JP7154725B2 - paint composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating composition suitable for in-mold coating, and particularly to a coating composition capable of forming a coating film with excellent adhesion to polyolefin materials without blending chlorinated polyolefin, modified polyolefin, or the like.

BACKGROUND ART In recent years, various plastic materials have been used as materials in place of metals in automobile parts and the like, and various coatings are applied to molded members. As a molding and painting method that saves processes and has a low environmental impact, after injecting a coating composition into the gap provided between the surface of a plastic molded body molded in a mold and the mold surface, this coating composition is applied. Attention is paid to an in-mold coating method (in-mold coating method) in which a coating is cured in a mold to produce an integrally molded product in which the coating adheres to the surface of the molded product. The present applicant also uses a thermosetting resin composition having a specific composition for in-mold coating of a fiber-reinforced plastic material (FRP) molded product in Patent Document 1 to form a coating film with excellent adhesion and finish. It proposes an in-mold coating method to obtain.

On the other hand, in-mold coat coating compositions that ensure adhesion to non-polar thermoplastic substrates such as polyolefin substrates, which are widely used as plastic materials, usually contain acrylic-modified polyolefins and chlorinated polyolefins. have been proposed (for example, Patent Document 2, Patent Document 3, etc.).

However, these compositions have the problem of poor compatibility between the polyolefin component and other resin components, resulting in poor long-term storage stability. is required.

On the other hand, in Patent Document 4, a polyolefin base material is a saturated aliphatic polyester urethane intermediate, a saturated aliphatic (meth)acrylate or a saturated cycloaliphatic (meth)acrylate (meth)acrylate, and one or more hydroxyalkyl It is disclosed to use a thermosetting coating composition comprising a (meth)acrylate, a polyacrylate ester of an alkylene polyol, one or more vinyl-substituted aromatics, and an initiator capable of generating free radicals.

JP 2013-184307 A Japanese Patent Application Laid-Open No. 2002-249680 JP-A-2003-138165 Japanese Patent Publication No. 2004-502570

However, when the composition of Patent Document 4 is used for in-mold coating, there is a problem that the releasability from the mold is insufficient, resulting in a poor yield in the production of the coating.

An object of the present invention is to provide a coating composition suitable for in-mold coating, which can be applied to various plastic materials, and which can form a coating film with excellent adhesion to polyolefin materials without the addition of chlorinated polyolefin. is to provide

As a result of earnest studies, the inventors of the present invention have found that the above object can be achieved by using a specific compounding composition, and have completed the present invention.
That is, the present invention provides (A) a polymerizable unsaturated compound having one polymerizable unsaturated group in one molecule and having a hydrocarbon group having 4 to 24 carbon atoms, (B) in one molecule (C) a polymerizable unsaturated compound having one polymerizable unsaturated group and a hydroxyl group, (C) a homopolymer glass having two polymerizable unsaturated groups in one molecule A polymerizable unsaturated compound having a transition temperature in the range of 100 to 250° C., (D) a carbon having 3 to 9 polymerizable unsaturated groups in one molecule and optionally containing an ester bond A coating composition containing a polymerizable unsaturated compound containing a linear alkylene group whose total number is 6 to 14, and (E) a polymerization initiator, wherein the content of component (C) is A), (B), (C) and (D), based on the total solid content of 100 parts by weight, is 5 to 35 parts by weight.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to form a coating film that can be suitably used for in-mold coating, can be applied to various plastic materials, and has excellent adhesion to polyolefin materials, especially without the addition of chlorinated polyolefin or the like. can be done.

Aspects of the present invention are described below.

The coating composition of the present invention includes (A) a polymerizable unsaturated compound having one polymerizable unsaturated group in one molecule and having a hydrocarbon group having 4 to 24 carbon atoms, (B) 1 A polymerizable unsaturated compound having one polymerizable unsaturated group in the molecule and having a hydroxyl group, (C) a homopolymer having two polymerizable unsaturated groups in one molecule A polymerizable unsaturated compound having a glass transition temperature in the range of 100 to 250 ° C., (D) having 3 to 9 polymerizable unsaturated groups in one molecule and containing an ester bond It contains a polymerizable unsaturated compound containing a linear alkylene group having a total of 6 to 14 carbon atoms, and (E) a polymerization initiator.

The polymerizable unsaturated compound (A) has one polymerizable unsaturated group in one molecule and a hydrocarbon group having 4 to 24 carbon atoms. The polymerizable unsaturated group is an unsaturated group capable of radical polymerization, and specific examples thereof include acryloyl group, methacryloyl group, vinyl group, allyl group, propenyl group, isopropenyl group, maleimide group, vinyl ether group, and the like. can be mentioned.

The polymerizable unsaturated compound (A) may include a vinyl aromatic compound (a1) and/or an ester (a2) of a monohydric alcohol having 4 to 24 carbon atoms and (meth)acrylic acid, particularly From the viewpoint of permeability into polyolefin materials, it is preferable to use the vinyl aromatic compound (a1).

