JP2021091744A - Coating material composition and coating film formation method - Google Patents

Abstract

To provide a coating material composition that has good storage stability as a coating material, forms a coating film excellent in stain resistance (dirt adhesion preventive property or dirt removability) and its durability, also excellent in scratch resistance of the coating film and being transparent and can protect an appearance over a long period of time and to provide a method for forming the coating film.SOLUTION: A coating material composition contains (A) a silyl group-containing acrylic resin, (B) a hydroxyl group-containing acrylic resin containing no silyl group, (C) an alkoxysilyl group-containing organopolysiloxane, (D) a polyisocyanate compound and (E) a catalyst in which the silyl group-containing acrylic resin (A) contains at least one kind of polydimethylsiloxane segment.SELECTED DRAWING: None

Description

The present invention provides stain resistance (dirt adhesion prevention or stains) by imparting water repellency to painted surfaces of automobile bodies, trucks, motorcycles, buses, automobile parts, railroad vehicles, industrial equipment, buildings, structures, etc., for example. The present invention relates to a coating composition having excellent removability) and stain resistance and durability, and capable of protecting the appearance of the coated surface for a long period of time, and a coating film forming method (coating method) thereof.

It is widely practiced to apply wax to protect and polish painted surfaces of automobile bodies and the like. In general, wax has the effect of improving the gloss of the painted surface immediately after application, but it is difficult to maintain the initial gloss for a long period of time, and it is necessary to apply wax regularly.

On the other hand, the painted surface formed on the car body is contaminated by the influence of the weather such as rain, snow, sleet, and ice formation, and environmental pollutants such as dust, dirt, dust, air pollutants, and bird manure. , And there is a need for the development of simple paints and / or painting methods to make such stains inconspicuous.

As one of the measures, for example, Patent Document 1 (International Publication No. 2006/001510) describes a hydrolyzable silyl group, an acrylic resin having a hydroxyl group and a polysiloxane chain, an organopolysiloxane having a hydrolyzable silyl group, and the like. Further, a surface treatment agent containing an organopolysiloxane having no hydrolyzable silyl group has been disclosed, but there are cases where both curability, storage stability, and stain prevention durability are insufficient.

Further, Patent Document 2 (Japanese Patent Laid-Open No. 10-37671) discloses a specific organopolysiloxane composition as a deteriorated coating film for automobiles and a small scratch repairing and polishing agent. It is stated that by using the composition, a deteriorated coating film can be repaired and a highly durable coating film having excellent gloss can be formed. However, since it contains a large amount of volatile components, the volatile components tend to volatilize after coating, and the volume of the coating film tends to decrease significantly over time. Therefore, when the polish is applied to, for example, the recesses of scratches formed on the painted surface, the coating film shrinks as it dries, and many of the recesses of the scratches are exposed again, and the glossing effect deteriorates with time. There is a drawback that the film becomes easy to get dirty and it becomes difficult to wipe off the attached dirt component.

Further, Patent Document 3 (International Publication No. 2019/168041) discloses a coating composition having an alkoxysilyl group-containing organopolysiloxane, a catalyst, and a binder, wherein the storage stability of the coating film is good. It is described that the coating film has excellent stain resistance (stain adhesion prevention property or stain removal property) and durability, and can protect the appearance of the coating film for a long period of time. However, when the content of the alkoxysilyl group-containing organopolysiloxane in the coating composition is large, the compatibility may deteriorate and the coating film may become cloudy. Further, when the content of the alkoxysilyl group-containing organopolysiloxane is small, the stain resistance may not be maintained for a long time.

Further, Patent Document 4 (Japanese Unexamined Patent Publication No. 11-57608) discloses a coating method for forming a topcoat clear coating film on a topcoat coloring base coating film, wherein the topcoat clear coating material is (A) a hydroxyl group-containing organic resin. It has at least one cross-linking agent selected from (B) melamine resin and blocked polyisocyanate compound, and (C) hydrophilicity imparting agent which is a specific silicon compound, and has antifouling property, coating performance, and coating appearance. It is stated that it is excellent. However, since the coating film is hydrophilic, the stain prevention effect can be exhibited to some extent, but the long-term coating film performance such as water resistance and weather resistance is not sufficient. Further, since the coating method is a curtain method or a die coating method on a moving metal plate, the finishability of the coating film is not sufficient.

International Publication No. 2006/001510 Japanese Patent Application Laid-Open No. 10-37671 International Publication No. 2019/168041 JP-A-11-57608

The problems to be solved by the present invention are good storage stability of the coating film, excellent stain resistance (stain adhesion prevention or stain removal property) and durability of the coating film, and excellent scratch resistance of the coating film. It is an object of the present invention to provide a coating composition which is transparent and can protect the appearance for a long period of time and a method for forming a coating film thereof.

As a result of diligent studies to solve the above problems, the inventors have conducted silyl group-containing acrylic resin (A), hydroxyl group-free hydroxyl group-containing acrylic resin (B), alkoxysilyl group-containing organopolysiloxane (C), and the like. It has been found that a solution to the above problems can be achieved by a coating composition containing a polyisocyanate compound (D) and a catalyst (E), and the present invention has been completed.

That is, the present invention provides the following coating composition and a coating method thereof.
Item 1. A coating composition containing a silyl group-containing acrylic resin (A), a silyl group-free hydroxyl group-containing acrylic resin (B), an alkoxysilyl group-containing organopolysiloxane (C), a polyisocyanate compound (D), and a catalyst (E). A coating composition comprising a silyl group-containing acrylic resin (A) containing at least one polydimethylsiloxane segment.
Item 2. The above-mentioned item, wherein the silyl group-containing acrylic resin (A) contains 0.1 part or more of a polymerizable unsaturated monomer (a1) having a polydimethylsiloxane segment in the structure based on 100 parts of all the monomers. The coating composition according to 1.
Item 3. The silyl group-containing acrylic resin (A) is a polymerizable unsaturated monomer (a1) having a polydimethylsiloxane segment represented by the following formulas (1) and / or (2), and a hydrolyzable silyl group-containing polymerizable unsaturated monomer. Item 2. The coating composition according to Item 1 or 2, which is obtained by copolymerizing (a2), a hydroxyl group-containing polymerizable unsaturated monomer, and, if necessary, another polymerizable unsaturated monomer copolymerizable therewith.

(In the formula, R ¹ represents an alkyl group having 1 to 10 carbon atoms, R ² represents a divalent hydrocarbon group having 1 to 6 carbon atoms, R ³ represents a hydrogen atom or a methyl group, and R ⁴ and R ⁷ is the same or different, representing a hydrogen atom or a methyl group, respectively, R ⁵ and R ⁶ are the same or different, representing a divalent hydrocarbon group having 1 to 6 carbon atoms, respectively, and n ¹ and n ² are the same or different. Each means the number of repetitions of the dimethylsiloxane unit, which is in the range of 6 to 300, preferably 6 to 100.)
Item 4. The coating composition according to Items 1 to 3, further containing the hydroxyl group-containing acrylic resin-coated silica particles (F).
Item 5. Item 2. The coating composition according to Item 1 to 4, wherein the number average molecular weight of the alkoxysilyl group-containing organopolysiloxane (C) is in the range of 500 to 10,000.
Item 6. Item 2. The coating composition according to Item 1 to 5, wherein the solid content of the alkoxysilyl group-containing organopolysiloxane (C) is 0.01 to 10% by mass based on the resin solid content in the coating material. ..
Item 7. A silyl group-containing acrylic resin (A), which is a multi-component coating composition containing a main agent component (I) and a curing agent component (II), wherein the main agent component (I) has at least one polydimethylsiloxane segment. , A hydroxyl group-containing acrylic resin (B) containing no silyl group, and an alkoxysilyl group-containing organopolysiloxane (C), and the curing agent component (II) contains a polyisocyanate compound (D) and a catalyst (E). A paint composition characterized by.
Item 8. A coating film forming method for forming a topcoat coating film by coating the coating compositions of Items 1 to 7.
Item 9. A coating film forming method in which the coating compositions of Items 1 to 7 are atomized to form a topcoat coating film having a curing film thickness of 1 to 50 μm, and then heat-cured at a temperature of 70 to 200 ° C.
Item 10. The process of painting a colored paint composition to form a colored coating film,
A step of coating the coating composition of the above items 1 to 7 on the colored coating film to form a top coating film.
A step of simultaneously heating and curing the obtained colored coating film and topcoat coating film,
A method for forming a multi-layer coating film, which comprises sequentially performing.
Item 11. A step of atomizing and coating a colored coating composition to form a colored coating film having a cured film thickness of 1 to 50 μm.
A step of atomizing and coating the coating composition of Items 1 to 7 on the colored coating film to form a topcoat coating film having a cured film thickness of 1 to 50 μm.
A step of simultaneously heating and curing the obtained colored coating film and topcoat coating film at a temperature of 70 to 200 ° C.
A method for forming a multi-layer coating film, which comprises sequentially performing.

