Brilliant coating material composition, coating film formation method, and multilayer coating film formation method

Abstract

The present disclosure addresses the problem of providing a brilliant coating material composition capable of forming a coating film having excellent brilliancy and suppressed uneven brilliancy.　Said problem is solved by a brilliant coating material composition including a hydroxyl group-containing resin (A), a scaly brilliant pigment (B), and particles (C) having a volume average particle diameter d0 in the range of 0.8-20 μm, wherein the particles (C) are at least one kind of particle selected from inorganic particles (C1) and resin particles (C2), and the brilliant coating material composition is configured to be coated onto an object to be coated by the inkjet method.

Description

Bright paint composition, coating film forming method, and multi-layer coating film forming method

[0001] The present invention relates to a bright coating composition, a coating film forming method, and a multilayer coating film forming method.

[0002] Inkjet coating involves ejecting droplets directly from extremely fine nozzles and depositing them onto the surface to form letters and images. In recent years, this method has come to be used not only in office and home output devices, but also for industrial purposes.

[0003] In the painting of automobile bodies, coating films of optically coherent coating colors such as metallic coating colors, mica coating colors, and pearl coating colors, which have become mainstream in recent years, are usually formed using a topcoat containing a paint containing a glittering pigment to achieve a high glittering effect. A coating film with a high glittering effect is generally one that exhibits a significant change in lightness depending on the angle of observation when the coating film is observed from different angles.

[0004] Furthermore, in coatings for automobile bodies, in addition to a high sense of brilliance, it is required that the brilliance pigment be distributed relatively uniformly throughout the coating film, with almost no unevenness in brilliance being observed.

[0005] Patent Literature 1 describes an inkjet recording method comprising, in this order, an image forming step of ejecting an effect pigment ink onto a recording medium to form an image, a transparent ink applying step of applying a transparent ink onto the recording medium, and a curing step of curing the effect pigment ink and the transparent ink on the recording medium, wherein the method does not include a step of curing the effect pigment ink between the image forming step and the transparent ink applying step, or if it does include a step, the curing rate of the effect pigment ink is 85% or less, the transparent ink contains a polymerization initiator and a polymerizable compound and is substantially free of pigment, and the effect pigment ink contains an effect pigment, a polymerization initiator, and a polymerizable compound, thereby providing an image with excellent metallic feel and excellent abrasion resistance.

[0006] Patent Publication No. 2012-210764

[0007] The technology described in Patent Document 1 provides images with excellent brilliance, but sometimes results in uneven brilliance. An object of the present invention is to provide a brilliance coating composition and a coating film forming method that can form a coating film with excellent brilliance and reduced uneven brilliance.

[0008] As a result of extensive research into achieving the above-mentioned object, the present inventors have found that the above-mentioned object can be achieved by a glittering coating composition comprising a hydroxyl group-containing resin (A), a scaly glittering pigment (B), and particles (C) having a volume average particle size d50 in the range of 0.8 to 20 μm, wherein the particles (C) are at least one type of particle selected from inorganic particles (C1) and resin particles (C2), the glittering coating composition being configured to be applied to a substrate by an inkjet system, and a coating film forming method in which the glittering coating composition is ejected onto the substrate by an inkjet system to form a glittering coating film on the substrate.

[0009] That is, the present invention relates to the following items <1> to <14>.

[0010] <1> A glittering coating composition comprising a hydroxyl-containing resin (A), a scaly glittering pigment (B), and particles (C) having a volume average particle size d50 in the range of 0.8 to 20 μm, wherein the particles (C) are at least one type of particle selected from inorganic particles (C1) and resin particles (C2), the glittering coating composition being adapted to be applied to a substrate by inkjet printing. <2> The glittering coating composition according to <1>, wherein the content of the particles (C) is in the range of 0.5 to 8 parts by mass in terms of solid content, based on 100 parts by mass of the resin solid content in the glittering coating composition. <3> The glittering coating composition according to <1> or <2>, wherein the hydroxyl-containing resin (A) comprises at least one resin selected from a hydroxyl-containing acrylic resin (A1) and a hydroxyl-containing polyester resin (A2). <4> The glittering coating composition according to any one of <1> to <3>, wherein the content of the scaly glittering pigment (B) is within the range of 4 to 45 parts by mass in terms of solid content, based on 100 parts by mass of the resin solid content in the glittering coating composition. <5> The glittering coating composition according to any one of <1> to <4>, wherein the particles (C) comprise the inorganic particles (C1), and the inorganic particles (C1) comprise silica particles (C11). <6> The glittering coating composition according to any one of <1> to <5>, further comprising a curing agent (D). <7> A method for forming a glittering coating film on a substrate by inkjet discharging onto the substrate a glittering coating composition comprising a hydroxyl-containing resin (A), a scaly glittering pigment (B), and particles (C) having a volume average particle size d50 of 0.8 to 20 μm, wherein the particles (C) are at least one type of particle selected from inorganic particles (C1) and resin particles (C2). <8> The method for forming a coating film according to <7>, wherein the content of the particles (C) is within the range of 0.5 to 8 parts by mass in terms of solid content, based on 100 parts by mass of the resin solid content in the glittering coating composition. <9> The method for forming a coating film according to <7> or <8>, wherein the hydroxyl-containing resin (A) comprises at least one resin selected from a hydroxyl-containing acrylic resin (A1) and a hydroxyl-containing polyester resin (A2). <10> The coating film forming method according to any one of <7> to <9>, wherein the content of the scaly luster pigment (B) is within the range of 4 to 45 parts by mass in terms of solid content, based on 100 parts by mass of the resin solid content in the luster coating composition.<11> The method for forming a coating film according to any one of <7> to <10>, wherein the particles (C) comprise the inorganic particles (C1), and the inorganic particles (C1) comprise silica particles (C11). <12> The method for forming a coating film according to any one of <7> to <11>, wherein the glittering coating composition further comprises a curing agent (D). <13> The method for forming a coating film according to any one of <7> to <12>, wherein the glittering coating film has a dry film thickness in the range of 5 to 20 μm. <14> A method for forming a multilayer coating film, comprising: step (1): forming the glittering coating film on the substrate by the method for forming a coating film according to any one of <7> to <13>, and step (2): applying a clear coating composition to the glittering coating film to form a clear coating film.

[0011] According to the present invention, it is possible to provide a glittering coating composition that can form a coating film that has excellent glitter and suppresses glitter unevenness.

[0012] The present invention will be described in detail below, but these are examples of preferred embodiments, and the present invention is not limited to these details.

[0013] [Glittering Coating Composition] The glittering coating composition of the present invention is a glittering coating composition comprising a hydroxyl group-containing resin (A), a scaly glittering pigment (B), and particles (C) having a volume average particle size d50 in the range of 0.8 to 20 μm.

[0014] [Hydroxyl-containing resin (A)] The hydroxyl-containing resin (A) is a resin having at least one hydroxyl group per molecule. Examples of the hydroxyl-containing resin (A) include hydroxyl-containing acrylic resin (A1), hydroxyl-containing polyester resin (A2), hydroxyl-containing polyurethane resin, hydroxyl-containing acrylic-modified polyester resin, hydroxyl-containing polyether resin, hydroxyl-containing polycarbonate resin, hydroxyl-containing epoxy resin, and hydroxyl-containing alkyd resin. These can be used alone or in combination of two or more.

[0015] The hydroxyl-containing resin (A) may contain hydroxyl-containing resin particles, provided that in the present invention, hydroxyl-containing resin particles having a volume average particle size d50 in the range of 0.8 to 20 μm are not included in the hydroxyl-containing resin (A) but are included in the particles (C).

[0016] From the viewpoint of the weather resistance of the coating film to be formed, the hydroxyl value of the hydroxyl-containing resin (A) is preferably in the range of 1 to 200 mgKOH / g, more preferably in the range of 2 to 180 mgKOH / g, and even more preferably in the range of 5 to 170 mgKOH / g.

[0017] From the viewpoint of the brightness and brightness unevenness of the coating film to be formed, the content of the hydroxyl group-containing resin (A) in the bright coating composition of this embodiment is preferably in the range of 20 to 90 mass %, more preferably in the range of 25 to 87 mass %, and even more preferably in the range of 30 to 85 mass %, based on the total resin solid content in the bright coating composition.

[0018] In this specification, the term "solid content" refers to non-volatile components such as resins, curing agents, and pigments that remain after drying for 1 hour at 110° C. The solid content can be determined, for example, by weighing a sample into a heat-resistant container such as an aluminum foil cup, spreading the sample on the bottom of the container, drying it for 1 hour at 110° C., and weighing the mass of the components remaining after drying.

[0019] In addition, in this specification, the "solid content concentration" means the mass ratio of the solid content in the composition. Therefore, for example, the solid content concentration of the composition can be calculated by weighing out the composition into a heat-resistant container such as an aluminum foil cup, spreading the composition on the bottom of the container, drying it at 110°C for 1 hour, weighing the mass of the components in the composition remaining after drying, and determining the ratio of the mass of the components remaining after drying to the total mass of the composition before drying.

[0020] From the viewpoint of the brightness and brightness unevenness of the coating film to be formed, the hydroxyl group-containing resin (A) preferably contains at least one resin selected from the group consisting of a hydroxyl group-containing acrylic resin (A1) and a hydroxyl group-containing polyester resin (A2).

[0021] Hydroxyl-containing acrylic resin (A1) The hydroxyl-containing acrylic resin (A1) can usually be produced by copolymerizing a hydroxyl-containing polymerizable unsaturated monomer (a) and another polymerizable unsaturated monomer (b) copolymerizable with the hydroxyl-containing polymerizable unsaturated monomer (a) by a method known per se, such as solution polymerization in an organic solvent or emulsion polymerization in an aqueous medium.

