The resin (a) obtained by a usual radical solution polymerization method using the above vinyl-based monomer, solvent and polymerization initiator has a weight average molecular weight of 1,000 to 200,000.
It is preferably 0, more preferably 2,000 to 100,000. When the weight average molecular weight is less than 1,000, it is difficult to obtain a satisfactory drying property, and the weather resistance and durability of the resulting coating film tend to decrease. On the other hand, 20
If it is more than 10,000, the finished appearance is deteriorated, which is not preferable.

In the present invention, the compound (b) containing at least one functional group selected from a siloxy group and an isocyanate group and capable of reacting with the functional group contained in the resin (a) may be a low molecular weight compound. It may be a resin, and when the resin (a) has a siloxy group, it is a compound containing an isocyanate group or a resin containing an isocyanate group and a siloxy group, and when the resin (a) has an isocyanate group. Is a compound containing a siloxy group or a resin containing a siloxy group and an isocyanate group. Further, the compound (b)
May be the same as the resin (a) when the resin (a) has both a siloxy group and an isocyanate group.

As the isocyanate group-containing compound used as the component (b), a polyisocyanate compound containing at least two isocyanate groups in one molecule can be used. Typical examples are tetramethylene diisocyanate, Aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; hydrogenated xylylene diisocyanates, 1,4-diisocyanates cycloaliphatic diisocyanates such as cyclohexane or isophorone diisocyanate; tolylene diisocyanates, 4,4 ′
-Organic diisocyanate itself such as aromatic diisocyanates such as diphenylmethane diisocyanate, or each of these organic diisocyanates and polyhydric alcohols,
Addition product with low molecular weight polyester or water, or a cyclized polymer of the above organic diisocyanates,
Further, an isocyanate / biuret body and the like can be mentioned. Examples of representative commercial products thereof include "Bernock D-750, -800, DN-950, -955,-.
970, -922 or 15-455 "[above, product of Dainippon Ink and Chemicals, Inc.]," Desmodur L,
N, HL, IL, or N3390 "[Product of Bayer Co.]," Sumijour N-3200 or N-350
0 "[Product of Sumika Bayer Urethane Co., Ltd.]," Takenate D-102, -202, -110N, -123N or -170N "[Takeda Pharmaceutical Co., Ltd. product]," Coronate L, HL, EH or 203 "[product of Nippon Polyurethane Industry Co., Ltd.] or" Duranate 24A-
90CX, TPA-100 "[Product of Asahi Kasei Corporation]
Etc. Further, as the component (b), a resin obtained by copolymerizing an isocyanate group-containing vinyl-based monomer with styrene, (meth) acrylic acid ester or the like can also be used.

From the viewpoint of scratch resistance and solubility in a solvent, the polyisocyanate compound is an adduct of diisocyanate and a long-chain polyhydric alcohol, for example, the above-mentioned diisocyanate and a C 10-30 carbon atom. Polyols such as alkylenediols, polycaprolactone polyols, polyether polyols and polyester polyols
A polyisocyanate compound obtained by reacting a diisocyanate compound with a polycaprolactone diol and / or triol can be preferably used. Specific examples of such polyisocyanate compounds include, for example, "Duranate E-402-90T, E-405-8.
Commercially available products such as "0T" [a product of Asahi Kasei Corporation] can be used.

As the siloxy group-containing compound used as the component (b), a compound containing at least two siloxy groups in one molecule can be used. Specifically, it contains at least two hydroxyl groups in one molecule. Any compound can be used as long as it is a compound in which the hydroxyl group of the compound is converted into a siloxy group by a known and commonly used silylating agent. Typical of these compounds are, for example, ethylene glycol, propylene glycol, 1,2-butanediol,
Dihydric alcohols such as 1,3-butanediol and 2,3-butanediol; polylactone diols obtained by adding lactones such as ε-caprolactone to these dihydric alcohols; glycerin, trimethylolpropane, pentaerythritol And other trihydric alcohols; polylactone polyols obtained by adding lactones such as ε-caprolactone to these trihydric or higher alcohols with silyl groups such as trimethylchlorosilane and t-butyldimethylchlorosilane. And the like. Further, as the component (b), the siloxy group-containing vinyl-based monomer listed in the description of the resin (a) is copolymerized with other vinyl-based monomers such as styrene and (meth) acrylic acid esters. The resulting resin can also be used.