The coating film obtained by the coating composition of the present invention has excellent transparency, stain resistance (stain adhesion prevention property or stain removal property), and durability. Specifically, the coating film obtained by the coating method of the present invention has a good finish, and is affected by the weather such as rain, snow, sleet, and ice formation, and dust, dirt, dust, and the like. Even after being exposed to environmental pollutants such as air pollutants and bird manure, the finished appearance can be maintained for a long period of time.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
It should be noted that the present invention is not limited to the following embodiments, and should be understood to include various modifications implemented without changing the gist of the present invention.

Further, in the present specification, "(meth) acrylate" means acrylate and / or methacrylate, and "(meth) acrylic acid" means acrylic acid and / or methacrylic acid. In addition, "(meth) acryloyl" means acryloyl and / or methacryloyl. In addition, "(meth) acrylamide" means acrylamide and / or methacrylamide.

The coating composition of the present invention comprises a silyl group-containing acrylic resin (A), a silyl group-free hydroxyl group-containing acrylic resin (B), an alkoxysilyl group-containing organopolysiloxane (C), a polyisocyanate compound (D), and a catalyst. A coating composition containing (E), wherein the silyl group-containing acrylic resin (A) contains at least one polydimethylsiloxane segment.

Cyril group-containing acrylic resin (A)
The silyl group-containing acrylic resin (A) that can be used in the coating composition of the present invention can be preferably used as long as the acrylic resin contains at least one polydimethylsiloxane segment, and is used as a production method. , A method of adding a polydimethylsiloxane segment to an acrylic resin, or a method of copolymerizing a polymerizable unsaturated monomer (a1) having a polydimethylsiloxane segment with another polymerizable unsaturated monomer.

In the present specification, the "polysiloxane" is a polymer containing a Si—O—Si bond, and the “silyl group” is a silicon compound group such as a trimethylsilyl group or a trimethoxysilyl group. , It may or may not have a substituent.

The polymerizable unsaturated monomer (a1) having the polydimethylsiloxane segment is a component for introducing the polydimethylsiloxane segment into an acrylic resin and imparting water repellency to the surface of the coating film. Specifically, for example, The following equations (1) and (2)

(In the formula, R ¹ represents an alkyl group having 1 to 10 carbon atoms, R ² represents a divalent hydrocarbon group having 1 to 6 carbon atoms, R ³ represents a hydrogen atom or a methyl group, and R ⁴ and R ⁷ is the same or different, representing a hydrogen atom or a methyl group, respectively, R ⁵ and R ⁶ are the same or different, representing a divalent hydrocarbon group having 1 to 6 carbon atoms, respectively, and n ¹ and n ² are the same or different. Each means the number of repetitions of the dimethylsiloxane unit, which is in the range of 6 to 300, preferably 6 to 100.)
Examples thereof include the compounds indicated by.

Examples of commercially available products of the polymerizable unsaturated monomer (a1) include silaplane FM-0721, silaplane FM-0711, and silaplane FM-0725 (all manufactured by JNC Corporation, trade name); X-22-174ASX. , X-22-174BX, KF-2012, X-22-2426, X-22-2404, X-22-2475 (all manufactured by Shin-Etsu Chemical Co., Ltd., trade name) and the like.

The polymerizable unsaturated monomer (a1) having the polydimethylsiloxane segment can have a number average molecular weight in the range of generally 300 to 30,000, preferably 500 to 20,000.

The silyl group-containing acrylic resin (A) has a polydimethylsiloxane segment in the structure based on 100 parts of all the monomers from the viewpoint of stain resistance and compatibility with the component (C) (transparency of the coating film). It is preferable to contain 0.1 part or more of the polymerizable unsaturated monomer (a1), more preferably 0.5 to 30 parts, and further preferably 1 to 15 parts.

Further, the silyl group-containing acrylic resin (A) contains a hydrolyzable silyl group-containing polymerizable unsaturated monomer (a2) and a monomer (a1) other than the polymerizable unsaturated monomer (a1) having a polydimethylsiloxane segment. It is preferable to use them together and copolymerize.

The hydrolyzable silyl group-containing polymerizable unsaturated monomer (a2) is a monomer component for imparting stain resistance (prevention of stain adhesion or stain removal). The hydrolyzable silyl group-containing polymerizable unsaturated monomer (a2) is a silyl group-containing polymerizable unsaturated monomer other than the above-mentioned polymerizable unsaturated monomer (a1) having a polydimethylsiloxane segment, and is polymerizable in one molecule. Compounds having both a double bond and a hydrolyzable silyl group are included. The "hydrolyzable silyl group" is a silicon compound group that imparts a silanol group by hydrolysis, and examples thereof include an alkoxysilyl group and a halogenated silyl group. Specifically, for example, vinyltri (C1-C6 alkoxy) silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris (2-methoxyethoxy) silane; vinyltri (C2-C6 alkanoyloxy) such as vinyltriacetooxysilane. ) Silane; (meth) acryloyloxyalkyltri-C1 to β- (meth) acryloyloxyethyltrimethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, etc. Examples thereof include C6 alkoxysilane. These can be used alone or in combination of two or more.

The silyl group-containing acrylic resin (A) preferably contains 0 to 50 parts of the polymerizable unsaturated monomer (a2) in the structure based on 100 parts of all the monomers, and more preferably 10 to 40 parts. preferable.

Further, the silyl group-containing acrylic resin (A) is a polymerizable unsaturated monomer other than the polymerizable unsaturated monomer (a1) having the polydimethylsiloxane segment and the hydrolyzable silyl group-containing polymerizable unsaturated monomer (a2). Is preferable, and as the monomer, for example, an alkyl (meth) acrylate having 3 or less carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and isopropyl (meth) acrylate. , N-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) ) Acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, Alkyl or cycloalkyl (meth) acrylates such as cyclododecyl (meth) acrylates and tricyclodecanyl (meth) acrylates; 2-hydroxyethyl (meth) acrylates, 2-hydroxypropyl (meth) acrylates, 3-hydroxypropyl (meth) acrylates. ) Acrylate, monoesterified product of (meth) acrylic acid and divalent alcohol such as 4-hydroxybutyl (meth) acrylate, ε-caprolactone modified product of monoesterified product of (meth) acrylic acid and divalent alcohol, N -Hydroxymethyl (meth) acrylamide, allyl alcohol, hydroxyl group-containing polymerizable unsaturated monomer such as (meth) acrylate having a polyoxyalkylene chain having a hydroxyl group at the molecular end; polymerization having an isobornyl group such as isobornyl (meth) acrylate Sexual unsaturated compound; polymerizable unsaturated compound having an adamantyl group such as adamantyl (meth) acrylate; aromatic ring-containing polymerizable unsaturated monomer such as benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene; (meth) ) Carboxyl group-containing polymerizable unsaturated monomers such as acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate; (meth) acrylonitrile, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, Nitrogen-containing polymerizable unsaturated monomer containing no urethane bond such as N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, glycidyl (meth) acrylate and an adduct of amines; A polymerizable unsaturated monomer having a urethane bond such as a reaction product of an isocyanate group-containing polymerizable unsaturated monomer and a hydroxyl group-containing compound or a reaction product of a hydroxyl group-containing polymerizable unsaturated monomer and an isocyanate group-containing compound; glycidyl (meth). ) Acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, allylglycidyl Epoxy group-containing polymerizable unsaturated monomer such as ether; (meth) acrylate having a polyoxyethylene chain whose molecular end is an alkoxy group; 2-acrylamide-2-methylpropanesulfonic acid, 2-sulfoethyl (meth) acrylate, allyl Polymerizable unsaturated monomers having sulfonic acid groups such as sulfonic acid, 4-styrene sulfonic acid, sodium salt and ammonium salt of these sulfonic acids; 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2- Polymerizable unsaturated monomer having a phosphate group such as acryloyloxypropyl acid phosphate and 2-methacryloyloxypropyl acid phosphate; perfluoroalkyl (meth) such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate. ) Acrylate; polymerizable unsaturated monomer having a fluorinated alkyl group such as fluoroolefin; polymerizable unsaturated monomer having a photopolymerizable functional group such as a maleimide group; having a polyoxyethylene chain having an alkoxy group at the molecular end ( Meta) acrylate; allyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimerol. Propanetri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) ) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethanedi (meth) acrylate, 1,1,1-trishydroxy One molecule has two or more polymerizable unsaturated groups such as methyl ethanetri (meth) acrylate, 1,1,1-trishydroxymethylpropantri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, and divinylbenzene. Examples thereof include polymerizable unsaturated monomers. These can be used alone or in combination of two or more.

As a method for polymerizing the acrylic resin, a conventionally known method can be used. For example, it can be produced by solution-polymerizing a polymerizable unsaturated monomer in an organic solvent, but the present invention is not limited to this, and for example, bulk polymerization, emulsion polymerization, suspension polymerization or the like may be used. When solution polymerization is carried out, continuous polymerization or batch polymerization may be performed, the polymerizable unsaturated monomers may be charged all at once, may be charged separately, or may be added continuously or intermittently. Good.