[0022] The hydroxyl group-containing polymerizable unsaturated monomer (a) is a compound having at least one hydroxyl group and one polymerizable unsaturated group per molecule, and examples thereof include monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; ε-caprolactone-modified products of these monoesters; N-hydroxymethyl (meth)acrylamide; allyl alcohol; and (meth)acrylates having a polyoxyethylene chain having a hydroxyl group at the molecular terminal.

[0023] However, in this embodiment, a monomer corresponding to the polymerizable unsaturated monomer having an ultraviolet-absorbing functional group (xvii) described later should be defined as the other polymerizable unsaturated monomer (b) copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer (a), and is excluded from the hydroxyl group-containing polymerizable unsaturated monomer (a). The hydroxyl group-containing polymerizable unsaturated monomer (a) can be used alone or in combination of two or more kinds.

[0024] In this specification, the term "polymerizable unsaturated group" refers to an unsaturated group that can undergo radical polymerization, such as a vinyl group, a (meth)acryloyl group, a (meth)acrylamide group, a vinyl ether group, an allyl group, a propenyl group, an isopropenyl group, or a maleimide group.

[0025] In this specification, "(meth)acrylate" means acrylate or methacrylate, "(meth)acrylic acid" means acrylic acid or methacrylic acid, "(meth)acryloyl" means acryloyl or methacryloyl, and "(meth)acrylamide" means acrylamide or methacrylamide.

[0026] The hydroxyl group-containing polymerizable unsaturated monomer (a) and the other copolymerizable polymerizable unsaturated monomer (b) can be appropriately selected and used depending on the properties desired for the hydroxyl group-containing acrylic resin (A1). Specific examples of the monomer (b) include those described in the following (i) to (xix). These can be used alone or in combination of two or more.

[0027] (i) Alkyl or cycloalkyl (meth)acrylates: for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, tricyclodecanyl (meth)acrylate, and the like. (ii) polymerizable unsaturated monomers having an isobornyl group: for example, isobornyl(meth)acrylate, etc. (iii) polymerizable unsaturated monomers having an adamantyl group: for example, adamantyl(meth)acrylate, etc. (iv) polymerizable unsaturated monomers having a tricyclodecenyl group: for example, tricyclodecenyl(meth)acrylate, etc. (v) aromatic ring-containing polymerizable unsaturated monomers: for example, benzyl(meth)acrylate, styrene, α-methylstyrene, vinyltoluene, etc.

[0028] (vi) Polymerizable unsaturated monomers having an alkoxysilyl group: for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, etc. (vii) Polymerizable unsaturated monomers having a fluorinated alkyl group: for example, perfluoroalkyl (meth)acrylates such as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl (meth)acrylate; fluoroolefins, etc. (viii) Polymerizable unsaturated monomers having a photopolymerizable functional group such as a maleimide group. (ix) Vinyl compounds: for example, N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate, etc. (x) Carboxyl group-containing polymerizable unsaturated monomers: for example, (meth)acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, etc.

[0029] (xi) Nitrogen-containing polymerizable unsaturated monomers: for example, (meth)acrylonitrile, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide, methylenebis(meth)acrylamide, ethylenebis(meth)acrylamide, 2-(methacryloyloxy)ethyltrimethylammonium chloride, adducts of glycidyl (meth)acrylate and amines, etc. (xii) Polymerizable unsaturated monomers having two or more polymerizable unsaturated groups in one molecule: for example, allyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, etc. (xiii) Epoxy group-containing polymerizable unsaturated monomers: for example, glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl (meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate, allyl glycidyl ether, etc. (xiv) (meth)acrylates having a polyoxyethylene chain having an alkoxy group at the molecular terminal. (xv) Sulfonic acid group-containing polymerizable unsaturated monomers: for example, 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth)acrylate, allylsulfonic acid, 4-styrenesulfonic acid, etc.; sodium salts and ammonium salts of these sulfonic acids, etc.

[0030] (xvi) Polymerizable unsaturated monomers having a phosphate group: acid phosphooxyethyl (meth)acrylate, acid phosphooxypropyl (meth)acrylate, acid phosphooxypoly(oxyethylene)glycol (meth)acrylate, acid phosphooxypoly(oxypropylene)glycol (meth)acrylate, etc. (xvii) Polymerizable unsaturated monomers having an ultraviolet absorbing functional group: for example, 2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone, 2-hydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone, 2,2'-dihydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone, 2,2'-dihydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone, 2-(2'-hydroxy-5'-methacryloyloxyethylphenyl)-2H-benzotriazole, etc. (xviii) Light-stable polymerizable unsaturated monomers: for example, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6 ,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, etc. (xix) Polymerizable unsaturated monomers having a carbonyl group: for example, acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), etc.

[0031] The hydroxyl group-containing acrylic resin (A1) can also be used in combination with a so-called urethane-modified acrylic resin, which is obtained by subjecting some of the hydroxyl groups in the resin to a urethane reaction with a polyisocyanate compound to elongate and increase the molecular weight.

[0032] From the viewpoint of the weather resistance of the coating film to be formed, the amount of the hydroxyl group-containing polymerizable unsaturated monomer (a) is preferably in the range of 1 to 50 mass %, more preferably in the range of 2 to 40 mass %, and even more preferably in the range of 3 to 30 mass %, based on the total amount of the hydroxyl group-containing polymerizable unsaturated monomer (a) and the other copolymerizable polymerizable unsaturated monomer (b), in view of the weather resistance of the coating film to be formed.

[0033] From the viewpoint of the weather resistance of the coating film to be formed, the hydroxyl value of the hydroxyl-containing acrylic resin (A1) is preferably in the range of 1 to 200 mgKOH / g, more preferably in the range of 2 to 150 mgKOH / g, and even more preferably in the range of 5 to 100 mgKOH / g.

[0034] The acid value of the hydroxyl group-containing acrylic resin (A1) is preferably in the range of 1 to 200 mgKOH / g, more preferably in the range of 2 to 150 mgKOH / g, and even more preferably in the range of 5 to 80 mgKOH / g, from the viewpoints of the brightness and brightness unevenness of the coating film to be formed.

[0035] The weight average molecular weight of the hydroxyl group-containing acrylic resin (A1) is preferably in the range of 2,000 to 5,000,000, more preferably in the range of 4,000 to 1,000,000, and even more preferably in the range of 8,000 to 500,000, from the viewpoints of the brightness and brightness unevenness of the coating film to be formed.

[0036] In this specification, the number average molecular weight and weight average molecular weight are values ​​obtained by converting the retention time (retention volume) measured using gel permeation chromatography (GPC) into the molecular weight of polystyrene based on the retention time (retention volume) of a standard polystyrene of known molecular weight measured under the same conditions. Specifically, the gel permeation chromatography apparatus used was "HLC-8120GPC" (trade name, manufactured by Tosoh Corporation), and four columns, "TSKgel G4000HXL," "TSKgel G3000HXL," "TSKgel G2500HXL," and "TSKgel G2000HXL" (trade names, all manufactured by Tosoh Corporation), and a differential refractometer was used as the detector. The mobile phase was tetrahydrofuran, the measurement temperature was 40°C, and the flow rate was 1 mL / min.

[0037] From the viewpoint of the weather resistance of the coating film to be formed, the glass transition temperature (Tg) of the hydroxyl group-containing acrylic resin (A1) is preferably within the range of −60 to 80° C., more preferably within the range of −50 to 70° C., and even more preferably within the range of −40 to 60° C.

[0038] In this specification, the glass transition temperature (Tg) of the hydroxyl group-containing acrylic resin is a value calculated by the following formula: 1 / Tg(K)=W1 / T1+W2 / T2+...Wn / Tn Tg(°C)=Tg(K)-273 In the formula, W1, W2,...Wn are the mass fractions of each monomer, and T1, T2,...Tn are the glass transition temperatures Tg(K) of the homopolymers of each monomer.

[0039] The glass transition temperature of the homopolymer of each monomer is a value according to POLYMER HANDBOOK Fourth Edition, edited by J. Brandrup, E. h. Immergut, and E. A. Grulke (1999). The glass transition temperature of a monomer not described in the document is the static glass transition temperature when a homopolymer of the monomer is synthesized so as to have a weight-average molecular weight of about 50,000.

[0040] When the hydroxyl group-containing compound (A) contains the hydroxyl group-containing acrylic resin (A1), the content of the hydroxyl group-containing acrylic resin (A1) is preferably in the range of 5 to 100 mass %, more preferably in the range of 10 to 75 mass %, and even more preferably in the range of 15 to 70 mass %, based on the total solid content of the hydroxyl group-containing compound (A), from the viewpoints of the brightness and brightness unevenness of the coating film to be formed.

[0041] Hydroxyl Group-Containing Polyester Resin (A2) The hydroxyl group-containing polyester resin (A2) can be obtained, for example, by using a polyol having two or more hydroxyl groups as the alcohol component and a polycarboxylic acid having two or more carboxyl groups as the acid component, and condensing the alcohol component and the acid component.

[0042] The polyol may be a polyhydric alcohol having two or more hydroxyl groups in one molecule, such as ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,2-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-4,3-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, tricyclohexane Examples of the polyol include dihydric alcohols such as rodecanedimethanol, hydroxypivalic acid neopentyl glycol ester, hydrogenated bisphenol A, hydrogenated bisphenol F, and dimethylolpropionic acid; polylactone diols obtained by adding a lactone compound such as ε-caprolactone to these dihydric alcohols; ester diol compounds such as bis(hydroxyethyl)terephthalate; polyether diol compounds such as alkylene oxide adducts of bisphenol A, polyethylene glycol, polypropylene glycol, and polybutylene glycol; trihydric or higher alcohols such as glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol, tris(2-hydroxyethyl)isocyanuric acid, sorbitol, and mannite; polylactone polyol compounds obtained by adding a lactone compound such as ε-caprolactone to these trihydric or higher alcohols; and fatty acid esters of glycerin.