As the siloxy group- and isocyanate group-containing resin used as the component (b), the siloxy group-containing vinyl type monomer and the isocyanate group-containing vinyl type monomer listed in the explanation of the resin (a) are used. The thing obtained by copolymerizing a monomer and these and other vinyl type monomers copolymerizable with them by a conventional method can be used.

The component (b) may further contain an alkoxysilyl group from the viewpoint of improving curability and acid resistance.
In order to contain the alkoxysilyl group, the alkoxysilyl group-containing vinyl-based monomer listed in the description of the resin (a) is further used as the copolymerization component.

In the present invention, in particular, as the component (a), a resin containing two or more siloxy groups in one molecule,
From the practical viewpoint, it is appropriate to select a polyisocyanate compound as the component (b).

The siloxy group content in the above-mentioned components (a) and (b) is the composition amount as the siloxy group-containing vinyl monomer and compound in both components, and the solid content is 5 to 60% by weight.
Further, it is preferably in the range of 10 to 50% by weight. If it is less than 10% by weight, the crosslink density of the coating film tends to be low, and the physical properties of the coating film tend to deteriorate. On the other hand, if the amount is more than 60% by weight, further improvement in performance cannot be expected.

The siloxy groups in the components (a) and (b) are hydrolyzed by water in the air after coating to form hydroxyl groups. Therefore, the composition amount as the isocyanate group-containing vinyl monomer and compound in the components (a) and (b) is such that the hydroxyl groups formed from the isocyanate group and the siloxy group have an equivalent ratio of NCO / OH = 0.5. It is preferable to be in the range of 2.0.

In the present invention, the polymerizable unsaturated group-containing compound (c) is a monomer or oligomer or polymer having an ethylenically unsaturated group, and examples of the monomer or oligomer include ethyl (meth) acrylate.
, Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, adamantyl (meth) acrylate, hydroxyethyl (meth) acrylate -, Trimethylolpropane tri (meth) acrylate, tetramethyl methanetetra (meth) acrylate, dipentaerythritol (meth) acrylate
, Tricyclodecane dimethanol di (meth) acrylate, neopentyl glycol di (meth) acrylate,
2,2-bis (4- (3-methacryloxy-2-hydroxypropoxy) -phenyl) propane, di (methacryloxyethyl) trimethylhexamethylenediurethane,
(Meth) of monovalent or polyvalent alcohols such as 2,2-bis (4-methacryloxypolyethoxyphenyl) propane
Acrylic ester; ethylene glycol dimaleate,
Propylene glycol diitaconate, etc .; 4- (meth) acryloyloxymethoxycarbonylphthalic acid,
Aromatic polycarboxylic acid containing 4- (meth) acryloyloxyl group such as 4- (meth) acryloyloxyethoxycarbonylphthalic acid and acid anhydride thereof; styrene, α
-Methylstyrene, chlorostyrene, vinyltoluene,
Aromatic vinyl compounds such as t-butyl styrene and divinyl benzene; diallyl phthalate, diallyl isophthalate, triallyl phthalate; epoxy acrylate,
Examples thereof include monomers and oligomers such as ethylene oxide-modified epoxy acrylate polyester acrylate, polydimethylsilicon di (meth) acrylate, and urethane acrylate. These can be used alone or in combination of two or more. As the polymer, for example, those obtained by introducing an ethylenically unsaturated group into various resins such as acrylic resins, polyester resins, polyurethane resins, and polyether resins can be used. Specifically, for example, a carboxyl group Acrylic resin or polyester resin having glycidyl (meth) acrylate added, vinyl resin having hydroxyl group or maleic anhydride or itaconic anhydride added to polyester resin, acrylic resin having epoxy group Addition of (meth) acrylic acid to polyester resin with hydroxyl group (meth)
Acrylic acid-condensed resin, unsaturated polyester resin, urethane resin having isocyanate group to which 2-hydroxyethyl (meth) acrylate or the like is added, acrylic resin having hydroxyl group to 2-hydroxyethyl ( Examples thereof include resins having an equimolar addition reaction product of a (meth) acrylate or the like and a diisocyanate compound added thereto.

Among these, as the polymerizable unsaturated compound (c), a monomer or oligomer having at least one acryloyl group or methacryloyl group in one molecule is particularly preferable from the viewpoint of weather resistance and coating film physical properties. .

The component (c) is used in an amount of 5 to 90 parts by weight, preferably 5 to 80 parts by weight, based on 100 parts by weight of the total resin solid content in the coating composition. If the amount used is less than 5 parts by weight, the rapid drying property due to photo-curing of the obtained coating film becomes insufficient, and if it exceeds 90 parts by weight, the volume shrinkage of the coating film becomes large and the adhesion and physical properties of the coating film deteriorate. Is not desirable.

