JP6422867B2 - Paint composition - Google Patents

Description

[Cross-reference of related applications]
This application claims priority based on Japanese Patent Application No. 2013-14459 filed on Jul. 10, 2013, the entire disclosure of which is incorporated herein by reference.
The present invention is a coating composition that can obtain a coating film that is excellent in adhesion to an object even by one-coat coating and that has excellent finish, coating film hardness, stain resistance, weather resistance, and hydrolysis resistance. Related to things.

  For example, plastic molded products such as ABS resin, urethane resin, and polyamide (nylon) resin are often used in place of metal as a member for automobile outer plate parts, home appliances, and the like.

  A plastic composition is usually coated with a coating composition in order to impart designability and durability. Conventionally, in order to impart designability and durability, for example, a two-coat system has been used as a coating method. The two-coat method is a method in which a colored base coating composition and a clear coating composition are sequentially applied (coated) and baked (baked) to form a multilayer coating film. For example, in the invention of Patent Document 1, a paint composition is applied, a clear paint is applied (2 coats) to the uncured colored paint application surface, and baked once (1 bake). It is related with the method of apply | coating by a 2 coat 1-bake system, and forming a multilayer coating film. By using a hydroxyl group-containing polyester resin in which a part or all of the starting polyhydric alcohol component is tris (2-hydroxyethyl) isocyanurate in the colored coating composition, a coating film excellent in chipping resistance and finish is obtained. It can be done.

  On the other hand, in recent years, from the viewpoint of considering the human body and the environment such as cost reduction (energy saving and productivity improvement) and low VOC (VOC: volatile organic compound) for coating and painting processes, toluene, xylene, etc. There is a strong need for a coating composition that can be reduced or substantially not included, and that can achieve design and coating performance by coating by a 1-coat 1-bake method.

  However, the invention described in Patent Document 1 does not satisfy the requirements for energy saving and productivity improvement, and if a clear coat is applied on a colored paint coating surface and heated and cured at 140 ° C. for 30 minutes, The coating film performance such as sufficient scratch resistance, particularly hydrolysis resistance and weather resistance was not satisfied.

  On the other hand, there are inventions described in Patent Document 2 and Patent Document 3 as 1-coat metallic paint compositions having excellent design properties. The invention described in Patent Document 2 relates to a one-coat metallic coating composition comprising a non-aqueous dispersion medium in which polymer particles are dispersed with a dispersion stabilizer, an acrylic resin, and a glittering material. Is. When the difference between the solubility parameter value of the acrylic resin and the solubility parameter value of the dispersion stabilizer of the non-aqueous polymer dispersion is within a specific range, the non-aqueous polymer forms an optimal pearl chain structure. With this, the glitter pigment is oriented well, and a coating film having an excellent metallic appearance can be formed. The invention of Patent Document 3 relates to a composition containing a specific hydroxyl group acrylic resin, a specific hydroxyl group cellulose acetate butyrate, a bright material and a polyisocyanate compound as a curing agent. When cellulose acetate butyrate is blended, the glossiness (glossiness) and glossiness of the coating surface become high even with one coat.

  However, both of the inventions described in Patent Documents 2 and 3 are insufficient in terms of weather resistance and hydrolysis resistance, and the viscosity increases when an attempt is made to increase the solid content of the paint during coating. Painting workability was poor, and finishing performance was sometimes insufficient.

JP-A-11-614 JP 2002-80776 A JP2013-124365A

  It is an object of the present invention to obtain a coating film that is excellent in adhesion to an object even by one-coat coating and that has excellent finish, coating film hardness, stain resistance, weather resistance, and hydrolysis resistance. It is to provide a coating composition.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved, and have completed the present invention.
That is, the present invention provides the following coating composition:
Item 1.
(A) a hydroxyl group-containing acrylic resin having a weight average molecular weight of 1,000 to 90,000,
(B) a hydroxyl group-containing polyester resin,
A coating composition containing (C) a colored pigment and / or a bright pigment, and (D) a polyisocyanate compound,
The hydroxyl group-containing polyester resin (B) is a polyester resin having a hydroxyl value of 20 to 250 mgKOH / g, which is obtained by a reaction between a polyhydric alcohol containing a cyclic polyol compound (b1) having a nurate structure and a polybasic acid. A coating composition, wherein the solid content of the polyester resin (B) is 5 to 60% by mass based on the total resin solid content of the component (A) and the component (B).

  Item 2. The hydroxyl group-containing acrylic resin (A) is a resin that does not contain methyl methacrylate or contains less than 50% by mass of methyl methacrylate, based on the total amount of copolymerization monomer components, and has a hydroxyl value of 20 to 200 mgKOH / The coating composition of claim | item 1 containing the hydroxyl-containing acrylic resin (A1) in the range of g, weight average molecular weight 1,000-10,000, and glass transition temperature (Tg) 0-90 degreeC.

  Item 3. Hydroxyl group-containing acrylic resin (A) is further a hydroxyl group containing 50 to 90% by weight of methyl methacrylate and 10 to 50% by weight of other polymerizable unsaturated monomer as a copolymerized monomer component, based on the total amount of the copolymerized monomer component. The coating composition of claim | item 2 containing a containing acrylic resin (A2).

  Item 4. Furthermore, the coating composition of any one of claim | item 1 -3 containing a rheology control agent (E).

  Item 5. Furthermore, the coating composition of any one of claim | item 1 -4 containing a higher fatty acid (F).

  Item 6. Item 6. A coated article obtained by applying the coating composition according to any one of Items 1 to 5 to an object to be coated.

  Item 7. The object to be coated is selected from the group consisting of acrylonitrile-butadiene-styrene resin, acrylonitrile-styrene-acrylate resin, polycarbonate resin, polybutylene terephthalate resin, polyvinyl chloride resin, polyamide resin, and at least two kinds of these hybrid resins. Item 7. The coated article according to Item 6, which is at least one kind.

  Item 8. A method for forming a multi-layer coating film by sequentially applying at least one layer of a colored base coat paint and at least one layer of a top coat paint on an object to be coated. A method for forming a multilayer coating film, wherein the coating composition according to claim 1 is applied.

  According to the coating composition of the present invention, a coating film having excellent adhesion to the object to be coated and excellent finish, coating film hardness, stain resistance, weather resistance and hydrolysis resistance even by one-coat coating. Can be obtained. Moreover, according to this invention, it is excellent in the finishing external appearance and hydrolysis resistance of a coating film, and can make the coating-solids content rate at the time of coating high.

  In addition, it can be cured at low temperatures, and by simply applying a colored paint directly to a synthetic resin molded product without using a primer and heat-curing it, the finish, hydrolysis resistance, chemical resistance, and weather resistance are also improved. An excellent coating film can be obtained.

≪Paint composition≫
The coating composition of the present invention comprises (A) a hydroxyl group-containing acrylic resin, (B) a hydroxyl group-containing polyester resin, (C) a colored pigment and / or a bright pigment, and (D) a polyisocyanate compound. The hydroxyl group-containing polyester resin (B) is a polyester resin having a hydroxyl value of 20 to 250 mgKOH / g obtained by a reaction between a polyhydric alcohol containing a cyclic polyol compound (b1) having a nurate structure and a polybasic acid. Yes, the solid content of the polyester resin (B) is 5 to 60% by mass based on the total resin solid content of the components (A) and (B).

≪Hydroxyl group-containing acrylic resin (A) ≫
The hydroxyl group-containing acrylic resin (A) which is a component constituting the coating composition of the present invention is a resin having a weight average molecular weight in the range of 1,000 to 90,000, preferably 3,000 to 10,000. The hydroxyl group-containing acrylic resin (A) can be produced, for example, by copolymerizing a hydroxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer. it can.

  The hydroxyl group-containing polymerizable unsaturated monomer is a compound having at least one hydroxyl group and one polymerizable unsaturated bond in one molecule. Examples of the hydroxyl group-containing polymerizable unsaturated monomer include dihydric alcohols having 2 to 22 carbon atoms such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and (meth) acrylic acid. Hydroxyalkyl esters such as monoesters of polyethylene; monoesters of polyether polyols such as polyethylene glycol, polypropylene glycol, polybutylene glycol and unsaturated carboxylic acids such as (meth) acrylic acid; polyethylene glycol, polypropylene glycol, polybutylene glycol Monoethers of polyether polyols such as 2-hydroxyethyl (meth) acrylate and other hydroxyl-containing unsaturated monomers; acids such as maleic anhydride and itaconic anhydride Monoester or diesterified product of water group-containing unsaturated compound and glycols such as ethylene glycol, 1,6-hexanediol and neopentyl glycol; hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether; allyl alcohol and the like; 2 -Hydroxypropyl (meth) acrylate; adduct of α, β-unsaturated carboxylic acid and monoepoxy compound such as Cardura E10 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.) and α-olefin epoxide; glycidyl (meth) Adducts of acrylates with acetic acid, propionic acid, p-tert-butylbenzoic acid, monobasic acids such as fatty acids; hydroxyl group-containing polymerizable unsaturated monomers and lactones (for example, ε-caprolactone, γ-valerolactone) N-hydroxymethyl (Meth) acrylamides, such as an adduct of allyl alcohol, can be further molecular ends and the like (meth) acrylate having a polyoxyethylene chain is a hydroxyl group. These can be used alone or in combination of two or more.