Examples of the vinyl aromatic compound (a1) include styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene and the like. Among these, styrene is preferable from the viewpoint of adhesion between the coating film to be formed and the substrate.

When the coating composition of the present invention contains the vinyl aromatic compound (a1), the content of the component (A), (B ), (C) and (D) in an amount of preferably 20 to 91 parts by mass, more preferably 35 to 65 parts by mass based on the total solid content of 100 parts by mass.

Examples of the ester (a2) of a monohydric alcohol having 4 to 24 carbon atoms and (meth)acrylic acid include n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2 - ethylhexyl (meth)acrylate, neopentyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate , 4-t-butylcyclohexyl (meth)acrylate, N-acryloyloxyethylhexahydrophthalimide and the like.

When the coating composition of the present invention contains an ester (a2) of a monohydric alcohol having 4 to 24 carbon atoms and (meth)acrylic acid, the content thereof is the difference between the formed coating film and the substrate. From the viewpoint of adhesion, etc., it is preferably 5 to 40 parts by mass, preferably 10 to 30 parts by mass, based on 100 parts by mass of the total solid content of the components (A), (B), (C) and (D). is more preferable.

As used herein, "(meth)acrylate" means acrylate or methacrylate. "(Meth)acrylic acid" means acrylic acid or methacrylic acid. Moreover, "(meth)acryloyl" means acryloyl or methacryloyl. "(Meth)acrylamide" means acrylamide or methacrylamide.

The polymerizable unsaturated compounds (A) may be used alone or in combination of two or more.

In the present invention, the content of the polymerizable unsaturated compound (A) is determined from the viewpoint of the flexibility of the coating film to be formed and the adhesion to the substrate. and (D) based on the total solid content of 100 parts by mass, preferably 20 to 91 parts by mass, more preferably 35 to 65 parts by mass.

Examples of the polymerizable unsaturated compound (B) having one polymerizable unsaturated group in one molecule and having a hydroxyl group include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl Hydroxyl group-containing (meth)acrylates such as (meth)acrylates can be mentioned.

In the present invention, the content of the polymerizable unsaturated compound (B) is, from the viewpoint of adhesion between the coating film to be formed and the top coating film, the components (A), (B), (C) and ( It is preferably 1 to 40 parts by mass, more preferably 2 to 25 parts by mass, based on 100 parts by mass of the total solid content of D).

In the present invention, the polymerizable unsaturated compound (C) having two polymerizable unsaturated groups in one molecule has a homopolymer glass transition temperature of 100 to 250°C, preferably 120 to 200°C. It is a compound that increases the reaction rate of the composition and contributes to ensuring releasability particularly in in-mold coating applications.

The glass transition temperature of the above compound is obtained by synthesizing a homopolymer having a weight average molecular weight of about 50,000 and measuring the glass transition temperature by differential scanning thermal analysis. By measuring with a differential scanning calorimeter, the temperature is raised from 10° C. to 350° C. at a rate of 20° C./min in a nitrogen atmosphere to determine the glass transition temperature.

Examples of the polymerizable unsaturated compound (C) include dipropylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and ethylene oxide-modified bisphenol A di(meth) acrylates, propylene oxide-modified di(meth)acrylate of bisphenol A, ethylene oxide-modified di(meth)acrylate of bisphenol F, tricyclodecanedimethanol di(meth)acrylate, tricyclodecanediol di(meth)acrylate, and the like; These can be used individually or in combination of 2 or more types.

The polymerizable unsaturated compound (C) preferably contains an ester (c1) of a polyhydric alcohol having an alicyclic skeleton and (meth)acrylic acid. Examples of the alicyclic skeleton include a cyclohexane ring and a tricyclodecane ring. Examples of the ester (c1) of a polyhydric alcohol having an alicyclic skeleton and (meth)acrylic acid include tricyclodecane di Methanol di(meth)acrylate, tricyclodecanediol di(meth)acrylate and the like can be mentioned.

In the present invention, the content of the polymerizable unsaturated compound (C) is determined from the viewpoint of improving the reaction rate and ensuring the releasability of the formed coating film. It is 5 to 35 parts by mass, preferably 5 to 25 parts by mass, based on 100 parts by mass of the total solid content of (D).

In the present invention, the polymerizable unsaturated compound (D) having 3 to 9 polymerizable unsaturated groups in one molecule is a linear alkylene having a total carbon number of 6 to 14 which may contain an ester bond. It is a compound containing a group, and is a component that increases the reaction rate of the composition and contributes to imparting toughness and flexibility to the formed coating film.

Examples of the polymerizable unsaturated compound (D) include pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, and trimethylolethane. Examples include alkyl-modified products such as tri(meth)acrylate, trimethylolpropane tri(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate, caprolactone-modified products, and polyoxyalkylene-modified products.