As the radical polymerization initiator used for the polymerization, a conventionally known method can be used. For example, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, 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, cumenehydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,3 -Bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, diisopropylbenzene peroxide, tert-butylcumyl peroxide, decanoylper Oxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, di-tert-amyl peroxide, bis (tert-butylcyclohexyl) peroxydicarbonate, tert-butylperoxybenzoate, 2,5- Peroxide-based polymerization initiators such as dimethyl-2,5-di (benzoylperoxy) hexane, tert-butylperoxy-2-ethylhexanoate; 2,2'-azobis (isobutyronitrile), 1 , 1-azobis (cyclohexane-1-carbonitrile), azocusmen, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobisdimethylvaleronitrile, 4,4'-azobis (4- Cyanovaleric acid), 2- (t-butylazo) -2-cyanopropane, 2,2'-azobis (2,4,4-trimethylpentane), 2,2'-azobis (2-methylpropane), dimethyl 2 , 2'-Azobis (2-methylpropionate) and other azo-based polymerization initiators can be mentioned. These can be used alone or in combination of two or more.

The solvent used for the above polymerization or dilution is not particularly limited, and examples thereof include water, an organic solvent, and a mixture thereof. Examples of the organic solvent include hydrocarbon solvents such as n-butane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane and cyclobutane; aromatic solvents such as toluene and xylene; and methylisobutylketone and the like. Ketone solvents; ether solvents such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol; ethyl acetate, n-butyl acetate, isobutyl acetate, Ester-based solvents such as ethylene glycol monomethyl ether acetate and butyl carbitol acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone; alcohol-based solvents such as ethanol, isopropanol, n-butanol, sec-butanol and isobutanol. Solvent; Equamid (trade name, manufactured by Idemitsu Kosan Co., Ltd.), N, N-dimethylformamide, N, N-dimethylacetamide, N-methylformamide, N-methylacetamide, N-methylpropioamide, N-methyl-2 − Examples of conventionally known solvents such as amide-based solvents such as pyrrolidone can be mentioned. These can be used alone or in combination of two or more.

In solution polymerization in an organic solvent, a method in which a polymerization initiator, a polymerizable unsaturated monomer component, and an organic solvent are mixed and heated while stirring, and an organic solvent is used in a reaction tank to suppress a temperature rise of the system due to reaction heat. The polymerizable unsaturated monomer component and the polymerization initiator are mixed and dropped or separated over a predetermined time while stirring at a temperature of 60 ° C. to 200 ° C. and blowing an inert gas such as nitrogen or argon as necessary. A method of dropping is used.

The polymerization can generally be carried out for about 1 to 10 hours. After each stage of polymerization, an additional catalyst step may be provided to heat the reaction vessel while dropping a polymerization initiator as needed.

The weight average molecular weight of the silyl group-containing acrylic resin (A) is preferably in the range of 1,000 to 100,000, more preferably 3,000 to 50,000.

In the present specification, the number average molecular weight and the weight average molecular weight are the holding times (holding capacity) measured by using a gel permeation chromatograph (GPC), and the holding time of standard polystyrene having a known molecular weight measured under the same conditions. It is a value obtained by converting to the molecular weight of polystyrene by (retention capacity). Specifically, "HLC8120GPC" (trade name, manufactured by Tosoh Corporation) is used as a gel permeation chromatograph, and "TSKgel G-4000HXL", "TSKgel G-3000HXL", and "TSKgel G-2500HXL" are used as columns. And "TSKgel G-2000HXL" (trade name, both manufactured by Tosoh Corporation) can be measured under the conditions of mobile phase tetrahydrofuran, measurement temperature 40 ° C., flow velocity 1 mL / min and detector RI. it can.

The silyl group-containing acrylic resin (A) is a polymerizable unsaturated monomer having a polydimethylsiloxane segment represented by the above formulas (1) and / or (2) from the viewpoint of compatibility and stain resistance. It is obtained by copolymerizing a1), a hydrolyzable silyl group-containing polymerizable unsaturated monomer (a2), a hydroxyl group-containing polymerizable unsaturated monomer, and, if necessary, another polymerizable unsaturated monomer copolymerizable with these. It is preferable that there is.

The hydroxyl value of the silyl group-containing acrylic resin (A) is preferably 0 to 250 mgKOH / g, more preferably 50 to 200 mgKOH / g.

As the blending amount of the silyl group-containing acrylic resin (A) in the coating composition, the solid content of the silyl group-containing acrylic resin (A) is 1 based on the mass of the resin solid content in the coating composition. It is preferably in the range of ~ 40% by mass, more preferably in the range of 5 to 35% by mass, and in the range of 12 to 30% by mass, compatibility (transparency of the coating film). It is more preferable from the viewpoint of stain resistance and durability.

Hydroxyl group-containing acrylic resin (B) containing no silyl group
The silyl group-free hydroxyl group-containing acrylic resin (B) that can be used in the coating composition of the present invention is a hydroxyl group-containing acrylic resin that does not contain a silyl group, and the acrylic resin (B) is the above-mentioned hydroxyl group. It can be produced by copolymerizing a containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer. It can be produced in the same manner as the above-mentioned silyl group-containing acrylic resin (A) except that it does not contain a silyl group. (However, it may contain a very small amount of silyl group as long as it does not affect various performances.)
The weight average molecular weight of the hydroxyl group-containing acrylic resin (B) containing no silyl group is preferably in the range of 1,000 to 100,000, more preferably 3,000 to 50,000.

The hydroxyl value of the hydroxyl group-containing acrylic resin (B) that does not contain a silyl group is preferably 0.1 to 250 mgKOH / g, and more preferably 50 to 200 mgKOH / g.

As the blending amount of the hydroxyl group-containing acrylic resin (B) containing no silyl group in the coating composition, the solid content of the acrylic resin (B) is based on the mass of the resin solid content in the coating composition. It is preferably in the range of 1 to 60% by mass, more preferably in the range of 5 to 50% by mass, and in the range of 10 to 45% by mass, it is compatible (transparency of the coating film). ) And more preferable from the viewpoint of stain resistance and durability.

Alkoxysilyl group-containing organopolysiloxane (C)
The alkoxysilyl group-containing organopolysiloxane (C) that can be used in the coating composition of the present invention includes an organopolysiloxane having a hydrolyzable alkoxysilyl group at the terminal or side chain of the molecule, and is hydrolyzed in the molecule. The sex alkoxysilyl group is hydrolyzed in contact with moisture or moisture in the air to form a silanol group, and the reaction proceeds between the silanol groups or between the silanol group and the functional group of another resin. By increasing the molecular weight, it is possible to impart stain resistance (stain adhesion prevention property or stain removal property) and durability to the coating film formed from the coating composition of the present invention.

The alkoxysilyl group-containing organopolysiloxane (C) of the present invention preferably contains a hydrocarbon group such as a methyl group or a phenyl group from the viewpoint of imparting water repellency to the coating film.

Commercially available products of the alkoxysilyl group-containing organopolysiloxane (C) include, for example, "SR2406", "SR2410", "SR2420", "SR2416", "SR2402", "AY42-161" (above Toray Dow Corning Silicone). (Made by Co., Ltd.), "FZ-3704", "FZ-3511" (manufactured by Nippon Unicar), "KC-89S", "KR-500", "X-40-9225", "X-40-9246" , "X-40-9250", "KR-217", "KR-9218", "KR-213", "KR-510", "X-40-9227", "X-40-9247", "X-41-1053", "X-41-1056", "X-41-1805", "X-41-1810", "X-40-2651", "X-40-2308", "X" -40-9238 "," X-40-2239 "," X-40-2327 "," KR-400 "," X-40-175 "," X-40-9740 "(above Shinetsu Chemical Industry Co., Ltd.) Commercial products such as (manufactured) are applicable.

The number average molecular weight of the alkoxysilyl group-containing organopolysiloxane (C) is preferably in the range of 500 to 10,000 from the viewpoint of sustainability of stain resistance (prevention of stain adhesion or stain removal). More preferably, it is in the range of 500 to 8,000.

When the amount of the alkoxysilyl group-containing organopolysiloxane (C) in the coating composition is extremely small, stain resistance (prevention of stain adhesion or removal of stains) is not exhibited, and when the amount is excessive, compatibility (coating) is achieved. The transparency of the film) and the tackiness of the coating film surface deteriorate. Therefore, the solid content of the alkoxysilyl group-containing organopolysiloxane (C) is preferably in the range of 0.01 to 10% by mass, based on the mass of the resin solid content in the coating composition. It is more preferably in the range of 07 to 5% by mass, and even more preferably in the range of 0.15 to 3% by mass.