  Examples of the other polymerizable unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer include, for example, a monoesterified product of (meth) acrylic acid and a monohydric alcohol having 1 to 22 carbon atoms such as methyl ( (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, 2-ethylhexyl ( Examples include meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate. Further, (meth) acrylic acid such as methoxybutyl (meth) acrylate and methoxyethyl (meth) acrylate and an alkoxy ester having 2 to 18 carbon atoms; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl Amino group-containing polymerizable unsaturated monomers such as (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate; (meth) acrylamide, N-methyl (meth) Amide group-containing polymerizable unsaturated monomers such as acrylamide, N-ethyl (meth) acrylamide, N-butylacrylamide, N-butylmethacrylamide and N, N-dimethyl (meth) acrylamide; Glycidyl groups such as glycidyl (meth) acrylate Contains no polymerizable Sum monomers; carboxyl group-containing polymerizable unsaturated monomers such as (meth) acrylic acid, maleic acid, itaconic acid, fumaric acid, mesaconic acid and their anhydrides and half-esterified products; styrene, α-methylstyrene, vinyltoluene, Examples include acrylonitrile, vinyl acetate, “Beova 9”, “Beova 10” (both oil-based shell epoxy), vinyl chloride, and the like.

  In the present specification, the polymerizable unsaturated group means an unsaturated group capable of radical polymerization. The unsaturated group capable of radical polymerization is, for example, a functional group having a carbon-carbon double bond (also called a polymerizable double bond), such as a vinyl group, a (meth) acryloyl group, or a (meth) acrylamide. Groups, vinyl ether groups, allyl groups, and the like.

  In the present specification, “(meth) acrylate” means “acrylate or methacrylate”. “(Meth) acrylic acid” means “acrylic acid or methacrylic acid”. “(Meth) acryloyl” means “acryloyl or methacryloyl”. “(Meth) acrylamide” means “acrylamide or methacrylamide”.

  The polymerization method for obtaining the hydroxyl group-containing acrylic resin (A) is not particularly limited, and is a polymerization method known per se, for example, bulk polymerization, solution polymerization, bulk in the presence of a radical polymerization initiator. Among them, a solution polymerization method can be preferably used, such as a bulk-suspension two-stage polymerization method in which suspension polymerization is performed after polymerization.

  Examples of the radical polymerization initiator include ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (tert-butylperoxy) -3 , 3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, 2,2-bis (4,4- Ditert-butylperoxycyclohexyl) propane, 2,2-bis (4,4-ditert-amylperoxycyclohexyl) propane, 2,2-bis (4,4-ditert-hexylperoxycyclohexyl) propane, 2,2-bis (4,4-di-tert-oct Peroxyketals such as ruperoxycyclohexyl) propane and 2,2-bis (4,4-dicumylperoxycyclohexyl) propane; cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide Hydroperoxides such as 1,3-bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, diisopropylbenzene peroxide, dialkyl peroxides such as tert-butylcumyl peroxide; diacyl peroxides such as decayl peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide; bis (tert-butyl) Peroxycarbonates such as (cyclohexyl) peroxydicarbonate; organic peroxides such as peroxyesters such as tert-butylperoxybenzoate and 2,5-dimethyl-2,5-di (benzoylperoxy) hexane Examples thereof include polymerization initiators and azo polymerization initiators such as 2,2′-azobisisobutyronitrile and 1,1-azobis (cyclohexane-1-carbonitrile).

  As the polymerization method by the solution polymerization method, for example, the monomer mixture is dissolved or dispersed in an organic solvent, and heated in the presence of the radical polymerization initiator, usually at a temperature of about 80 ° C. to 200 ° C. with stirring. The method of doing can be mentioned. The reaction time can usually be about 1 to 24 hours.

  Examples of the organic solvent include hydrocarbon solvents such as heptane, toluene, xylene, octane, and mineral spirit; ester solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, and diethylene glycol monobutyl ether acetate. Solvents; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol, isobutanol; n-butyl ether, dioxane, ethylene glycol monomethyl ether , Ethers such as ethylene glycol monoethyl ether; SWAZOL 310, SWAZOL 1000, SWAZOL 150 (All of the above are aromatic hydrocarbon solvents such as Cosmo Oil Co., Ltd., SWASOL \ Swasol is a registered trademark), SHELLSOL A (Shellsol A, manufactured by Shell Chemical Co., Ltd., Shellzol is a registered trademark), etc. be able to. These organic solvents can be used alone or in combination of two or more. The type of organic solvent is not particularly limited. The hydroxyl acrylic resin (A) of the present invention can be produced without containing toluene or xylene.

  The hydroxyl group-containing acrylic resin (A) can be used alone or in combination of two or more.

  The hydroxyl group-containing acrylic resin (A) is a resin that does not contain methyl methacrylate or contains less than 50% by mass of methyl methacrylate, based on the total amount of copolymerizable monomer components, and has a hydroxyl value of 20 to 200 mgKOH / It is preferable to include a hydroxyl group-containing acrylic resin (A1) in the range of g, a weight average molecular weight of 1,000 to 10,000, and a glass transition temperature (Tg) of 0 to 90 ° C.

  The weight-average molecular weight of the hydroxyl group-containing acrylic resin (A1) is 1,000 to 10,000, preferably 3,000 to 9,000, from the viewpoints of coating film properties and improvement in paint solids content during coating and finish properties. It is suitable to be in the range.

  The hydroxyl value of the hydroxyl group-containing acrylic resin (A1) is in the range of 20 to 200 mgKOH / g, more preferably 30 to 170 mgKOH / g, particularly 90 to 150 mgKOH / g, from the viewpoint of the curability and finish of the coating film. Is suitable.

  The glass transition temperature (Tg) of the hydroxyl group-containing acrylic resin (A1) is 0 to 90 ° C. from the viewpoint of physical properties (particularly scratch resistance and hydrolysis resistance) of the resulting coating film and adhesion to the object to be coated. A range of 20 ° C. to 80 ° C. is suitable.

  As the copolymerization monomer component used in the synthesis of the hydroxyl group-containing acrylic resin (A1), from the viewpoint of the weather resistance and water resistance of the coating film, it does not contain methyl methacrylate, based on the total amount of the copolymerization monomer component. Or it is resin which the amount of methyl methacrylate contains in less than 50 mass%.

  In order to set the glass transition temperature (Tg) of the resin (A1) to 0 to 90 ° C, it is preferable to use a monomer having a glass transition temperature of 0 ° C or higher, more preferably 20 ° C or higher.

  Here, in this specification, the glass transition temperature of the monomer is the glass transition temperature of the homopolymer of each monomer in Polymer Handbook (4th Edition, edited by J. Brandup, E. H. Immergut). The glass transition temperature of a monomer not described in the literature is a value obtained by synthesizing a homopolymer of the monomer so that the weight average molecular weight is about 50,000, and measuring the glass transition temperature by differential scanning thermal analysis. Use the value.

  Specific examples of the monomer having a glass transition temperature of 0 ° C. or more include styrene, methyl methacrylate, methacrylate having a branched alkyl group, such as t-butyl methacrylate, and (meth) acrylate having a cyclic alkyl structure, such as cyclohexyl. (Meth) acrylate, isobornyl (meth) acrylate, etc. are mentioned.

  Further, from the viewpoint of adhesion to the object to be coated and coating film hardness, the hydroxyl group-containing acrylic resin (A1), 50 to 90% by mass of methyl methacrylate and 10 to 50% by mass of other polymerizable unsaturated monomers other than methyl methacrylate. % Can be used in combination with a hydroxyl group-containing acrylic resin (A2) having% as a copolymerization monomer component.

  The hydroxyl group-containing acrylic resin (A2) is based on the total amount of the copolymerization monomer component based on the adhesion to the article to be coated and the coating film hardness, and is preferably 50 to 90% by mass, more preferably 65 to 80% by mass, The other polymerizable unsaturated monomer is preferably 10 to 50% by mass, more preferably 20 to 35% by mass. The other polymerizable unsaturated monomer contains the hydroxyl group-containing polymerizable unsaturated monomer.

  By containing 50 to 90% by mass of methyl methacrylate based on the total amount of the copolymerizable monomer components, particularly the adhesion to the plastic material is good, and at the same time, the glass transition temperature of the entire coating film can be increased. And a tough film can be formed.

  The hydroxyl value of the hydroxyl group-containing acrylic resin (A2) preferably has a hydroxyl value in the range of 1 to 200 mgKOH / g, particularly 2 to 100 mgKOH / g, from the viewpoint of reactivity with the polyisocyanate compound (D).

  The hydroxyl group-containing acrylic resin (A2) is generally 3,000 to 90,000, particularly 4,000 to 30,000, more particularly 5, from the viewpoint of compatibility with other components, weather resistance and finish of the coating film. It is preferred to have a weight average molecular weight in the range of 000 to 10,000.

  The coating composition of the present invention has a hydroxyl group-containing acrylic resin (A) from the viewpoint of improving the solid content of paint during coating, scratch resistance, coating film hardness and finish, and adhesion to the object. It is preferable that it consists of the said resin (A1) and the said resin (A2).