In particular, as the polymerizable unsaturated compound (D), a polyhydric alcohol and a caprolactone-modified polyfunctional (meth)acrylic acid and ε-caprolactone esterified product ( It preferably contains meth)acrylate (d1). Caprolactone-modified polyfunctional (meth)acrylates (d1) include, for example, caprolactone-modified pentaerythritol tri(meth)acrylate, caprolactone-modified pentaerythritol tetra(meth)acrylate, caprolactone-modified dipentaerythritol penta(meth)acrylate, caprolactone-modified dipentaerythritol Examples include pentaerythritol hexa(meth)acrylate and the like, and particularly caprolactone-modified dipentaerythritol hexa(meth)acrylate can be preferably used.

In the present invention, the content of the polymerizable unsaturated compound (D) is, from the viewpoint of imparting toughness and flexibility to the coating film formed, the components (A), (B), (C) and (D) Based on the total solid content of 100 parts by mass, it is preferably 3 to 40 parts by mass, more preferably 5 to 25 parts by mass.

In the present invention, the polymerization initiator (E) is a polymerization initiator selected from thermal polymerization initiators and photopolymerization initiators. Among them, it is preferable to use a thermal polymerization initiator as at least one of the polymerization initiators because a coating film can be formed regardless of the shape of the substrate. Moreover, as a polymerization initiator (E), a thermal polymerization initiator and a photopolymerization initiator can be used in combination.

Thermal initiators are compounds or mixtures of these compounds that generate free radicals (also in the form of intermediates) upon heating. Thermal polymerization initiators include, for example, benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, tert-butylperoxylaurate, tert-butylperoxy Organic peroxides such as benzoate, tert-butylperoxyisopropyl carbonate, tert-butylperoxyacetate, diisopropylbenzene hydroperoxide; azobisisobutyronitrile, azobis(2,4-dimethylvaleronitrile), azobis(2 -methylpropionitrile), azobis(2-methylbutyronitrile), 4,4'-azobis(4-cyanobutanoic acid), dimethylazobis(2-methylpropionate), azobis[2-methyl-N-( 2-hydroxyethyl)-propionamide], azo compounds such as azobis {2-methyl-N-[2-(1-hydroxybutyl)]-propionamide}; potassium persulfate, ammonium persulfate, sodium persulfate, etc. Sulfate and the like can be mentioned.

Commercially available thermal polymerization initiators include, for example, “VA-044”, “VA-046B”, “V-50”, “VA-057”, “VA-061”, “VA-067”, “VA -086", "V-60", "V-70", "V-65", "V-601", "V-59", "V-40", "VF-096", "VAm-110" ” (manufactured by Wako Pure Chemical Industries, Ltd., trade names), “Perbutyl H”, “Perbutyl Z”, “Perbutyl O”, “Perocta O” (manufactured by NOF Corporation, trade names), etc. can.

The polymerization initiators (E) may be used alone or in combination of two or more.

In the present invention, the content of the polymerization initiator (E) is 0.01 to 10 parts by mass based on 100 parts by mass of the total solid content of the components (A), (B), (C) and (D). and more preferably 0.1 to 5 parts by mass.

The coating composition of the present invention has one polymerizable unsaturated group in one molecule, and a polymerizable unsaturated compound (A) having a hydrocarbon group having 4 to 24 carbon atoms, A polymerizable unsaturated compound (B) having one polymerizable unsaturated group and a hydroxyl group, and a glass transition of a homopolymer having two polymerizable unsaturated groups in one molecule A polymerizable unsaturated compound (C) having a temperature within the range of 100 to 250 ° C., having 3 to 9 polymerizable unsaturated groups in one molecule, and the number of carbon atoms that may contain an ester bond A total of 6 to 14 linear alkylene group-containing polymerizable unsaturated compounds (D) and a polymerization initiator (E) are essentially contained.

In addition to the above, the coating composition of the present invention may further contain an ultraviolet absorber and/or a light stabilizer. In addition, if necessary, resin components such as chlorinated polyolefin, cross-linking agents, solvents (organic solvents, water), pigments, curing accelerators, polymerization inhibitors, antioxidants, surface conditioners, antifoaming agents, emulsifiers, Other additive components commonly used in the field of coating, such as surfactants, antifouling agents, wetting agents, thickeners, dyes, scratch resistance improvers, gloss modifiers, etc., can be appropriately contained. Moreover, when the coating composition of the present invention is applied by an in-mold coating method, it preferably contains a release agent.

Conventionally known ultraviolet absorbers can be used, for example, benzotriazole-based absorbers, triazine-based absorbers, salicylic acid derivative-based absorbers, benzophenone-based absorbers, and the like can be used. Moreover, the said ultraviolet absorber may have a polymerizable unsaturated group.