Polyisocyanate compound (D)
The polyisocyanate compound that can be used in the coating composition of the present invention is a compound having at least two isocyanate groups in one molecule, and is, for example, an aliphatic polyisocyanate, an alicyclic polyisocyanate, or an aromatic aliphatic poly. Examples thereof include isocyanates, aromatic polyisocyanates, and derivatives of the polyisocyanates.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, and 1,3. Aliphatic diisocyanates such as −butylene diisocyanate, 2,4,4 or 2,2,4-trimethylhexamethylene diisocyanate, diisocyanate dimerate, methyl 2,6-diisocyanatohexanate (common name: lysine diisocyanate); 2-Isocyanatoethyl 6-diisocyanatohexanoate, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane, 1, 8-Diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane, 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane and other aliphatic triisocyanates Can be mentioned.

Examples of the alicyclic polyisocyanate include 1,3-cyclopentenediisocyanate, 1,4-cyclohexanediisocyanate, 1,3-cyclohexanediisocyanate, and 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (common name). : Isophorone diisocyanate), 4-methyl-1,3-cyclohexylene diisocyanate (common name: hydrogenated TDI), 2-methyl-1,3-cyclohexylene diisocyanate, 1,3- or 1,4-bis (isocyanato) Alicyclic diisocyanates such as methyl) cyclohexane (common name: hydrogenated xylylene diisocyanate) or a mixture thereof, methylenebis (4,1-cyclohexanediyl) diisocyanate (common name: hydrogenated MDI), norbornan diisocyanate; -Triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane, 2- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 2- (3-Isocyanatopropyl) -2,6-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 3- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl)- Bicyclo (2.2.1) heptane, 5- (2-isocyanatoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 6- (2) -Isocyanatoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 5- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-Isocyanatopropyl) -bicyclo (2.2.1) -heptane, 6- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanatopropyl) -bicyclo (2.2) . 1) Examples of alicyclic triisocyanates such as heptane can be mentioned.

Examples of the aromatic aliphatic polyisocyanate include methylenebis (4,1-phenylene) diisocyanate (common name: MDI), 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω, ω'-diisocyanato-. Arophilic aliphatic diisocyanates such as 1,4-diethylbenzene, 1,3- or 1,4-bis (1-isocyanato-1-methylethyl) benzene (common name: tetramethylxylylene diisocyanate) or a mixture thereof; 1,3 , 5-Triisosocyanatomethylbenzene and other aromatic aliphatic triisocyanates and the like can be mentioned.

Examples of the aromatic polyisocyanate include m-phenylenediocyanate, p-phenylenediocyanate, 4,4'-diphenyldiisocyanate, 1,5-naphthalenediocyanate, and 2,4-tolylene diisocyanate (common name: 2,4-). TDI) or 2,6-tolylene diisocyanate (common name: 2,6-TDI) or a mixture thereof, aromatic diisocyanates such as 4,4'-toluene diisocyanate and 4,4'-diphenyl ether diisocyanate; triphenylmethane-4 , 4', 4''-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene and other aromatic triisocyanates; 4,4'-diphenylmethane-2,2' , 5, 5'-Tetraisocyanate and other aromatic tetraisocyanates and the like.
Examples of the polyisocyanate derivative include dimer, trimmer, biuret, allophanate, uretdione, uretoimine, isocyanurate, oxadiazine trione, and polymethylene polyphenyl polyisocyanate (crude MDI, polypeptide MDI) of the polyisocyanate. Crude TDI and the like can be mentioned.
The polyisocyanate and its derivatives may be used alone or in combination of two or more.

As the polyisocyanate compound, a blocked polyisocyanate compound in which the isocyanate group contained in the polyisocyanate compound is blocked may be used. As the blocking agent, for example, an active methylene compound such as a phenol compound; a lactam compound; an alcohol compound; an oxime compound; a mercaptan compound; dimethyl malonate; or a diethyl malonate can be preferably used. Blocking can be easily performed by mixing an unblocked polyisocyanate compound with a blocking agent. These polyisocyanate compounds can be used alone or in combination of two or more, and unblocked polyisocyanate compounds and blocked polyisocyanate compounds can also be used in combination.

As the blending amount of the polyisocyanate compound (D) in the coating composition, the solid content of the polyisocyanate compound (D) is determined based on the mass of the resin solid content in the coating composition from the viewpoint of curability. It is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 5 to 45% by mass, and even more preferably in the range of 10 to 40% by mass.

Catalyst (E)
The catalyst (E) that can be used in the coating composition of the present invention is a hydrolysis condensation of a hydrolyzable alkoxysilyl group contained in the silyl group-containing acrylic resin (A) and the alkoxysilyl group-containing organopolysiloxane (C). A curing catalyst that promotes hydrolysis and condensation can be used without particular limitation as a catalyst for hydrolysis and condensation. Specifically, for example, diacetyltin diacetate, dibutyltin dilaurate, dibutyltin diacetate, and dioctyl can be used. Organic tin compounds such as tin dilaurate, diacetyltin dioctate, tin octylate, dibutyltin diacetate, dibutyltin dioctate; aluminum trimethoxyde, aluminum tris (acetylacetonate), aluminum tri-n-butoxide, aluminum tris (acetoacetate). Organic aluminum compounds such as ethyl), aluminum diisopropoxy (acetoacetate ethyl), aluminum acetylacetonate; titanium tetra (monoethylethoxydo), titanium tetra (monoethylethoxydo), titanium tetra (monobutylethoxydo), Organic titanium compounds such as titanium tetrakis (acetylacetonate) and tetranormal butyl titanate; zirconium tetra (monomethylethoxydo), zirconium tetra (monoethylethoxydo), zirconium tetra (monobutylethoxydo), zirconium normal propylate, zirconium Organic zirconium compounds such as normal butyrate and zirconite tetrakis (acetylacetonate); organic zinc compounds such as zinc naphthenate; organic cobalt compounds such as cobalt octylate and cobalt naphthenate; trimethyl borate, triethyl borate, triborate Borate compounds such as propyl, tributyl borate, triphenyl borate, tri (4-chlorophenyl) borate, trihexafluoroisopropyl borate; sulfonates such as methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, sulfuric acid Acid compounds; Sulfonate compounds such as pyridinium p-toluenesulfonate; Aminosilane compounds such as γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane; Tertiary ammonium such as tetramethylammonium chloride and benzalconium chloride. Salt compounds; Tertiary amine compounds containing multiple nitrogens such as guanidine and amidine; trimethylphosphate, triethi Phosphorous acid, tripropyl phosphorous acid, tributyl phosphorous acid, trihexyl phosphorous acid, tris (2-ethylhexyl) phosphorous acid, trioctyl phosphorous acid, trinonyl phosphorous acid, tridecyl phosphoric acid, trilauryl phosphoric acid, trimyristyl phosphate, tricetyl phosphoric acid Tristearyl phosphate, trioleyl phosphate, tribehenyl phosphate, monomethyl phosphate, dimethyl phosphate, monoethyl phosphate, diethyl phosphate, monopropyl phosphate, dipropyl phosphate, monoisopropyl phosphate, diisopropyl phosphate, phosphorus Monobutyl Acid, Dibutyl Phosphate, Monopentyl Phosphate, Dipentyl Phosphate, Monohexyl Phosphate, Dihexyl Phosphate, Monooctyl Phosphate, Dioctyl Phosphate, Mono2-Ethylhexyl Phosphate, Di2-ethylhexyl Phosphate, Monodecyl Phosphate , Didecyl Phosphate, Monoisodecyl Phosphate, Diisodecyl Phosphate, Monoundecyl Phosphate, Diundecyl Phosphate, Monododecyl Phosphate, Didodecyl Phosphate, Monotetradecyl Phosphate, Ditetradecyl Phosphate, Monohexadecyl Phosphate, Dihexadecyl Phosphate, Phosphate ester compounds such as monooctadecyl phosphate, dioctadecil phosphate, monophenyl phosphate, diphenyl phosphate, monobenzyl phosphate, dibenzyl phosphate; triphenyl phosphate, diphenyl phosphate, tri-phosphate o-trill, di-o-tolyl phosphate, tri-m-tolyl phosphite, di-m-tolyl phosphite, tri-p-tolyl phosphite, di-p-tolyl phosphite, sub Examples thereof include phosphite ester compounds such as di-o-chlorophenyl phosphate, tri-p-chlorophenyl phosphite, and di-p-chlorophenyl phosphite, and these may be used alone or in combination of two or more. Can be used.
Among them, it is preferable that it contains at least one phosphoric acid ester compound from the viewpoint of curability.

The catalyst (E) preferably has a number average molecular weight of 2000 or less, more preferably a number average molecular weight of 1800 or less, and even more preferably a number average molecular weight of 1500 or less.

The catalyst (E) is preferably contained in the range of 0.01 to 10% by mass, preferably 0.1 to 7% by mass, based on the mass of the resin solid content in the coating composition.

Hydroxy group-containing acrylic resin-coated silica particles (F)
The coating composition of the present invention can contain hydroxyl group-containing acrylic resin-coated silica particles (F), if necessary. As the hydroxyl group-containing acrylic resin-coated silica particles (F), any silica particles coated with the hydroxyl group-containing acrylic resin can be preferably used, and those known per se can be used without limitation. Specifically, for example, silica particles obtained by a production method including the following steps 1 and 2 are preferable.