[0043] Alcohol components other than the above polyols can also be used, and examples of such alcohol components include, but are not limited to, monoalcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, stearyl alcohol, and 2-phenoxyethanol; and alcohol compounds obtained by reacting a monoepoxy compound such as propylene oxide, butylene oxide, or "Cardura E10" (trade name, manufactured by HEXION, a glycidyl ester of synthetic highly branched saturated fatty acid) with an acid.

[0044] The polycarboxylic acid may be a compound that is commonly used in the production of polyester resins, such as an aliphatic polybasic acid, an alicyclic polybasic acid, or an aromatic polybasic acid.

[0045] The aliphatic polybasic acid is generally an aliphatic compound having two or more carboxyl groups per molecule, an acid anhydride of the aliphatic compound, or an ester of the aliphatic compound. Examples of the aliphatic polybasic acid include aliphatic polycarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, octadecanedioic acid, citric acid, and butanetetracarboxylic acid; anhydrides of the aliphatic polycarboxylic acids; and lower alkyl esters of the aliphatic polycarboxylic acids having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms. The aliphatic polybasic acids can be used alone or in combination of two or more.

[0046] The alicyclic polybasic acids are generally compounds having one or more alicyclic structures and two or more carboxyl groups per molecule, acid anhydrides of such compounds, and esterified products of such compounds. The alicyclic structures can be primarily 4- to 6-membered ring structures. Examples of alicyclic polybasic acids include alicyclic polycarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 1,3,5-cyclohexanetricarboxylic acid; anhydrides of such alicyclic polycarboxylic acids; and lower alkyl esters of such alicyclic polycarboxylic acids having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms. The alicyclic polybasic acids can be used alone or in combination of two or more.

[0047] The aromatic polybasic acid is generally an aromatic compound having two or more carboxyl groups per molecule, an acid anhydride of the aromatic compound, or an ester of the aromatic compound. Examples of the aromatic polybasic acid include aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, trimellitic acid, and pyromellitic acid; anhydrides of the aromatic polycarboxylic acids; and lower alkyl esters of the aromatic polycarboxylic acids having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms. The aromatic polybasic acids can be used alone or in combination of two or more. Phthalic acid, phthalic anhydride, isophthalic acid, trimellitic acid, and trimellitic anhydride are preferred as the aromatic polybasic acid, with trimellitic anhydride being particularly preferred.

[0048] Acid components other than the above-mentioned aliphatic polybasic acids, alicyclic polybasic acids, and aromatic polybasic acids can also be used. Such acid components are not particularly limited, and examples include fatty acids such as coconut oil fatty acids, cottonseed oil fatty acids, hempseed oil fatty acids, rice bran oil fatty acids, fish oil fatty acids, tall oil fatty acids, soybean oil fatty acids, linseed oil fatty acids, tung oil fatty acids, rapeseed oil fatty acids, castor oil fatty acids, dehydrated castor oil fatty acids, and safflower oil fatty acids; monocarboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexanoic acid, and 10-phenyloctadecanoic acid; and hydroxycarboxylic acids such as lactic acid, 3-hydroxybutanoic acid, and 3-hydroxy-4-ethoxybenzoic acid. These acid components can be used alone or in combination of two or more.

[0049] The method for producing the hydroxyl-containing polyester resin (A2) is not particularly limited and can be carried out according to a conventional method. For example, the hydroxyl-containing polyester resin (A2) can be produced by heating the alcohol component and the acid component in a nitrogen stream at about 150 to 250°C for about 5 to 10 hours to cause an esterification reaction or transesterification reaction between the alcohol component and the acid component.

[0050] When the alcohol component and the acid component are subjected to an esterification reaction or transesterification reaction, these components may be added to a reaction vessel all at once, or one or both may be added in several portions. Alternatively, a hydroxyl-containing polyester resin may be first synthesized, and then the resulting hydroxyl-containing polyester resin may be reacted with an acid anhydride to half-esterify it into a carboxyl- and hydroxyl-containing polyester resin. Alternatively, a carboxyl-containing polyester resin may be first synthesized, and then the alcohol component may be added to produce the hydroxyl-containing polyester resin.

[0051] In the esterification or transesterification reaction, a catalyst known per se, such as dibutyltin oxide, antimony trioxide, zinc acetate, manganese acetate, cobalt acetate, calcium acetate, lead acetate, tetrabutyl titanate, or tetraisopropyl titanate, can be used as a catalyst for promoting the reaction.

[0052] The hydroxyl group-containing polyester resin (A2) can be modified with a fatty acid, a monoepoxy compound, a polyisocyanate compound, or the like during or after the production of the resin.

[0053] Examples of the fatty acids include coconut oil fatty acids, cottonseed oil fatty acids, hempseed oil fatty acids, rice bran oil fatty acids, fish oil fatty acids, tall oil fatty acids, soybean oil fatty acids, linseed oil fatty acids, tung oil fatty acids, rapeseed oil fatty acids, castor oil fatty acids, dehydrated castor oil fatty acids, and safflower oil fatty acids. An example of the monoepoxy compound that can be suitably used is "Cardura E10P" (trade name, manufactured by HEXION, glycidyl ester of synthetic highly branched saturated fatty acid).

[0054] As the polyisocyanate compound, the polyisocyanate compounds exemplified below in the polyisocyanate compound section can be used. These can be used alone or in combination of two or more kinds.

[0055] From the viewpoint of the weather resistance of the coating film to be formed, the hydroxyl value of the hydroxyl-containing polyester resin (A2) is preferably in the range of 1 to 200 mgKOH / g, more preferably in the range of 2 to 180 mgKOH / g, and even more preferably in the range of 5 to 170 mgKOH / g.

[0056] The number average molecular weight of the hydroxyl group-containing polyester resin (A2) is preferably in the range of 500 to 50,000, more preferably in the range of 1,000 to 30,000, and even more preferably in the range of 1,200 to 20,000, from the viewpoints of the brightness and brightness unevenness of the coating film to be formed.

[0057] From the viewpoint of the brightness and brightness unevenness of the coating film formed, the glass transition temperature (Tg) of the hydroxyl-containing polyester resin (A2) is preferably within the range of −20° C. to 50° C., more preferably within the range of −10° C. to 40° C., and even more preferably within the range of −5° C. to 35° C. In this specification, the glass transition temperature (Tg) of the hydroxyl-containing polyester resin is measured by differential thermal analysis (DSC) using a differential scanning calorimeter.

[0058] The hydroxyl group-containing polyester resin (A2) preferably contains a carboxyl group from the viewpoint of the brightness and uneven brightness of the coating film to be formed.

[0059] When the hydroxyl group-containing polyester resin (A2) has a carboxyl group, the acid value of the hydroxyl group-containing polyester resin (A2) is preferably in the range of 5 to 150 mgKOH / g, more preferably in the range of 10 to 140 mgKOH / g, and even more preferably in the range of 15 to 120 mgKOH / g, from the viewpoints of the brightness and brightness unevenness of the coating film to be formed.

[0060] When the coating composition of this embodiment contains the above-mentioned hydroxyl group-containing polyester resin (A2), the content of the hydroxyl group-containing polyester resin (A2) is preferably in the range of 1 to 45 mass %, more preferably in the range of 5 to 40 mass %, and even more preferably in the range of 10 to 35 mass %, based on the total solid content of the hydroxyl group-containing compound (A), from the viewpoints of the brightness and uneven brightness of the coating film to be formed.

[0061] Scaly luster pigment (B) Examples of the scaly luster pigment (B) in the luster coating composition of this embodiment include pigments that can impart a luster to the coating film that is formed, such as aluminum flake pigments, vapor-deposited metal flake pigments, and optical interference pigments. One or more of these pigments can be appropriately selected and used depending on the texture required for the resulting coating film.

[0062] The aluminum flake pigment is generally produced by pulverizing and grinding aluminum in a ball mill or attritor mill in the presence of a grinding medium using a grinding aid. 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. The grinding medium used is an aliphatic hydrocarbon such as mineral spirits.

[0063] The above-mentioned aluminum flake pigments can be broadly classified into leafing type and non-leafing type depending on the type of grinding aid. In the glitter coating composition of this embodiment, non-leafing type scaly aluminum pigments are preferred from the viewpoint of the glitter and weather resistance of the coating film formed. As the non-leafing type scaly aluminum pigment, those with no particular surface treatment can be used, but those with a resin-coated surface, those with a silica treatment, and those with a surface treatment using phosphoric acid, molybdic acid, or a silane coupling agent can also be used. Those that have undergone one of the above various surface treatments can be used, but those that have undergone multiple types of treatments can also be used.

[0064] Furthermore, the above-mentioned aluminum flake pigment may be a colored aluminum pigment in which the surface of the aluminum flake pigment is coated with a colored pigment and then further coated with a resin, or in which the surface of the aluminum flake pigment is coated with a metal oxide such as iron oxide.

[0065] The volume average particle size d50 of the aluminum flake pigment is preferably 1 to 100 μm, more preferably 5 to 50 μm, and even more preferably 7 to 30 μm, from the viewpoints of the brightness and brightness unevenness of the coating film to be formed, etc. The thickness of the aluminum flake pigment is preferably 0.01 to 1.0 μm, and more preferably 0.02 to 0.5 μm.