  The solid content of the hydroxyl group-containing acrylic resin (A) is based on the total resin solid content of the component (A) and the component (B) described later, from the viewpoint of scratch resistance, coating film hardness and water resistance of the coating film. The range of 40 to 80% by mass is preferable.

  When the hydroxyl group-containing acrylic resin (A1) is used as at least a part of the hydroxyl group-containing acrylic resin (A), the blending amount thereof is improved in the solid content of paint at the time of coating, scratch resistance, coating film hardness and finish properties. From the viewpoint, the content within the range of 20 to 80% by mass, particularly 20 to 60% by mass, based on the total resin solid content of the component (A) and the component (B) is preferable.

  When using together a hydroxyl-containing acrylic resin (A1) and a hydroxyl-containing acrylic resin (A2) as a hydroxyl-containing acrylic resin (A), content of this resin (A2) is points, such as adhesiveness with a to-be-coated article. From less than 35% by weight, particularly 5 to 30% by weight, based on the total resin solid content of the component (A) and the component (B).

  In this specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are measured by a gel permeation chromatograph (gel permeation chromatograph: GPC) using a standard polystyrene calibration curve. It is.

  As a gel permeation chromatograph, “HLC-8120GPC” (trade name, manufactured by Tosoh Corporation) is used. As a column, one “TSKgel G4000HXL”, two “TSKgel G3000HXL”, and “TSKgel G2000HXL” are 1 A total of four of these (trade names, all manufactured by Tosoh Corporation) are used, and a differential refractometer is used as a detector. The conditions are mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 mL / min. Can be measured.

  Moreover, "glass transition temperature" of a hydroxyl-containing acrylic resin (A) and the hydroxyl-containing polyester resin (B) mentioned later is a static glass transition temperature. As a method for measuring the glass transition temperature, for example, using a differential scanning calorimeter “DSC-50Q type” (manufactured by Shimadzu Corporation, trade name), the sample is taken into a measuring cup and vacuum-suctioned to completely remove the solvent. There is a method of measuring a change in calorie within a range of −100 ° C. to + 100 ° C. at a rate of temperature increase of 3 ° C./min. The first baseline change point on the low temperature side is defined as the static glass transition temperature.

≪Hydroxyl-containing polyester resin (B) ≫
The hydroxyl group-containing polyester resin (B), which is a component constituting the coating composition of the present invention, has a hydroxyl value of 20 obtained by a reaction between a polyhydric alcohol containing a cyclic polyol compound (b1) having a nurate structure and a polybasic acid. A polyester resin of ˜250 mg KOH / g.

  The hydroxyl group-containing polyester resin (B) can be produced by a method known per se, for example, by esterifying a polybasic acid and a polyhydric alcohol.

  A polybasic acid is a compound having two or more carboxyl groups in one molecule. For example, adipic acid, azelaic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, octadecenyl succinic acid, azelaic acid , Sebacic acid, tetrahydrophthalic acid, alkyl hexahydrophthalic acid, hexahydrophthalic acid, het acid, maleic acid, fumaric acid, itaconic acid, trimellitic acid, pyromellitic acid, sodium 5-sulfoisophthalate, naphthalenedicarboxylic acid, Biphenyl dicarboxylic acid, dimer acid, suberic acid, tetrafluorophthalic acid and acid anhydrides thereof may be mentioned.

  As the polybasic acid component, 1,2-acid anhydrides having about 4 to 32 carbon atoms can be suitably used, and those mentioned in the specific examples of the acid anhydrides are preferably used.

  Examples of these acid anhydrides include succinic anhydride, methyl succinic anhydride, hexahydrophthalic anhydride, dodecenyl succinic anhydride, phthalic acid, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic acid. Examples thereof include acid anhydride, endomethylenetetrahydrophthalic anhydride, chlorendic anhydride, itaconic anhydride, citraconic anhydride, maleic anhydride and trimellitic anhydride. These polybasic acids may be used alone or in combination of two or more.

  A polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule.

  The hydroxyl group-containing polyester resin (B) that is a component of the present invention uses a cyclic polyol compound (b1) having a nurate structure as at least a part of the polyhydric alcohol. Examples of the cyclic polyol compound (b1) having a nurate structure include tris (2-hydroxyalkyl) isocyanurate. From the viewpoints of adhesion to an object to be coated, weather resistance, and hydrolysis resistance, tris (2- Hydroxyethyl) isocyanurate (THEIC) is preferred. The cyclic polyol compound (b1) is a compound having three hydroxyl groups, and a compound obtained by adding a lactone to a part or all of the three hydroxyl groups can also be used.

  The polyhydric alcohol component used for the preparation of the hydroxyl group-containing polyester resin (B) may be composed only of the cyclic polyol compound (b1), or may be composed of the cyclic polyol compound (b1) and other polyhydric alcohols. It doesn't matter if you do.

  Examples of other polyhydric alcohols other than the cyclic polyol compound (b1) include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, 1,2- or 1,3-propanediol, 1 Divalent alcohols such as 1,6-hexanediol, 1,4-dimethylolcyclohexane, dipropylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, bis (hydroxymethyl) xylene; glycerin, 1,1,1 -Trivalent or higher alcohols such as trimethylolpropane, 1,2,3-butanetriol, pentaerythritol, dipentaerythritol and the like. A hydroxyl group-containing modified oligomer obtained by subjecting a polyhydric alcohol having two or more hydroxyl groups per molecule and a lactone to a ring-opening esterification reaction can also be applied as a compound having a hydroxyl group. As commercially available products corresponding to these, for example, “TONE 0200 Polyol”, “TONE 0301 Polyol”, “TONE 0305 Polyol” (both manufactured by Union Carbide, trade name, TONE is a registered trademark), “Placcel 205”, “ Plaxel 303 "," Placcel 305 "(both manufactured by Daicel Chemical Industries, trade name, Plaxel \ PLACCEL is a registered trademark) and the like.

  Furthermore, the hydroxyl group-containing polyester resin (B) is composed of monobasic acids such as benzoic acid and t-butylbenzoic acid, castor oil, tung oil, safflower oil, soybean oil, linseed oil, tall oil, coconut oil, and fatty acids thereof. It may be modified with an oil component or the like, and may be modified with an epoxy compound such as neodecanoic acid glycidyl ester.

  In the polyhydric alcohol component, the component ratio of both components in the system in which the cyclic polyol compound (b1) and other polyhydric alcohol are used in combination is, for example, based on the total hydroxyl group molar amount of the two components. ) Is 2 to 100 mol%, preferably 5 to 70 mol%, more preferably 10 to 50 mol%, and other polyvalent alcohols are 99 to 0 mol%, preferably 95 to 30 mol%, more preferably. A range of 90 to 50 mol% is suitable.

  The hydroxyl group-containing polyester resin (B) is obtained by esterifying a polyhydric alcohol component containing the cyclic polyol compound (b1) and a polybasic acid. Specifically, these components are obtained by reacting at a temperature of 100 to 200 ° C. for 1 to 24 hours in the presence or absence of an organic solvent. Examples of the organic solvent include hydrocarbon solvents, ester solvents, ether solvents, alcohol solvents, and ketone solvents.

  Moreover, in said manufacture, a tertiary amine can be used as a catalyst as needed.

  As the above-mentioned hydroxyl group-containing polyester resin (B), from the viewpoint of compatibility with other components, curability of the coating film, adhesion to the object to be coated, coating workability, and improvement in the solid content of the paint during coating, The number average molecular weight is 1,000 to 10,000, preferably 1,200 to 5,000, more particularly 1,500 to 3,000, and the hydroxyl value is 20 to 250 mgKOH / g, preferably 50 to 200 mgKOH / It is suitable that the acid value is less than 15 mgKOH / g, preferably in the range of 1 to 10 mgKOH / g, within the range of g.

  The content of the hydroxyl group-containing polyester resin (B) is 5 to 60% by mass, particularly 8 to 30% by mass, based on the total resin solid content of the component (A) and the component (B), from the viewpoint of hydrolysis resistance. In particular, 11 to 25% by mass is preferable.

  When the solid content in the coating composition of the hydroxyl group-containing polyester resin (B) is in the above range, the coating composition has excellent adhesion to the article to be coated, and has physical properties such as hydrolysis resistance and the resulting coating film. It is possible to obtain a very excellent coating film having both finish properties.

  Since the hydroxyl group-containing polyester resin (B) has a nurate skeleton, the polarity of the coating material and the coating composition can be brought close to each other even when the coating material is a plastic material. It is thought to improve. Moreover, since it is excellent in compatibility with a hydroxyl-containing acrylic resin (A) and a polyisocyanate compound (D), it is thought that the coating film which is not biased to the surface in the curing process and has excellent finish and hydrolysis resistance can be obtained. .

≪Colored pigment and / or glitter pigment (C) ≫
The coating composition of the present invention contains a color pigment and / or a bright pigment. For example, various pigments exemplified below can be used singly or in combination of two or more in order to obtain a desired coating color tone. However, it is not limited to the following examples.

  Examples of the coloring pigment include titanium oxide, zinc white, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindoline pigment, selenium pigment, perylene pigment, Examples include dioxazine pigments and diketopyrrolopyrrole pigments.