Specific examples of benzotriazole-based absorbents include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole, 2-( 2′-hydroxy-3′,5′-di-t-butylphenyl)benzotriazole, 2-(2′-hydroxy-3′-t-butyl-5′-methylphenyl)-5-chlorobenzotriazole, 2 -(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-amylphenyl)benzotriazole , 2-(2′-hydroxy-4′-octoxyphenyl)benzotriazole, 2-{2′-hydroxy-3′-(3″,4″,5″,6″-tetrahydrophthalimidomethyl )-5′-methylphenyl}benzotriazole, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole and the like.

Specific examples of triazine-based absorbents include 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-isooctyloxyphenyl)-1,3,5-triazine, 2-[ 4((2-hydroxy-3-dodecyloxypropyl)-oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4 -((2-hydroxy-3-tridecyloxypropyl)-oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-( 2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and the like.

Specific examples of salicylic acid derivative-based absorbents include phenyl salicylate, p-octylphenyl salicylate, 4-tert-butylphenyl salicylate and the like.

Specific examples of benzophenone-based absorbents include 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-octadecyloxy Benzophenone, sodium 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 5-chloro-2 -hydroxybenzophenone, resorcinol monobenzoate, 2,4-dibenzoylresorcinol, 4,6-dibenzoylresorcinol, hydroxydodecylbenzophenone, 2,2'-dihydroxy-4(3-methacryloxy-2-hydroxypropoxy)benzophenone, etc. mentioned.

In addition, commercially available products of the ultraviolet absorbent include, for example, "TINUVIN 900", "TINUVIN 928", "TINUVIN 384-2", "TINUVIN 479", "TINUVIN 405", "TINUVIN 400" (manufactured by BASF , trade name, TINUVIN is a registered trademark), and "RUVA 93" (manufactured by Otsuka Chemical Co., Ltd., trade name).

When the coating composition of the present invention contains the UV absorber, the content of the UV absorber is in the range of 0.5 to 10% by mass with respect to the total solid content of the coating composition. is preferred, more preferably 0.8 to 9% by mass, and still more preferably 1.0 to 8% by mass.

The light stabilizer is used as a radical chain inhibitor that captures active radical species generated during the deterioration process of the coating film, and examples thereof include light stabilizers of hindered amine compounds.

Among light stabilizers, light stabilizers exhibiting excellent light stabilizing action include hindered piperidine compounds. Hindered piperidine compounds include, for example, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis( N-methyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 4-benzoyloxy-2,2',6,6'-tetramethylpiperidine, bis(1,2,2,6, 6-Pentamethyl-4-piperidyl){[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl}butyl malonate; poly{[6-(1,1 ,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2, 2,6,6-tetramethyl-4-piperidyl)iminol]}; polyester compound of 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and succinic acid; , but not limited to these. As light stabilizers it is also possible to use known polymerizable light stabilizers.

Commercially available products of the light stabilizer include, for example, "TINUVIN 123", "TINUVIN 152", "TINUVIN 292" (manufactured by BASF, trade name, TINUVIN/TINUVIN is a registered trademark), "HOSTAVIN 3058" (manufactured by Clariant , trade name, Hostavin is a registered trademark), "ADEKA STAB LA-82" (manufactured by ADEKA Co., Ltd., trade name, ADEKA STAB/ADKSTAB and ADEKA STAB are registered trademarks), and the like.

When the coating composition of the present invention contains the light stabilizer, the content of the light stabilizer is in the range of 0.5 to 10% by mass with respect to the total solid content of the coating composition. is preferred, more preferably 0.8 to 9% by mass, and still more preferably 1.0 to 8% by mass.

As the solvent, for example, an organic solvent, water, or the like can be used. Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate, butyl acetate, methyl benzoate, ethyl ethoxypropionate, ethyl propionate and methyl propionate; tetrahydrofuran; , dioxane, dimethoxyethane and other ether solvents; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate and other glycol ether solvents; toluene, xylene, "Swasol 1000" (manufactured by Cosmo Oil Co., Ltd., trade name, high boiling point petroleum solvent); and aliphatic hydrocarbon solvents such as hexane and heptane.

Examples of the pigment include luster pigments, coloring pigments, and extender pigments. The pigments may be used alone or in combination of two or more.

Examples of the curing accelerator include tertiary amines such as diethylenetriamine, triethanolamine, 4-dimethylaminobenzoic acid and 3-dimethylaminobenzoic acid, quaternary ammonium salts, cobalt naphthenate, copper naphthenate, and naphthenic acid. Metal dryers such as barium, cobalt octylate, manganese octylate, zinc octylate, and vanadium octylate. These can be used individually or in combination of 2 or more types.

Examples of the release agent include stearic acid, stearates such as zinc stearate, aluminum stearate, magnesium stearate, and calcium stearate; nonionic surfactants such as polyoxyethylene alkyl ethers and sorbitan alkyl esters; Fluorinated compounds such as polytetrafluoroethylene, fluoropolyethers, perfluoroalkyl esters and perfluoroalkyl ester salts; soybean oil lecithin, silicone oil, fatty acid esters and fatty acid alcohol dibasic acid esters, which can be used alone or in combination of two or more.

