WO2023048206A1

WO2023048206A1 - Organic solvent-type photoluminescent coating composition and multilayer coating film forming method

Info

Publication number: WO2023048206A1
Application number: PCT/JP2022/035305
Authority: WO
Inventors: 健吾前田; 龍介村本
Original assignee: 関西ペイント株式会社
Priority date: 2021-09-23
Filing date: 2022-09-22
Publication date: 2023-03-30
Also published as: TW202323456A; JPWO2023048206A1

Abstract

The present invention addresses the problem of providing an organic solvent-type photoluminescent coating composition which has excellent precipitation stability and circulation suitability and from which a coating film that exhibits excellent pearly or metallic tone gloss can be formed. The present invention provides an organic solvent-type photoluminescent coating composition that contains a binder resin (A), a cellulose-based viscosity modifier (B), a polyurea-based viscosity modifier (C), and a photoluminescent pigment (D), and that has a solid content percentage of 1-20 mass%. The contained amount of the polyurea-based viscosity modifier (C) is within a range of 0.1-3 parts by mass with reference to 100 parts by mass of the solid content of the organic solvent-type photoluminescent coating composition.

Description

Organic solvent type glitter coating composition and method for forming multi-layer coating film

This application claims priority based on Japanese Patent Application No. 2021-154950 filed on September 23, 2021 (the entire disclosure of which is incorporated herein by reference). TECHNICAL FIELD The present invention relates to an organic solvent type luster coating composition and a method for forming a multilayer coating film.

The purpose of applying paint is mainly to protect the material and give it a beautiful appearance. Aesthetics, especially "texture", are important for industrial products from the point of view of enhancing their product appeal. The texture of industrial products demanded by consumers is diverse, but in recent years, in the fields of automobile outer panels, automobile parts, home appliances, etc., luster like pearls or metals is required (hereinafter referred to as pearls). Such luster and metallic luster are collectively referred to as “pearl or metallic luster”).

Pearl or metallic luster means that the surface does not have a grainy feel like a mirror surface, and when the painted plate is viewed near specular light (highlight), it shines brightly. Comparison of reflected light intensity away from specular light. This is a texture that looks dark when viewed in a small area (shade), that is, is characterized by a large difference in brightness between the highlight area and the shade area.

Techniques for imparting pearly or metallic luster to the surface of industrial products include metal plating treatment, metal vapor deposition treatment, etc. (for example, Patent Document 1). And it is advantageous from the viewpoint of cost and the like.

However, in a bright paint composition containing a bright pigment, when performing circulation at the time of painting, a filter installed to remove dust and debris in the circulation pipe contains the bright pigment and the bright paint. However, there has been a problem that agglomerates of viscosity modifiers, etc., which are used to prevent sedimentation of the pigment, tend to clog the nozzles.

JP-A-63-272544

An object of the present invention is to provide an organic solvent-based luster coating composition that has excellent sedimentation stability and circulation aptitude and is capable of forming a coating film exhibiting an excellent pearly or metallic luster. and

The present invention encompasses subject matter described in the following sections:
Section 1. (A) a binder resin, (B) a cellulose-based viscosity modifier, (C) a polyurea-based viscosity modifier, and (D) a glitter organic solvent-based glitter having a solid content of 1 to 20 mass% A coating composition,
The content of the polyurea-based viscosity modifier (C) is in the range of 0.1 to 3 parts by mass based on 100 parts by mass of the solid content of the organic solvent glitter coating composition. paint composition.
Section 2. Item 2. The organic solvent-based glitter coating composition according to Item 1, wherein the binder resin (A) contains a hydroxyl group-containing resin (A1) and a cross-linking agent (A2).
Item 3. Item 3. The organic solvent-based glitter coating composition according to Item 1 or 2, wherein the cellulose-based viscosity modifier (B) contains nanocellulose (B2).
Section 4. 4. The organic solvent-based bright coating composition according to any one of items 1 to 3, wherein the bright pigment (D) contains a light interference pigment (D1).
Item 5. Step (1): A step of applying the colored paint (X) onto the object to be coated to form a colored coating film;
Step (2): A step of applying the organic solvent-based bright coating composition according to any one of items 1 to 4 onto the colored coating film to form a bright coating film;
Step (3): A step of applying a clear paint (Z) on the glitter coating film to form a clear coating film, and
Step (4): Separately or A method for forming a multi-layer coating film, comprising a step of curing by heating simultaneously.
Item 6. Item 6. The method for forming a multilayer coating film according to Item 5, wherein the dry film thickness of the glitter coating film is in the range of 0.025 to 5 μm.

According to the organic solvent-based bright coating composition of the present invention, it is possible to form a coating film that has excellent sedimentation stability and circulation aptitude, and exhibits an excellent pearly or metallic luster.

The organic solvent-based bright coating composition of the present invention contains (A) a binder resin, (B) a cellulose-based viscosity modifier, (C) a polyurea-based viscosity modifier and (D) a bright pigment, and contains solids. An organic solvent-based bright coating composition having a ratio of 1 to 20% by mass,
The content of the polyurea-based viscosity modifier (C) is in the range of 0.1 to 3 parts by mass based on 100 parts by mass of the solid content of the organic solvent glitter coating composition. A paint composition.

Binder resin (A)
The binder resin (A) itself has film-forming properties, and may be either a non-crosslinked type or a crosslinked type, preferably a crosslinked type. As the binder resin (A), a known film-forming resin that has been conventionally used as a binder resin for paints can be used.

Examples of the types of film-forming resins include acrylic resins, polyester resins, alkyd resins, polyurethane resins, and the like. The film-forming resin preferably has a crosslinkable functional group such as a hydroxyl group, a carboxyl group, or an epoxy group. These can be used individually or in combination of 2 or more types.

Further, as the binder resin (A), a cross-linking agent can be used in addition to the film-forming resin. When the cross-linking agent is used as part of the binder resin (A), the film-forming resin usually has a cross-linkable functional group such as a hydroxyl group, a carboxyl group, or an epoxy group, and reacts with the cross-linking agent. Therefore, a resin (base resin) capable of forming a crosslinked film can be used. From the viewpoint of the water resistance of the coating film to be formed, the organic solvent-type bright coating composition of the present invention is preferably a cross-linking coating containing the base resin and the cross-linking agent.

Among them, in the organic solvent-based bright coating composition of the present invention, at least part of the base resin contains the hydroxyl group-containing resin (A1), and at least part of the crosslinking agent is the hydroxyl group-containing resin. It is preferable to contain a cross-linking agent (A2) having a reactivity of

Hydroxyl group-containing resin (A1)
The hydroxyl group-containing resin (A1) is a resin having at least one hydroxyl group in one molecule. As the hydroxyl-containing resin (A1), a wide range of known resins can be used, for example, hydroxyl-containing acrylic resins, hydroxyl-containing polyester resins, hydroxyl-containing acrylic-modified polyester resins, hydroxyl-containing polyether resins, and hydroxyl-containing polycarbonates. resins, polyurethane resins having hydroxyl groups, epoxy resins having hydroxyl groups, and alkyd resins having hydroxyl groups. These can be used alone or in combination of two or more. Among them, the hydroxyl-containing resin (A1) preferably contains the hydroxyl-containing acrylic resin (A1-1) from the viewpoint of the water resistance of the coating film to be formed.

Hydroxyl group-containing acrylic resin (A1-1)
The hydroxyl group-containing acrylic resin (A1-1) is obtained, for example, by copolymerizing a hydroxyl group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomers (polymerizable unsaturated monomers other than the hydroxyl group-containing polymerizable unsaturated monomer). Obtainable.

The hydroxyl group-containing polymerizable unsaturated monomer is a compound having one or more hydroxyl groups and one or more polymerizable unsaturated bonds in one molecule. Examples of the hydroxyl group-containing polymerizable unsaturated monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. Monoesterified product of (meth)acrylic acid and a dihydric alcohol having 2 to 8 carbon atoms; ε-caprolactone modified product of the monoesterified product of (meth)acrylic acid and a dihydric alcohol having 2 to 8 carbon atoms; adduct of meth)acrylic acid and an epoxy group-containing compound (e.g., "Cardura E10P" (trade name), manufactured by Momentive Specialty Chemicals, neodecanoic acid glycidyl ester); N-hydroxymethyl (meth)acrylamide; allyl alcohol; , a (meth)acrylate having a polyoxyethylene chain with a hydroxyl group at the molecular end, and the like. These hydroxyl group-containing polymerizable unsaturated monomers may be used alone or in combination of two or more.

As other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer, for example, monomers shown in (1) to (6) below can be used. These polymerizable unsaturated monomers can be used alone or in combination of two or more.