The resin component of the present invention includes the above-mentioned (a),
Although (b) and (c) are sufficient, if necessary, they are different from the above (a) and (b) and selected from a siloxy group, an isocyanate group and an alkoxysilyl group in one molecule. One or more kinds of the compound (f) containing two or more kinds of the one or more kinds of functional groups may be added to the resins (a) and (b).

The compound (f) may be either a low molecular weight compound or a resin. As the low molecular weight compound, those listed in the above compound (b) can be used, and the resin is a structural unit of the resin (a). Siloxy group-containing vinyl-based monomer, isocyanate group-containing vinyl-based monomer, alkoxysilyl group-containing vinyl-based monomer and other vinyl-based monomers appropriately selected from the above-mentioned conventional methods Those obtained by (co) polymerizing according to the above can be used.

In the present invention, the siloxy group is hydrolyzed by water in the air after coating to form a hydroxyl group.
In the present invention, the siloxy group dissociation catalyst (d) is an essential component for promoting this hydrolysis reaction. Typical examples of the compound used as the siloxy group dissociation catalyst (d) are, for example, phosphoric acid and its acidic esters, phosphites; sulfonic acids such as paratoluenesulfonic acid and naphthalenedisulfonic acid, and amine salts thereof; Examples thereof include carboxylic acids such as trichloroacetic acid and trifluoroacetic acid, and acidic compounds such as amine salts thereof.

The siloxy group dissociation catalyst (d) is added in an amount of 0.01 to 1 with respect to the solid content of the resin composition in the coating material.
It is preferably in the range of 0% by weight, more preferably 0.1 to 5% by weight. If it is less than 0.01% by weight, the curability is lowered, and if it is more than 10% by weight, the water resistance of the coating film tends to be poor.

In the present invention, the photopolymerization initiator (e) is 3
Any conventionally known one can be used without particular limitation as long as it generates a radical by being excited by light energy in the region of 00 nm or more and initiates radical polymerization. Specifically, for example, 4-phenoxydichloroacetophenone,
4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl)
2-hydroxy-2-methylpropan-1-one, 1
-(4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyphenoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone,
2-Methyl-1- [4- (methylthio) phenyl] -2-
Acetophenone compounds such as morpholinopropanone-1; thioxanthone, 2-chlorothioxanthone, 2-
Thioxanthone compounds such as methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, and 2,4-dichlorothioxanthone; benzyl,
Benzyl compounds such as benzyl dimethyl ketal, benzyl-β-methoxyethyl acetal, 1-hydroxycyclohexyl phenyl ketone; benzophenone, o-
Methyl benzoylbenzoate, Michler's ketone, 4,
4'-bisdiethylaminobenzophenone, 4,4'-
Benzophenone compounds such as dichlorobenzophenone;
Benzoin ether compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isobutyl ether; camphor-quinone, anthraquinone, 3-ketocoumarin, α-naphthyl, 2,4,6
-Trimethylbenzoyl, diphenylphosphine oxide, acylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 10-butyl-2-chloroacridone, Examples include fluorenone. Other known initiator systems include cationic dyes-ionic dyes such as borate anion compounds-counterion compounds (for example, JP-A 1-60606 and JP-A 2-111607), metal arrays. Compounds and organic dye systems (for example,
JP-A-4-363308, JP-A-5-17525), and the like. Further, cyanine dyes, phthalocyanine dyes, pyrylium dyes, thiopyrylium dyes, azulenium dyes, squarylium dyes, N
Metal complex salt type dyes such as i and Cr, naphthoquinone type / anthraquinone type dyes, indophenol type dyes, indoaniline type dyes, triphenylmethane type dyes, triallylmethane type dyes, aminium type / diimmonium type dyes, nitroso compounds Complexes of cationic dyes such as those mentioned above can be used, and specifically, they are described in JP-A-62-143044 and JP-A-2-11.
No. 607, JP-A-3-111402, JP-A-5-19
4619, Japanese Patent Application Laid-Open No. 4-77503, and the like, near-infrared light absorbing cationic dye-borate anion complex, and cyanine dyes and halogenated compounds disclosed in Japanese Patent Application Laid-Open No. 2-189548. A triazine compound or a cyanine compound having a methyl group and a metal arene compound, a metal arene compound and a squarylium dye disclosed in JP-A-5-17525, and JP-A-2-4804.
Examples thereof include cationic dyes and borate salts disclosed in Japanese Patent Laid-Open Publications and the like.