[0066] The vapor-deposited metal flake pigment is obtained by depositing a metal film on a base substrate, peeling off the base substrate, and then pulverizing the vapor-deposited metal film. Examples of the base substrate include a film.

[0067] The metal material is not particularly limited, but examples include aluminum, gold, silver, copper, brass, titanium, chromium, nickel, nickel chromium, stainless steel, etc. Among these, aluminum or chromium is particularly preferred from the viewpoints of availability and ease of handling. In this specification, a vapor-deposited metal flake pigment obtained by vapor-depositing aluminum is referred to as a "vapor-deposited aluminum flake pigment," and a vapor-deposited metal flake pigment obtained by vapor-depositing chromium is referred to as a "vapor-deposited chromium flake pigment."

[0068] The vapor-deposited aluminum flake pigment is preferably surface-treated with silica from the viewpoints of storage stability and the brightness of the coating film formed.

[0069] Examples of commercially available products that can be used as the vapor-deposited aluminum flake pigment include the "METALURE" series (trade name, manufactured by Ecart), the "Hydroshine WS" series (trade name, manufactured by Ecart), the "Decomet" series (trade name, manufactured by Schlenk), and the "Metasheen" series (trade name, manufactured by BASF).

[0070] Examples of commercially available vapor-deposited chrome flake pigments that can be used include the "Metalure Liquid Black" series (trade name, manufactured by Ecart).

[0071] The average thickness of the vapor-deposited metal flake pigment is preferably within the range of 0.01 to 1.0 μm, and more preferably within the range of 0.015 to 0.1 μm.

[0072] The volume average particle size d50 of the vapor-deposited metal flake pigment is preferably in the range of 1 to 50 μm, more preferably in the range of 5 to 20 μm.

[0073] The average particle size referred to here means the median diameter of the volume-based particle size distribution measured by a 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 measurements obtained by observing the cross section of a coating film containing the scaly bright pigment under a microscope and measuring the thickness using image processing software.

[0074] As the optical interference pigment, it is preferable to use an optical interference pigment in which a transparent or translucent substrate is coated with titanium oxide. In this specification, 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.

[0075] The optical interference pigment is a bright pigment in which the surface of a transparent or translucent, scaly substrate, such as mica, artificial mica, glass, iron oxide, aluminum oxide, or various metal oxides, is coated with a metal oxide having a refractive index different from that of the substrate. Examples of such metal oxides include titanium oxide and iron oxide, and optical interference pigments can exhibit a variety of different interference colors depending on the thickness of the metal oxide.

[0076] Specific examples of the light interference pigment include metal oxide-coated mica pigments, metal oxide-coated alumina flake pigments, metal oxide-coated glass flake pigments, and metal oxide-coated silica flake pigments, as shown below.

[0077] The metal oxide-coated mica pigment is a pigment that uses natural or artificial mica as a base material and has the surface of the base material coated with a metal oxide. Natural mica is a scaly base material made by pulverizing mica ore. Artificial mica is synthesized by heating industrial raw materials such as SiO, MgO, AlO, KSiF, and NaSiF to a high temperature of approximately 1500°C, melting the mixture, and then cooling it to crystallize. Compared to natural mica, artificial mica contains fewer impurities and is more uniform in size and thickness. Specific examples of known artificial mica substrates include fluorphlogopite (KMg3AlSi3O10F2), potassium tetrasilicic mica (KMg2.5AlSi4O10F2), sodium tetrasilicic mica (NaMg2.5AlSi4O10F2), Na taeniolite (NaMg2LiSi4O10F2), and LiNa taeniolite (LiMg2LiSi4O10F2).

[0078] The metal oxide-coated alumina flake pigment is a pigment in which alumina flakes are used as a base material and the surface of the base material is coated with a metal oxide. The alumina flakes refer to scaly (thin) aluminum oxide, and are colorless and transparent. The alumina flakes do not necessarily have to be composed solely of aluminum oxide, but may also contain oxides of other metals.

[0079] The metal oxide-coated glass flake pigment is a pigment in which a scaly glass substrate is coated with a metal oxide, and the metal oxide-coated glass flake pigment has a smooth substrate surface, which causes strong light reflection.

[0080] The metal oxide-coated silica flake pigment is a pigment in which scaly silica, which is a base material having a smooth surface and a uniform thickness, is coated with a metal oxide.

[0081] The light interference pigment may be subjected to a surface treatment to improve dispersibility, water resistance, chemical resistance, weather resistance, and the like.

[0082] The volume average particle size d50 of the above-mentioned light interference pigment is preferably in the range of 5 to 30 μm, more preferably in the range of 7 to 20 μm, from the viewpoint of the brightness and brightness unevenness of the coating film to be formed.

[0083] The average thickness of the light interference pigment is preferably in the range of 0.05 to 1.5 μm, more preferably in the range of 0.1 to 1.0 μm, from the viewpoint of the brightness and brightness unevenness of the coating film to be formed.

[0084] The average particle size referred to here means the median diameter of the volume-based particle size distribution measured by a 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 measurements obtained by observing the cross section of a coating film containing the optical interference pigment under a microscope and measuring the thickness using image processing software.

[0085] The average particle size of the scaly luster pigment (B) in the luster coating composition of this embodiment is preferably within the range of 1 to 100 μm, more preferably within the range of 5 to 50 μm, and even more preferably within the range of 7 to 30 μm, from the viewpoints of the luster of the coating film formed and the unevenness of luster, etc. The thickness of the scaly luster pigment (B) is preferably within the range of 0.01 to 1.0 μm, and more preferably within the range of 0.02 to 0.5 μm.

[0086] From the viewpoint of the brightness and brightness unevenness of the coating film formed, the content of the scaly bright pigment (B) in the bright coating composition of this embodiment is preferably within the range of 4 to 45 parts by mass in terms of solid content, more preferably within the range of 6 to 30 parts by mass, and even more preferably within the range of 8 to 15 parts by mass, based on 100 parts by mass of the resin solid content in the bright coating composition.

[0087] Particles (C) The volume average particle size d50 of the particles (C) in the bright coating composition of the present invention is in the range of 0.8 to 20 μm, and the particles (C) are at least one type of particles selected from inorganic particles (C1) and resin particles (C2).

[0088] The volume average particle size d50 can be measured by measuring the volume-based particle size distribution by a laser diffraction scattering method using a submicron particle size distribution measuring device "Microtrac MT3000" (trade name, manufactured by Microtrac Bell Co., Ltd.).

[0089] The volume average particle size d50 of the particles (C) is preferably in the range of 1.0 to 15 μm, more preferably in the range of 2.0 to 10 μm, and even more preferably in the range of 3.0 to 9.0 μm, from the viewpoints of the brightness and brightness unevenness of the coating film to be formed.

[0090] Examples of the inorganic particles (C1) include silica particles (C11), alumina particles, titania particles, zirconia particles, zircon particles, tin oxide particles, magnesia particles, etc. These can be used alone or in combination of two or more.

[0091] However, in the present invention, the scaly luster pigment (B) is not included in the inorganic particles (C1).

[0092] The silica particles (C11) may be untreated particles or may be particles that have been surface-treated with an organic or inorganic compound. Examples of the treatment with an organic compound include polyethylene treatment, polyethylene wax treatment, and hydrophobic surface treatment.

[0093] Commercially available products that can be used as the silica particles (C11) include, for example, the SYLYSIA series ("SYLYSIA350", "SYLYSIA430", "SYLYSIA435", "SYLYSIA436", "SYLYSIA450", "SYLYSIA470", etc.), the SYLOPHOBIC series ("SYLOPHOBIC100", "SYLOPHOBIC200", "SYLOPHOBIC702", "SYLOPHOBIC4004", etc.), the SYLOSPHERE series ("SYLOSPHERE C-1504", "SYLOSPHERE C-1510", etc.) manufactured by Fuji Silysia Chemical Ltd., and the ACEMATT series ("ACEMATT HK125", "ACEMATT HK460, "ACEMATT HK400", "ACEMATT OK412", "ACEMATT K520", "ACEMATT K607", "ACEMATT S100", "ACEMATT 200", "ACEMATT 300", "ACEMATT 600", etc.), Mizusawa Chemical Industries' Mizukasil series ("Mizukasil P-73", "Mizukasil P-526", etc.), Evonik's Carplex series ("Carplex S-8", etc.), Showa Chemical Industry's Radiolite series ("Radiolite 100", "Radiolite 200", etc.), Nippon Shokubai's Seahoster series ("Seahoster KE-E150", "Seahoster KE-P100", "Seahoster KE-P150", "Seahoster KE-P250", "Seahoster KE-S100", "Seahoster KE-S100", "Seahoster KE-S200", "Seahoster KE-S300", "Seahoster KE-S400", "Seahoster KE-S500", "Seahoster KE-S600", "Seahoster KE-S100", "Seahoster KE-S100", "Seahoster KE-S100", "Seahoster KE-S100", "Seahoster KE-S2 ...100", "Seahoster KE-S KE-S150, "Seahoster KE-S250", etc.

[0094] When the particles (C) contain the inorganic particles (C1), it is preferable that the inorganic particles (C1) contain silica particles (C11) from the viewpoints of the brightness, brightness unevenness, weather resistance, etc. of the coating film to be formed.

[0095] The shape of the silica particles (C11) is not particularly limited, and spherical, hollow, porous, rod-like, plate-like, fibrous, or irregularly shaped particles can be used.