When the coating composition of the present invention contains the release agent, the content of the release agent is determined from the viewpoint of adhesion between the coating film to be formed and the substrate, weather resistance, and coating film hardness. Based on 100 parts by mass of the solid content in the coating composition, it is preferably in the range of 0.1 to 10 parts by mass, more preferably 0.2 to 7 parts by mass, and still more preferably 0.3 to 5 parts by mass. Department.

The coating composition of the present invention obtained as described above preferably has a solid content of 90 to 100% by mass, more preferably 95 to 100% by mass, and still more preferably 99 to 100% by mass. type coating compositions are preferred, and heat-curable coating compositions are more preferred. In the present specification, the solid content refers to all components excluding the solvent among the components constituting the coating composition.

In the present invention, a wet coating film (uncured coating film) is formed by coating the coating composition obtained as described above on a substrate, and the desired coating film is formed by curing the wet coating film. can be formed. The material of the substrate may be an inorganic material, an organic material, or a hybrid material of an organic material and an inorganic material. can be done.

Examples of plastic materials include acrylic resins such as polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, polyethylene-1,2-diphenoxyethane-4,4'-dicarboxy Polyester resins such as polybutylene terephthalate, epoxy resins, polycarbonate resins, polyimide resins, novolac resins, phenolic resins, acrylonitrile -butadiene-styrene (ABS) resins, acrylonitrile-ethylene-styrene (AES) resins, acrylonitrile-styrene-acrylate (ASA) resins, vinyl chloride resins, vinylidene chloride resins, polyurethane resins, cellulose esters (e.g., triacetyl cellulose, diacetyl) cellulose, propionyl cellulose, butyryl cellulose, acetylpropionyl cellulose, nitrocellulose), polyamides, polystyrene (e.g. syndiotactic polystyrene), polyolefins (e.g. polypropylene, polyethylene, polymethylpentene), polysulfones, polyethersulfones, polyarylates , polyetherimide, polyetherketone, various fiber reinforced plastics (hereinafter sometimes abbreviated as FRP material or simply FRP), etc., and polyolefin is particularly preferred.

The coating composition of the present invention can be a coating composition with a relatively low viscosity even when it has a high solid content, so it can be suitably used in coating by an in-mold coating method (in-mold coating method). .

In the in-mold coating method of the present invention, a plastic material is heated and molded in a mold, and then the coating composition of the present invention is injected as an in-mold coating coating composition between the resulting molding and the inner wall of the mold. and removing the coated molding from the mold after curing the in-mold coating composition.

At least one layer of a colored coating film can be further formed on the coated article obtained by the in-mold coating method.

Examples of the colored coating composition that forms the colored coating film include conventionally known colored base coating compositions. For example, organic solvent-based, water-based, or powder-based paints containing a resin component, a coloring agent, a solvent, and optionally matting agents and general paint additives can be used.
As the resin component, normal temperature-drying type, normal temperature-setting type, and heat-setting type resins for ordinary coatings can be used. Examples thereof include base resins such as acrylic resins, vinyl resins, and polyester resins. A cross-linking agent such as a block) polyisocyanate compound can also be used in combination. In the present invention, a colored coating film formed by a paint containing a base resin having a hydroxyl group and a polyisocyanate compound as a cross-linking agent is particularly suitable from the viewpoint of adhesion to the coated article of the present invention.
As the coloring agent, any conventionally known coloring pigments, luster pigments, and the like can be used. Examples of coloring pigments include inorganic pigments such as titanium oxide, zinc white, carbon black, cadmium red, molybdenum red, chrome yellow, chromium oxide, Prussian blue, and cobalt blue; azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, Examples include organic pigments such as threne pigments and perylene pigments. Brilliant pigments are pigments that impart glittering luster and light interference to paint films. For example, they are coated with flake-like aluminum, bronze, stainless steel, nickel powder, mica-like iron oxide, mica, and metal oxides. mica, etc. Colorants are not limited to those shown above.
Further, as a matting agent for adjusting the glossiness of the coating film, calcium carbonate, kaolin, clay, diatomaceous earth, white carbon, talc, silica powder, wollastonite and the like can be used.

In the present invention, at least one layer of a clear coating film can be further formed on the coated article obtained by the in-mold coating method, and on the coated article further comprising at least one layer of a colored coating film.

Examples of the clear coating composition for forming the clear coating film include conventionally known clear coating compositions. For example, organic solvent-based, water-based, or powder-based paints containing a resin component and a solvent and, if necessary, additives for ordinary paints can be used.
As the resin component, normal temperature-drying type, normal temperature-setting type, and heat-setting type resins for ordinary coatings can be used. Examples thereof include base resins such as acrylic resins, vinyl resins, and polyester resins. A cross-linking agent such as a block) polyisocyanate compound can also be used in combination. In the present invention, a clear coating film made of a coating material containing a base resin having a hydroxyl group and a polyisocyanate compound as a cross-linking agent is particularly suitable from the viewpoint of adhesion to the coated article.