The content of the photopolymerization initiator (e) is 0.01 to 10% by weight based on the solid content of the resin composition in the coating material.
The range of is suitable.

The coating composition of the present invention comprises the resin component described above, a siloxy group dissociation catalyst, and a photopolymerization initiator. Further, in order to promote the reaction between the hydroxyl group formed and the isocyanate group, an organic material such as dibutyltin dilaurate is used. A known and commonly used urethane-forming catalyst such as a tin compound may be added in advance. Further, in order to accelerate the photopolymerization reaction, known photosensitizers, chain transfer agents and the like can be added.

In order to prevent hydrolysis of siloxy groups and ensure long-term storage stability, it is desirable to add a water-binding agent for trapping water to the composition of the present invention. As a water-binding agent, trimethyl orthoformate, triethyl orthoformate,
Trialkyl orthoformates such as tributyl orthoformate;
Trialkyl orthoacetates such as trimethyl orthoacetate, triethyl orthoacetate and tributyl orthoacetate, and monoisocyanate compounds such as phenylisocyanate, p-chlorophenylisocyanate and p-toluenesulfonyl isocyanate, for example, "Additive TI"
Commercially available products such as (produced by Sumika Bayer Urethane Co., Ltd.) can be used.

The composition of the present invention obtained as described above can be used as a one-pack type paint by adjusting the viscosity to a suitable level with a diluting solvent.

The diluting solvent used has a flash point of 0.
It is not particularly limited as long as it is an organic solvent having a temperature of ℃ or more, for example, hydrocarbons such as toluene, xylene, mineral spirits,
Ketones such as methyl isobutyl ketone, esters such as ethyl acetate, butyl acetate and amyl acetate, ethers such as dioxane, ethylene glycol, diethylene glycol
Methyl ether such as propylene glycol, propylene glycol, hexylene glycol, ethyl ether, propyl ether,
Examples include glycol ether acetate such as butyl ether, and propionates. These may be used alone or in combination of two or more, and it is desirable from the viewpoint of safety that the flash point of the whole organic solvent in the composition is selected to be 21 ° C. or higher.

The composition of the present invention can also be made into an aerosol paint by adding a propellant to the above-mentioned paint component and filling the paint component together with the propellant into an aerosol container. As the propellant, known dimethyl ether, LP gas and the like can be used alone or in combination.

The composition of the present invention may further be blended with a fibrin resin such as nitrocellulose, cellulose acetate butyrate or an epoxy resin in order to improve the physical properties. Furthermore, if necessary, pigments (for example, aluminum paste, pearl powder, graphite,
Additives for paints such as metallic pigments such as MIO, organic and inorganic coloring pigments such as titanium oxide and carbon black, extender pigments, etc., ultraviolet absorbers, light stabilizers, antioxidants, surface conditioners, dispersants, etc. Etc. may be contained.

Further, in the present invention, there is provided a coating finishing method in which the coating composition obtained as described above is used as a clear coat coating, which is coated on the base coat coating surface and irradiated with light to simultaneously cross-link and cure both coating layers. It is provided.

Examples of the surface to be coated with the base coat paint include metal surfaces such as iron, zinc, and aluminum, chemically treated surfaces thereof, plastics, wood, and the like, and the coating surface coated on these. Examples of the surface include an automobile body on which an electrodeposition coating or an intermediate coating is applied, or a repair coating surface of the automobile body.

As the base coat paint, any conventionally known base coat paint containing a metallic pigment and / or a coloring pigment can be used without particular limitation, and a lacquer paint containing no crosslinking agent or a crosslinking agent such as a polyisocyanate compound is contained. Organic solvent-based paints such as curable paints and water-based paints can be used without particular limitation. When cross-linking and curing are simultaneously performed with the clear coat coating film, a resin having an active hydrogen group such as a hydroxyl group and a composition containing a metallic pigment and / or a coloring pigment as main components are suitable as the base coat coating material. As the hydroxyl group-containing resin, for example,
Hydroxyl group-containing acrylic resin, hydroxyl group-containing polyester resin, hydroxyl group-containing polyurethane resin, hydroxyl group-containing polyester resin
Tell resin etc. are mentioned. Also, for the base coat paint,
Furthermore, if necessary, additives for paints such as a phosphoric acid group-containing acrylic resin, an ultraviolet absorber, a light stabilizer, an antioxidant, a surface conditioner, a pigment dispersant, and a curing catalyst can be appropriately mixed.