<Step 1> A polymerizable unsaturated group-containing silica particle dispersion is prepared by mixing and heating silica particles (f1), a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group (f2), and an organic solvent (f3). The process of obtaining.

<Step 2> A step of mixing and heating a polymerizable unsaturated monomer (f4) with the dispersion liquid to obtain a hydroxyl group-containing acrylic resin-coated silica particle dispersion.

<Step 1>
Step 1 is a step of mixing and heating silica particles (f1), a monomer having a polymerizable unsaturated group and a hydrolyzable silyl group (f2), and an organic solvent to obtain a polymerizable unsaturated group-containing silica particle dispersion. is there.

Silica particles (f1)
The silica particles (f1) can be surface-modified with a polymerizable unsaturated group by binding to the monomer (f2) having a polymerizable unsaturated group and a hydrolyzable silyl group, which will be described later. Any particle can be used. Examples of such silica particles (f1) include dry silica, wet silica, silica gel, calcium ion-exchanged silica fine particles, colloidal silica, and the like. In particular, the silica particles have a hydroxyl group and / or an alkoxy group on the particle surface. Colloidal silica, which is silica fine particles dispersed in a dispersion medium, is preferable.

Examples of colloidal silica include methanol silica sol, IPA-ST, MEKST, NBA-ST, XBA-ST, DMAC-ST, PGM-ST, ST-UP, ST-OUP, ST-20, ST-40, ST- Examples thereof include C, ST-N, ST-O, ST-50, and ST-OL (all manufactured by Nissan Chemical Industries, Ltd.).

The average primary particle size of the silica particles (f1) is preferably 5 to 100 nm, more preferably 5 to 50 nm. If the average primary particle size is less than 5 nm, the effect of scratch resistance and the like may be reduced when the dispersion is mixed with another organic material and used. If the average primary particle size exceeds 100 nm, transparency may be impaired.

In the present specification, the "average primary particle size" means the median diameter (d50) of the volume-based particle size distribution, and the volume-based particle size distribution is measured by the laser diffraction / scattering method. In the present invention, the volume-based particle size distribution of the dispersion was measured using a laser diffraction / scattering particle size distribution measuring device "Microtrack NT3300" (trade name, manufactured by Nikkiso Co., Ltd.). At that time, the sample concentration was adjusted so as to be within a predetermined transmittance range set in the apparatus.

Monomer having a polymerizable unsaturated group and a hydrolyzable silyl group (f2)
The monomer (f2) having a polymerizable unsaturated group and a hydrolyzable silyl group is, for example, 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 2- (meth). Acryloyloxyethyl trimethoxysilane, 2- (meth) acryloyloxyethyl triethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane, 2- (meth) acryloyloxyethylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltri Non-polymerizable property obtained by reacting a functional group other than the hydrolyzable silyl group of ethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, and various silane coupling agents with a functional group other than the unsaturated group of the unsaturated compound. Examples thereof include a monomer having a saturated group and a hydrolyzable silyl group.

Organic solvent (f3)
The organic solvent is preferably a hydrophilic organic solvent, and examples of the hydrophilic organic solvent include alcohol-based organic solvent; ether-based organic solvent; glycol ether-based organic solvent; ester-based organic solvent, and the like. Can be used alone or in combination of two or more. Of these, alcohols and / or glycol ethers are preferable from the viewpoint of storability and scratch resistance.

<Process 2>
Step 2 is a step of mixing and heating the polymerizable unsaturated group-containing silica particle dispersion obtained in the above step 1 and the polymerizable unsaturated monomer (f4) to obtain a hydroxyl group-containing acrylic resin-coated silica particle dispersion. ..

The polymerization method of the acrylic resin is not particularly limited, and a polymerization method known per se can be used. Among them, the polymerization method is polymerizable in an organic solvent containing polymerizable unsaturated group-containing silica particles. Solution polymerization in which the unsaturated monomer (f4), the polymerization initiator and the like are dropped and polymerized can be preferably used.

Polymerizable unsaturated monomer (f4)
The polymerizable unsaturated monomer (f4) is a compound having one or more polymerizable unsaturated groups in one molecule, and specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl. Alkyl (meth) acrylate having 3 or less carbon atoms such as (meth) acrylate and isopropyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (Meta) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, Alkyl or cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) acrylate; isobornyl ( Polymerizable unsaturated compound having an isobornyl group such as meta) acrylate; polymerizable unsaturated compound having an adamantyl group such as adamantyl (meth) acrylate; Fragrance such as benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene, etc. Ring-containing polymerizable unsaturated monomer; (meth) acrylic acid such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate Monoesterified product of divalent alcohol and ε-caprolactone modified product of the monoesterified product of (meth) acrylic acid and divalent alcohol, N-hydroxymethyl (meth) acrylamide, allyl alcohol, molecular terminal with hydroxyl group A hydroxyl group-containing polymerizable unsaturated monomer such as (meth) acrylate having a certain polyoxyalkylene chain; a carboxyl group-containing polymerizable unsaturated monomer such as (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate; With meta) acrylonitrile, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, glycidyl (meth) acrylate Ami Nitrogen-containing polymerizable unsaturated monomer that does not contain urethane bonds such as additives with acrylates; reaction product of isocyanate group-containing polymerizable unsaturated monomer and hydroxyl group-containing compound, or hydroxyl group-containing polymerizable unsaturated monomer and isocyanate group-containing Polymerizable unsaturated monomer having urethane bond such as reaction product with compound; glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxy Epoxy group-containing polymerizable unsaturated monomer such as cyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, and allylglycidyl ether; (meth) acrylate having a polyoxyethylene chain having an alkoxy group at the molecular end. 2-acrylamide-2-methylpropanesulfonic acid, 2-sulfoethyl (meth) acrylate, allylsulfonic acid, 4-styrenesulfonic acid, etc., non-polymerizable non-polymerizable material having sulfonic acid groups such as sodium salt and ammonium salt of these sulfonic acids. Saturated monomer; polymerizable unsaturated monomer having a phosphate group such as 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, 2-methacryloyloxypropyl acid phosphate; perfluorobutyl Perfluoroalkyl (meth) acrylates such as ethyl (meth) acrylates and perfluorooctyl ethyl (meth) acrylates; polymerizable unsaturated monomers having fluorinated alkyl groups such as fluoroolefins; photopolymerizable functional groups such as maleimide groups Polymerizable unsaturated monomer; (meth) acrylate having a polyoxyethylene chain whose molecular end is an alkoxy group; allyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene Glycoldi (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylpropantri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1 , 6-Hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate 1,1,1-Trishydroxymethylethanedi (meth) acrylate, 1,1,1-Trishydroxymethylethanetri (meth) acrylate, 1,1,1-Trishydroxymethylpropanthry (meth) acrylate, Examples thereof include polymerizable unsaturated monomers having two or more polymerizable unsaturated groups in one molecule, such as triallyl isocyanurate, diallyl terephthalate, and divinylbenzene. These can be used alone or in combination of two or more. Among them, from the viewpoint of scratch resistance and the like of the obtained coating film, the polymerizable unsaturated monomer (f4) preferably contains a hydroxyl group-containing polymerizable unsaturated monomer as at least a part thereof.

When the silica particle (f1) component is 100 parts, the ratio of the acrylic resin component of the monomer (f4) is 5 to 150 parts in terms of solid content from the viewpoint of storage stability and scratch resistance. It is preferably 30 to 120 parts, and more preferably 30 to 120 parts.

The hydroxyl value of the acrylic resin component of the monomer (f4) is preferably 10 to 250 mgKOH / g, more preferably 50 to 200 mgKOH / g.

As the molecular weight of the acrylic resin component of the monomer (f4), the weight average molecular weight is preferably 500 to 100,000, more preferably 1,000 to 20,000.

As the blending amount of the hydroxyl group-containing acrylic resin-coated silica particles (F) in the coating composition, the solid content of the silica particles (F) is 0, based on the mass of the resin solid content in the coating composition. It is preferably in the range of 1 to 20% by mass, more preferably in the range of 0.5 to 13% by mass, and preferably in the range of 1 to 8% by mass, that is, the scratch resistance of the coating film. It is more preferable from the viewpoint of transparency.

Other Resin Components The coating composition of the present invention may contain resin components other than the above (A), (B), (C), (D), and (F), for example, the above (A). , (B), (C), (D), and a hydroxyl group-containing resin other than (F), a curing agent, and the like can be contained.

Examples of the hydroxyl group-containing resin include polyester resin, urethane resin, epoxy resin, polyether resin, alkyd resin, polycarbonate resin, fluororesin, and composite resins thereof, and one type may be used alone or two types may be used. The above can be used in combination.

The curing agent is a compound capable of curing the coating composition of the present invention by reacting with a hydroxyl group or a functional group such as a carboxyl group or an epoxy group in a hydroxyl group-containing resin. Examples of the curing agent include amino resins, epoxy group-containing compounds, carboxyl group-containing compounds, carbodiimide group-containing compounds, and the like, and one type can be used alone or two or more types can be used in combination.