  Further, examples of the bright pigment include non-colored or colored metal bright agents such as metals, alloys such as aluminum, aluminum oxide, copper, zinc, iron, nickel, tin, and the like. Film flakes and the like are also included. Further, mica, mica whose surface is coated with a metal oxide, mica-like iron oxide, graphite pigment, glass flake, hologram pigment and the like can also be mentioned. These bright pigments can be used alone or in combination of two or more.

  The luster pigment is not particularly limited in shape, and may be further colored or treated with various surface treatment agents or dispersants. For example, the volume average particle diameter (D50) is It is preferably 2 to 50 μm (major axis) and having a thickness of 0.1 to 5 μm. Among them, those having a volume average particle diameter (D50) in the range of 5 to 20 μm (major axis) are excellent in glitter and are particularly preferably used.

  These coloring pigments and / or glittering pigments may be added directly to the coating composition, or may be mixed and dispersed with a dispersant and a dispersing resin to form a paste and then blended into the coating. Known dispersants, dispersion resins, and dispersion methods can be used.

  The content of the color pigment and / or the luster pigment is not particularly limited, but is 1 to 250 mass based on the total resin solid content of the component (A) and the component (B) from the viewpoint of material concealment and design. % Is preferable, and more preferably in the range of 2 to 150% by mass.

≪Polyisocyanate compound (D) ≫
The coating composition of the present invention contains a polyisocyanate compound (D).
The polyisocyanate compound is a compound having two or more free isocyanate groups in one molecule, for example, an aliphatic diisocyanate compound such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, or lysine diisocyanate; Alicyclic diisocyanate compounds such as diisocyanate, cyclohexylene diisocyanate, methylenebis (cyclohexyl isocyanate), isophorone diisocyanate; tolylene diisocyanate, phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate Aromatic diisocyanate compounds such as 2; -Isocyanatoethyl-2,6-diisocyanatocaproate, 3-isocyanatomethyl-1,6-hexamethylene diisocyanate, 4-isocyanatomethyl-1,8-octamethylene diisocyanate (commonly known as triaminononane triisocyanate) And trivalent or higher organic polyisocyanates. Also, dimers or trimers of the above polyisocyanate compounds; prepolymers obtained by urethanation reaction of polyisocyanate compounds with polyhydric alcohols, low molecular weight polyester resins, water, etc. under conditions where the isocyanate groups are excessive. It can also be used.

  Examples of typical commercial products of the above polyisocyanate compounds include “Bernock D-750, Burnock D-800, Burnock DN-950, Burnock DN-970 or Burnock 15-455” (above DIC Corporation, trade names, BURNOCK \ Barnock or Barnock is a registered trademark), "Sumijour N3300, Sumidur N3390EA" (manufactured by Sumitomo Bayer Urethane Co., Ltd., trade name, SUMIDUR \ Sumijour is a registered trademark) , Takenate D-110 or Takenate D-123N ”(Mitsui Chemicals, trade name, Takenet \ TAKENATE is a registered trademark),“ Coronate EH, L, HL or 203 ”(Nippon Polyurethane Industry Co., Ltd., trade name , Coronate is a registered trademark ) Or “Duranate TLA-100, Duranate 24A-90CX” (manufactured by Asahi Kasei Corporation, trade name, Duranate \ DURANATE is a registered trademark), and the like.

  The coating composition of the present invention containing the polyisocyanate compound (D) has curability at a low temperature, and desired scratch resistance, weather resistance, etc. without heating at a high temperature (eg, 100 ° C. or higher). It is possible to obtain the performance of Among the polyisocyanate compounds (D), isocyanurate cycloadducts of hexamethylene diisocyanate, which are isocyanurate cycloadducts of aliphatic polyisocyanate compounds, uretdione type adducts, and adduct type adducts, It is particularly suitable because of its excellent compatibility, coating film hardness, coating film adhesion and weather resistance.

  The blending ratio of the polyisocyanate compound (D) includes the isocyanate groups of the polyisocyanate compound and the total hydroxyl groups of the hydroxyl group-containing resin component and the rheology control agent in the coating composition of the present invention from the viewpoints of coating film hardness and stain resistance. It is preferable that the equivalent ratio (NCO / OH) is selected so that it is usually in the range of 0.8 to 1.5, particularly 1.0 to 1.3.

≪Rheology control agent (E) ≫
The coating composition of the present invention may contain a rheology control agent (E).
As the rheology control agent (E), those known per se can be used, and examples thereof include known additives as thickeners and anti-settling agents such as oxidized polyethylene and fatty acid amide wax. In addition, examples include alkoxysilyl compounds or condensates thereof, polyurea compounds, and organic resin fine particles such as non-aqueous dispersion resins, inorganic fine particles, and the like.

  As the rheology control agent (E), when it is blended, those having thixotropy and exhibiting viscosity when shearing force is not applied can be used. Particularly in the coating composition of the present invention, when spray coating is performed using a luster pigment, the rheology control agent (E) is contained, thereby further strengthening the action of suppressing orientation failure of aluminum flakes after coating the coating particles. It can be used to prevent convex spots (spits) and unevenness on the painted surface and improve the finish.

  Examples of the organic resin fine particles include, for example, resin particles such as polymer beads known per se, and gelled polymer fine particles obtained by finely pulverizing a polymer of the monomers (for example, JP-A-3-66770, 6-70110) can be used.

  Specific examples include poly (12-hydroxystearic acid) molecular chains as disclosed in JP-B-6-70110, and an average of about 1 polymerizable unsaturated double bond per molecule. In the presence of a mixture of a macromonomer (a) having at least one and a macromonomer (b) having an average of about 1.0 to about 1.5 polymerizable unsaturated double bonds per molecule. A vinyl monomer mixture containing at least 0.5% by mass of at least two vinyl monomers each having a complementary functional group capable of reacting with and binding to macromonomer (a), macromonomer (b) and Non-aqueous dispersion of gel polymer fine particles obtained by copolymerization and crosslinking reaction in an organic solvent in which the vinyl monomer is dissolved but the polymer of the vinyl monomer is not substantially dissolved is used. Door can be.

  Such organic resin fine particles have a crosslink density higher than that of the hydroxyl group-containing acrylic resin (A), and are substantially non-swelling and non-fusible even in an organic solvent having a high polymer dissolving power such as toluene and ethyl acetate. It is wearing. When added to the present paint composition containing an organic solvent, a solution (dispersion) having a high resin content, that is, a high solid content can be obtained without substantially increasing the viscosity of the present paint composition. It can be suitably used for the coating composition.

  The organic resin fine particles generally have a volume average particle size in the range of 0.01 to about 2 μm, particularly 0.05 to 0.5 μm, and the fine particles having a particle size in this range are preferably A coating film excellent in sagging prevention effect and finish can be obtained.

  As the inorganic fine particles, for example, colloidal or amorphous inorganic oxide particles such as silica and alumina can be used.

  As the rheology control agent (E), known commercial products may be used as additives. For example, Celny HPC-H, HPC-M, HPC-L, HPC-SL and HPC-SSL (Nippon Soda Co., Ltd.) ), Dianal BR series (manufactured by Mitsubishi Rayon Co., Ltd.), Disparon # 6900-10X, Disparon # 6900-20X, Disparon # 4200, Disparon KS-873N and Disparon # 1850 (manufactured by Enomoto Kasei Co., Ltd.) BYK-405 and BYK-410 (Bic Chemie Japan), Primal RW-12W (Rohm and Haas), AS-AT-20S, AS-AT-350F, A- S-AD-10A and AS-AD-160 (manufactured by Ito Oil Co., Ltd.), Setalux C-7176VB- 0 (Akzo Nobel), and the like.

  In the case where the rheology control agent (E) is contained in the coating composition of the present invention, the content is based on the total resin solid content of the component (A) and the component (B), from the viewpoint of viscosity development and finish. 50 mass% or less, and the range of 2-40 mass% is preferable.

  The coating composition of the present invention may further contain a hydroxyl group-containing resin other than the component (A) and the component (B) as long as the coating film performance is not impaired.

  Examples of other hydroxyl group-containing resins include hydroxyl group-containing polyether resins, polycarbonate resins, polyurethane resins, epoxy resins, alkyd resins, cellulose resins, and acrylic resins other than the component (A). These can be used alone or in combination of two or more.

  When mix | blending the said other hydroxyl-containing resin, the compounding ratio has preferable 30 mass% or less on the basis of the total resin solid content of (A) component and (B) component.

  The coating composition of the present invention further comprises a curing catalyst, a higher fatty acid (F), a plasticizer, an ultraviolet absorber, a light stabilizer, an antifoaming agent, a rust inhibitor, an extender pigment other than the inorganic fine particles, an organic solvent, a surface Ordinary paint additives such as regulators can be contained alone or in combination of two or more.

  Examples of the curing catalyst include tin octylate, dibutyltin diacetate, dibutyltin di (2-ethylhexanoate), dibutyltin dilaurate, dioctyltin diacetate, dioctyltin di (2-ethylhexanoate), Dibutyltin oxide, dioctyltin oxide, dibutyltin fatty acid salt, lead 2-ethylhexanoate, zinc octylate, zinc naphthenate, zinc fatty acid, cobalt naphthenate, calcium octylate, copper naphthenate, tetra (2-ethylhexyl) Organometallic compounds such as titanate; tertiary amines and the like can be mentioned, and these can be used alone or in combination of two or more.