(1) Acid group-containing polymerizable unsaturated monomer The acid group-containing polymerizable unsaturated monomer is a compound having one or more acid groups and one or more polymerizable unsaturated bonds in one molecule. Examples of the monomer include carboxyl group-containing monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid and maleic anhydride; sulfonic acid group-containing monomers such as vinylsulfonic acid and 2-sulfoethyl (meth)acrylate. 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxypropyl acid phosphate, 2-(meth)acryloyloxy-3-chloropropyl acid phosphate, 2-methacryloyloxyethyl phenyl phosphoric acid, etc. Phosphate ester-based monomers and the like can be mentioned. These can be used alone or in combination of two or more. When the acid group-containing polymerizable unsaturated monomer is used, the acid value of the hydroxyl group-containing acrylic resin (A1-1) is preferably 0.5 to 15 mgKOH/g, more preferably 1 to 12 mgKOH/g. .

(2) Esterified products of acrylic acid or methacrylic acid and monohydric alcohols having 1 to 20 carbon atoms Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) ) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isomyristyl (meth) acrylate, stearyl (meth) acrylate, isostearyl acrylate (Osaka organic Kagaku Kogyo Co., Ltd., trade name), lauryl (meth)acrylate, tridecyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and the like.

(3) Aromatic Vinyl Monomer Specific examples include styrene, α-methylstyrene, vinyltoluene, and the like.

By using an aromatic vinyl monomer as a constituent component, the glass transition temperature of the resin obtained increases, and a hydrophobic coating film with a high refractive index can be obtained. improvement effect can be obtained.

When the aromatic vinyl monomer is used as a component, the blending ratio is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, based on the total amount of the monomer components.

(4) Glycidyl Group-Containing Polymerizable Unsaturated Monomer A glycidyl group-containing polymerizable unsaturated monomer is a compound having one or more glycidyl groups and one or more polymerizable unsaturated bonds in one molecule. Acrylate, glycidyl methacrylate and the like can be mentioned.

(5) polymerizable unsaturated bond-containing nitrogen atom-containing compounds such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-[3-(dimethylamino)propyl](meth)acrylamide, N-butoxymethyl (Meth)acrylamide, diacetone (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, vinylpyridine, vinylimidazole, acrylonitrile, methacrylonitrile and the like.

(6) Other Vinyl Compounds Examples include vinyl acetate, vinyl propionate, vinyl chloride, and vinyl versatate. Versatic acid vinyl esters include commercially available products such as "Veova 9" and "Veova 10" (both trade names, manufactured by Japan Epoxy Resin Co., Ltd.).

As other polymerizable unsaturated monomers, the monomers shown in (1) to (6) above can be used singly or in combination of two or more.

In the present invention, the polymerizable unsaturated monomer refers to a monomer having one or more (eg, 1 to 4) polymerizable unsaturated groups. A polymerizable unsaturated group means an unsaturated group capable of undergoing radical polymerization. Examples of such polymerizable unsaturated groups include vinyl groups, (meth)acryloyl groups, (meth)acrylamide groups, vinyl ether groups, allyl groups, propenyl groups, isopropenyl groups, and maleimide groups.

Also, in this specification, "(meth)acrylate" means acrylate or methacrylate. "(Meth)acrylic acid" means acrylic acid or methacrylic acid. Moreover, "(meth)acryloyl" means acryloyl or methacryloyl. "(Meth)acrylamide" means acrylamide or methacrylamide.

The hydroxyl value of the hydroxyl-containing acrylic resin (A1-1) is preferably 20 to 200 mgKOH/g, more preferably 25 to 180 mgKOH/g, particularly preferably 30 to 160 mgKOH/g, from the viewpoint of curability and water resistance. is within the range of

The weight-average molecular weight of the hydroxyl group-containing acrylic resin (A1-1) is preferably 5,000 to 100,000, more preferably 10,000 to 95,000, and particularly preferably 15,000, from the viewpoint of the finished appearance and curability of the coating film. ~90000.

In this specification, the average molecular weight is a value calculated based on the molecular weight of standard polystyrene from a chromatogram measured with a gel permeation chromatograph. "HLC8120GPC" (manufactured by Tosoh Corporation) was used as the gel permeation chromatograph. Four columns, "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL", and "TSKgel G-2000HXL" (all manufactured by Tosoh Corporation, trade names) were used, Mobile phase: tetrahydrofuran, measurement temperature: 40°C, flow rate: 1 cc/min, detector: RI.

The glass transition temperature of the hydroxyl group-containing acrylic resin (A1-1) is preferably -30 to 85°C, more preferably -10 to 80°C, particularly preferably 10°C, from the viewpoint of the hardness and finished appearance of the coating film. ~75°C.

In this specification, the glass transition temperature (°C) of the acrylic resin was calculated by the following formula.
1/Tg(K)=(W1/T1)+(W2/T2)+ (1)
Tg (°C) = Tg (K) - 273 (2)
In each formula, W1, W2, .
T1, T2, . Further, when the Tg of the homopolymer of the monomer is not clear, the glass transition temperature (° C.) is the static glass transition temperature. Take the sample in a measuring cup, vacuum aspirate to completely remove the solvent, then measure the calorific value change in the range of -20 ° C to +200 ° C at a heating rate of 3 ° C / min, and the first baseline on the low temperature side. The change point was taken as the static glass transition temperature.

The copolymerization method for obtaining the hydroxyl group-containing acrylic resin (A1-1) by copolymerizing the above monomer mixture is not particularly limited, and a known copolymerization method can be used. A solution polymerization method in which polymerization is carried out in an organic solvent in the presence of a polymerization initiator can be preferably used.

Examples of the organic solvent used in the solution polymerization method include aromatic solvents such as toluene, xylene, Swasol 1000 (manufactured by Cosmo Oil Co., Ltd., trade name, high boiling point petroleum solvent); ethyl acetate, butyl acetate, propyl Ester solvents such as propionate, butyl propionate, 1-methoxy-2-propyl acetate, 2-ethoxyethyl propionate, 3-methoxybutyl acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate; methyl ethyl ketone , methyl isobutyl ketone and methyl amyl ketone, and alcohol solvents such as isopropanol, n-butanol, isobutanol and 2-ethylhexanol.

These organic solvents can be used alone or in combination of two or more, but from the viewpoint of the solubility of the acrylic resin, it is preferable to use an ester solvent, a ketone solvent, or the like. Further, it is also possible to use an aromatic solvent in suitable combination.

Polymerization initiators that can be used in copolymerizing the hydroxyl group-containing acrylic resin (A1-1) include, for example, 2,2′-azobisisobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, di-t -Known radical polymerization initiators such as amyl peroxide, t-butyl peroctoate, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile) can be mentioned.

The hydroxyl group-containing acrylic resin (A1-1) can be used alone or in combination of two or more.

When the organic solvent-based bright coating composition of the present invention contains the hydroxyl group-containing acrylic resin (A1-1), the content of the hydroxyl group-containing acrylic resin (A1-1) is the solid content of the binder resin (A) Based on the amount, it is preferably 20 to 80% by mass, more preferably 25 to 75% by mass, and even more preferably 30 to 70% by mass. In the present invention, "the content of the hydroxyl group-containing acrylic resin (A1-1)" means the content of the hydroxyl group-containing acrylic resin (A1-1) as a solid mass. Hereinafter, similarly, in the present invention, when the content of each component contained in the organic solvent-type bright coating composition is indicated, it means the content as a solid content mass of the component unless it is clear otherwise. .

Further, when the organic solvent-type bright coating composition of the present invention contains the hydroxyl group-containing acrylic resin (A1-1), the content of the hydroxyl group-containing acrylic resin (A1-1) is It is preferably 5 to 50 parts by mass, more preferably 6 to 45 parts by mass, and even more preferably 7 to 40 parts by mass based on 100 parts by mass of the solid content of the coating composition.

Crosslinking agent (A2)
In the organic solvent-type bright coating composition of the present invention, the binder resin (A) can contain a cross-linking agent (A2). The cross-linking agent (A2) is a compound capable of reacting with the cross-linkable functional group in the binder resin (A) and capable of forming a cross-linked structure through the reaction. Among them, it is preferable that the crosslinkable functional group in the binder resin (A) is a hydroxyl group, and the crosslinker (A2) is a compound having reactivity with the hydroxyl group.

As the cross-linking agent (A2), specifically, for example, a polyisocyanate compound (A2-1), a blocked polyisocyanate compound (A2-2), an amino resin (A2-3), etc. can be suitably used. . Among them, the blocked polyisocyanate compound (A2-2) and the melamine resin (A2-3) are preferable from the viewpoint of excellent productivity without the need for a coating mixing step, and the blocked polyisocyanate compound (A2-2) is preferred. Especially preferred. The cross-linking agent (A2) can be used alone or in combination of two or more.

Blocked polyisocyanate compound (A2-2)
The blocked polyisocyanate compound (A2-2) is a compound obtained by blocking the isocyanate groups of the polyisocyanate compound (A2-1) with a blocking agent.