Conventionally known methods can be appropriately employed as the method for coating the above-mentioned colored coating composition and clear coating composition, and it is also possible to employ an in-mold coating method.

When a coating film is formed by an in-mold coating method using the above-mentioned colored coating composition or clear coating composition, the coating is desirably a so-called solvent-free type, and the coating surface to which it is applied is cured by heating. preferably.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited only to these examples. "Parts" and "%" are based on mass.

Production Examples 1 to 10 and Comparative Examples 1 to 6 of coating compositions
In a reaction vessel equipped with a thermometer, a thermostat and a stirrer, each component (A) to (D) was charged so that the solid content shown in Table 1 was obtained, and the temperature was raised to 50 ° C. with stirring. C. and stirred for 3 hours. After that, it is cooled to room temperature, and 3.5 parts (solid content) of a polymerization initiator (“Perbutyl O”, t-butylperoxy-2-ethylhexanoate) which is the component (E), and zinc stearate as an example. etc. were added and uniformly mixed to obtain respective coating compositions (1) to (16) having a solid content of 99.6%.

Preparation of test plate 1 The surface of a 100 mm × 150 mm × 3.0 mm polypropylene plate was degreased with isopropyl alcohol, and the coating composition obtained in Examples or Comparative Examples was applied using a bar coater so that the cured film thickness was 50 μm. and set at room temperature for 1 minute. After that, a 200 mm×200 mm×50 mm “NAK80” (trade name: metal plate made by Daido Steel) heated in advance to 120° C. was pressed and fixed at a pressure of 200 kg/cm ² . Then, after curing by holding at 120° C. for 3 minutes, test plate 1 was prepared by removing the metal plate.

Preparation of test plate 2 A topcoat colored base coat paint composition (trade name “WBC-713T”, manufactured by Kansai Paint Co., Ltd., an acrylic resin/amino resin water-based paint composition) is applied to the coated plate of test plate 1 to a film thickness of 20 μm. After leaving it for 2 minutes, it was preheated at 80°C for 3 minutes. Next, "SOFLEX 7175 Clear" (manufactured by Kansai Paint Co., Ltd., trade name, acrylic urethane-based organic solvent-based clear paint) is applied to the uncured coated surface as a topcoat clear paint composition to a film thickness of 35 μm. Then, after leaving it for 7 minutes, it was heated at 120° C. for 20 minutes to cure both coating films at the same time, thereby producing a test plate 2.

Adhesion (initial) and releasability were evaluated for each test plate 1 obtained, and adhesion (initial) and adhesion (water resistance) were evaluated for test plate 2 . The results are also shown in Table 1.

Adhesion (initial):
On the coated surface of each test plate, make 100 squares of 2 mm x 2 mm according to JIS K 5600-5-6 (1990), attach an adhesive tape to the surface, and peel it off rapidly. The remaining state of the coating film was examined, and the adhesion was evaluated according to the following criteria. ◎, ○, △, and × mean the following respectively, and ◎ and ○ mean pass.

⊚: Remaining number/total number = 100 pieces/100 pieces, no edge chipping,
○: Remaining number / total number = 100 / 100 with edge chipping,
△: remaining number / total number = 90 to 99 / 100,
×: remaining number/total number=0 to 89/100.

Adhesion (water resistance):
Each test plate was immersed in warm water of 40° C. and taken out after 240 hours, and the same adhesion test as the adhesion (initial) was performed, and the evaluation was performed according to the above criteria.

Releasability:
Ease of peeling the test plate 1 from the metal plate used to obtain the test plate 1 was evaluated. ◎, ○, △, and × mean the following, respectively, and ◎ and ○ mean pass.

◎: The test plate 1 was peeled off from the metal plate by its own weight,
Good: The test plate 1 did not immediately peel off from the metal plate due to its own weight, and when peeled using a scraper or the like, the coating film and the substrate were peeled without defects.
△: The test plate 1 did not immediately peel off from the metal plate due to its own weight, and when peeled using a scraper or the like, 0 to less than 10% of the coating film area peeled off.
x: The test plate 1 did not separate from the metal plate, and defects occurred in 11% or more of the coating film area and/or the substrate when the test plate was separated using a scraper or the like.