[0096] Examples of the resin particles (C2) include PMMA (polymethyl methacrylate) resin particles, acrylic resin particles, MMA-EGDM (ethylene glycol dimethacrylate) copolymer resin particles, nylon resin particles, polytetrafluoroethylene resin particles, polycarbonate resin particles, etc. These can be used alone or in combination of two or more.

[0097] Examples of commercially available products that can be used as the resin particles (C2) include the Techpolymer MBX series manufactured by Sekisui Plastics Co., Ltd. (such as "MBX-5," "MBX-8," "MBX-12," and "MBX-20"); the MX series manufactured by Soken Chemical & Engineering Co., Ltd. (such as "MX-80H3wT," "MX-150," "MX-180TA," "MX-300," "MX-500L," "MX-1000," "MX-1500H," and "MX-2000"); and the Eposter series manufactured by Nippon Shokubai Co., Ltd. (such as "MS," "M05," "L15," "S12," "MV1002," "MV1004," "MV1006," "MV1010," and "MA2003").

[0098] From the viewpoint of the brightness and brightness unevenness of the coating film to be formed, the content of the particles (C) in the glittering coating composition of this embodiment is preferably in the range of 0.5 to 8 parts by mass in terms of solid content, more preferably in the range of 1 to 6 parts by mass, and even more preferably in the range of 1.5 to 5 parts by mass, based on 100 parts by mass of resin solid content in the glittering coating composition.

[0099] Curing agent (D) The bright coating composition of this embodiment preferably contains a curing agent (D) from the viewpoint of the weather resistance of the coating film formed. The curing agent (D) is a compound that can react with the reactive functional groups in the hydroxyl group-containing resin (A) and can form a crosslinked structure by the reaction. The curing agent (D) is preferably a compound that is reactive with hydroxyl groups.

[0100] Specific examples of the curing agent (D) that can be suitably used include amino resins, polyisocyanate compounds, blocked polyisocyanate compounds, etc. Among these, from the viewpoint of the weather resistance of the coating film to be formed, it is preferable that the curing agent contains an amino resin.

[0101] The amino resin usable as the curing agent (D) may be a partially methylolated amino resin or a fully methylolated amino resin obtained by reacting an amino component with an aldehyde component. Examples of the amino component include melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, and dicyandiamide. Examples of the aldehyde component include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde.

[0102] Alternatively, the methylolated amino resins may be partially or completely etherified with an appropriate alcohol, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, or 2-ethylhexanol.

[0103] The amino resin is preferably a melamine resin, for example, an alkyl-etherified melamine resin obtained by partially or completely etherifying the methylol groups of a partially or completely methylolated melamine resin with the above-mentioned alcohol.

[0104] Suitable examples of the alkyl etherified melamine resin include methyl etherified melamine resins obtained by partially or completely etherifying the methylol groups of partially or completely methylolated melamine resins with methyl alcohol; butyl etherified melamine resins obtained by partially or completely etherifying the methylol groups of partially or completely methylolated melamine resins with butyl alcohol; and methyl-butyl mixed etherified melamine resins obtained by partially or completely etherifying the methylol groups of partially or completely methylolated melamine resins with methyl alcohol and butyl alcohol.

[0105] Furthermore, from the viewpoint of the brightness and brightness unevenness of the coating film to be formed, the weight average molecular weight of the melamine resin is preferably in the range of 400 to 6000, more preferably in the range of 500 to 5000, and even more preferably in the range of 500 to 4000.

[0106] The melamine resin may be a commercially available product, such as "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," or "Cymel 1130" (all manufactured by Allnex Japan Co., Ltd.), or "U-BAN 120," "U-BAN 20HS," "U-BAN 20SE60," "U-BAN 2021," "U-BAN 2028," or "U-BAN 28-60" (all manufactured by Mitsui Chemicals, Inc.).

[0107] The above-mentioned melamine resins can be used either alone or in combination of two or more.

[0108] When the glittering coating composition of this embodiment contains the amino resin as the curing agent (D), the content thereof is preferably in the range of 5 to 60 mass %, more preferably in the range of 10 to 50 mass %, and even more preferably in the range of 15 to 45 mass %, based on the total resin solids in the glittering coating composition, from the viewpoints of the glittering feel of the coating film formed and uneven glitter.

[0109] The polyisocyanate compound is a compound having at least two isocyanate groups in one molecule, and examples thereof include an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, an aromatic aliphatic polyisocyanate compound, an aromatic polyisocyanate compound, and derivatives of the polyisocyanate compounds.

[0110] Examples of the aliphatic polyisocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, methyl 2,6-diisocyanatohexanoate (common name: lysine diisocyanate), isocyanate); and aliphatic triisocyanate compounds such as 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.

[0111] 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 (common name: isophorone diisocyanate), 4-methyl-1,3-cyclohexylene diisocyanate (common name: hydrogenated TDI), 2-methyl-1,3-cyclohexylene diisocyanate, Alicyclic diisocyanate compounds such as 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane (common name: hydrogenated xylylene diisocyanate) or mixtures thereof, methylenebis(4,1-cyclohexanediyl)diisocyanate (common name: hydrogenated MDI), and norbornane diisocyanate; 1,3,5-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-isocyanatopropyl)-

[0033] Examples of the alicyclic triisocyanate compounds include alicyclic triisocyanate compounds such as 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, and 6-(2-isocyanatoethyl)-2-isocyanatomethyl-2-(3-isocyanatopropyl)-bicyclo(2.2.1)heptane.

[0112] Examples of the aromatic aliphatic polyisocyanate compound include aromatic aliphatic diisocyanate compounds such as methylenebis(4,1-phenylene)diisocyanate (common name: MDI), 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω,ω'-diisocyanato-1,4-diethylbenzene, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene (common name: tetramethylxylylene diisocyanate) or a mixture thereof; and aromatic aliphatic triisocyanate compounds such as 1,3,5-triisocyanatomethylbenzene.

[0113] Examples of the aromatic polyisocyanate compound include aromatic diisocyanate compounds such as 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, 4,4'-toluidine diisocyanate, and 4,4'-diphenyl ether diisocyanate; aromatic triisocyanate compounds such as triphenylmethane-4,4',4''-triisocyanate, 1,3,5-triisocyanatobenzene, and 2,4,6-triisocyanatotoluene; and aromatic tetraisocyanate compounds such as 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate.

[0114] Furthermore, examples of derivatives of the polyisocyanate compounds include dimers, trimers, biurets, allophanates, uretdione, uretoimine, isocyanurates, oxadiazinetriones, polymethylene polyphenyl polyisocyanates (crude MDI, polymeric MDI), crude TDI, and the like of the above-mentioned polyisocyanate compounds.

[0115] The above polyisocyanate compounds and derivatives thereof may be used alone or in combination of two or more kinds.

[0116] From the viewpoint of the weather resistance of the coating film to be formed, it is preferable to use at least one polyisocyanate compound selected from aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and derivatives thereof, and it is more preferable to use an aliphatic polyisocyanate compound and / or a derivative thereof.

[0117] As the aliphatic polyisocyanate compound and / or its derivative, it is preferable to use an aliphatic diisocyanate compound and / or its isocyanurate, and it is more preferable to use hexamethylene diisocyanate and / or its isocyanurate.

[0118] When the glittering coating composition of this embodiment contains the polyisocyanate compound as the curing agent (D), the content thereof is preferably in the range of 5 to 60 mass %, more preferably in the range of 15 to 50 mass %, and even more preferably in the range of 25 to 45 mass %, based on the total resin solid content in the glittering coating composition, from the viewpoints of the glittering feel of the coating film formed and uneven glitter.

[0119] The blocked polyisocyanate compound that can be used as the curing agent (D) is a compound in which the isocyanate groups of the polyisocyanate compound are blocked with a blocking agent.

[0120] Examples of the blocking agent include phenol-based agents such as phenol, cresol, xylenol, nitrophenol, ethylphenol, hydroxydiphenyl, butylphenol, isopropylphenol, nonylphenol, octylphenol, and methyl hydroxybenzoate; lactam-based agents such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam; aliphatic alcohol-based agents such as methanol, ethanol, propyl alcohol, butyl alcohol, amyl alcohol, and lauryl alcohol; ether-based agents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and methoxymethanol; benzyl alcohol, glycolic acid, methyl glycolate, ethyl glycolate, butyl glycolate, lactic acid, methyl lactate, ethyl lactate, butyl lactate, methylol urea, methylol melamine, diacetone alcohol, 2-hydroxyethyl acrylate ... alcohol-based solvents such as hydroxyethyl methacrylate; oxime-based solvents such as formamide oxime, acetamide oxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, and cyclohexane oxime; active methylene-based solvents such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, and acetylacetone; butyl mercaptan, t-butyl mercaptan, hexyl mercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, and methylthiophenone mercaptans such as acetanilide, acetanisidide, acetotoluide, acrylamide, methacrylamide, acetic amide, stearic acid amide, benzamide, and other acid amides; imides such as succinimide, phthalic acid imide, and maleic acid imide; amines such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, and butylphenylamine; imidazoles such as imidazole and 2-ethylimidazole;Examples of the azole compounds include urea-based compounds such as urea, thiourea, ethyleneurea, ethylenethiourea, and diphenylurea; carbamate ester-based compounds such as N-phenylphenylcarbamate; imine-based compounds such as ethyleneimine and propyleneimine; sulfite-based compounds such as sodium bisulfite and potassium bisulfite; and azole-based compounds. Examples of the azole-based compounds include pyrazole or pyrazole derivatives such as pyrazole, 3,5-dimethylpyrazole, 3-methylpyrazole, 4-benzyl-3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, 4-bromo-3,5-dimethylpyrazole, and 3-methyl-5-phenylpyrazole; imidazole or imidazole derivatives such as imidazole, benzimidazole, 2-methylimidazole, 2-ethylimidazole, and 2-phenylimidazole; and imidazoline derivatives such as 2-methylimidazoline and 2-phenylimidazoline.