The polyisocyanate compound (A2-1) is a compound having at least two isocyanate groups in one molecule, such as an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, an araliphatic polyisocyanate compound, Examples include aromatic polyisocyanate compounds and derivatives of the polyisocyanate compounds.

Examples of the aliphatic polyisocyanate compounds include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1, Aliphatic diisocyanate compounds such as 3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, and methyl 2,6-diisocyanatohexanoate (common name: lysine diisocyanate) 2-isocyanatoethyl 2,6-diisocyanatohexanoate, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane , 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane, and 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane. An isocyanate compound etc. can be mentioned.

Examples of the alicyclic polyisocyanate compound include 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (commonly used 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(isocyanate alicyclic diisocyanate compounds such as natomethyl)cyclohexane (common name: hydrogenated xylylene diisocyanate) or mixtures thereof, methylenebis(4,1-cyclohexanediyl) diisocyanate (common name: hydrogenated MDI), norbornane diisocyanate; ,5-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) Alicyclic triisocyanate compounds such as heptane and the like can be mentioned.

Examples of the araliphatic polyisocyanate compound include methylenebis(4,1-phenylene) diisocyanate (common name: MDI), 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω,ω'-diisocyanate, -araliphatic diisocyanate compounds such as 1,4-diethylbenzene, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene (common name: tetramethylxylylene diisocyanate) or mixtures thereof;1 , 3,5-triisocyanatomethylbenzene and other araliphatic triisocyanate compounds.

Examples of the aromatic polyisocyanate compound include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 2,4-tolylene diisocyanate (common name: 2,4 -TDI) or 2,6-tolylene diisocyanate (common name: 2,6-TDI) or mixtures thereof, aromatic diisocyanate compounds such as 4,4'-toluidine diisocyanate and 4,4'-diphenyl ether diisocyanate; triphenylmethane -aromatic triisocyanate compounds such as 4,4',4''-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene; 4,4'-diphenylmethane-2 , 2′,5,5′-tetraisocyanate and other aromatic tetraisocyanate compounds.

Examples of the derivative of the polyisocyanate compound include dimers, trimers, biuret, allophanate, uretdione, uretimine, isocyanurate, oxadiazinetrione, polymethylene polyphenyl polyisocyanate (crude MDI, polymeric MDI), crude TDI, and the like.

As the polyisocyanate compound (A2-1), aliphatic diisocyanates, alicyclic diisocyanates and their derivatives are preferred, especially since the resulting blocked polyisocyanate compound (A2-2) is less likely to yellow when heated. Aliphatic diisocyanates and derivatives thereof are more preferred from the viewpoint of improving the flexibility of the coating film formed. Examples of the aliphatic diisocyanate derivatives include dimers, trimers, biurets, allophanates, uretdiones, uretimines, isocyanurates, and oxadiazinetriones of the above aliphatic diisocyanates.

Examples of the blocking agent include phenols such as phenol, cresol, xylenol, nitrophenol, ethylphenol, hydroxydiphenyl, butylphenol, isopropylphenol, nonylphenol, octylphenol, and methyl hydroxybenzoate; ε-caprolactam, δ-valerolactam, Lactams such as γ-butyrolactam and β-propiolactam; Aliphatic alcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, amyl alcohol and lauryl alcohol; Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono Ethers such as butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, methoxymethanol; benzyl alcohol, glycolic acid, methyl glycolate, ethyl glycolate, butyl glycolate, lactic acid, methyl lactate, ethyl lactate, lactic acid alcohols such as butyl, methylol urea, methylol melamine, diacetone alcohol, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate; oxime series; dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, active methylene series such as acetylacetone; Mercaptans such as phenol, methylthiophenol, ethylthiophenol; acid amides such as acetanilide, acetanisidide, acetotolide, acrylamide, methacrylamide, acetic acid amide, stearamide, benzamide; succinimide, phthalimide, maleic acid imide, etc. imides; amines such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, butylphenylamine; imidazoles such as imidazole and 2-ethylimidazole; urea, thiourea , ethylene urea, ethylene thiourea, diphenyl urea compounds such as urea; carbamic acid ester compounds such as phenyl N-phenylcarbamate; imine compounds such as ethyleneimine and propyleneimine; sulfite compounds such as sodium bisulfite and potassium bisulfite; . Examples of the azole compounds include pyrazole, 3,5-dimethylpyrazole, 3-methylpyrazole, 4-benzyl-3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, 4-bromo-3, pyrazole or pyrazole derivatives such as 5-dimethylpyrazole, 3-methyl-5-phenylpyrazole; imidazole or imidazole derivatives such as imidazole, benzimidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole; 2-methylimidazoline , 2-phenylimidazoline and other imidazoline derivatives.

Among them, preferred blocking agents include oxime-based blocking agents, active methylene-based blocking agents, pyrazoles and pyrazole derivatives.

When performing blocking (reacting the blocking agent), a solvent can be added as necessary. The solvent used for the blocking reaction is preferably one that is not reactive with isocyanate groups. A solvent such as

The blocked polyisocyanate compound (A2-2) can be used alone or in combination of two or more.

When the organic solvent-based bright coating composition of the present invention contains the blocked polyisocyanate compound (A2-2), the content of the blocked polyisocyanate compound (A2-2) is the binder resin (A) 20 to 80% by mass, more preferably 25 to 75% by mass, and even more preferably 30 to 70% by mass, based on the solid content of the.

Further, when the organic solvent-type bright coating composition of the present invention contains the blocked polyisocyanate compound (A2-2), the content of the blocked polyisocyanate compound (A2-2) is the organic solvent-type It is preferably 5 to 40 parts by mass, more preferably 7 to 35 parts by mass, and even more preferably 10 to 30 parts by mass based on 100 parts by mass of the solid content of the glitter coating composition.

As the melamine resin (A2-3), a partially methylolated melamine resin or a fully methylolated melamine resin obtained by reacting a melamine component and an aldehyde component can be used. Examples of aldehyde components include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde.

In addition, the methylol group of the above methylolated melamine resin may be partially or completely etherified with a suitable alcohol. Examples of alcohols used for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, 2-ethyl-1-butanol, 2-ethyl-1 - hexanol and the like.

The melamine resin (A2-3) includes a methyl-etherified melamine resin obtained by partially or completely etherifying the methylol groups of a partially or completely methylolated melamine resin with methyl alcohol, and the methylol groups of a partially or completely methylolated melamine resin. Butyl-etherified melamine resins partially or fully etherified with butyl alcohol, methyl-butyl mixed-etherified melamine in which the methylol groups of partially or fully-methylolated melamine resins are partially or fully etherified with methyl alcohol and butyl alcohol A resin or the like can be preferably used.

In addition, the melamine resin (A2-3) preferably has a weight average molecular weight within the range of 400 to 6,000, more preferably 500 to 5,000, and even more preferably 800 to 4,000.

A commercially available product can be used as the melamine resin. Commercial product names include, for example, "Cymel 202", "Cymel 203", "Cymel 238", "Cymel 251", "Cymel 303", "Cymel 323", "Cymel 324", "Cymel 325", "Cymel 327", "Cymel 350", "Cymel 385", "Cymel 1156", "Cymel 1158", "Cymel 1116", "Cymel 1130" (manufactured by Allnex Japan), "Uvan 120", " U-Van 20HS", "U-Van 20SE60", "U-Van 2021", "U-Van 2028", and "U-Van 28-60" (manufactured by Mitsui Chemicals, Inc.).

The above melamine resins (A2-3) can be used alone or in combination of two or more.

When the organic solvent-based bright coating composition of the present invention contains the melamine resin (A2-3), the content (solid content) of the melamine resin (A2-3) is the binder resin (A) 5 to 50% by mass, more preferably 5 to 45% by mass, and even more preferably 5 to 40% by mass, based on the solid content of

Further, when the organic solvent-type bright coating composition of the present invention contains the melamine resin (A2-3), the content (solid content) of the melamine resin (A2-3) is the organic solvent-type It is preferably 1 to 30 parts by mass, more preferably 1 to 25 parts by mass, even more preferably 1 to 20 parts by mass based on 100 parts by mass of the solid content of the glitter coating composition.

When the organic solvent-based bright coating composition of the present invention contains the hydroxyl-containing resin (A1), the content (solid content) of the hydroxyl-containing resin (A1) in the organic solvent-based bright coating composition of the present invention is preferably 5 to 50 parts by mass, more preferably 6 to 45 parts by mass, based on 100 parts by mass of the solid content of the organic solvent-type bright coating composition, from the viewpoint of the water resistance of the coating film to be formed, etc. 7 ~40 parts by mass is more preferable.

When the organic solvent-based bright coating composition of the present invention contains the cross-linking agent (A2), the content of the cross-linking agent (A2) in the organic solvent-based bright coating composition of the present invention is From the viewpoint of properties and the like, it is preferably 5 to 45 parts by mass, more preferably 7 to 40 parts by mass, and even more preferably 10 to 35 parts by mass, based on 100 parts by mass of the solid content of the organic solvent-type bright coating composition.