  When the coating composition of the present invention contains a curing catalyst, the content is 5% by mass or less based on the total resin solid content of the component (A) and the component (B) from the viewpoint of curability and finish. In the range of 0.002 to 1.0 mass%.

As the higher fatty acid (F), those known per se can be used. A fatty acid is a monovalent carboxylic acid of a long-chain hydrocarbon and can be represented by the general formula C _n H _m COOH. A fatty acid having 12 or more carbon atoms is called a higher fatty acid (long-chain fatty acid). Those having 14 or more carbon atoms are preferred, and those having 18 or more carbon atoms are more preferred. Although the upper limit of the carbon number is not limited, for example, those having 24 or less carbon atoms are preferable, and those having 22 or less carbon atoms are more preferable. Examples of higher fatty acids include lauric acid (also known as dodecanoic acid, hereinafter also referred to in parentheses), tetradecanoic acid (myristic acid), pentadecanoic acid (pentadecylic acid), hexadecanoic acid (paltimic acid), heptadecanoic acid (margaric acid), and octadecane. Acid (stearic acid), oleic acid, 2-heptylundecanoic acid (isostearic acid), eicosanoic acid (arachidic acid or icosanoic acid), docosanoic acid (behenic acid), tetracosanoic acid (lignoceric acid), hexacosanoic acid (serotic acid), Saturated fatty acids such as octacosanoic acid (montanic acid) and triacontanoic acid (melicinic acid), 9-hexadecenoic acid (palmitoleic acid), cis-9-octadecenoic acid (oleic acid), linoleic acid, linolenic acid, eleostearic acid, , Eicosadienoic acid, eicosatrienoic acid , Eicosatetraenoic acid (arachidonic acid), arachidic acid, caproleic acid, Linderic acid, myristoleic acid, cadreic acid, decagenic acid, hiragoic acid, docosatrienoic acid, hexadecatetraenoic acid, stearidonic acid, docosatetraenoic acid, Unsaturated fatty acids such as eicosapentaenoic acid, sardine acid, sabinic acid, iprolic acid, yarapinolic acid, ferronic acid cis-13-docosenoic acid (erucic acid), hydroxy fatty acids such as ricinoleic acid, 12-hydroxystearic acid, or beef tallow, Milk fat, pork fat, fish fat, flaxseed oil, olive oil, corn oil, sesame oil, rice bran oil, safflower oil, soybean oil, rapeseed oil, palm oil, palm kernel oil, castor oil, sunflower oil, cottonseed oil, palm oil, Examples include fatty acids (alkanoic acids) obtained from animal and vegetable oils such as peanut oil. Those obtained by reacting these higher fatty acids with a polyhydric alcohol such as glycerin to cause esterification can also be used.

  The higher fatty acids may be used alone or in combination of two or more. From the viewpoint of finish, it is preferable that the higher fatty acid having 18 to 22 carbon atoms is contained in an amount of 50% by mass or more, more preferably 60% by mass or more in the total fatty acids to be blended. .

  When the higher fatty acid is blended, the molecular weight is relatively lower than that of the other components, so that a coating film that intervenes on the coating film surface and has excellent finish (glossiness) can be formed.

  When the coating composition of the present invention contains a higher fatty acid, the content thereof is 20% by mass or less based on the total resin solid content of the component (A) and the component (B) from the viewpoint of finish, and further 1 The range of -10 mass% is preferable.

  The plasticizer is not particularly limited, but is a phosphate ester plasticizer, a phthalate ester plasticizer, a trimellitic ester plasticizer, a pyromellitic acid plasticizer, a glycolate plasticizer, or a citrate ester plasticizer. Agents, polyester plasticizers, and the like can be used. Specific examples include arylene bis (diaryl phosphate) ester, tricresyl phosphate, and tri (2-ethylhexyl) trimellitic acid.

  When the coating composition of the present invention contains a plasticizer, the content is the sum of the components (A) and (B) from the viewpoint of compatibility with the coating composition, finish, and storage stability of the coating. Based on the solid content of the resin, it is preferably 20% by mass or less, and more preferably 1.5 to 10% by mass.

  The coating composition of the present invention is preferably an organic solvent-type coating composition from the viewpoint of low temperature curability. In the present specification, the organic solvent-type coating composition is a coating that does not substantially contain water as a solvent. Although it does not specifically limit as a kind of organic solvent, It is preferable that the coating composition of this invention does not contain toluene or xylene from a viewpoint of the influence on a human body or an environment.

  In the coating composition of the present invention, a diluent can be used at the time of coating, the solid content is 15% by mass or more, particularly preferably in the range of 35 to 60% by mass, and the viscosity is 5 to 30 seconds / Ford cup. It is preferable to adjust the coating within the range of # 4/20 ° C. from the viewpoint of coating workability and reduction of the amount of discharged organic solvent. The diluent is not particularly limited, and those listed in the section of the organic solvent can be used, but from the viewpoint of influence on the human body and the environment, it is preferable not to contain toluene or xylene.

  A coated article can be obtained by coating the coating composition of the present invention on an article to be coated.

  The object to be coated with the coating composition of the present invention is an acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene-acrylate (ABS) resin from the viewpoint of achieving both coating properties such as adhesion and finish in one coat. An ASA) resin, a polycarbonate (PC) resin, a polybutylene terephthalate (PBT) resin, a polyvinyl chloride (PVC) resin, a polyamide (PA) resin, and at least two kinds of these hybrid resins are preferable.

  In addition to the above objects to be coated, the following can also be used as long as there is no problem in adhesion and coating film performance. Polyolefin resins such as polyethylene and polypropylene, polymethyl methacrylate resin, acrylic resin, polyphenylene ether resin, polyoxymethylene resin, polyurethane resin, epoxy resin, etc., or hybrid resins and fiber-reinforced plastics (Fiber-Reinforced Plastics) And plastic materials (synthetic resin moldings) such as engineering resins; inorganic materials such as glass, cement and concrete; wood; fiber materials (paper, cloth, cardboard, etc.); metal materials (iron, aluminum, brass, copper, stainless steel) Steel, tinplate, galvanized steel, alloyed zinc [Zn-Al, Zn-Ni, Zn-Fe, etc.], plated steel, etc.). Depending on these materials, it can be appropriately subjected to a degreasing treatment or a surface treatment to obtain an article to be coated. Furthermore, what formed the undercoat coating film (basecoat coating material) in the said to-be-coated object can also be made into a to-be-coated object.

  The undercoat coating is a coating formed under the coating formed by the coating composition of the present invention, and the undercoating for forming the undercoat can be applied to the type or state of the surface to be coated. Painted accordingly. By providing a film between the coating film formed by the coating composition of the present invention, adhesion to the surface to be coated can be improved.

  Specific examples of the constituents of the undercoat paint constituting the undercoat coating film include, for example, a film-forming resin, a crosslinking agent, a color pigment, an extender pigment, a glitter pigment, a rust preventive pigment, a conductive pigment, and the like. In addition, the undercoating composition can be used as an ultraviolet absorber, a light stabilizer, a curing catalyst, a plasticizer, an adhesion-imparting agent, a compatibilizer, an antifoaming agent, a viscosity modifier, Paint additives such as a rusting agent and a surface conditioner can be appropriately contained.

  Examples of the film-forming resin include polyols, acrylic resins, polyester resins, alkyd resins, urethane resins, polyolefin resins, epoxy resins, phenol resins, polyamide resins, and hydroxyl group-containing resins. Or two or more types can be used in combination.

  It may be crosslinked by blending a crosslinking agent, or may be substantially uncrosslinked without blending a crosslinking agent. Moreover, you may make it bridge | crosslink by the penetration of the crosslinking agent contained in the upper layer coating film.

  As a crosslinking agent, amino resins, such as a melamine resin and a urea resin, a polyisocyanate compound, a blocked polyisocyanate compound, etc. can be used conveniently, for example. As the undercoat coating composition, either an organic solvent-type coating composition or an aqueous coating composition may be used, or a solvent-free coating composition may be used.

  In addition, the object to be coated with the coating composition of the present invention is not particularly limited, and examples thereof include an outer plate part of an automobile body such as a passenger car, a truck, a motorcycle, and a bus; an automobile part; a mobile phone, an audio device, and the like. As an example, the outer plate of a household electric product can be cited.

  The method for applying the coating composition and the undercoat coating composition of the present invention is not particularly limited. For example, it can be applied by air spray, airless spray, rotary atomizing coater, dip coating, brush or the like. Electrostatic application may be performed during coating.

  The coating film thickness of the coating composition of the present invention can be within a range of usually 10 to 100 μm, preferably 12 to 50 μm, and more preferably 15 to 35 μm as a cured film thickness.

  Although the heating conditions in the coating-film formation method of the coating composition of this invention are not specifically limited, It can carry out by hold | maintaining for 10 to 90 minutes at 70-100 degreeC, Preferably 70-90 degreeC. When the plastic material is deformed by heat, for example, when an ABS resin is used, the heating condition is preferably maintained at 70 ° C. to 90 ° C. for 20 to 90 minutes.