[0121] Among these, preferred blocking agents include oxime-based blocking agents, active methylene-based blocking agents, pyrazole, and pyrazole derivatives.

[0122] When blocking (reacting with a blocking agent), a solvent can be added as needed. The solvent used in the blocking reaction is preferably one that is not reactive with isocyanate groups, and examples thereof include ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate, and N-methyl-2-pyrrolidone (NMP).

[0123] When the glittering coating composition of this embodiment contains the blocked polyisocyanate compound as the curing agent (D), the content of the blocked polyisocyanate compound is, from the viewpoint of the glittering feel and glitter unevenness of the coating film to be formed, preferably in the range of 5 to 60 mass %, more preferably in the range of 10 to 50 mass %, and even more preferably in the range of 15 to 45 mass %, based on the total resin solids in the glittering coating composition.

[0124] The curing agents (D) may be used either alone or in combination of two or more.

[0125] Other Components The bright coating composition of this embodiment may further contain, as necessary, a resin (A') other than the hydroxyl group-containing resin (A), a coloring pigment, an extender pigment, an organic solvent, a curing catalyst, a dispersant, an anti-settling agent, an antifoaming agent, a thickener, an ultraviolet absorber, a light stabilizer, a surface conditioner, etc.

[0126] Examples of the resin (A') other than the hydroxyl group-containing resin (A) include hydroxyl group-free acrylic resins, hydroxyl group-free polyester resins, hydroxyl group-free polyurethane resins, hydroxyl group-free acrylic-modified polyester resins, hydroxyl group-free polyether resins, hydroxyl group-free polycarbonate resins, hydroxyl group-free epoxy resins, hydroxyl group-free alkyd resins, etc. These can be used alone or in combination of two or more.

[0127] The resin (A') other than the hydroxyl group-containing resin (A) may contain resin particles that do not contain hydroxyl groups.

[0128] However, in the present invention, resin particles that do not contain hydroxyl groups and have a volume average particle size d50 in the range of 0.8 to 20 μm are not included in the resin (A') other than the hydroxyl group-containing resin (A), but are included in the particles (C).

[0129] Examples of the color pigment include titanium oxide, zinc oxide, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, threne pigments, perylene pigments, dioxazine pigments, diketopyrrolopyrrole pigments, etc. Among these, titanium oxide and carbon black are preferably used.

[0130] When the glitter coating composition of this embodiment contains the above-mentioned coloring pigment, the amount of the coloring pigment blended is preferably in the range of 1 to 180 parts by mass, more preferably in the range of 5 to 150 parts by mass, and even more preferably in the range of 15 to 130 parts by mass, based on 100 parts by mass of the resin solids in the glitter coating composition.

[0131] Examples of the extender pigment include barium sulfate, talc, clay, kaolin, barium carbonate, calcium carbonate, silica, alumina white, etc. From the viewpoints of paint stability and finish quality, barium sulfate and talc are preferably used as the extender pigment.

[0132] When the glitter coating composition of this embodiment contains the above-mentioned extender pigment, the blending amount of the extender pigment is preferably in the range of 1 to 180 parts by mass, more preferably in the range of 5 to 140 parts by mass, and even more preferably in the range of 10 to 120 parts by mass, based on 100 parts by mass of the resin solids in the glitter coating composition.

[0133] Examples of the organic solvent include ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based solvents such as ethyl acetate, butyl acetate, methyl benzoate, ethyl ethoxypropionate, ethyl propionate, and methyl propionate; alcohol-based solvents such as isopropanol, n-butanol, isobutanol, and 2-ethylhexanol; ether-based solvents such as tetrahydrofuran, dioxane, and dimethoxyethane; glycol ether-based solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; aromatic hydrocarbon-based solvents; and aliphatic hydrocarbon-based solvents.

[0134] When used, the bright coating composition of this embodiment can be diluted by adding water and / or an organic solvent, etc., as necessary, to adjust the viscosity to an appropriate level before application.

[0135] The appropriate viscosity varies depending on the coating composition, but for example, the viscosity after 1 minute at 60 rpm measured with a Brookfield viscometer at a temperature of 20°C (sometimes referred to herein as the "B60 value") is preferably in the range of 100 to 3000 mPa·s, more preferably in the range of 300 to 2000 mPa·s, and even more preferably in the range of 500 to 1500 mPa·s, from the viewpoint of the brightness and brightness unevenness of the coating film to be formed. The viscometer used here is "LVDV-I" (trade name, Brookfield, Brookfield viscometer).

[0136] In addition, in the above, the coating solids concentration of the glitter coating composition is preferably in the range of 5 to 70 mass %, more preferably in the range of 10 to 55 mass %, and even more preferably in the range of 15 to 45 mass %, from the viewpoint of the glitter and glitter unevenness of the coating film to be formed.

[0137] Specific examples of the thickener include silica-based fine powder, mineral-based thickeners, barium sulfate fine powder, polyamide (polyamide)-based thickeners such as fatty acid amides, polyamides, acrylamides, long-chain polyaminoamides, aminoamides, and salts thereof (e.g., phosphates), aminoplast-based thickeners such as hydrophobically modified ethoxylate aminoplasts, organic resin fine particle thickeners, diurea-based thickeners, urethane association-type thickeners, polyacrylic acid-based thickeners (also called alkali-swelling thickeners), and cellulose-based thickeners.

[0138] From the viewpoint of the brightness and brightness unevenness of the coating film to be formed, the thickener is preferably a mineral-based viscosity thickener, a polyacrylic acid-based thickener, a cellulose-based thickener, or a urethane association-type thickener, and among these, it is more preferable to include at least one selected from a cellulose-based thickener, a polyacrylic acid-based thickener, and a urethane association-type thickener, and a urethane association-type thickener is particularly preferable. These thickeners can be used alone or in appropriate combination of two or more.

[0139] Examples of the ultraviolet absorber include benzotriazole-based absorbers, triazine-based absorbers, salicylic acid derivative-based absorbers, and benzophenone-based absorbers.

[0140] Examples of the light stabilizer include hindered amine light stabilizers.The glittering coating composition of the present invention is a glittering coating composition that is applied by the inkjet method.

[0141] There are no particular limitations on the type of inkjet coating, and examples include on-demand types (for example, piezo type, thermal type, and valve type), continuous types, and the like.

[0142] Examples of the piezo type liquid ejection head include a piezo jet dispenser, X JET (high viscosity liquid compatible model), manufactured by SSI JAPAN.

[0143] [Coating Film Formation Method] The coating film formation method of this embodiment is a coating film formation method in which a glittering coating film is formed on a substrate by ejecting, by inkjet printing, onto the substrate a glittering coating composition comprising a hydroxyl group-containing resin (A), a scaly glittering pigment (B) and particles (C) having a volume average particle size d50 in the range of 0.8 to 20 μm, wherein the particles (C) are at least one type of particle selected from inorganic particles (C1) and resin particles (C2).

[0144] The material of the substrate is not particularly limited, and examples thereof include metal materials such as iron, aluminum, brass, copper, tinplate, stainless steel, zinc-plated steel, and zinc alloy (Zn-Al, Zn-Ni, Zn-Fe, etc.)-plated steel; resins such as polyethylene resin, polypropylene resin, acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, and epoxy resin; plastic materials such as various fiber-reinforced plastics (FRP); inorganic materials such as glass, cement, and concrete; wood; and fibrous materials such as paper and cloth.

[0145] The surface of the substrate may be a metal surface such as an outer panel of an automobile body, an automobile part, a household electrical appliance, or a metal substrate such as the steel plate that constitutes these, which has been subjected to a surface treatment such as phosphate treatment, chromate treatment, or composite oxide treatment.

[0146] A coating film may be further formed on an object that may or may not have been surface-treated. For example, a surface treatment may be applied to the substrate to be coated as needed, and a primer coating film may be formed thereon, or an intermediate coating film may be formed on the primer coating film, or a topcoat coating film may be formed on the intermediate coating film. For example, when the object to be coated is an automobile body, the primer coating film, intermediate coating film, and topcoat coating film may be formed using known primer coating, intermediate coating, and topcoat coating films that are commonly used in painting automobile bodies.

[0147] The dry film thickness of the glittering coating film formed from the glittering coating composition varies depending on the application of the substrate and is not particularly limited, but from the viewpoint of the glittering feel of the coating film to be formed, it is preferably in the range of 5 to 20 μm, more preferably in the range of 8 to 17 μm, and even more preferably in the range of 10 to 17 μm.

[0148] When the lustrous coating composition is applied by an inkjet method, the distance between the discharge port and the substrate is preferably within the range of 0.1 to 50.0 mm, more preferably within the range of 0.5 to 30.0 mm, and even more preferably within the range of 1.0 to 10.0 mm, from the viewpoint of the lustrous appearance of the coating film formed and uneven lustre.

[0149] The frequency when the above-mentioned glittering coating composition is applied by the inkjet method is preferably in the range of 10 to 10,000 Hz, more preferably in the range of 30 to 5,000 Hz, and even more preferably in the range of 50 to 3,000 Hz, from the viewpoint of the glittering feeling and glitter unevenness of the coating film formed.

[0150] When the above-mentioned glittering coating composition is applied by the inkjet method, the supply pressure of the glittering coating composition is preferably in the range of 0.001 to 10 MPa, more preferably in the range of 0.005 to 5.0 MPa, and even more preferably in the range of 0.01 to 1.0 MPa, from the viewpoint of the glittering feeling and glitter unevenness of the coating film formed.