Further, when the organic solvent-based bright coating composition of the present invention contains a hydroxyl group-containing resin (A1) and a cross-linking agent (A2), the content ratio is hydroxyl group-containing resin (A1) / cross-linking agent (A2). The mass ratio is preferably 90/10 to 20/80, more preferably 80/20 to 30/70.

Cellulose-based viscosity modifier (B)
Cellulose-based viscosity modifiers (B) include, for example, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, nitrocellulose (B1) and nanocellulose (B2).

From the viewpoint of excellent sedimentation stability and circulation suitability, the cellulose-based viscosity modifier (B) preferably contains nitrocellulose (B1) or nanocellulose (B2), and may contain nanocellulose (B2). More preferred.

Nitrocellulose (B1)
Nitrocellulose (B1) is a cellulose derivative obtained by nitrate-esterifying natural cellulose, and is obtained by replacing hydroxyl groups in cellulose with nitrate groups. The properties of nitrocellulose are determined by the degree of polymerization and the degree of substitution of nitrate groups for hydroxyl groups in cellulose. The higher the degree of polymerization, the higher the viscosity of the solution, and the higher the degree of substitution of hydroxyl groups for nitric acid groups, the better the solubility in organic solvents.

When the organic solvent-type bright coating composition of the present invention contains the nitrocellulose (B1), the content of the nitrocellulose (B1) is an organic solvent from the viewpoint of excellent sedimentation stability and circulation suitability. It is preferably 1 to 10 parts by mass, more preferably 1 to 7 parts by mass, and even more preferably 1 to 5 parts by mass based on 100 parts by mass of the solid content of the glitter coating composition.

Nanocellulose (B2)
Nanocellulose (B2) is cellulose obtained by disentangling (fibrillating) a material containing cellulose fibers (e.g., wood pulp, etc.) to a nano-size level. Specifically, for example, cellulose nanofibers (CNF), At least one selected from the group consisting of cellulose nanocrystals (CNC) and composites of CNF and CNC can be used. In particular, it is preferable to use CNF and/or CNC.

The nanocellulose (B2) preferably has a number average fiber diameter of 1 to 500 nm, more preferably in the range of 1.2 to 200 nm, and more preferably in the range of 1.5 to 50 nm. is more preferred.

The nanocellulose (B2) preferably has a number average length of 10 to 10,000 nm, more preferably in the range of 20 to 2,000 nm, and further preferably in the range of 30 to 600 nm. preferable.

The number average fiber diameter and number average length of nanocellulose (B2) can be examined by SEM analysis. For example, 50 nanocellulose (B2) fibers can be examined and the average value can be calculated.

The nanocellulose (B2) used in the organic solvent-based bright coating composition of the present invention preferably has a number average aspect ratio, which is the ratio of the number average length to the number average fiber diameter, of 3 to 10,000. ~1,000 is more preferred.

The above nanocellulose (B2) can be modified with acid groups such as carboxyl groups, sulfonic acid groups, and phosphono groups.

In addition, it is preferable to introduce a hydrophobic group into the nanocellulose (B2) in order to increase its dispersibility in an organic solvent.

When the organic solvent-type bright coating composition of the present invention contains the nanocellulose (B2), the content of the nanocellulose (B2) is, from the viewpoint of excellent sedimentation stability and circulation suitability, the organic solvent-type It is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, and even more preferably 3 to 20 parts by mass based on 100 parts by mass of the solid content of the glitter coating composition. These cellulose-based viscosity modifiers (B) can be used either alone or in combination of two or more.

Polyurea-based viscosity modifier (C)
The polyurea-based viscosity modifier (C) is a viscosity modifier obtained by reacting a monoisocyanate or diisocyanate compound with a primary or secondary polyamine, and generally exists as particles of 0.01 to 50 μm.

A commercially available product can be used as the polyurea-based viscosity modifier (C). Commercially available product names include, for example, BYK-410, BYK-411, BYK-420, BYK-425, BYK-428, BYK-430, BYK-431 manufactured by Big Chemie. These can be used individually or in combination of 2 or more types.

The content of the polyurea-based viscosity modifier (C) in the organic solvent-based bright coating composition of the present invention is 0.1 to 3 mass parts based on 100 parts by mass of the solid content of the organic solvent-based bright coating composition. within the scope of the In the present invention, "the content of the polyurea-based viscosity modifier (C)" means the content of the polyurea-based viscosity modifier (C) as a solid mass.

From the viewpoint of enhancing the sedimentation stability to suppress the sedimentation of the bright pigment (D) described below and to provide sufficient circulation aptitude to suppress filter clogging, the content of the polyurea-based viscosity modifier (C) is It is preferably within the above range.

Among them, the content of the polyurea-based viscosity modifier (C) in the organic solvent-based glitter coating composition of the present invention is, from the viewpoint of excellent sedimentation stability and circulation suitability, the amount of the organic solvent-based glitter coating composition. It is preferably in the range of 0.2 to 2.5 parts by mass, more preferably in the range of 0.3 to 2 parts by mass, based on 100 parts by mass of the total solid content. In the present invention, the content of the polyurea-based viscosity modifier (C) of 0.1 parts by mass or more means that it is 0.1% by mass or more after being rounded down to the second decimal place, in other words, the polyurea-based viscosity modifier. It means that the content of (C) is 0.10% by mass or more. Therefore, in the present invention, "the content of the polyurea-based viscosity modifier (C) is in the range of 0.1 to 3 parts by mass based on 100 parts by mass of the solid content of the organic solvent-based bright coating composition. "Organic solvent glitter coating composition" means that "the content of the polyurea-based viscosity modifier (C) is 0.10 to 3 parts based on the solid content of 100 parts by mass of the organic solvent glitter coating composition. "Organic solvent type glitter coating composition within the range of parts by mass". Similarly, 0.2 parts by mass or more and 0.3 parts by mass or more mean 0.20 parts by mass or more and 0.30 parts by mass or more, respectively.

Bright pigment (D)
Examples of the bright pigment (D) in the organic solvent bright paint composition of the present invention include a light interference pigment (D1), a vapor-deposited metal flake pigment (D2), an aluminum flake pigment (D3), and the like. can. One or more of these pigments can be appropriately selected and used depending on the texture required for the coating film to be obtained. From the viewpoint of obtaining a coating film with excellent pearlescent luster, it is preferable that the optical interference pigment (D1) is included. On the other hand, from the viewpoint of obtaining a coating film excellent in metallic luster, it is preferable to contain vapor-deposited metal flake pigment (D2) and aluminum flake pigment (D3).

As the light interference pigment (D1), it is preferable to use a light interference pigment obtained by coating a transparent or translucent base material with titanium oxide. As used herein, a transparent substrate refers to a substrate that transmits at least 90% of visible light. A translucent substrate refers to a substrate that transmits at least 10% to less than 90% of visible light.

The optical interference pigment (D1) is a transparent or translucent scale-like substrate such as mica, artificial mica, glass, iron oxide, aluminum oxide, and various metal oxides. are luster pigments coated with different metal oxides. Examples of the metal oxide include titanium oxide and iron oxide, and the light interference pigment (D1) can exhibit various different interference colors depending on the thickness of the metal oxide.

Specific examples of the light interference pigment (D1) include the following metal oxide-coated mica pigments, metal oxide-coated alumina flake pigments, metal oxide-coated glass flake pigments, metal oxide-coated silica flake pigments, and the like. can be mentioned.

Metal oxide-coated mica pigments are pigments in which natural mica or artificial mica is used as a base material and the surface of the base material is coated with a metal oxide. Natural mica is a scaly base material obtained by pulverizing ore mica (mica). Artificial mica is synthesized by heating industrial raw materials such as SiO ₂ , MgO, Al ₂ O ₃ , K ₂ SiF ₆ and Na ₂ SiF ₆ , melting them at a high temperature of about 1500° C., cooling them and crystallizing them. It contains less impurities and is more uniform in size and thickness than natural mica. Specific examples of artificial mica substrates include fluorine phlogopite (KMg ₃ AlSi ₃ O ₁₀ F ₂ ), potassium tetrasilisic mica (KMg _2.5 AlSi ₄ O ₁₀ F ₂ ), sodium tetrasilisic mica (NaMg _{2 .5} AlSi ₄ O ₁₀ F ₂ ), Na teniolite (NaMg ₂ LiSi ₄ O ₁₀ F ₂ ), LiNa teniolite (LiMg ₂ LiSi ₄ O ₁₀ F ₂ ) and the like are known.

　Metal oxide-coated alumina flake pigments are pigments in which alumina flakes are used as a base material and the surface of the base material is coated with a metal oxide. Alumina flakes mean scaly (flake-like) aluminum oxide, and are colorless and transparent. The alumina flakes need not consist of aluminum oxide alone, and may contain oxides of other metals.