Preparation Example 11 of Test Plate 3
Colored coating composition No. 1 was applied to the coated plate of test plate 1 using the coating composition (4). 1 (Note 1) was applied using a bar coater so that the cured film thickness was 50 μm, and the setting was performed at room temperature for 1 minute. After that, a 200 mm×200 mm×50 mm “NAK80” (trade name: metal plate made by Daido Special Steel) preheated to 80° C. was pressed and fixed at a pressure of 200 kg/cm ² . Then, after curing by holding at 80° C. for 1 minute, the metal plate was removed to form a colored coating film layer. Next, clear coating composition No. 1 was applied on top of the colored coating film. 1 (Note 3) was applied using a bar coater so that the cured film thickness was 50 μm, and the setting was performed at room temperature for 1 minute. After that, a 200 mm×200 mm×50 mm “NAK80” (trade name: metal plate made by Daido Special Steel) preheated to 80° C. was pressed and fixed at a pressure of 200 kg/cm ² . Next, after curing by holding at 80° C. for 1 minute, the metal plate was removed to form a clear coating film layer and prepare a test plate.

Example 12
In Example 11, clear paint composition No. Clear paint composition No. 1 (Note 3) A test plate was prepared in the same manner as in Example 11, except that No. 2 (Note 4) was used.

Example 13
In Example 11, colored coating composition No. 1 (note 1) instead of colored paint composition No. A test plate was prepared in the same manner as in Example 11, except that No. 2 (Note 2) was used.

Example 14
In Example 13, clear paint composition No. Clear paint composition No. 1 (Note 3) A test plate was prepared in the same manner as in Example 13, except that No. 2 (Note 4) was used.

For each test plate obtained in Examples 11 to 14 above, the adhesion (initial) and adhesion (water resistance) were evaluated in the same manner as in the adhesion test described above. None) was evaluated. Table 2 shows the results.

(Note 1) Colored paint composition No. 1: In a container, 32 parts of "Desmophen XP2488" (trade name, manufactured by Covestro Co., Ltd., hydroxyl group-containing polyester resin), "Sumidur N3300" (trade name, manufactured by Sumika Covestro Urethane Co., Ltd., isocyanurate cycloaddition product of hexamethylene diisocyanate) ) 62 parts, 3 parts of benzyl alcohol, 1 part of carbon black, "DISPERBYK-2013" (trade name, manufactured by BYK-Chemie, dispersant) 0.25 parts, "DISPERBYK-333" (trade name, manufactured by BYK-Chemie, surface adjustment agent) 0.4 parts, "TINUVIN400" (trade name, manufactured by BASF, UV absorber) 1 part, "TINUVIN292" (trade name, manufactured by BASF, light stabilizer) 1 part, "Neostan U-830" ( 0.6 parts of tin catalyst (trade name, manufactured by Nitto Kasei Co., Ltd.) and 1 part of zinc stearate are blended and uniformly mixed, and the viscosity measured by a Brookfield viscometer at 25° C. and 60 rpm is 6000 mPa s, and the solid content is 99. % of colored paint composition no. got 1.

(Note 2) Colored paint composition No. 2: In a container, 26 parts of "Desmofen XP2488" (trade name, manufactured by Covestro, hydroxyl group-containing polyester resin), 7 parts of "Desmofen VPLS 2249/1" (trade name, manufactured by Covestro, hydroxyl group-containing polyester resin), "Sumidur" N3300" (trade name, manufactured by Sumika Covestro Urethane Co., Ltd., isocyanurate cycloaddition product of hexamethylene diisocyanate) 61 parts, benzyl alcohol 3 parts, carbon black 1 part, "DISPERBYK-2013" (trade name, manufactured by BYK Chemie, Dispersant) 0.25 parts, "DISPERBYK-333" (trade name, manufactured by BYK-Chemie, surface control agent) 0.4 parts, "TINUVIN400" (trade name, manufactured by BASF, UV absorber) 1 part, "TINUVIN292 ” (trade name, manufactured by BASF Corporation, light stabilizer), 0.6 parts of “Neostan U-830” (trade name, manufactured by Nitto Kasei Co., Ltd., tin catalyst) and 1 part of zinc stearate are blended uniformly. By mixing, a colored coating composition No. having a viscosity of 6000 mPa·s according to a Brookfield viscometer at 25° C. and 60 rpm and a solid content of 99%. got 2.

(Note 3) Clear paint composition No. 1: In a container, 32 parts of "Desmophen XP2488" (trade name, manufactured by Covestro Co., Ltd., hydroxyl group-containing polyester resin), "Sumidur N3300" (trade name, manufactured by Sumika Covestro Urethane Co., Ltd., isocyanurate cycloaddition product of hexamethylene diisocyanate) ) 62 parts, 3 parts of benzyl alcohol, "DISPERBYK-333" (trade name, manufactured by BYK-Chemie, surface conditioner) 0.4 parts, "TINUVIN400" (trade name, manufactured by BASF, UV absorber) 1 part, " TINUVIN292" (trade name, manufactured by BASF Corporation, light stabilizer) 1 part, "Neostan U-830" (trade name, manufactured by Nitto Kasei Co., Ltd., tin catalyst) 0.6 parts and 1 part of zinc stearate are blended uniformly. to give a clear coating composition No. 4000 mPa·s with a solids content of 99%, measured by a Brookfield viscometer at 25° C. and 60 rpm. got 1.