[0151] When the above-mentioned glittering coating composition is applied by the inkjet method, the scanning speed of the liquid ejection head ejecting the glittering coating composition is preferably within the range of 10 to 1,500 mm / s, more preferably within the range of 50 to 1,000 mm / s, and even more preferably within the range of 100 to 800 mm / s, from the viewpoint of the glittering feeling and glitter unevenness of the coating film to be formed.

[0152] When the above-mentioned glittering coating composition is applied by an inkjet method, the pitch when scanning the liquid ejection head that ejects the glittering coating composition is preferably within the range of 0.001 to 1.0 mm, more preferably within the range of 0.005 to 1.0 mm, and even more preferably within the range of 0.01 to 1.0 mm, from the viewpoint of the glittering feeling and glitter unevenness of the coating film that is formed.

[0153] [Method for forming a multilayer coating film] The glittering coating composition of this embodiment can be suitably used as a glittering coating composition in a method for forming a multilayer coating film, which comprises the following steps (1) and (2): step (1): a step of ejecting the glittering coating composition onto a substrate by an inkjet method to form a glittering coating film on the substrate; and step (2): a step of applying a clear coating composition to the glittering coating film to form a clear coating film.

[0154] The step of forming the above-mentioned glossy coating film is as explained in the section "Coating Film Formation Method." Examples of the above-mentioned clear coating composition include curable clear coating compositions (e.g., thermosetting clear coating compositions, photocurable clear coating compositions) and non-curable clear coating compositions. Examples of the above-mentioned thermosetting clear coating composition include organic solvent-based thermosetting coating compositions containing a base resin having a crosslinkable functional group and a curing agent, aqueous thermosetting coating compositions, powder thermosetting coating compositions, etc.

[0155] Examples of crosslinkable functional groups possessed by the base resin include carboxyl groups, hydroxyl groups, epoxy groups, silanol groups, etc. Types of base resins include acrylic resins, polyester resins, alkyd resins, urethane resins, epoxy resins, fluororesins, etc. 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.

[0156] Preferred combinations of base resin / curing agent for the above clear coating composition include hydroxyl group-containing resin / polyisocyanate compound, carboxyl group-containing resin / epoxy group-containing resin, hydroxyl group-containing resin / blocked polyisocyanate compound, and hydroxyl group-containing resin / melamine resin, with hydroxyl group-containing resin / polyisocyanate compound being more preferred.

[0157] The clear coating composition may be a one-component coating, or may be a multi-component coating such as a two-component urethane resin coating.

[0158] Furthermore, the above-mentioned clear coating composition may contain coloring pigments, luster pigments, dyes, etc., as needed, to the extent that transparency is not impaired, and may further contain extender pigments, ultraviolet absorbers, light stabilizers, antifoaming agents, thickeners, rust inhibitors, surface conditioners, etc., as appropriate.

[0159] The method for applying the clear coating composition is not particularly limited, but a wet coating film can be formed by coating methods such as air spray coating, airless spray coating, rotary atomization coating, curtain coat coating, inkjet coating, and slit nozzle coating. In these coating methods, electrostatic application may be performed as necessary. Of these, air spray coating and rotary atomization coating are particularly preferred. The amount of clear coating composition applied is usually preferably an amount that results in a cured film thickness in the range of 10 to 70 μm, more preferably an amount that results in a cured film thickness in the range of 20 to 50 μm.

[0160] The present invention will be explained in more detail below with reference to Production Examples, Examples, and Comparative Examples. However, the present invention is not limited thereto. In each example, "parts" and "%" are based on mass unless otherwise specified. Furthermore, the film thickness of the coating film is based on the cured coating film.

[0161] Preparation of Hydroxyl Group-Containing Acrylic Resin (A1) Preparation Example 1 A mixed solvent of 27.5 parts of methoxypropanol and 27.5 parts of isobutanol was placed in a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and dropping device and heated to 110°C. 121.5 parts of a mixture consisting of 25.0 parts of styrene, 27.5 parts of n-butyl methacrylate, 20.0 parts of "Isostearyl Acrylate" (trade name, branched higher alkyl acrylate, manufactured by Osaka Organic Chemical Industry Ltd.), 7.5 parts of 4-hydroxybutyl acrylate, 15.0 parts of the phosphoric acid group-containing polymerizable monomer shown below, 12.5 parts of 2-methacryloyloxyethyl acid phosphate, 10.0 parts of isobutanol, and 4.0 parts of t-butyl peroxyoctanoate was added to the mixed solvent over 4 hours, and a mixture of 0.5 parts of t-butyl peroxyoctanoate and 20.0 parts of isopropanol was then added dropwise over 1 hour. The mixture was then stirred and aged for 1 hour to obtain a solution of hydroxyl-containing acrylic resin (A1-1) with a solids content of 50%. The resulting hydroxyl-containing acrylic resin (A1-1) had an acid value of 83 mg KOH / g, a hydroxyl value of 29 mg KOH / g, and a weight-average molecular weight of 10,000.

[0162] Phosphate group-containing polymerizable monomer: 57.5 parts of monobutyl phosphate and 41.0 parts of isobutanol were placed in a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and dropping device, and the mixture was heated to 90°C. 42.5 parts of glycidyl methacrylate was added dropwise over 2 hours, and the mixture was then stirred and aged for an additional 1 hour. Subsequently, 59.0 parts of isopropanol was added to obtain a phosphate group-containing polymerizable monomer solution with a solids concentration of 50%. The acid value of the resulting monomer was 285 mgKOH / g.

[0163] Production Example 2 A reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and dropping device was charged with 130 parts of deionized water and 0.52 parts of "Aqualon KH-10" (trade name, Dai-ichi Kogyo Seiyaku Co., Ltd., emulsifier, active ingredient 97%), and the mixture was stirred and mixed in a nitrogen stream and heated to 80°C. Next, 1% of the total amount of the monomer emulsion (1) shown below and 5.3 parts of a 6% aqueous ammonium persulfate solution were introduced into the reaction vessel and maintained at 80°C for 15 minutes. Thereafter, the remaining monomer emulsion (1) was added dropwise over 3 hours into the reaction vessel maintained at the same temperature, and after completion of the dropwise addition, the mixture was aged for 1 hour. Thereafter, the following monomer emulsion (2) was added dropwise over 1 hour, and after aging for 1 hour, 40 parts of a 5% aqueous dimethylethanolamine solution was gradually added to the reaction vessel while cooling to 30°C, and the mixture was discharged while being filtered through a 100-mesh nylon cloth, yielding a hydroxyl-containing acrylic resin (A1-2) emulsion with a solids concentration of 30%. The obtained hydroxyl-containing acrylic resin (A1-2) emulsion had an acid value of 33 mgKOH / g, a hydroxyl value of 25 mgKOH / g, and a volume average particle size d50 of 100 nm.

[0164] Monomer emulsion (1): 42 parts of deionized water, 0.72 parts of "Aqualon KH-10", 2.1 parts of methylenebisacrylamide, 2.8 parts of styrene, 16.1 parts of methyl methacrylate, 28 parts of ethyl acrylate, and 21 parts of n-butyl acrylate were mixed and stirred to obtain a monomer emulsion (1).

[0165] Monomer emulsion (2): A monomer emulsion (2) was obtained by mixing and stirring 18 parts of deionized water, 0.31 parts of "Aqualon KH-10", 0.03 parts of ammonium persulfate, 5.1 parts of methacrylic acid, 5.1 parts of 2-hydroxyethyl acrylate, 3 parts of styrene, 6 parts of methyl methacrylate, 1.8 parts of ethyl acrylate, and 9 parts of n-butyl acrylate.

[0166] Preparation of Hydroxyl Group-Containing Polyester Resin (A2) Preparation Example 3: 118 parts of 1,6-hexanediol and 102 parts of adipic acid were mixed in a reactor equipped with a thermometer, a stirrer, a heating device, and a rectification column, and a small amount of xylene for reflux was added. The mixture was gradually heated to 250°C and maintained at that temperature for 5 hours to carry out an esterification reaction while dehydrating, yielding a polyester resin. Per 100 parts of the polyester resin, 102.5 parts of ethylene glycol monobutyl ether and 2.5 parts of orthophosphoric acid were added, and the mixture was maintained at 100°C for 3 hours to obtain a polyester resin (A2-1) solution with a solids concentration of 50%. The number average molecular weight of the polyester resin (A2-1) was 4,000.

[0167] Production of a scaly luster pigment dispersion (P) Production Example 4 In a stirring mixing vessel, 17.9 parts (solids content: 12 parts) of aluminum pigment paste "Aluminum Paste 6390NS" (trade name, manufactured by Toyo Aluminum K.K., aluminum flake pigment, solids concentration: 67%), 34.8 parts of 2-ethyl-1-hexanol, 10 parts (solids content: 5 parts) of the hydroxyl group-containing acrylic resin (A-1) solution obtained in Production Example 1, and 0.2 parts of 2-(dimethylamino)ethanol were uniformly mixed to obtain a scaly luster pigment dispersion (P-1).

[0168] Production Examples 5 to 11 Scaly luster pigment dispersions (P-2) to (P-8) were obtained in the same manner as in Production Example 4, except that the blending compositions in Production Example 4 were as shown in the following Table 1. The values ​​shown in Table 1 refer to solid contents.

[0169]

[0170] The components listed in the table are as follows: (Note 1) "GX-180A": Trade name, manufactured by Asahi Kasei Metals Corporation, aluminum flake pigment, solids concentration 74%, (Note 2) "Jetfluid WB 21001": Trade name, manufactured by Eckart, aluminum flake pigment, solids concentration 25%, (Note 3) "TWINCLEPEARL SXC-SO": Trade name, manufactured by Nihon Koken Co., Ltd., artificial mica interference silver pearl, solids concentration 100%.