A metal oxide-coated glass flake pigment is a pigment in which a glass flake is used as a base material, and the surface of the base material is coated with a metal oxide. Since the metal oxide-coated glass flake pigment has a smooth substrate surface, strong light reflection occurs.

A metal oxide-coated silica flake pigment is a pigment in which a metal oxide coats scaly silica, which is a base material with a smooth surface and uniform thickness.

Among the optical interference pigments (D1), it is preferable to include a metal oxide-coated mica pigment and/or a metal oxide-coated alumina flake pigment from the viewpoint of forming a coating film exhibiting excellent pearlescent luster.

The optical interference pigment (D1) may be surface-treated for improving dispersibility, water resistance, chemical resistance, weather resistance, and the like.

The optical interference pigment (D1) preferably has an average particle size of 5 to 30 μm, particularly 5 to 20 μm, from the viewpoint of obtaining a coating film excellent in pearly luster.
The optical interference pigment (D1) has a thickness of 0.05 to 1 μm, particularly 0.1 to 0.8 μm, from the viewpoint of obtaining a coating film with excellent pearlescent luster. is preferred.

The average particle size here means the median size of the volume-based particle size distribution measured by the laser diffraction scattering method using a Microtrac particle size distribution analyzer MT3300 (trade name, manufactured by Nikkiso Co., Ltd.). The thickness is defined as the average value of 100 or more measured values obtained by observing the cross section of the coating film containing the scale-like bright pigment with a microscope and measuring the thickness using image processing software. .

The vapor-deposited metal flake pigment (D2) is obtained by vapor-depositing a metal film on the base material, peeling off the base material, and pulverizing the vapor-deposited metal film. Examples of the base material include films.

The material of the metal is not particularly limited, but examples include aluminum, gold, silver, copper, brass, titanium, chromium, nickel, nickel-chromium, and stainless steel. Among them, aluminum or chromium is particularly preferable from the viewpoint of availability and ease of handling. In this specification, vapor-deposited metal flake pigments obtained by vapor-depositing aluminum are referred to as "vapor-deposited aluminum flake pigments," and vapor-deposited metal flake pigments obtained by vapor-depositing chromium are referred to as "vapor-deposited chromium flake pigments."

From the viewpoint of obtaining a coating film with excellent storage stability and metallic luster, it is preferable that the surface of the deposited aluminum flake pigment is treated with silica.

Commercially available products that can be used as the vapor deposition aluminum flake pigment include, for example, the "METALURE" series (trade name, manufactured by Ekart), the "Hydroshine WS" series (trade name, manufactured by Ekart), the "Decomet" series (trade name, Schlenk (manufactured by BASF), "Metasheen" series (trade name, manufactured by BASF), and the like.

Examples of commercially available products that can be used as the vapor-deposited chrome flake pigment include the "Metalure Liquid Black" series (trade name, manufactured by Ecarto).

The average particle size (D50) of the vapor-deposited metal flake pigment (D2) is preferably 1-50 μm, more preferably 5-20 μm.

The average particle size is preferably within the above range from the viewpoint of suppressing graininess in the multilayer coating film, increasing the change in brightness from highlights to shades, and providing metallic luster.

The average thickness of the vapor-deposited metal flake pigment (D2) is preferably 0.01 to 1.0 μm, more preferably 0.015 to 0.1 μm.

The aluminum flake pigment (D3) is generally produced by pulverizing and grinding aluminum in a ball mill or attritor mill in the presence of a grinding medium liquid using a grinding aid. Examples of grinding aids used in the production process of the aluminum flake pigment include higher fatty acids such as oleic acid, stearic acid, isostearic acid, lauric acid, palmitic acid, and myristic acid, as well as aliphatic amines, aliphatic amides, and aliphatic alcohols. used. Aliphatic hydrocarbons such as mineral spirits are used as the grinding medium.

The above aluminum flake pigment (D3) can be used even if the surface is not particularly treated, but the surface is coated with a resin; silica-treated; Those whose surfaces have been treated can also be used. One of the various surface treatments described above can be used, but a plurality of kinds of treatments may be used.
The aluminum flake pigment (D3) is a colored aluminum pigment such as one obtained by coating the surface of the aluminum flake pigment with a coloring pigment and further coating with a resin, or one obtained by coating the surface of the aluminum flake pigment with a metal oxide such as iron oxide. may be used.
The above-mentioned aluminum flake pigment (D3) has an average particle size in the range of 1 to 100 μm, and has a high glossiness in highlights, and forms a dense metallic coating film with a small graininess. From this point of view, the average particle size is preferably in the range of 5 to 50 μm, particularly preferably in the range of 7 to 30 μm. The thickness to be used is preferably in the range of 0.01 to 1.0 μm, particularly preferably in the range of 0.02 to 0.5 μm.
As the bright pigment (D) in the organic solvent bright paint composition of the present invention, the vapor-deposited metal flake pigment (D2) and the aluminum flake pigment (D3) can be used in combination.

The content of the bright pigment (D) in the organic solvent bright paint composition of the present invention is 100 solids of the organic solvent bright paint composition from the viewpoint of obtaining a coating film excellent in pearly or metallic luster. Based on parts by mass, it is preferably 5 to 70 parts by mass, more preferably 10 to 65 parts by mass, and even more preferably 15 to 60 parts by mass.

Organic Solvent-Type Luminous Paint Composition The organic solvent-type luster paint composition of the present invention comprises a binder resin (A), a cellulose-based viscosity modifier (B), a polyurea-based viscosity modifier (C) and a luster pigment (D). ) and having a solid content of 1 to 20% by mass, wherein the content of the polyurea-based viscosity modifier (C) is Based on 100 parts by mass of the solid content of , it is an organic solvent type glitter coating composition in the range of 0.1 to 3 parts by mass.

The above-mentioned solids content has excellent sedimentation stability and circulation aptitude, and is capable of forming a coating film exhibiting excellent pearly or metallic luster. Therefore, it is preferably 4 to 18% by mass, more preferably 7 to 15% by mass. In the present invention, a solid content of 1% by mass or more means that the solid content is 1.0% by mass or more, rounded down to the nearest whole number. Therefore, in the present invention, "an organic solvent-based bright coating composition having a solid content of 1 to 20% by mass" means "an organic solvent-based bright coating having a solid content of 1.0 to 20% by mass. means "composition". Similarly, 4% by mass or more and 7% by mass or more mean 4.0% by mass or more and 7.0% by mass or more, respectively.

In this specification, organic solvent-based paint is a term that is contrasted with water-based paint, and is a paint that contains an organic solvent as a solvent and does not substantially contain water.

Examples of the organic solvent include aromatic solvents such as toluene, xylene, Swasol 1000 (manufactured by Cosmo Oil Co., Ltd., trade name, high boiling point petroleum solvent); ethyl acetate, butyl acetate, propyl propionate, butyl propionate; Ester solvents such as phosphate, 1-methoxy-2-propyl acetate, 2-ethoxyethyl propionate, 3-methoxybutyl acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate; methyl ethyl ketone, methyl isobutyl ketone, methyl amyl Examples include ketone solvents such as ketones, alcohol solvents such as isopropanol, n-butanol, isobutanol, and 2-ethylhexanol.

The content (solid content) of the binder resin (A) in the organic solvent-based bright coating composition of the present invention is determined from the viewpoint of the water resistance of the coating film to be formed, and the solid content of the organic solvent-based bright coating composition It is preferably 20 to 90 parts by mass, more preferably 30 to 80 parts by mass, and even more preferably 35 to 70 parts by mass based on 100 parts by mass per minute.

The content (solid content) of (B) the cellulose-based viscosity modifier in the organic solvent-based bright coating composition of the present invention is from the viewpoint of excellent sedimentation stability and circulation suitability. It is preferably 1 to 30 parts by mass, more preferably 1 to 25 parts by mass, and even more preferably 1 to 20 parts by mass based on 100 parts by mass of the solid content of the product.

Other Ingredients The organic solvent type glitter coating composition may further contain pigments other than the glitter pigment (D), viscosity modifiers other than the cellulose-based viscosity modifier (B) and the polyurea-based viscosity modifier (C), if necessary. A modifier, a curing catalyst, a dispersant, an antifoaming agent, a surface conditioner, an ultraviolet absorber, a light stabilizer, and the like may be added as appropriate.

As the surface conditioner, those used in the technical field of organic solvent-based paints to which the present invention belongs can be widely used. Therefore, the surface modifier is not particularly limited as long as it is used to adjust the surface tension in the organic solvent-based paint. Examples include acrylic silicone surface modifiers, silicone surface modifiers, and acrylic surface modifiers. agents, vinyl-based surface control agents, fluorine-based surface control agents, acetylene diol-based surface control agents, and the like. These surface conditioners can be used alone or in combination of two or more. When a surface modifier is used, the content (solid content) of the surface modifier in the organic solvent-based bright coating composition of the present invention is determined from the viewpoint of the finished appearance of the coating film to be formed. It is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the solid content of the coating composition.