(Note 4) Clear paint composition No. 2: In a container, 26 parts of "Desmofen XP2488" (trade name, manufactured by Covestro, hydroxyl group-containing polyester resin), 7 parts of "Desmofen VPLS 2249/1" (trade name, manufactured by Covestro, hydroxyl group-containing polyester resin), "Sumidur" N3300" (trade name, manufactured by Sumika Covestro Urethane Co., Ltd., isocyanurate cycloaddition of hexamethylene diisocyanate) 61 parts, benzyl alcohol 3 parts, "DISPERBYK-333" (trade name, manufactured by BYK-Chemie, surface conditioner) 0 .4 parts, "TINUVIN400" (trade name, manufactured by BASF, UV absorber) 1 part, "TINUVIN292" (trade name, manufactured by BASF, light stabilizer) 1 part, "Neostan U-830" (trade name, 0.6 parts of tin catalyst manufactured by Nitto Kasei Co., Ltd.) and 1 part of zinc stearate are blended and uniformly mixed to obtain a clear clear powder having a viscosity of 4000 mPa s and a solid content of 99% by a Brookfield viscometer at 25°C and 60 rpm. Paint composition no. got 2.

Claims (14)

(A) a polymerizable unsaturated compound having one polymerizable unsaturated group in one molecule and having a hydrocarbon group having 4 to 24 carbon atoms;
(B) a polymerizable unsaturated compound having one polymerizable unsaturated group in one molecule and having a hydroxyl group;
(C) a polymerizable unsaturated compound having two polymerizable unsaturated groups in one molecule and a homopolymer having a glass transition temperature in the range of 100 to 250°C;
(D) Polymerizable having 3 to 9 polymerizable unsaturated groups in one molecule and containing a linear alkylene group having a total carbon number of 6 to 14 which may contain an ester bond A coating composition containing an unsaturated compound and (E) a polymerization initiator,
Component (A) contains a vinyl aromatic compound (a1) and/or an ester (a2) of a monohydric alcohol having 4 to 24 carbon atoms and (meth)acrylic acid,
A coating composition characterized in that the content of component (C) is 5 to 35 parts by mass based on 100 parts by mass of the total solid content of components (A), (B), (C) and (D). thing. 2. The coating composition according to claim 1, wherein component (B) contains a hydroxyl group-containing (meth)acrylate. 3. The coating composition according to claim 1, wherein the component (C) contains an ester (c1) of a polyhydric alcohol having an alicyclic skeleton and (meth)acrylic acid. The ester (c1) of a polyhydric alcohol having an alicyclic skeleton and (meth)acrylic acid is at least one selected from tricyclodecanedimethanol di(meth)acrylate and tricyclodecanedioldiol di(meth)acrylate. The coating composition according to claim 3, wherein Component (C) is dipropylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, bisphenol A propylene oxide-modified. 5. The coating composition according to any one of claims 1 to 4, comprising at least one selected from di(meth)acrylates and ethylene oxide-modified bisphenol F di(meth)acrylates. 6. The component (D) according to any one of claims 1 to 5 , comprising a polyhydric alcohol and a caprolactone-modified polyfunctional (meth)acrylate (d1) which is an ester of (meth)acrylic acid and ε-caprolactone. paint composition. Caprolactone-modified polyfunctional (meth)acrylate (d1), which is an ester of polyhydric alcohol, (meth)acrylic acid and ε-caprolactone, is caprolactone-modified pentaerythritol tri(meth)acrylate, caprolactone-modified pentaerythritol tetra(meth) 7. The coating composition according to claim 6, which is at least one selected from acrylates, caprolactone-modified dipentaerythritol penta(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate. Component (D) is pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, trimethylolethane tri (meth) acrylate, tri 8. The coating composition according to any one of claims 1 to 7, comprising at least one selected from methylolpropane tri(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate. Based on the total solid content of components (A), (B), (C) and (D) of 100 parts by mass, the content of component (A) is 30 to 91 parts by mass and the content of component (B) is 1 The coating composition according to any one of claims 1 to 8 , wherein the content of component (C) is 5 to 35 parts by mass, and the content of component (D) is 3 to 40 parts by mass. . A coated article having a coating film formed thereon with the coating composition according to any one of claims 1 to 9 on the surface of a molding made of a plastic material. 11. A coated article according to claim 10 , wherein the plastic material is polyolefin. A plastic material is heated and molded in a mold, then an in-mold coating coating composition is injected between the resulting molding and the inner wall of the mold, and after curing the in-mold coating coating composition, the coating An in-mold coating method comprising a step of removing the molded product from the mold, wherein the in-mold coating coating composition is the coating composition according to any one of claims 1 to 9 . An in-mold coating method comprising forming at least one layer of a colored coating film on the coated surface obtained by the method of claim 12 . An in-mold coating method comprising forming at least one layer of a clear coating film on the coated surface obtained by the method of claim 12 or 13 .