The base coat paint and the clear coat paint of the present invention can be applied by any known method in the field of coating such as spray coating, brush coating, roller coating, gravure and screen coating. Usually, the base coating is a dry film. The thickness is about 5 to 60 μm, preferably about 10 to 50 μm,
The clear coat is applied to a dry film thickness of about 10 to 80 μm, preferably about 20 to 50 μm.

As a light source used for light irradiation, 300
It can be used without particular limitation as long as it emits a wavelength of not less than nm, and examples thereof include a halogen lamp, a xenon lamp, a krypton lamp, a metal halide lamp, a fluorescent lamp, sunlight, a semiconductor laser, and a light emitting diode. The irradiation conditions can be appropriately selected depending on the thickness and composition of the base layer and the clear layer.

[0048]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. Hereinafter, "parts" and "%" are based on weight unless otherwise specified.

Production of Acrylic Resin Production Examples 1 to 4 A reactor was equipped with a thermometer, a thermostat, a stirrer, a reflux condenser and a dropping pump, and 60 parts by weight of xylene was charged and the temperature was raised to 110 ° C. with stirring. While maintaining the mixture of the monomer and the polymerization initiator shown in 1 at 110 ° C., the mixture was dropped at a constant rate over 3 hours using a dropping pump.
After completion of dropping, the temperature was maintained at 110 ° C. for 1 hour, and stirring was continued. Then, an additional 0.5 parts by weight of a polymerization initiator dissolved in 5 parts by weight of xylene was added dropwise at a constant rate over 1 hour, and the reaction was terminated by maintaining the temperature at 110 ° C. for 1 hour. Each of the obtained resin solutions (a-1) to (a-4) has a nonvolatile content of 60% by weight.
Was a uniform and transparent solution. Table 1 also shows property values of the obtained resins and resin solutions.

[0050]

[Table 1]

Preparation of clear paint Examples 1 to 5 and Comparative Examples 1 to 5 Resin solutions obtained in the above production examples, polyisocyanate compound (Note 1), diisopropyl phosphate (siloxy group dissociation catalyst), dibutyltin dilaurate (Urethane-forming catalyst), trimethyl orthoacetate (water binder), urethane acrylate (Note 2), isobornyl acrylate, and photopolymerization initiator (Note 3) were compounded in the composition shown in Table 2, and further organic Solvent (xylene / ethyl acetate = 80/2
0) was appropriately added, mixed and stirred, and the viscosity was adjusted to about 15 seconds (Ford cup # 4/25 ° C.) to prepare each clear paint.

(Note 1) "TPA-100": Asahi Kasei Corporation, trade name, hexamethylene diisocyanate-based polyisocyanate (Note 2) "CN983": Sartomer, trade name, urethane acrylate oligomer (Note 3) " IRGACURE-184 ": manufactured by Ciba Specialty Chemicals, trade name, 1-hydroxy-cyclohexyl-phenyl ketone

[0053]

[Table 2]

Performance test [Magiclon TC-71 clear] (Kansai Paint Co., Ltd., amino acrylic resin clear) was coated on a steel plate so that the dry film thickness was 40 μm, and baked at 140 ° C. for 20 minutes to form a coated plate. As a test plate, each of the clear coatings obtained by viscous adjustment as described above was dried to a thickness of about 40.
Spray coating to a size of μm, and using a halogen lamp “PAR36MF” (product name, manufactured by Iwasaki Electric Co., Ltd.) as a light source on this coated surface, light is irradiated for 10 minutes under the irradiation conditions of 110 V, 500 W and irradiation distance of 50 cm, and each test coated plate Got The test coated plate thus obtained was subjected to the following performance test. The results are shown in Table 3.

(* 1) Curability: The tackiness of the surface of the test coated plate immediately after light irradiation was examined by touching with a finger and evaluated according to the following criteria. ◯: Good with no tackiness on the surface, Δ: Slightly tacky on the surface, X: Significantly tacky on the surface.

(* 2) Finishing property: 24 at 20 ° C. after light irradiation
The smoothness of the surface of the test coated plate after being left for a period of time was visually evaluated (◯: good, Δ: somewhat bad, ×: bad).

(* 3) Pencil hardness: 24 at 20 ° C. after light irradiation
The pencil hardness of the surface of the test coated plate after being left for a time is JIS K-5.
It measured based on 400. The evaluation was broken.