Examples of pigments other than the bright pigment (D) include coloring pigments and extender pigments. The pigments may be used alone or in combination of two or more. Examples of the coloring pigment include titanium oxide, zinc oxide, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, threne pigments, and perylene pigments. , dioxazine-based pigments, diketopyrrolopyrrole-based pigments, and the like. Examples of the extender pigment include clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, and alumina white.

As the ultraviolet absorber, conventionally known ones can be used, and examples include ultraviolet absorbers such as benzotriazole-based absorbers, triazine-based absorbers, salicylic acid derivative-based absorbers, and benzophenone-based absorbers. can. These can be used alone or in combination of two or more.

When the organic solvent glitter coating composition of the present invention contains an ultraviolet absorber, the amount of the ultraviolet absorber is usually 0.1 to 0.1 based on the total solid content in the organic solvent glitter paint composition. It is preferably in the range of 10% by weight, especially 0.2 to 5% by weight, more especially 0.3 to 2% by weight.

As the light stabilizer, conventionally known ones can be used, and examples thereof include hindered amine light stabilizers.

As the hindered amine light stabilizer, a hindered amine light stabilizer with low basicity can be preferably used from the viewpoint of pot life. Examples of such hindered amine light stabilizers include acylated hindered amines and amino ether hindered amines. , manufactured by BASF) and the like.

Method for forming a multilayer coating film The method for forming a multilayer coating film of the present invention comprises:
Step (1): A step of applying the colored paint (X) onto the object to be coated to form a colored coating film;
Step (2): A step of applying the organic solvent-based bright coating composition of the present invention onto the colored coating film to form a bright coating film;
Step (3): A step of applying a clear paint (Z) on the glitter coating film to form a clear coating film, and
Step (4): Separately or It is a method for forming a multi-layer coating film including a step of curing by heating at the same time.

Objects to be coated The above-mentioned objects to be coated are not particularly limited. An outer plate part etc. can be mentioned. Among these, outer plate portions of automobile bodies and automobile parts are preferred.

The material of these objects to be coated is not particularly limited. For example, metal materials such as iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel, zinc alloy (Zn-Al, Zn-Ni, Zn-Fe, etc.) plated steel; polyethylene resin, polypropylene resin, acrylonitrile- Resins such as butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin, plastic materials such as various FRP; inorganic materials such as glass, cement, concrete; wood ; fibrous materials such as paper and cloth; Among these, metal materials and plastic materials are preferred.

Examples of the metal materials include iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel and zinc alloy (eg, Zn-Al, Zn-Ni and Zn-Fe) plated steel.

The above metal material may be subjected to surface treatment such as phosphate treatment, chromate treatment, and composite oxide treatment, and may be further coated with an undercoat paint film thereon. may Examples of the undercoat paint include electrodeposition paints, among which cationic electrodeposition paints are preferred.

As the plastic material, for example, polyolefin obtained by (co)polymerizing one or more of olefins having 2 to 10 carbon atoms such as ethylene, propylene, butylene, hexene, etc. is particularly suitable. Polycarbonate, ABS resin, urethane resin, polyamide and the like are also mentioned.

The plastic material may have a primer coating film formed on its surface with a primer coating.

Colored paint (X)
As the coloring paint (X), specifically, a thermosetting paint known per se containing a base resin, a cross-linking agent, a pigment, and a solvent such as an organic solvent and/or water as main components can be used. Examples of the thermosetting coating include intermediate coating and base coating.

Examples of the base resin used in the colored paint (X) include thermosetting resins and room-temperature-setting resins. is desirable.
As the base resin, a resin having good weather resistance, transparency, and the like is suitable, and specific examples include acrylic resin, polyester resin, epoxy resin, urethane resin, and the like.
Examples of the acrylic resin include α,β-ethylenically unsaturated carboxylic acids, hydroxyl groups, amide groups, methylol groups, (meth)acrylic acid esters having functional groups such as epoxy groups, and other (meth)acrylic acids. Examples thereof include resins obtained by copolymerizing esters, styrene, and the like.
Examples of polyester resins include polyhydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride, hexahydro A polyester resin or the like obtained by a condensation reaction with a polyvalent carboxylic acid component such as phthalic anhydride and trimellitic anhydride can be used.

Examples of epoxy resins include so-called bisphenol A type epoxy resins produced by a condensation reaction of bisphenol A and epichlorohydrin.
Examples of the urethane resin include compounds obtained by an addition reaction of a diisocyanate compound and a polyhydric alcohol, and those obtained by reacting a diisocyanate compound with the above acrylic resin, polyester resin or epoxy resin to increase the molecular weight.
The colored paint (X) may be either a water-based paint or a solvent-based paint. When the colored paint (X) is a water-based paint, the base resin contains a sufficient amount of hydrophilic groups, such as carboxyl groups, hydroxyl groups, methylol groups, amino groups, sulfonic acid groups, to make the resin water-soluble or water-dispersible. To make the base resin water-soluble or water-dispersible by using a resin containing a group, polyoxyethylene bond or the like, most commonly a carboxyl group, and neutralizing the hydrophilic group to an alkali salt. can be done. At that time, the amount of the hydrophilic group, for example, the carboxyl group is not particularly limited, and can be arbitrarily selected according to the degree of water-solubilization or water-dispersibility. g or more, preferably in the range of 30 to 200 mgKOH/g. Examples of alkaline substances used for neutralization include sodium hydroxide and amine compounds.

The cross-linking agent is for cross-linking and curing the base resin by heating, and the one exemplified as the cross-linking agent (A2) in the explanation column of the organic solvent-type bright coating composition of the present invention can be used. can be done.

The ratio of each of the above components in the colored paint (X) can be arbitrarily selected as necessary, but from the viewpoint of water resistance, finishing properties, etc., the base resin and the cross-linking agent are generally Based on the total weight, it is preferred that the former be in the range of 60-90% by weight, especially 70-85% by weight, and the latter be in the range of 10-40% by weight, especially 15-30% by weight.

The pigment imparts color and base-hiding properties to the colored coating film formed from the colored paint (X). The type and/or the blending amount of the pigment can be appropriately adjusted according to the hue or brightness required for the multilayer coating film. For example, by adjusting the type and / or blending amount of the pigment, the lightness L ^* value of the coating film obtained by the colored paint (X) is 0.1 to 90, preferably 10 to 90, more preferably 30 to It can be adjusted to be within the range of 90. Examples of the pigment include metallic pigments, antirust pigments, coloring pigments, extender pigments, etc. Among them, coloring pigments are preferably used. The type and/or blending amount of the pigment in the colored paint (X) is preferably adjusted so that the L ^* of the colored coating film falls within the above range.

The cured film thickness of the colored coating film obtained by the colored coating material (X) is preferably 3 μm to 50 μm, more preferably 5 to 5 μm, from the viewpoint of the hiding property of the base and the pearly or metallic luster of the multilayer coating film. 45 μm, more preferably 8 to 40 μm.

Application of the colored paint (X) can be carried out according to a conventional method, by adding deionized water and/or an organic solvent to the colored paint (X) and, if necessary, additives such as a thickener and an antifoaming agent. After adjusting the solid content to about 30 to 70% by mass and the viscosity to 500 to 6000 cps/6 rpm (Brookfield viscometer), the surface of the article to be coated can be spray-coated, rotary-atomized coating, or the like. During coating, static electricity can be applied as necessary.
From the viewpoint of color stability, etc., the colored paint (X) preferably has a black and white hiding film thickness of 80 μm or less, more preferably 10 to 60 μm, and still more preferably 15 to 50 μm. As used herein, the term "black-and-white hiding film thickness" refers to a black-and-white checkered hiding rate test paper specified in 4.1.2 of JIS K5600-4-1. After drying or curing, visually observe the painted surface under diffuse daylight and check the black and white border of the checkerboard pattern on the hiding rate test paper. It is a value obtained by measuring the film thickness with an electromagnetic film thickness meter.

When the organic solvent-based bright coating composition of the present invention is applied onto an uncured colored coating film of the colored coating material (X), the colored coating material (X) is applied and allowed to stand at room temperature for 2 to 10 minutes. Alternatively, after heating at a temperature of 35 to 100° C. for 30 seconds to 10 minutes, the organic solvent type luster coating composition of the present invention can be applied.

When curing a colored coating film, the heating temperature is preferably 60 to 180°C, particularly preferably 70 to 160°C. The heat treatment time is preferably 10 to 60 minutes, particularly preferably 15 to 50 minutes.

Coating of Organic Solvent-Type Luster Coating Composition The organic solvent-type luster coating composition of the present invention can be applied by methods such as electrostatic coating, air spray, and airless spray. These coating methods may include electrostatic application, if desired.

The dry film thickness of the glitter coating film is preferably 0.025 to 5 µm, more preferably 0.15 to 3 µm.