Other Ingredients Examples of other ingredients contained in the coating composition of the present invention include pigments, additives, solvents and the like, which can be contained as necessary.

Examples of the pigment include a coloring pigment, an extender pigment, a brilliant pigment, and the like, and the pigment can be used alone or in combination of two or more as long as the transparency is not impaired.

The pigment may be added directly to the coating composition, or may be mixed with a pigment dispersant and a pigment-dispersing resin, dispersed, made into a paste, and then blended into the coating material. Known pigment dispersants, pigment dispersion resins, and dispersion methods can be used.

Examples of the additive include an ultraviolet absorber (for example, a benzotriazole-based absorber, a triazine-based absorber, a salicylic acid derivative-based absorber, a benzophenone-based absorber, etc.), a light stabilizer (for example, hindered amines, etc.), and a thickening agent. Known paint additives such as agents, antifoaming agents, surface conditioners, anti-settling agents, rust preventives, chelating agents (acetylacetone and the like), dehydrating agents, neutralizing agents and plasticizing agents can be included.
Further, from the viewpoint of suppressing hydrolysis, it is preferable to contain a dehydrating agent. As the dehydrating agent, a dehydrating agent known per se can be used, and specifically, for example, aluminum isopropyrate, aluminum sec-butylate, tetraisopropyl titanate, tetranormal butyl titanate, zirconium normal butyrate, ethyl. Metal alkoxides such as silicate and vinyltrimethoxysilane; organic alkoxy compounds such as methyl orthomate, ethyl orthomate, methyl orthoacetate, ethyl orthoacetate, isopurpil orthoacetate, dimethoxypropane; "Additive TI" (Suika Bayer Urethane) Monofunctional isocyanates such as (manufactured by the company, trade name) can be mentioned, and these can be used alone or in combination of two or more.
The blending amount of the dehydrating agent in the coating composition shall be in the range of 0.01 to 15% by mass, preferably 0.1 to 8% by mass, based on the mass of the resin solid content in the coating composition. Can be done.

As the solvent, the solvent described in the above-mentioned "silyl group-containing acrylic resin (A)" can be preferably used.

Further, as the coating composition of the present invention, a multi-component coating composition containing a main agent component (I) and a curing agent component (II) is preferable from the viewpoint of storage stability.
Here, the "multi-component coating composition" is a coating composition in which two or more liquids (preferably two liquids) are mixed and used before painting, and is in a state of being mixed from the beginning of production. It is distinguished from the "one-component paint composition" of. The term "before painting" includes mixing in a painting device, mixing in a pipe, mixing in a paint storage tank, and the like, and all of them can be preferably used. From the viewpoint of storage stability, the mixing time is from 0.01 seconds to 3 months before coating, preferably from 0.1 seconds to 10 days before coating, and more preferably from 0.1 seconds before coating. It is preferably 10 hours before.

When the coating composition of the present invention is a multi-component coating composition, the main component (I) is a silyl group-containing acrylic resin (A), a silyl group-free hydroxyl group-containing acrylic resin (B), and an alkoxysilyl group. It is preferable that the containing organopolysiloxane (C) is contained and the curing agent component (II) contains the polyisocyanate compound (D) and the catalyst (E).

Coating Method The coating composition of the present invention thus obtained can be coated on an object to be coated.
Examples of the coating method include methods known per se, such as atomization coating (air spray coating, airless spray coating, rotary atomization coating), brush coating, immersion coating, roll coating, and the like. Atomized coating is preferable from the viewpoint of film finish.

The object to be coated is not particularly limited, and examples thereof include a cured or uncured painted surface coated with various base materials and paints, and examples of the base material include iron, zinc, and iron / zinc alloy. , Metal such as steel plate; wood, concrete, gypsum board, slate, siding material, porcelain tile wall surface, lightweight cellular concrete, mortar, brick, stone, inorganic base material such as glass; plastic base material; leather; fiber, etc. Can be done.

On the other hand, the cured or uncured painted surface on which the paint is applied is not particularly limited, and for example, a top coat formed by painting a solid color paint or a top coat formed by painting a metallic paint. Two or more types of topcoats selected from coatings, topcoats formed by painting light-interfering paints, topcoats formed by painting clear paints, solid color paints, metallic paints and clear paints. Examples thereof include a multi-layer coating film formed by sequentially applying paints.

Among them, a step of coating a colored coating film to form a colored coating film (preferably 1 to 50 μm, more preferably 7 to 40 μm as a curing film thickness), the coating composition of the present invention on the colored coating film. It is preferable that the method for forming a multi-layer coating film is a step of sequentially performing a step of coating the above to form a topcoat coating film and a step of simultaneously heating and curing the obtained colored coating film and the topcoat coating film.

The uncured coating film obtained by applying the coating composition of the present invention to an object to be coated can be preheated (preheated) or air blown under conditions that the coating film is not substantially cured. The preheat is preferably at a temperature of about 40 to about 100 ° C., more preferably about 50 to about 90 ° C., and even more preferably about 60 ° C. or higher and less than about 80 ° C., preferably for about 30 seconds to about 15 minutes. More preferably, it is carried out for about 1 to about 10 minutes. Further, the air blow can be generally carried out by blowing air heated to room temperature or a temperature of about 25 to about 80 ° C. on the coated surface of the object to be coated for about 30 seconds to about 15 minutes.
The uncured coating is then heated to cure the coating.

The uncured coating film can be cured by ordinary heating (baking) means of the coating film, for example, hot air heating, infrared heating, high frequency heating and the like.
The uncured coating is heated at a temperature of preferably 70-200 ° C, more preferably 80-160 ° C, preferably 10-60 minutes, and more preferably 15-40 minutes. Under the above conditions, the uncured coating film is cured.

The cured film thickness of the coating film coated with the coating composition of the present invention is preferably 1 to 50 μm, more preferably 10 to 40 μm, and even more preferably 12 to 40 μm.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In each example, "part" indicates a mass part and "%" indicates a mass%.

Example of production of silyl group-containing acrylic resin 1 Production of acrylic resin (A1) 200 parts of Swazole 1000 (Note 1) and n in a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a nitrogen introduction tube and a dropping device. -150 parts of butanol was charged, and after nitrogen substitution, the temperature was kept at 120 ° C. (within plus or minus 10 ° C.). The monomer mixture shown below was added dropwise thereto over 3 hours.
<Monomer mixture>
Styrene 100 parts 2-Ethylhexylacryllate 400 parts 2-Hydroxyethyl methacrylate 200 parts KBM-503 (Note 2) 300 parts t-Butylperoxy-2-ethylhexanoate 40 parts 1 hour after the completion of dropping A solution prepared by dissolving 5 parts of t-butylperoxy-2-ethylhexanoate in 200 parts of Swazole 1000 (Note 1) was added dropwise thereto over 1 hour. After completion of the dropping, the mixture was kept at 120 ° C. (within plus or minus 10 ° C.) for 1 hour, and then Swazole 1000 (Note 1) was added to adjust the solid content, and finally the acrylic resin (A1) having a solid content of 50%. ) A solution was obtained. The acrylic resin (A1) had a hydroxyl value of 86 mgKOH / g and a weight average molecular weight of 10,000.
(Note 1) Swazole 1000: Trade name, manufactured by Cosmo Oil Co., Ltd., aromatic hydrocarbon solvent.

Production Examples 2 to 6 Production of Acrylic Resins (A2) to (A6) A solution of acrylic resins (A2) to (A6) was obtained in the same manner as in Production Example 1 except that the monomers were blended as shown in Table 1 below.

(Note 2) KBM-503: Trade name, manufactured by Shin-Etsu Chemical Co., Ltd., 3-methacrylooxypropyltrimethoxysilane.
(Note 3) X-22-174ASX: Trade name, manufactured by Shin-Etsu Chemical Co., Ltd., single-ended methacryl-modified polydimethylsiloxane.

Example 7 of production of hydroxyl group-containing acrylic resin containing no silyl group Swazol 1000 (Note 1) in a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a nitrogen introduction tube and a dropping device. 200 parts and 150 parts of n-butanol were charged, and after nitrogen substitution, the temperature was kept at 120 ° C. (within plus or minus 10 ° C.). The monomer mixture shown below was added dropwise thereto over 3 hours.
<Monomer mixture>
Styrene 200 parts n-Butyl acrylate 500 parts 2-Hydroxyethyl methacrylate 300 parts t-Butylperoxy-2-ethylhexanoate 40 parts One hour after the completion of dropping, t-butylperoxy-2- A solution prepared by dissolving 5 parts of ethylhexanoate in 200 parts of Swazole 1000 (Note 1) was added dropwise over 1 hour. After completion of the dropping, the mixture was kept at 120 ° C. (within plus or minus 10 ° C.) for 1 hour, and then Swazole 1000 (Note 1) was added to adjust the solid content, and finally the acrylic resin (B1) having a solid content of 50%. ) A solution was obtained. The acrylic resin (B1) had a hydroxyl value of 130 mgKOH / g and a weight average molecular weight of 10,000.