(* 4) Accelerated weather resistance: 2 at 20 ° C. after light irradiation
The test coated plate after being left for 4 hours was tested with a sunshine weatherometer for 1,000 hours, and it was confirmed whether or not the coated surface was changed. ◯: The coated surface is good with no change, Δ: Slightly shiny, ×: Significantly shiny.

(* 5) Pot life: Each clear paint was sealed and stored at 20 ° C., and the period until gelation was examined.

[0060]

[Table 3]

Coating Examples 6 to 11 and Comparative Examples 6 to 9 A commercially available two-pack type urethane curable primer surfacer was coated on a tin plate to a dry film thickness of 40 μm.
The base coat paint A (Note 4) or B (Note 5) was diluted with thinner for 11 to 12 seconds (Ford Cup #
(4/25 ° C.) and spray-coated so that the dry film thickness is 15 μm, and after touch-drying, each clear coating obtained by viscous adjustment is dried with the combination shown in Table 4. Spray paint to a film thickness of 40 μm, and use a halogen lamp “PAR36MF” (product name, manufactured by Iwasaki Electric Co., Ltd.) as a light source on this coated surface, 110 V / 500 W, irradiation distance 5
Each test coated plate was obtained by irradiating with light for 10 minutes under the irradiation condition of 0 cm. The test coated plate thus obtained was subjected to a performance test. The curability, finish, and accelerated weather resistance are the same as in the above test. The results are shown in Table 4.

(Note 4) Base coat paint A: "Retan P"
G-Hybrid # 835 Metallic Flash White "manufactured by Kansai Paint Co., Ltd., an acrylic polyol-based paint containing no isocyanate crosslinking agent.

(Note 5) Base coat paint B: "Retan P"
G2K # 835 Metallic Flash White ", two-component acrylic urethane paint manufactured by Kansai Paint Co., Ltd.

(* 6) Adhesion: After irradiating with light for 24 hours at 20 ° C., the coating film of the test coated plate was cut with a knife to reach the base material, and 100 pieces of 2 mm intervals were formed.
When the cellophane tape was applied on top of it, and was rapidly peeled off, the number of burrs left on the coated surface was evaluated (○: 100,
X: 99 or less).

(* 7) Water resistance: After the test coated plate, which had been left at 20 ° C. for 24 hours after being irradiated with light, was immersed in 20 ° C. clean water for 7 days, blisters, glossiness and whitening of the coated surface were visually evaluated (◯: No abnormality, △: Slight gloss is seen, ×: Blisters,
Luster and bleaching are seen).

[0066]

EFFECTS OF THE INVENTION According to the present invention, a one-pack type coating composition having a fast curing property can be obtained without impairing the coating performance such as adhesion and weather resistance. The composition of the present invention is suitable for coating automobile repairs, automobile parts, railway vehicles, industrial equipment, woodwork and the like.

[0067]

[Table 4]

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D075 AE03 AE06 AE09 BB26Z                       CA13 CA32 DA06 DA23 DB31                       DC12 EA07 EA43 EB22 EB23                       EB24 EB38 EB43 EB56 EC02                       EC37                 4J038 DG262 FA012 FA112 FA161                       FA211 FA241 GA11 GA15                       KA03

Claims (6)

[Claims] 1. A resin containing (a) at least one functional group selected from a siloxy group and an isocyanate group, and (b) a resin containing a resin (a) selected from a siloxy group and an isocyanate group. A compound containing at least one functional group capable of reacting with a functional group, a compound containing a polymerizable unsaturated group, (c) a siloxy group dissociation catalyst, and (e) a photopolymerization initiator. A coating composition characterized by: 2. The coating composition according to claim 1, wherein the component (a) is a resin containing two or more siloxy groups in one molecule, and the component (b) is a polyisocyanate compound. 3. Hydroxyl groups formed from isocyanate groups and siloxy groups in the composition have an equivalent ratio of NCO / OH = 0.5.
The coating composition according to claim 1, wherein the coating composition is in the range of 2.0. 4. The coating composition according to claim 1, wherein the component (c) is a monomer or oligomer having at least one acryloyl group or methacryloyl group in one molecule. 5. The coating composition according to claim 1, wherein the amount of the component (c) used is in the range of 5 to 90 parts by weight based on 100 parts by weight of the total resin solid content in the coating. 6. A coating finishing method comprising coating a base coat paint on a surface to be coated, then coating a clear coat paint on the coating surface, and irradiating with light to simultaneously cross-link and cure both coating films. A coating finish method comprising using the coating composition according to any one of claims 1 to 5 as a clear coat coating.