[0171] Preparation of Glittering Coating Composition Example 1 Into a stirring vessel were added 62.9 parts (17 parts solids) of the scaly glittering pigment dispersion (P-1) obtained in Production Example 4, 116.7 parts (35 parts solids) of the hydroxyl-containing acrylic resin (A1-2) emulsion obtained in Production Example 2, 40 parts (20 parts solids) of the hydroxyl-containing polyester resin (A2-1) obtained in Production Example 3, 3 parts (3 parts solids) of "ACEMATT OK607" (trade name, manufactured by Evonik Corporation, silica particles, volume average particle size (d50) 4.4 μm, solids concentration 100%), 37.5 parts (30 parts solids) of "Cymel 325" (trade name, manufactured by Allnex Corporation, melamine resin, solids concentration 80%), 28.6 parts (10 parts solids) of "U-coat UX-8100" (trade name, manufactured by Sanyo Chemical Industries, Ltd., urethane emulsion, solids concentration 35%), and "Primal 1.8 parts (0.5 parts solids) of ASE-60 (trade name, manufactured by The Dow Chemical Company, polyacrylic acid-based thickener, solids concentration 28%), 2.0 parts (1.0 part solids) of "LHP-96" (trade name, manufactured by Kusumoto Chemicals Co., Ltd., surface conditioner, solids concentration 50%), 1.0 part (1.0 part solids) of "BYK348" (trade name, manufactured by BYK Corporation, silicone-based surface conditioner, solids concentration 100%), and 1.1 parts (1.0 part solids) of "TINUVIN 384-2" (trade name, manufactured by BASF Corporation, benzotriazole-based ultraviolet absorber, solids concentration 95%) were uniformly mixed, and 2-(dimethylamino)ethanol and deionized water were added to obtain lustrous coating composition No. 1 having a pH of 8.0 and a coating solids concentration of 24.5%.

[0172] Examples 2 to 25 and Comparative Examples 1 to 5 Brilliant coating compositions Nos. 1 to 30 were obtained in the same manner as in Example 1, except that the blending compositions in Example 1 were as shown in Table 2 below.

[0173] Unless otherwise specified, the values ​​shown in Table 2 refer to solid contents.

[0174]

[0175]

[0176]

[0177] The components listed in the table are as follows: (Note 4) "Seahoster KE-E150": Trade name, manufactured by Nippon Shokubai Co., Ltd., silica particles, volume average particle size (d50) 1.5 μm, solid content 20%, (Note 5) "ACEMATT HK-125": Trade name, manufactured by Evonik, silica particles, volume average particle size (d50) 11 μm, solid content 100%, (Note 6) "SYLYSIA 470": Trade name, manufactured by Fuji Silysia Chemical Ltd., silica particles, volume average particle size (d50) 14.1 μm, solid content 100%, (Note 7) "MX-80H3wT": Trade name, manufactured by Soken Chemical & Engineering Co., Ltd., crosslinked acrylic particles, volume average particle size (d50) 0.8 μm, solid content 100%, (Note 8) "MBX-5": Trade name, manufactured by Sekisui Plastics Co., Ltd., polymethyl methacrylate particles, volume average particle diameter (d50) 5 μm, solid content 100%, (Note 9) "MBX-8": Trade name, manufactured by Sekisui Plastics Co., Ltd., polymethyl methacrylate particles, volume average particle diameter (d50) 8 μm, solid content 100%, (Note 10) "MBX-12": Trade name, manufactured by Sekisui Plastics Co., Ltd., polymethyl methacrylate particles, volume average particle diameter (d50) 12 μm, solid content 100%, (Note 11) "MBX-20": Trade name, manufactured by Sekisui Plastics Co., Ltd., polymethyl methacrylate particles, volume average particle diameter (d50) 20 μm, solid content 100%, (Note 12) "Sea Horse Star KE-P10": Trade name, manufactured by Nippon Shokubai Co., Ltd., silica particles, volume average particle size (d50) 0.1 μm, solid content 100%, (Note 13) "MBX-30": Trade name, manufactured by Sekisui Plastics Co., Ltd., polymethyl methacrylate particles, volume average particle size (d50) 30 μm, solid content 100%, (Note 14) "Bayhydur VPLS2310": Trade name, manufactured by Sumika Covestro Urethane Co., Ltd., blocked polyisocyanate compound, solid content 38%.

[0178] Preparation of coated test panels Examples 26 to 54, Comparative Examples 6 to 10

[0179] Each of glitter coating compositions No. 1 to No. 30 was filled into an "X JET" (trade name, manufactured by SSI JAPAN, high-viscosity micro-piezo jet dispenser, discharge port diameter 100 μm). Next, each of glitter coating compositions No. 1 to No. 30 was applied to a substrate under conditions of a frequency of 350 Hz, a speed of 230 mm / s, a pitch of 0.4 mm, and a distance of 10 mm between the discharge port and the substrate, with the supply pressure adjusted according to the target dry film thickness, and the coating was heated at 140°C for 30 minutes to crosslink and cure, forming a glitter coating film.

[0180] Next, a clear coating material "Magicron KINO-1210" (trade name, manufactured by Kansai Paint Co., Ltd., an acrylic resin-based solvent-based topcoat clear coating material) was electrostatically applied using a rotary atomizing bell-type coating machine so that the cured film thickness was 35 μm, and the coating material was heated at 140°C for 30 minutes to crosslink and cure, forming a clear coating material, which was used as a coated test panel.

[0181] Evaluation of uneven brightness The test coated panels obtained above were visually observed, and uneven brightness was evaluated according to the following evaluation criteria. A, B, C, and D are acceptable. The evaluation results are shown in Table 3. A: No uneven brightness is observed, B: Uneven brightness is observed but very little, C: Slight uneven brightness is observed, D: Uneven brightness is observed but not a problem in practical use, E: Excessive uneven brightness is observed and is a problem in practical use.

[0182] Evaluation of brilliance The test coated panels obtained above were visually observed and brilliance was evaluated according to the following evaluation criteria. Coatings that did not contain the scaly luster pigment (B) were deemed unrated. A, B, C, and D are acceptable. The evaluation results are shown in Table 3. A: Very large change in lightness depending on the viewing angle; B: Large change in lightness depending on the viewing angle; C: Slightly small change in lightness depending on the viewing angle; D: Small change in lightness depending on the viewing angle; E: Almost no change in lightness depending on the viewing angle.

[0183]

[0184]

Claims

1. A glitter paint composition comprising a hydroxyl group-containing resin (A), a scaly glitter pigment (B), and particles (C) having a volume average particle diameter d50 in the range of 0.8 to 20 μm, wherein the particles (C) are at least one kind of particles selected from inorganic particles (C1) and resin particles (C2), and the glitter paint composition is configured to be applied to an object to be coated by an inkjet method.

2. The glitter paint composition according to claim 1, wherein the content of the particles (C) is in the range of 0.5 to 8 parts by mass in terms of solid content based on 100 parts by mass of the resin solid content in the glitter paint composition.

3. The glitter paint composition according to claim 1 or 2, wherein the hydroxyl group-containing resin (A) contains at least one resin selected from a hydroxyl group-containing acrylic resin (A1) and a hydroxyl group-containing polyester resin (A2).

4. The glitter paint composition according to any one of claims 1 to 3, wherein the content of the scaly glitter pigment (B) is in the range of 4 to 45 parts by mass in terms of solid content based on 100 parts by mass of the resin solid content in the glitter paint composition.

5. The glitter paint composition according to any one of claims 1 to 4, wherein the particles (C) contain the inorganic particles (C1), and the inorganic particles (C1) contain silica particles (C11).

6. The glitter paint composition according to any one of claims 1 to 5, further comprising a curing agent (D).

7. A coating film forming method for forming a glitter coating film on an object to be coated by discharging a glitter paint composition comprising a hydroxyl group-containing resin (A), a scaly glitter pigment (B), and particles (C) having a volume average particle diameter d50 in the range of 0.8 to 20 μm, wherein the particles (C) are at least one kind of particles selected from inorganic particles (C1) and resin particles (C2), onto the object to be coated by an inkjet method.

8. The coating film forming method according to claim 7, wherein the content of the particles (C) is in the range of 0.5 to 8 parts by mass in terms of solid content based on 100 parts by mass of the resin solid content in the glitter paint composition.

9. The coating film forming method according to claim 7 or 8, wherein the hydroxyl group-containing resin (A) contains at least one resin selected from a hydroxyl group-containing acrylic resin (A1) and a hydroxyl group-containing polyester resin (A2).

10. The coating film forming method according to any one of claims 7 to 9, wherein the content of the scaly glitter pigment (B) is in the range of 4 to 45 parts by mass in terms of solid content based on 100 parts by mass of the resin solid content in the glitter paint composition.

11. The coating film forming method according to any one of claims 7 to 10, wherein the particles (C) contain the inorganic particles (C1), and the inorganic particles (C1) contain silica particles (C11).

12. The coating film forming method according to any one of claims 7 to 11, wherein the fluorescent paint composition further contains a curing agent (D).

13. The coating film forming method according to any one of claims 7 to 12, wherein the dry film thickness of the fluorescent coating film is in the range of 5 to 20 μm.

14. Step (1): A step of forming the fluorescent coating film on the object to be coated by the coating film forming method according to any one of claims 7 to 13; Step (2): A step of coating the fluorescent coating film with a clear paint composition to form a clear coating film. A multilayer coating film forming method comprising the steps.

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