Production Example 8 Production of hydroxyl group-containing acrylic resin-coated silica particles PGM-ST (trade name, manufactured by Nissan Chemical Industries, Ltd., silica average primary particle diameter; 15 nm, silica) is placed in a separable flask equipped with a reflux condenser, a thermometer and a stirrer. Concentration: 30% by mass, dispersion medium: propylene glycol monomethyl ether) After adding 333 parts (solid content 100 parts) and 10 parts of deionized water, KBM-503 (trade name, manufactured by Shin-Etsu Chemical Industry Co., Ltd., 3-methacry) Add 10 parts of looxypropyltrimethoxysilane) and carry out a dehydration condensation reaction while stirring at 80 ° C. for 2 hours, then add 0.03 part of tetra-n-butylammonium fluoride and stir for another 1 hour. It was reacted. After completion of the reaction, 30 parts of propylene glycol monomethyl ether was added, and then the volatile components were distilled off under reduced pressure to obtain a surface-modified silica particle dispersion containing a polymerizable unsaturated group having a solid content of 40%. Obtained.
Subsequently, 130 parts of propylene glycol monomethyl ether was placed in a separable flask equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen gas inlet, and the temperature was raised to 100 ° C. under ventilation of nitrogen gas. After reaching 100 ° C., 250 parts of the above polymerizable unsaturated group-containing silica particle dispersion (100 parts of solid content), 20 parts of styrene, 35 parts of 4-hydroxybutyl acrylate, 44 parts of isobornyl acrylate, and 1 part of acrylic acid. , 2,2 Azobis (2-methylbutyronitrile) (trade name V-59, manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 2 hours. Then, after aging at 100 ° C. for 1 hour, a mixed solution of 0.83 parts of V-59 and 20 parts of propylene glycol monomethyl ether was added dropwise over 0.5 hours, and the mixture was further aged for 2 hours. The polymerization rate obtained from the non-volatile component was 99%. Then, ethoxyethyl propionate was added, and the solvent was replaced by azeotropic distillation under reduced pressure to obtain hydroxyl group-containing acrylic resin-coated silica particles having an actually measured non-volatile content of 40%.

Production Example 9 Production of non-aqueous dispersion type acrylic resin Heptane 93 in a four-necked flask equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen gas inlet.
Parts and 98 parts of the following 55% polymer dispersion stabilizer solution were charged and heated to reflux, and 15 parts of styrene, 40 parts of methyl methacrylate, 30 parts of acrylonitrile, 15 parts of 2-hydroxyethyl methacrylate and t-butylperoxy-2-ethylhexa A mixture of 1.5 parts of Noate was added dropwise over 3 hours and aged for another 2 hours to obtain a non-aqueous dispersion type acrylic resin. The obtained non-aqueous dispersion type acrylic resin has a mass solid content concentration of 53%, a Gardner viscosity B, and an average particle size (measured by an electron microscope) of 0.2 to 0.3 μm. It was a liquid.

<Synthesis of 55% Polymer Dispersion Stabilizer Solution>
40 parts of isobutyl acetate and 40 parts of toluene were placed in a four-necked flask equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen gas inlet, and heated to reflux to make 10 parts of styrene, 49 parts of isobutyl methacrylate, and 30 parts of 2-ethylhexyl methacrylate. A mixture of 11 parts of 2-hydroxyethyl methacrylate and 2 parts of azobisisobutyronitrile was added dropwise over 3 hours, and aging was carried out for 2 hours after the addition to obtain a polymer dispersion stabilizer solution. The obtained polymer dispersion stabilizer solution had a mass solid content concentration of 55%, a Gardner viscosity G, and a weight average molecular weight of 16000.

Production Example 10 Production of main agent component (I-1) 0.5 parts of X-40-9250 (trade name, alkoxysilyl group-containing organopolysiloxane, manufactured by Shin-Etsu Chemical Industry Co., Ltd.), acrylic resin obtained in Production Example 1. (A1) 40 parts (resin solid content 20 parts), acrylic resin (B1) 80 parts (resin solid content 40 parts) obtained in Production Example 7, non-aqueous dispersion type acrylic resin 9 obtained in Production Example 8. .4 parts (5 parts of resin solid content), 1 part of Neostan U-100 (trade name, dibutyltin dilaurate, manufactured by Nitto Kasei Co., Ltd., 100% solid content), BYK-300 (trade name, manufactured by Big Chemie, surface conditioner) , Active ingredient 52%) 0.2 parts (solid content 0.1 parts), TINUVIN900 (trade name, benzotriazole-based ultraviolet absorber, manufactured by BASF, 100% active ingredient) 2.0 parts, TINUVIN292 (trade name, 1 part of hindered amine light stabilizer, BASF, 100% active ingredient) and 5 parts of methyl orthoacetate are uniformly mixed, and Swazole 1000 (trade name, Cosmo Petroleum, hydrocarbon solvent) is added. Stir well with a disper, and ford cup No. at 20 ° C. The main ingredient component (I-1) was obtained by adjusting the viscosity according to No. 4 to 25 seconds.

Production Examples 11 to 34 Production of Main Agent Components (I-2) to (I-25) Main Agent Ingredients (I-2) to (I-) by the same composition and method as in Production Example 10 except as shown in Table 2 below. 25) was obtained.

The blending amount in the above table is the value of the solid content.
(Note 4) XR31-B1410: Trade name, manufactured by Momentive, alkoxysilyl group-containing organopolysiloxane, number average molecular weight 800.
(Note 5) KR-500: Trade name, manufactured by Shin-Etsu Chemical Co., Ltd., alkoxysilyl group-containing organopolysiloxane, number average molecular weight 900.
(Note 6) KR-510: Trade name, manufactured by Shin-Etsu Chemical Co., Ltd., alkoxysilyl group-containing organopolysiloxane, number average molecular weight 950.

Production Example 35 Production of hardener component (II-1) 35 parts of Sumijour N3300 (trade name, manufactured by Sumika Bayer Urethane, isocyanurate of hexamethylene diisocyanate, solid content 100%, NCO content 21.8%) and 0.5 parts of tris (2-ethylhexyl) phosphate ester is uniformly mixed, and Swazole 1000 (trade name, manufactured by Cosmo Petroleum Co., Ltd., hydrocarbon-based solvent) is added, and the mixture is sufficiently stirred with a disper, and at 20 ° C. Ford Cup No. The solvent was adjusted so that the viscosity according to No. 4 was 25 seconds, and a curing agent component (II-1) was obtained.

Production Example 36 Production of hardener component (II-2) 35 parts of Sumijour N3300 (trade name, manufactured by Sumika Bayer Urethane, isocyanurate of hexamethylene diisocyanate, solid content 100%, NCO content 21.8%) and Swazole 1000 (trade name, manufactured by Cosmo Oil Co., Ltd., hydrocarbon-based solvent) was added, and the mixture was sufficiently stirred with a disper. The solvent was adjusted so that the viscosity according to No. 4 was 25 seconds, and a curing agent component (II-2) was obtained.

Production of Examples 1 to 16 and Comparative Examples 1 to 9 Paints (X-1) to (X-25) The total amounts of the main agent component and the curing agent component obtained in the above production examples were mixed in the combination shown in the table below.
Then, the mixture was uniformly stirred with a disper to obtain paints (X-1) to (X-25).

Comparative Example 10 Production of paint (X-26) 40 parts (resin solid content 20 parts) of acrylic resin (A1) obtained in Production Example 1, 80 parts (resin solid) of acrylic resin (B1) obtained in Production Example 7. 40 parts), 9.4 parts of the non-aqueous dispersion type acrylic resin obtained in Production Example 8 (5 parts of resin solid content), X-40-9250 (trade name, alkoxysilyl group-containing organopolysiloxane, Shin-Etsu Chemical Co., Ltd.) (Manufactured by Kogyo Co., Ltd.) 0.5 parts, Neostan U-100 (trade name, dibutyltin dilaurate, manufactured by Nitto Kasei Co., Ltd., solid content 100%) 1 part, BYK-300 (trade name, manufactured by Big Chemie, surface conditioner, Active ingredient 52%) 0.2 parts (solid content 0.1 parts), TINUVIN900 (trade name, benzotriazole-based ultraviolet absorber, manufactured by BASF, 100% active ingredient) 2.0 parts, TINUVIN292 (trade name, hindered amine) Photostabilizer, BASF, 100% active ingredient) 1 part, methyl orthoacetate 5 parts, Sumijour N3300 (trade name, Sumika Bayer Urethane, isocyanurate of hexamethylene diisocyanate, solid content 100%, NCO 35 parts (content rate 21.8%) and 0.5 part of tris (2-ethylhexyl) phosphate ester are uniformly mixed, and Swazole 1000 (trade name, manufactured by Cosmo Petroleum Co., Ltd., hydrocarbon solvent) is further added. Stir well with a disper, and ford cup No. at 20 ° C. The solvent was adjusted so that the viscosity according to No. 4 was 25 seconds, and a paint (X-26) was obtained.