After applying the organic solvent-type bright paint composition, it may be allowed to stand at room temperature for 2 to 15 minutes, or heated at a temperature of 50 to 100° C. for 30 seconds to 10 minutes, and then the clear paint (Z) may be applied. can.

Clear paint (Z)
Any known thermosetting clear coating composition can be used as the clear coating (Z). The thermosetting clear coating composition includes, for example, an organic solvent type thermosetting coating composition containing a base resin having a crosslinkable functional group and a curing agent, a water-based thermosetting coating composition, and a powder thermosetting coating composition. A paint composition etc. can be mentioned.

Examples of crosslinkable functional groups possessed by the base resin include carboxyl groups, hydroxyl groups, epoxy groups, and silanol groups. Examples of types of base resins include acrylic resins, polyester resins, alkyd resins, urethane resins, epoxy resins, and fluorine resins. Examples of curing agents include polyisocyanate compounds, blocked polyisocyanate compounds, melamine resins, urea resins, carboxyl group-containing compounds, carboxyl group-containing resins, epoxy group-containing resins, and epoxy group-containing compounds.

Combinations of base resin/curing agent for clear paint (Z) include carboxyl group-containing resin/epoxy group-containing resin, hydroxyl group-containing resin/polyisocyanate compound, hydroxyl group-containing resin/blocked polyisocyanate compound, and hydroxyl group-containing resin/melamine resin. etc. are preferred.

Further, the clear paint (Z) may be a one-component paint or a multi-component paint such as a two-component paint.

Among them, the clear paint (Z) is preferably a two-component clear paint containing the following hydroxyl group-containing resin and polyisocyanate compound from the viewpoint of adhesion of the resulting coating film.

As the hydroxyl group-containing resin, those exemplified as the hydroxyl group-containing resin (A1) in the description of the organic solvent-type bright coating composition of the present invention can be used.

As the polyisocyanate compound, those exemplified as the polyisocyanate compound (A2-1) in the description of the organic solvent-type bright coating composition of the present invention can be used.

When a two-component clear paint containing a hydroxyl group-containing resin and a polyisocyanate compound is used as the clear paint (Z), it is preferable that the hydroxyl group-containing resin and the polyisocyanate compound are separated from the viewpoint of storage stability. Preferably, both are mixed and adjusted just before use.

A one-component paint may be used as the clear paint (Z). Combinations of the base resin/curing agent in the one-component paint include carboxyl group-containing resin/epoxy group-containing resin, hydroxyl group-containing resin/blocked polyisocyanate compound, and hydroxyl group-containing resin/melamine resin.

The clear paint (Z) may further contain additives such as water, solvents such as organic solvents, curing catalysts, antifoaming agents, and ultraviolet absorbers as necessary.

A coloring pigment can be appropriately added to the above clear paint (Z) within a range that does not impair the transparency. As the color pigment, conventionally known pigments for inks and paints can be blended singly or in combination of two or more. The amount to be added may be appropriately determined, but it is 30 parts by weight or less, preferably 0.01 to 10 parts by weight, per 100 parts by weight of the vehicle-forming resin composition in the clear paint.

Although the form of the clear paint (Z) is not particularly limited, it is usually used as an organic solvent-type paint composition. As the organic solvent used in this case, various organic solvents for coatings, such as aromatic or aliphatic hydrocarbon solvents, ester solvents, ketone solvents, ether solvents and the like can be used. As the organic solvent to be used, the one used in the preparation of the hydroxyl group-containing resin may be used as it is, or it may be added as appropriate.

The solid content concentration of the clear paint (Z) is preferably about 30-70% by mass, more preferably about 40-60% by mass.

The above-mentioned clear paint (Z) is applied on the glitter coating film. Coating of the clear paint (Z) is not particularly limited and can be carried out in the same manner as the colored paint (X). can do. These coating methods may include electrostatic application, if desired. The coating amount of the clear paint (Z) is generally preferably such that the cured film thickness is about 10 to 50 μm.

In addition, when applying the clear paint (Z), the viscosity of the clear paint (Z) should be adjusted to a viscosity range suitable for the coating method, for example, in rotary atomization coating by electrostatic application, Ford Cup No. 2 at 20°C. 4 It is preferable to adjust the viscosity appropriately using a solvent such as an organic solvent so that the viscosity ranges from about 15 to 60 seconds as measured by a viscometer.

The method of forming a multi-layer coating film of the present invention includes a step of curing by separately or simultaneously heating the colored coating film, the glitter coating film and the clear coating film.

From the viewpoint of shortening the process, it is preferable that the colored coating film, the glitter coating film and the clear coating film are heat-cured at the same time.

The above heating can be performed by known means, for example, a drying furnace such as a hot air furnace, an electric furnace, an infrared induction heating furnace can be applied. The heating temperature is suitably in the range of 60-180°C, preferably 70-160°C. The heating time is not particularly limited, but is preferably 10 to 60 minutes, particularly preferably 20 to 50 minutes.

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

[1] Preparation of coated object A water-based primer paint "Asscalex 3807CD Primer" (trade name, manufactured by Kansai Paint Co., Ltd.) was applied to a degreased black polypropylene plate so that the film thickness was 10 μm based on the cured coating film. and preheated at 40° C. for 5 minutes to form an uncured primer coating film, which was used as an object to be coated.

[2] Production of paint Production of hydroxyl-containing acrylic resin (A1-1) Production Example 1
50 parts of xylene and 20 parts of butyl acetate were charged in a reactor equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a nitrogen inlet tube and a dropping device, and after the temperature was raised to 115° C., 5 parts of styrene and 50 parts of methyl methacrylate were added. , n-butyl acrylate 15.5 parts, 2-hydroxyethyl acrylate 15 parts, "PLAXEL FM3X" (trade name, manufactured by Daicel Chemical Industries, Ltd., 2-hydroxyethyl methacrylate ε-caprolactone 3 mol adduct diluted in xylene, solid A mixture of 20 parts of dimethylaminoethyl methacrylate, 1 part of acrylic acid, 15 parts of xylene and 1.2 parts of 2,2'-azobisisobutyronitrile was added dropwise over 3 hours, After completion of dropping, the mixture was aged for 1 hour. After that, a mixture of 5 parts of xylene and 1.2 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) was added dropwise over 1 hour, and after completion of dropping, the mixture was aged for 1 hour. Further, 10 parts of xylene was added to obtain a hydroxyl group-containing acrylic resin (A1-1-1) solution with a solid content of 50%. The resulting hydroxyl group-containing acrylic resin (A1-1-1) had an acid value of 7.8 mgKOH/g, a hydroxyl value of 69.5 mgKOH/g and a weight average molecular weight of 30,000.

Production of nanocellulose (B2) Production Example 2
After adding 20 g of pulp dry weight of bleached hardwood kraft pulp (LBKP, Oji Holdings Co., Ltd.: 30% moisture content, freeness 600 mLcsf) as a cellulose fiber raw material and 2 L of air into a container, an ozone/oxygen mixed gas with an ozone concentration of 200 g/m3 was added. was added, followed by shaking at 25° C. for 2 minutes and standing for 6 hours, followed by removing the ozone and air in the vessel and performing ozone treatment. This operation was repeated twice, and the cellulose fibers were sufficiently washed/dehydrated with deionized water to obtain ozone-treated cellulose fibers. 200 g of a 0.2% by weight sodium chlorite aqueous solution adjusted to an aqueous solution pH of 4 to 5 with hydrochloric acid was added to the obtained cellulose fibers after ozone treatment (solid concentration: 20% by mass). (equivalent to 3% by mass as sodium chlorite relative to the dry weight) was added and treated at 70°C for 3 hours to obtain carboxy group-containing cellulose fibers. The carboxy group content of the obtained carboxy group-containing cellulose fibers was 0.37 mmol/g. 580 g of acetic anhydride was added to 20 g of the absolute dry weight of this carboxy group-containing cellulose fiber, and the mixture was reacted with stirring at 60° C. for 1 hour and at 115° C. for 3 hours. After cooling, the reaction solution was filtered, washed with methanol and then with water until neutral, and acetylated. The degree of substitution for acetylation was 0.78.

Next, the carboxy group-containing cellulose fibers were dispersed in isopropanol and filtered, and then dispersed in butyl acetate (ester solvent, solubility parameter value 8.7) and filtered, which was performed twice to replace the solvent. Next, cellulose fibers containing carboxy groups were added to butyl acetate so that the content of cellulose fibers containing carboxy groups was 5% by mass, and after pre-dispersion with a homogenizer, beads with a diameter of 0.0. Cellulose fibers were fibrillated by 10 passes at 3 mm and a peripheral speed of 11.4 m/sec to obtain 5% carboxyl group-containing nanocellulose (B2-1). The number average fiber diameter of the obtained cellulose fibers was 40 nm.