  After applying the coating composition of the present invention, before curing by heating, in order to reduce the volatile content of the coating film immediately after coating or to remove the volatile content, setting (leaving at room temperature for several minutes) and / or preheating ( It is also possible to perform forced drying at a temperature of about 50 to 80 ° C. for several minutes. Preheating is performed in a drying furnace such as an air blow, hot air furnace, electric furnace, or IR (infrared induction heating) furnace that blows air heated to a room temperature or a temperature of about 25 ° C. to about 80 ° C. on the surface to be coated. Can be done.

  As described above, in the present invention, a material in which an undercoat film (base coat film) is formed on the object to be coated can also be used. Moreover, you may mix | blend a pigment etc. with undercoat. Accordingly, in one embodiment of the present invention, the present invention provides a method for forming a multi-layer coating film by sequentially applying at least one layer of a colored base coating composition and at least one layer of a top coating to an object to be coated. And the multilayer coating-film formation method which coats the above-mentioned coating composition of this invention as top coat (top) coating material of the uppermost layer is provided.

  Specifically, for example, 2 coat 1 bake method (base coat / top coat), 2 coat 2 bake method (base coat / top coat), 3 coat 1 bake method (base coat / clear coat / top coat), 3 coat 2 bake It can be carried out according to a conventionally known method such as a method (base coat / clear coat / top coat).

  After applying the base coating composition, the obtained uncured undercoating film is dried by setting and / or preheating, if necessary, to such an extent that it does not substantially harden or solid content to the extent that it does not dry. The content rate may be adjusted.

  In the present invention, the cured coating film is a cured and dried state specified in JIS K 5600-1-1, that is, the center of the coating surface is strongly sandwiched between the thumb and the index finger, and the coating surface is free from dents due to fingerprints. In this coating film, no movement of the coating film is felt, the center of the coating surface is rubbed rapidly with the fingertips, and the coating surface is not rubbed. On the other hand, an uncured coating film is a state in which the coating film has not reached the above-mentioned cured and dried state, and includes a finger-touch dried state and a semi-cured dried state defined in JIS K 5600-1-1.

  The top coating composition of the present invention can be applied to a cured or uncured coating film of the base coating composition, but it is possible to apply on the cured coating film from the point of adhesion (2-coat 2-bake method). Particularly preferred.

  The curing condition of the base coating composition can be appropriately selected from the baking conditions for curing the coating, but at room temperature (25 ° C.) to 160 ° C., particularly at a temperature in the range of 40 ° C. to 140 ° C. The baking time is preferably in the range of 30 seconds to 60 minutes, particularly 1 to 40 minutes. Moreover, the coating film thickness in that case is 3-100 micrometers in dry coating film thickness, and the inside of the range of 5-80 micrometers is especially suitable.

  Further, a clear coating or the like may be applied to the object to be coated after applying the coating composition of the present invention to form a multilayer coating film.

  When the coating composition of the present invention is applied, even if it is 35 μm or less, even if it is one coat, a coating film having excellent scratch resistance and finish properties equivalent to two coats and excellent in hydrolysis resistance is formed.

  Hereinafter, the present invention will be described in more detail with reference to examples. “Part” and “%” indicate “part by mass” and “% by mass” unless otherwise specified.

(Production Example 1) Production of hydroxyl group-containing acrylic resin (A-1) In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a thermostat and a dropping pump, 60 parts of Swazol 1000 (Note 1) were charged, and nitrogen The temperature was raised to 145 ° C. while blowing gas and stirring, and the following monomer and polymerization initiator 2-hydroxyethyl methacrylate 29.0 parts into the reaction vessel,
10.0 parts of styrene,
11.7 parts of methyl methacrylate,
18.0 parts of iso-butyl methacrylate,
iso-butyl acrylate 11.0 parts Cardura E10P (Note 2) 15.3 parts,
5.0 parts of acrylic acid and
A mixture of 6.0 parts of di-tert-amyl peroxide was added dropwise at a constant rate over 3 hours using a dropping pump. Thereafter, a mixture of 0.5 part of di-tert-amyl peroxide and 10.0 parts of Swazole 1000 was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was terminated by aging for 3 hours at the same temperature. The obtained solution of the hydroxyl group-containing acrylic resin (A-1) was a uniform transparent solution having a solid content of 60%. The weight average molecular weight of the resin (A-1) was about 4,700, the glass transition temperature was 45.1 ° C., the hydroxyl value was 125 mgKOH / g, and the acid value was 5.0 mgKOH / g.

Note 1) Swazol ^{(registered trademark)} 1000: manufactured by Maruzen Petrochemical Co., Ltd., trade name, aromatic hydrocarbon solvent Note 2) Cardura E10P: manufactured by Japan Epoxy Resin Co., Ltd., trade name, neoglycanoyl monoglycidyl ester.

(Production Examples 2 to 5) Production of hydroxyl group-containing acrylic resins (A-2) to (A-5) In Production Example 1, except that the formulation is as shown in Table 1, the same procedure as in Production Example 1 was carried out. Hydroxyl group-containing acrylic resins (A-2) and (A-5) solutions were obtained. Table 1 shows the solid content, weight average molecular weight, glass transition temperature, hydroxyl value, and acid value of the obtained hydroxyl group-containing acrylic resins (A-2) to (A-5).

(Production Example 6) Production of hydroxyl group-containing polyester resin (B-1) In a reaction vessel equipped with a stirrer, a thermometer, a rectification tower and a water separator,
48.8 parts hexahydrophthalic anhydride,
31.1 parts of 1,6-hexanediol,
25.8 parts of tris (2-hydroxyethyl) isocyanurate was heated to 230 ° C. in the presence of the esterification catalyst dibutyltin oxide (0.025 parts) and maintained for 1 hour, then xylene was added at the same temperature. The reaction was allowed to reflux for about 6 hours while distilling off the water. After completion of the reaction, the volatile component was distilled off under reduced pressure, and the solvent was replaced and diluted with Swazol 1500 (Note 3) / Butyl acetate = 70/30 to obtain a hydroxyl group-containing polyester resin (B-1) having a solid content of 70%. ) The number average molecular weight, hydroxyl value, and acid value of this hydroxyl group-containing polyester resin (B-1) are shown in Table 2:
Note 3) Swazol ^{(registered trademark)} 1500: Maruzen Petrochemical Co., Ltd., trade name, aromatic hydrocarbon solvent.

(Production Example 7) Production of hydroxyl group-containing polyester resin (B-2) To a reaction vessel equipped with a stirrer, a thermometer, a rectification tower and a water separator,
52.8 parts hexahydrophthalic anhydride,
14.8 parts of 1,4-cyclohexanedicarboxylic acid,
1,3-propanediol 31.7 parts trimethylolpropane 10.0 parts,
Was heated to 230 ° C. in the presence of an esterification catalyst dibutyltin oxide (0.025 parts) and maintained for 1 hour, then xylene was added, and the reaction was carried out at reflux for about 6 hours while distilling off water. I let you. After completion of the reaction, the volatile component was distilled off under reduced pressure, and the solvent was replaced and diluted with Swazol 1500 / butyl acetate = 70/30 to obtain a hydroxyl group-containing polyester resin (B-2) having a solid content of 70%. . Table 2 shows the number average molecular weight, hydroxyl value, and acid value of this hydroxyl group-containing polyester resin (B-2).

(Production Example 8) Production of macromonomer (fa) for rheology control agent 12-hydroxystearic acid is dehydrated and condensed with methanesulfonic acid as a catalyst under reflux of toluene, and has a number average molecular weight of about 1,800. A glycidyl methacrylate was added to the terminal carboxyl group of the self-condensed polyester resin using dimethylaminoethanol as a catalyst to introduce a polymerizable double bond to obtain a macromonomer (fa) solution. This had a solid content of 70% and had about one polymerizable double bond based on the number average molecular weight per molecule.

(Production Example 9) Production of macromonomer (fb) for rheology control agent 174 parts of butyl acetate was placed in a reaction vessel and heated to reflux.
297.0 parts of a 70% macromonomer (fa) solution,
195.9 parts methyl methacrylate,
18.5 parts of glycidyl methacrylate,
163.0 parts xylene,
A mixture consisting of 9.6 parts of 2,2-azobisisobutyronitrile was added dropwise at a uniform rate over 3 hours and further aged for 2 hours.
Next, 0.05 parts of pt-butylcatechol,
3.8 parts of methacrylic acid,
A mixture consisting of 0.5 parts of dimethylaminoethanol was added to the flask and reacted at 140 ° C. for about 5 hours until the resin acid value reached 0.5, and a macromonomer (fb) solution having a solid content of 50% was obtained. Obtained. The obtained macromonomer (fb) is a graft polymer having a first segment made of poly-12-hydroxystearic acid and a second segment made of a copolymer of methyl methacrylate and glycidyl methacrylate. It had an average of 4 polymerizable double bonds.