In addition, evaluation tests of storage stability, stain resistance (initial, after accelerated weather resistance test), transparency of the coating film, and scratch resistance (gloss retention), which will be described later, were conducted, and the results are shown in Table 3 above. .. As for the evaluation, S, A, and B are acceptable, and C is unacceptable. If any one of the evaluation tests fails, the paint fails.
In Comparative Example 10, the evaluation result of the storage stability was unacceptable, so the coating film was not evaluated. (Marked "*").

Preparation of test plate Eleklon GT-10 (manufactured by Kansai Paint Co., Ltd., trade name, thermosetting epoxy resin-based cationic electrodeposition paint) is a cured film on a 0.8 mm thick dull steel plate that has been subjected to zinc phosphate chemical conversion treatment. Electrodeposition coating to a thickness of 20 μm, heating at 170 ° C for 30 minutes to cure, and then Amirac TP-67-P (manufactured by Kansai Paint Co., Ltd., trade name, polyester / melamine resin-based automobile intermediate coating). (Dark gray coating color) was air-spray coated so as to have a film thickness of 35 μm, and heat-cured at 140 ° C. for 30 minutes. Subsequently, two of the above intermediate coating plates were prepared, and the water-based base coat "WBC713T" (trade name, manufactured by Kansai Paint Co., Ltd., acrylic / melamine resin-based water-based metallic color base coating) was applied on the intermediate coating with a curing film thickness of 15 μm. One sheet was preheated at 80 ° C. for 5 minutes, and one sheet was heat-cured at 140 ° C. for 30 minutes. The paints (X-1) to (X-25) obtained in Examples and Comparative Examples were air-sprayed on two coated plates so as to have a cured film thickness of 35 μm, and left at room temperature for 7 minutes. It was heat-cured at 140 ° C. for 30 minutes.
The paints (X-1) to (X-25) were painted within 1 hour after the components (I) and (II) were mixed.

Evaluation test <storage stability>
The paint (X) used in Examples and Comparative Examples was stored in an environment of a temperature of 20 ° C. and a humidity of 60% for 72 hours, and the state of the paint was evaluated according to the following criteria. In the paints (X-1) to (X-25), the respective components were observed without mixing the components (I) and (II).
S: Ingredients (I) and (II), or paint (X), were found in Ford Cup No. 20 at 20 ° C. after the storage test. The viscosity of 4 is less than plus 20 seconds of the initial viscosity, and no significant change is observed.
C: Ingredients (I) and (II), or paint (X), were found in Ford Cup No. 20 at 20 ° C. after the storage test. The viscosity of 4 is greater than or equal to the initial viscosity plus 20 seconds or gelled.

<Stain resistance (initial)>
Each of the obtained test plates (within 2 hours after baking and curing) was spot-contaminated with oil-based black magic. Subsequently, a dry Kimwipe (trade name) was used to wipe off the contaminated part, and the above part was observed and evaluated according to the following criteria. The test was conducted with two coated plates, one in which the water-based base coat was preheated (non-cured) and the other in which it was heat-cured, but there was no difference.
S: No pollution.
A: There is no contamination (color), but there are slight traces.
B: Slight contamination (color) remains.
C: Contamination remains significantly.

<Stain resistance (after accelerated weather resistance test)>
Each of the obtained test plates was tested in a "Sunshine Weather Meter" (manufactured by Suga Test Instruments Co., Ltd., accelerated weather resistance tester) for 600 hours, and then spot-contaminated on the coated plate with oil-based black magic. Subsequently, a dry Kimwipe (trade name) was used to wipe off the contaminated part, and the above part was observed and evaluated according to the following criteria. The test was conducted with two coated plates, one in which the water-based base coat was preheated (non-cured) and the other in which it was heat-cured, but there was no difference.
S: No pollution.
A: There is no contamination (color), but there are slight traces.
B: Slight contamination (color) remains.
C: Contamination remains significantly.

<Transparency of coating film>
The paint (X) obtained in Examples and Comparative Examples was air-spray coated on a glass plate so as to have a cured film thickness of 35 μm, left at room temperature for 7 minutes, and then heat-cured at 140 ° C. for 30 minutes. Subsequently, the appearance of the coating film was visually observed.
A: Transparent or slightly turbid.
B: White and turbid, but transparent (visible through the other side).
C: Significant cloudiness and no transparency (not visible through the other side).

<Scratch resistance (gloss retention rate)>
Each of the obtained test plates was fixed to a test stand of a car wash tester (Car-wash Lab Appatratus, manufactured by Amtec) in an atmosphere of 20 ° C., and Sicron SH200 (trade name, silica having a particle size of 24 μm) was placed on the test plate. While spraying a test solution prepared by mixing 1.5 g of fine particles (manufactured by Quarzwerke) with 1 liter of water, the car wash brush was rotated at 127 rpm to reciprocate the test table 10 times. Then, it was washed with water and dried, and the 20 ° gloss before and after the test was measured using a gloss meter (manufactured by Byk-Gardner, device name: Micro Tri-Gloss), and the gloss retention rate was calculated from the following formula.
Gloss retention rate (%) = Gloss after test / Initial gloss x 100
The test was conducted with two coated plates, one in which the water-based base coat was preheated (non-cured) and the other in which it was heat-cured, but there was no difference.
A: 70% or more.
B: 50 to less than 70%.
C: Less than 50%.

Claims (11)

A coating composition containing a silyl group-containing acrylic resin (A), a silyl group-free hydroxyl group-containing acrylic resin (B), an alkoxysilyl group-containing organopolysiloxane (C), a polyisocyanate compound (D), and a catalyst (E). A coating composition comprising a silyl group-containing acrylic resin (A) containing at least one polydimethylsiloxane segment. The claim is that the silyl group-containing acrylic resin (A) contains 0.1 part or more of a polymerizable unsaturated monomer (a1) having a polydimethylsiloxane segment in the structure based on 100 parts of all the monomers. The coating composition according to 1. The silyl group-containing acrylic resin (A) is a polymerizable unsaturated monomer (a1) having a polydimethylsiloxane segment represented by the following formulas (1) and / or (2), and a hydrolyzable silyl group-containing polymerizable unsaturated monomer. The coating composition according to claim 1 or 2, which is obtained by copolymerizing (a2), a hydroxyl group-containing polymerizable unsaturated monomer, and, if necessary, another polymerizable unsaturated monomer copolymerizable therewith.

(In the formula, R ¹ represents an alkyl group having 1 to 10 carbon atoms, R ² represents a divalent hydrocarbon group having 1 to 6 carbon atoms, R ³ represents a hydrogen atom or a methyl group, and R ⁴ and R ⁷ is the same or different, representing a hydrogen atom or a methyl group, respectively, R ⁵ and R ⁶ are the same or different, representing a divalent hydrocarbon group having 1 to 6 carbon atoms, respectively, and n ¹ and n ² are the same or different. Each means the number of repetitions of the dimethylsiloxane unit, which is in the range of 6 to 300, preferably 6 to 100.) The coating composition according to any one of claims 1 to 3, further containing the hydroxyl group-containing acrylic resin-coated silica particles (F). The coating composition according to claim 1, wherein the number average molecular weight of the alkoxysilyl group-containing organopolysiloxane (C) is in the range of 500 to 10,000. The coating composition according to claim 1 to 5, wherein the solid content of the alkoxysilyl group-containing organopolysiloxane (C) is 0.01 to 10% by mass based on the resin solid content in the coating material. .. A silyl group-containing acrylic resin (A), which is a multi-component coating composition containing a main agent component (I) and a curing agent component (II), wherein the main agent component (I) has at least one polydimethylsiloxane segment. , A hydroxyl group-containing acrylic resin (B) containing no silyl group, and an alkoxysilyl group-containing organopolysiloxane (C), and the curing agent component (II) contains a polyisocyanate compound (D) and a catalyst (E). A paint composition characterized by. A coating film forming method for forming a topcoat coating film by coating the coating compositions of claims 1 to 7. A coating film forming method in which the coating compositions of claims 1 to 7 are atomized to form a topcoat coating film having a curing film thickness of 1 to 50 μm, and then heat-cured at a temperature of 70 to 200 ° C. The process of painting a colored paint composition to form a colored coating film,
A step of coating the coating composition of claims 1 to 7 on the colored coating film to form a top coating film.
A step of simultaneously heating and curing the obtained colored coating film and topcoat coating film,
A method for forming a multi-layer coating film, which comprises sequentially performing. A step of atomizing and coating a colored coating composition to form a colored coating film having a cured film thickness of 1 to 50 μm.
A step of atomizing and coating the coating composition of claims 1 to 7 on the colored coating film to form an overcoat coating film having a cured film thickness of 1 to 50 μm.
A step of simultaneously heating and curing the obtained colored coating film and topcoat coating film at a temperature of 70 to 200 ° C.
A method for forming a multi-layer coating film, which comprises sequentially performing.