Production Example 1 of Organic Solvent Luminous Paint Composition
In a stirring and mixing container, 80 parts of the hydroxyl group-containing acrylic resin (A1-1-1) obtained in Production Example 1 (40 parts of solid content), "Duranate MF-K60X" (trade name, Asahi Kasei Co., Ltd., active methylene of polyisocyanate Adduct product, solid content 60%) 43.3 parts (solid content 26 parts), "Xirallic T61-10 Micro Silver" (trade name, manufactured by Merck Co., Ltd., titanium oxide-coated alumina flake pigment, average particle size 11.8 μm) 30 part (solid content 30 parts), "Disparon UVX-2285" (trade name, manufactured by Kusumoto Kasei Co., Ltd., acrylic silicone surface conditioner, solid content 50% by mass) 3 parts (solid content 1.5 parts), "Industrial Nitrified cotton TR20" (trade name, manufactured by TNC INDUSTRIAL, nitrocellulose propanol wet product, solid content 70%) 2.9 parts (solid content 2 parts), "BYK-410" (trade name, Polyurea-based viscosity modifier manufactured by Big Chemie Co., Ltd., solid content 52% by mass) 1 part (solid content 0.5 part) and butyl acetate are stirred and mixed to form a paint, and an organic solvent type with a solid content of 10% by mass A glitter coating composition (Y-1) was obtained.

Examples 2-13 and Comparative Examples 1-4
Organic solvent-based bright coating compositions (Y-2) to (Y-17) were obtained in the same manner as in Example 1, except that the formulations shown in Table 1 were used. The composition shown in Table 1 is based on the solid mass of each component.

(Note 1) “Xirallic T60-10 Crystal Silver”: trade name, manufactured by Merck, titanium oxide-coated alumina flake pigment, average particle size 18.5 μm,
(Note 2) “TWINCLEPEARL SXA-SO”: trade name, manufactured by Nihon Koken Kogyo Co., Ltd., titanium oxide-coated artificial mica pigment, average particle size 10.7 μm,
(Note 3) "IRIODIN 121 Rutile Luster Satin": Trade name, manufactured by Merck, titanium oxide-coated natural mica pigment, average particle size 9.7 μm,
(Note 4) “Metashine SBE025RS-J5”: trade name, manufactured by Nippon Sheet Glass Co., Ltd., titanium oxide-coated glass flakes, average particle size 25.0 μm.

Sedimentation Stability 500 g of each organic solvent type bright coating composition was placed in a 1 L round can and stored in a constant temperature room at 20° C. for 3 days. After that, the state inside the container was visually observed and evaluated according to the following criteria. ◎ and ○ are accepted.
◎: no sedimentation of the luster pigment is observed,
○: Soft caking and / or separation is observed, but becomes uniform by stirring,
x: Hard caking and/or separation was observed and did not return to the original state.

Circulation Adaptability For each organic solvent type bright coating composition, a 150 μm filter was used to visually confirm the condition of the filter after a three-day circulation test. ◎ and ○ are accepted. The circulation test conditions were sample volume: 4 liters, flow rate: 2 liters/minute, device: DP-10BA manufactured by Yamada Corporation, pipe inner diameter: 8φ, back pressure: 0.4 MPa.
◎: clogging is not observed,
〇: almost no clogging,
x: Remarkable clogging is observed.

Adjustment of colored paint (X) Colored paint (X-1): "Soflex 415H NH883P Color Base" (trade name, manufactured by Kansai Paint Co., Ltd., polyester resin solvent paint) is added with a black pigment paste, and the resulting coating film is prepared. A color paint (X-1) having an L ^* 45 value of 73 was used.

Preparation of clear paint (Z) Clear paint (Z-1): “Soflex 7500 Clear” (product name: Kansai Paint Co., Ltd., hydroxyl/isocyanate group-curable acrylic resin/urethane resin-based two-component organic solvent-based paint) was used as a clear paint (Z-1).

Preparation of test plate Example 14
On the object to be coated prepared in [1] above, the colored paint (X-1) is electrostatically coated using a rotary atomizing bell-type coating machine so that the cured film thickness is 15 μm, and left for 3 minutes. to form an uncured colored coating film.

Next, on the uncured colored coating film, the organic solvent-based bright coating composition (Y-1) prepared in Example 1 was applied using a robot bell manufactured by ABB at a booth temperature of 25 ° C. and a humidity of 70%. was applied so that the film thickness of the dry coating film was 1.0 μm. It was allowed to stand for 7 minutes to form an uncured glitter coating film.

Next, a clear paint (Z-1) is applied to the uncured glitter coating film using a robot bell manufactured by ABB under the conditions of a booth temperature of 25 ° C. and a humidity of 70%. A clear coating film was formed by coating so as to have a thickness of 35 μm. After coating, it was allowed to stand at room temperature for 10 minutes and then heated at 80°C for 30 minutes in a hot air circulating drying oven to simultaneously dry the multi-layer coating film to obtain a test panel.

Here, the film thickness of the dry coating film of the glitter coating film was calculated from the following formula. The same applies to the following examples.
x=sc/sg/S*10000
x: Film thickness [μm]
sc: coating solid content [g]
sg: specific gravity of coating [g/cm ³ ]
S: Evaluation area of solid content [cm ² ]

Examples 15-28 and Comparative Examples 5-8
A test panel was obtained in the same manner as in Example 14, except that the coating and film thickness shown in Table 2 were used.

Evaluation of coating film Each test plate obtained as described above was evaluated for the following items, and the results are shown in Table 2.

Luminance "Y5 value"
Luminance Y value (Y5) in the XYZ color system is calculated based on the spectral reflectance obtained by irradiating the coating film at an angle of 45 degrees and receiving it at an angle of 5 degrees with respect to the specularly reflected light. bottom. For measurement and calculation, a colorimeter "Goniometer GCMS-4 (trade name)" manufactured by Murakami Color Laboratory was used. A larger value indicates a higher brightness. A score of 200 or more is accepted.

Flip-flop value This is a numerical value indicating the magnitude of change in brightness depending on the viewing angle, and was calculated from the following formula. A larger number indicates better metallic luster. A score of 3.0 or higher is accepted.
Flip-flop value = luminance "Y5 value" / brightness L ^* (110°) value (*)
(*) Brightness L ^* (110 °): Brightness L ^* (110 °) value was measured using a multi-angle spectrophotometer “MA-68II” (trade name, manufactured by x-rite) perpendicular to the measurement target surface. Lightness L ^* in the L ^* C ^* h color system is measured for light received at an angle of 45° from the specular reflection angle in the direction of the measurement light. .

Particle feeling "HG value"
Graininess is represented by a Hi-light Graininess value (hereinafter abbreviated as “HG value”). The HG value is one of the scales of micro-brightness, which is the texture when observed microscopically, and represents the graininess on the highlight side (observation of the coating film from the vicinity of specular reflection of incident light). is a parameter. The coating film is imaged with a CCD camera at an incident angle of 15 degrees / a light receiving angle of 0 degrees, and the obtained digital image data, that is, the two-dimensional luminance distribution data is subjected to two-dimensional Fourier transform to obtain the obtained power spectrum image. . Next, from this power spectrum image, the measurement parameters calculated by extracting only the spatial frequency region corresponding to the graininess are further taken as numerical values from 0 to 100, and a linear relationship is maintained between the graininess and the graininess. The HG value is the value obtained by the drastic conversion. The HG value is 0 when there is no graininess of the bright pigment, and 100 when the graininess of the bright pigment is the largest. A score of 65 or less is accepted.

Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications are possible based on the technical concept of the present invention.

Claims

(A) a binder resin, (B) a cellulose-based viscosity modifier, (C) a polyurea-based viscosity modifier, and (D) a glitter organic solvent-based glitter having a solid content of 1 to 20 mass% A coating composition,
The content of the polyurea-based viscosity modifier (C) is in the range of 0.1 to 3 parts by mass based on 100 parts by mass of the solid content of the organic solvent glitter coating composition. paint composition.
The organic solvent-based glitter coating composition according to claim 1, wherein the binder resin (A) contains a hydroxyl group-containing resin (A1) and a cross-linking agent (A2).
The organic solvent-based glitter coating composition according to claim 1 or 2, wherein the cellulose-based viscosity modifier (B) contains nanocellulose (B2).
The organic solvent-based bright paint composition according to any one of claims 1 to 3, wherein the bright pigment (D) contains a light interference pigment (D1).
Step (1): A step of applying the colored paint (X) onto the object to be coated to form a colored coating film;
Step (2): A step of applying the organic solvent-based bright coating composition according to any one of claims 1 to 4 onto the colored coating film to form a bright coating film;
Step (3): A step of applying a clear paint (Z) on the glitter coating film to form a clear coating film, and
Step (4): Separately or A method for forming a multi-layer coating film, comprising a step of curing by heating simultaneously.
The method for forming a multilayer coating film according to claim 5, wherein the dry film thickness of the glitter coating film is in the range of 0.025 to 5 µm.