(Production Example 10) Production of macromonomer (fc) for rheology control agent
After placing 153 parts of xylene in the reaction vessel and heating to 125 ° C,
2-ethylhexyl acrylate 50.0 parts,
n-butyl acrylate 23.0 parts,
25.0 parts 2-hydroxyethyl acrylate,
2.0 parts acrylic acid,
A mixture consisting of 4.5 parts of tert-butyl peroctoate was added dropwise over 4 hours, followed by aging for 2 hours.
The obtained acrylic resin varnish had a solid content of 65% and a number average molecular weight of 7,000. In 100.0 parts of this acrylic resin varnish,
2.0 parts of glycidyl methacrylate,
4-tert-butylpyrocatechol 0.01 part,
0.15 part of tetrabutylammonium bromide was added and stirred at 115 ° C. for 7 hours to introduce a copolymer double bond into the molecule to obtain a macromonomer (fc). The number of introduced double bonds in the obtained macromonomer (fc) was about 1.0 per number average molecular weight per molecule, the SP value was 8.70, and the hydroxyl value was 121 mgKOH / g.

(Production Example 11) Production of rheology control agent (No. 1) In a reaction vessel under a nitrogen atmosphere,
190.0 parts heptane,
20.0 parts of a 50% macromonomer (fb) solution,
Charge 23.0 parts of 65% macromonomer (fc) solution at reflux temperature while stirring.
20.0 parts of a 50% macromonomer (fb) solution,
23.0 parts of 65% macromonomer (fc) solution,
50.0 parts of methyl methacrylate,
2-hydroxyethyl acrylate 50.0 parts,
1.5 parts of glycidyl methacrylate,
Methacrylic acid 0.8 parts,
A mixture consisting of 2.0 parts of 2,2′-azobisisobutyronitrile was added dropwise over 5 hours, followed by aging for 2 hours. Next,
0.1 part of dimethylaminoethanol was added, and the mixture was further aged for 4 hours to obtain a non-aqueous dispersion of polymer fine particles (No. 1). The polymer fine particles (No. 1) had a weight average molecular weight of 100,000, the obtained non-aqueous dispersion was a white dispersion having a solid content of 40%, and the particle size was about 160 nm (peak particle size). It was. The particle size was measured with a Coulter N4 submicron particle analyzer manufactured by Coulter. The particles were insoluble in organic solvents such as acetone, ethyl acetate and xylene.

<Preparation of the object>
(ABS substrate)
The surface of a 100 mm × 150 mm × 3.0 mm acrylonitrile-butadiene-styrene plate was degreased with isopropyl alcohol to obtain an ABS coating.

(PC / PBT substrate)
The surface of a 100 mm × 150 mm × 3.0 mm polycarbonate-polybutylene terephthalate plate was degreased with isopropyl alcohol to obtain a PC / PBT coated object.

(PVC coated object)
The surface of a polyvinyl chloride resin of 100 mm × 150 mm × 1.0 mm was degreased with isopropyl alcohol to obtain a PVC coated object.

(Nylon coating)
The surface of a 100 mm × 150 mm × 1.0 mm polyamide resin (nylon) was degreased with isopropyl alcohol to obtain a nylon coating.

(Example 1) Coating composition No. 1 Production of hydroxyl group-containing acrylic resin (A-1) 60% solution 111.7 parts (solid content 67.0 parts),
25.7 parts of a hydroxyl group-containing polyester resin (B-1) 70% solution (solid content: 18.0 parts),
Rheology control agent (No. 1) 40% solution 43.5 parts (solid content 17.4 parts),
Pigment (C-1) (Note 4) 17.4 parts,
BYK-346 (Note 7) 1.0 part,
Disparon ^{(registered trademark)} LF1985-50 (Note 8) 1.0 part,
TINUVIN 384-2 (Note 9) 1.6 parts and TINUVIN 292 (Note 10) 0.8 parts were mixed uniformly,
Furthermore, Sumidur ^{(registered trademark)} N3300 (Note 11) is added in an amount such that the equivalent ratio of NCO / OH is 1.10 with respect to the total hydroxyl groups of the hydroxyl group-containing resin component and the rheology control agent in the coating composition of the present invention. The solid content was adjusted with SWAZOL 1000, and the coating composition No. with a solid content of 55% was prepared. 1 was obtained. In addition, the coating composition No. Table 3 shows the results of evaluating the tack-free property of No. 1.

(Examples 2-18, Comparative Examples 1-3) Coating composition No. 2-No. Production of No. 21 In the same manner as in Example 1 except that the composition of each component is as shown in Table 3, paint composition No. 21 having a solid content of 55% shown in Table 3 was prepared. 2-No. 21 was obtained. In addition, the compounding quantity of Table 3 shows the compounding quantity of solid content. Coating composition No. 2-No. Table 3 shows the results of evaluating the tack-free property of 21.

(Comparative example 4) Coating composition No. 22
The composition of each component is the same as in Example 1 except that the composition shown in Table 3 and the isocyanate compound is 57.5 parts (solid content 34.5 parts) of Euban 20SE-60 (Note 12). The coating composition No. with a solid content of 55% shown in Table 3 was used. 22 was obtained.

Note 4) C-1: Aluminum paste BP-6360, manufactured by Toyo Aluminum Co., Ltd., trade name, surface-treated aluminum,
Note 5) C-2: Black paste, 52.4 parts of methoxypropyl acetate, 15 parts of carbon black, DISPERBYK-2001 (manufactured by Big Chemie Japan, dispersant, 46% active ingredient) is mixed with 32.6 parts. A mill base was prepared, dispersed for 60 minutes in a bead mill, and the beads were removed, and used as a black paste. The pigment concentration was 15% by weight.

Note 6) Higher fatty acid No. 1: oleic acid having 18 carbon atoms,
Higher fatty acid No. 2: Eicosanoic acid having 20 carbon atoms (Japanese name: arachidic acid),
Higher fatty acid No. 3: C22 docosanoic acid (Japanese name: behenic acid)
Other fatty acid No. 4: Lauric acid having 12 carbon atoms,
Note 7) BYK ^{(registered trademark)} -346: manufactured by Big Chemie Japan, trade name, surface conditioner,
Note 8) Disparon ^{(registered trademark)} LF-1985-50: manufactured by Enomoto Kasei Co., Ltd., trade name, surface conditioner,
Note 9) TINUVIN ^{(registered trademark)} 384-2: manufactured by BASF, trade name, UV absorber,
Note 10) TINUVIN ^{(registered trademark)} 292: manufactured by BASF, trade name, light stabilizer,
Note 11) Polyisocyanate compound (D): Sumidur ^{(registered trademark)} N3300, manufactured by Sumitomo Bayer Urethane Co., Ltd., trade name, isocyanurate cycloadduct of hexamethylene diisocyanate, solid content 100%, isocyanate group content 21.8%,
Note 12) Uban 20SE-60: a butyl etherified melamine resin solution having a trade name and a solid content of about 60% by mass, manufactured by Mitsui Toatsu Chemical Co., Ltd.

Note 13) Non-stickiness;
Each coating composition was applied on a degreased ABS resin flat plate (100 × 100 mm) to a cured film thickness of 80 μm, set at room temperature for 5 minutes, and baked at 70 ° C. for 20 minutes. Two sheets were created. Tissue paper ("Scotty tissue (manufactured by Crecia Co., Ltd.)" cut into test plate sizes is sandwiched between test plates so that the coated surfaces face each other, and left at a load of 0.2 kg / cm ² for 2 hours. The tissue was easily peeled off by hand and the state of the coating film was confirmed and evaluated according to the following criteria: The test temperature was 40 ° C .:
S: The tissue paper peels off immediately, and there is no abnormality in the appearance of the coating film. A: The tissue paper peels off immediately, and there is a slight trace of the part where the tissue paper is overlaid on the coating surface. Recover within hours,
B: The tissue paper peels off immediately, and there is a considerable trace of the tissue paper overlaid on the coating surface, and the trace does not recover within 24 hours even when left at room temperature.
C: Tissue paper is difficult to peel off and marks are left on the coated surface.

Preparation of test plate (Example 19)
The coating composition No. obtained in Example 1 was used. 1 is adjusted to the solid content shown in Table 4 with Swazol 1000, and using an air spray, the test plate is coated with the coating, dry film thickness, setting time at room temperature, baking temperature, baking time shown in Table 4. Got.

(Examples 20 to 42, Comparative Examples 5 to 8)
A test plate was prepared in the same manner as in Example 19 except that the coating composition shown in Table 4 was used as the object to be coated, the solid content during coating, the baking temperature, and the baking time.
Each coated plate obtained as described above was allowed to stand for 24 hours in an atmosphere of 23 ° C. and 50% relative humidity as a test plate, which was subjected to various tests. The test results are shown in Table 4.

≪Test method≫
(Note 14) Finishability:
The finish was evaluated for each test plate by the following visual evaluation and gloss measurement:
<Appearance (visual)>
Each test plate was visually observed, and the presence or absence of material deformation and the degree of occurrence of unevenness and convexity were evaluated according to the following criteria:
S: Almost no material deformation due to heat, no unevenness or unevenness is observed, and has an extremely excellent coating film appearance. A: There is almost no material deformation due to heat, and slight unevenness or unevenness is observed, but an excellent coating film Appearance B: There is almost no deformation of the material due to heat, unevenness or unevenness is considerably recognized and the appearance of the coating film is slightly inferior C: There is material deformation due to heat or many unevenness or unevenness is observed, and the appearance of the coating film is inferior <Glossy Degree>
The glossiness of each coated surface was measured according to the specular glossiness (60 degrees) of JIS K5600-4-7 (1999). The measured glossiness was evaluated according to the following criteria. If the specular gloss (60 degrees) is 85 or more, it is a practical level.

(Note 15) Coating film hardness:
<Pencil hardness (after 1 hour and 3 days)>
The paint film surface of each test plate was subjected to a pencil scratch test (hand-scratch method, scratch evaluation [the hardness of the hardest pencil without scars]) according to JIS K 5600-5-4 (1999). Each test plate was allowed to stand for 1 hour in an atmosphere of 23 ° C. and 50% relative humidity and for 3 days. 2B, B, HB, F, H, the pencil core becomes harder, indicating that the coating film is harder. If it is equal to or higher than HB, it is a practical level. <Abrasion Resistance (Visual)>
An automobile with a test plate attached to the roof with water resistant tape manufactured by Nichiban Co., Ltd. was washed 15 times with a car wash under a condition of 20 ° C. Each test plate before and after the test was visually observed and evaluated according to the following criteria. The car wash machine used was “PO20 FWRC” manufactured by Yasui Sangyo Co., Ltd .:
S: The surface of the coating film is slightly glossy due to scratches on the coating film before the test, but the appearance of the coating film is good. A: The coating film surface is scratched against the coating film before the test. Slightly deep and glossy appearance is observed, but the appearance of the coating film is a level that is not problematic when the product is made into a product. B: The coating film surface is deeply scratched and glossiness is considerably observed compared to the coating film before the test. C: The substrate can be seen with respect to the coating film before the test, and the gloss is remarkably visible.

(Note 16) Contamination resistance:
<Alkali resistance (gloss retention)>
A 0.1 mL caustic soda aqueous solution having a concentration of 0.1 N was spot-dropped onto the coated surface of the test plate, left at a temperature of 65 ° C. and a relative humidity of 75% for 4 hours, and washed with water. About the coating film of the spot part before and behind a test, the glossiness of each coating surface was measured 3 times according to the mirror surface glossiness (60 degree | times) of JISK5600-4-7 (1999), and the average value was calculated | required. The glossiness after the test relative to the glossiness before the test was determined as the gloss retention (%) and evaluated by the gloss retention (%). The higher the gloss retention, the better the alkali resistance. If the gloss retention is 80 (%) or more, it is a practical level. <Gasoline resistance (visual appearance)>
Gauze soaked with gasoline on the coated surface of the test plate was rubbed 8 times with a load of 4.9 N, and the adhesiveness of the coating film and the coated surface state were observed:
S: No change in appearance with respect to the coating film before the test A: The coating film before the test is slightly glossy, blistered or discolored, but there is no problem when it is used as a product. B: Sticky, glossy, blistered or discolored with respect to the film before the test C: Significantly sticky, glossy, blistered or discolored with respect to the film before the test It can be seen.

(Note 17) Water resistance (hydrolysis resistance):
About each test plate, after immersing in 40 degreeC warm water for 240 hours, the external appearance and adhesiveness of the test plate washed with water were evaluated on the following reference | standard:
<Appearance [after water resistance test]>
S: No change in appearance with respect to the coating film before the test A: The coating film before the test is slightly glossy, blistered, whitened or discolored. No level B: Significant glossiness, blistering, whitening or discoloration is observed with respect to the coating film before the test. ×: Significant glossiness, blistering, whitening or discoloration is observed with respect to the coating film before the test. .

<Adhesion [after water resistance test]>
After making 100 2mm x 2mm gobangs on the coated surface according to JIS K 5600-5-6 (1990) on each coated surface, affixing adhesive tape to the surface and removing it rapidly, The number of remaining gobang eyes was evaluated:
S: Remaining number / total number = 100/100, no edge missing A: Remaining number / total number = 100/100, no edge missing B: Remaining number / total number = 99 to 90/100 C: Remaining number / total number = 89 or less / 100.

(Note 18) Weather resistance:
For the accelerated weather resistance test, a super xenon weatherometer specified by JIS B 7754 (trade name, manufactured by Suga Test Instruments Co., Ltd.) was used, and irradiation was performed for 1 hour 42 minutes with xenon arc lamp and 18 minutes of rain. The evaluation was carried out by comparing 2 hours of irradiation with the same lamp as 1 cycle, after completion of the 500 cycle repetition test, in comparison with the pre-coated plate stored in the laboratory:
<Appearance [after weather resistance test (visual)]>
S: No abnormality is observed in the coating film A: Slight yellowing is observed in the coating film, but there is no cracking and there is no problem with the product B: Yellowing is observed in the coating film C: Coating The film is yellowed or cracked <Appearance [after weather resistance test (color difference)]>
The color difference ΔE based on JIS Z 8730 was measured on the test plate at the initial stage and after the test. The smaller the value of ΔE, the better the value, and the practical value when ΔE is less than 2.0. <Appearance [after weather resistance test (gloss retention)]>
About the coating film before and behind a test, the glossiness of each coating surface was measured according to the specular glossiness (60 degree | times) of JISK5600-4-7 (1999). The glossiness after the test with respect to the glossiness before the test was determined as a gloss retention (%) and evaluated according to the following criteria. If the gloss retention is 80% or more, it is a practical level. <Adhesion [after weather resistance test]>
On each coated surface after the weather resistance test, 100 2 mm × 2 mm gobangs were made on the coating film according to JIS K 5600-5-6 (1990), and adhesive tape was affixed to the surface and peeled off rapidly. Later, the number of goby eye coatings remaining on the paint surface was evaluated:
S: Remaining number / total number = 100/100, no edge missing A: Remaining number / total number = 100/100, no edge missing B: Remaining number / total number = 99 to 90/100 C: Remaining number / total number = 89 or less / 100.

  In the field of the paint to which the present invention belongs, it is preferable that the finish of the coating film, the coating film hardness, the stain resistance, the water resistance and the weather resistance are all excellent.

Note 19: Acrylic resin / melamine resin-based organic solvent type base paint (cured film thickness 20μ) is applied to a metal plate that has been coated with cationic electrodeposition paint and intermediate paint and heat-cured, and left at room temperature for 5 minutes. What was heated at 140 ° C. for 30 minutes was used as an article to be coated.

Claims (10)

(A) a hydroxyl group-containing acrylic resin having a weight average molecular weight of 1,000 to 90,000,
(B) a hydroxyl group-containing polyester resin,
(C) a coloring pigment and / or a luster pigment, and (D) a polyisocyanate compound, for use in one-coat coating, or on an object to be coated, at least one colored base coat paint and at least one overcoat In a method of forming a multilayer coating film by sequentially applying paint, a coating composition for use in top coating of the uppermost layer ,
The hydroxyl group-containing polyester resin (B) is obtained by a reaction between a polyhydric alcohol containing a cyclic polyol compound (b1) having a nurate structure and a polybasic acid, and has a number average molecular weight of 1,000 to 10,000 and a hydroxyl value. 20 to 250 mg KOH / g polyester resin, and the solid content of the hydroxyl group-containing polyester resin (B) is 5 to 60% by mass based on the total resin solid content of the component (A) and the component (B). The coating composition characterized by the above-mentioned. The hydroxyl group-containing acrylic resin (A) is a resin that does not contain methyl methacrylate or contains less than 50% by mass of methyl methacrylate, based on the total amount of copolymerization monomer components, and has a hydroxyl value of 20 to 200 mgKOH / The coating composition according to claim 1, comprising a hydroxyl group-containing acrylic resin (A1) in the range of g, a weight average molecular weight of 1,000 to 10,000 and a glass transition temperature (Tg) of 0 to 90 ° C. Hydroxyl group-containing acrylic resin (A) is further a hydroxyl group containing 50 to 90% by weight of methyl methacrylate and 10 to 50% by weight of other polymerizable unsaturated monomer as a copolymerized monomer component, based on the total amount of the copolymerized monomer component. The coating composition of Claim 2 containing a containing acrylic resin (A2). Furthermore, the coating composition of any one of Claims 1-3 containing a rheology control agent (E). Furthermore, the coating composition of any one of Claims 1-4 containing a higher fatty acid (F). The coating composition of any one of Claims 1-5 in which the said (C) component contains a luster pigment. The coating composition according to any one of claims 1 to 6, for use in one-coat coating. A coated article obtained by coating the article to be coated with the coating composition according to any one of claims 1 to 7. The object to be coated is selected from the group consisting of acrylonitrile-butadiene-styrene resin, acrylonitrile-styrene-acrylate resin, polycarbonate resin, polybutylene terephthalate resin, polyvinyl chloride resin, polyamide resin, and at least two kinds of these hybrid resins. The coated article according to claim 8, wherein the article is at least one kind. A method for forming a multi-layer coating film by sequentially applying at least one layer of a colored base coat paint and at least one layer of a top coat paint on an object, wherein the top coat paint of claim 1-6. A method for forming a multilayer coating film, wherein the coating composition according to any one of the above is applied.