Photoluminescent pigment dispersion liquid, photoluminescent coating material composition, and method for forming multilayer coating film

Abstract

Provided is a photoluminescent pigment dispersion liquid which contains a silica-treated aluminum pigment (A) that has an amino group on the surface, and a dispersion resin (B). The dispersion resin (B) is a polymer of a composition which contains a polymerizable unsaturated monomer (b1) that contains a phosphoric acid group and another polymerizable unsaturated monomer (b2), and has a weight average molecular weight within the range of 100,000-500,000.

Description

Luminous pigment dispersion, luminous paint composition, and method for forming a multi-layer coating film.

[0001] The present invention relates to a lustrous pigment dispersion, a lustrous paint composition, and a method for forming a multi-layer coating.

[0002] In recent years, from the perspective of protecting the global environment, there has been a demand to reduce volatile organic compounds (VOCs) released from paints, and the replacement of solvent-based paints with water-based paints is rapidly progressing in various fields.

[0003] On the other hand, the paint film formed by applying paint is required to protect the painted object and also to give it an aesthetically pleasing appearance. Among these, metallic paints are particularly popular because they give off a sense of luxury.

[0004] In metallic paints, for example, in water-based paints for automotive coatings, the use of silica-treated aluminum instead of conventional molybdenum-treated or resin-coated aluminum for the aluminum flakes that act as the glossing agent has improved gas generation suppression and weather resistance.

[0005] However, when thermal or physical loads such as circulation loads are applied, particularly when the paint's pH falls below 8.0, the silica-treated aluminum can sometimes aggregate.

[0006] Patent Document 1 describes an aqueous paint that comprises a synthetic resin emulsion (A) and a metal powder pigment (B) as essential components, wherein the aqueous paint contains 1 to 100 parts by weight of the metal powder pigment (B) per 100 parts by weight of the solid content of the synthetic resin emulsion (A), and the total electrical conductivity of the paint is 3.0 mS / cm or less. This invention provides an aqueous metallic paint that suppresses discoloration and aggregation of the metal powder pigment over time and can form a coating film with excellent metallic luster.

[0007] While the above-mentioned water-based metallic paint exhibits good metallic luster, it sometimes exhibits a problem where the metallic powder pigment aggregates when subjected to thermal or physical loads such as circulation loads.

[0008] Japanese Patent Publication No. 2006-36991

[0009] The present invention aims to provide a glossy pigment dispersion that can be used in the production of a glossy paint composition that is excellent in terms of circulation resistance, gas generation suppression ability, and weather resistance, as well as excellent agglomeration resistance of aluminum pigments.

[0010] The inventors, after diligent research to achieve the above objective, discovered a high correlation between the molecular weight of the dispersion resin for the aluminum pigment and the agglomeration resistance of the aluminum pigment. They found that the above objective can be achieved by a lustrous pigment dispersion containing a silica-treated aluminum pigment (A) having amino groups on its surface and a dispersion resin (B), wherein the dispersion resin (B) is a polymer of a composition containing a polymerizable unsaturated monomer (b1) containing a phosphate group and other polymerizable unsaturated monomers (b2), and the weight-average molecular weight of the resin is in the range of 100,000 to 500,000.

[0011] According to the present invention, a lustrous pigment dispersion, a lustrous paint composition, and a method for forming a multilayer coating film are provided, comprising the following embodiments.

[0012] Item 1. A lustrous pigment dispersion containing a silica-treated aluminum pigment (A) having amino groups on its surface, and a dispersion resin (B), wherein the dispersion resin (B) is a polymer of a composition containing a polymerizable unsaturated monomer (b1) containing phosphate groups and other polymerizable unsaturated monomers (b2), and the weight-average molecular weight of the resin is in the range of 100,000 to 500,000.

[0013] Item 2. The luminous pigment dispersion according to Item 1, wherein the silica-treated aluminum pigment (A) having an amino group on its surface comprises a silica-treated aluminum pigment (A1) having an amino group and an alkyl group on its surface.

[0014] Item 3. The luminous pigment dispersion according to item 1 or 2, wherein the polymerizable unsaturated monomer (b1) containing the phosphate group is at least one selected from the group consisting of acid phosphooxyalkyl (meth)acrylate, mono(hydroxyalkyl (meth)acrylate) phosphate, and acid phosphooxypoly(oxyalkylene) glycol (meth)acrylate.

[0015] Item 4. The luminous pigment dispersion according to item 1 or 2, wherein the other polymerizable unsaturated monomer (b2) comprises a polymerizable unsaturated monomer containing a hydroxyl group.

[0016] Item 5. A luminous pigment dispersion according to item 1 or 2, further comprising a nitrogen-containing compound (C).

[0017] Item 6. A glossy paint composition containing the glossy pigment dispersion and film-forming resin described in Item 1 or 2.

[0018] Item 7. A method for forming a multilayer coating, comprising the following steps (1) to (4): Step (1): Applying a colored coating composition (X) to an object to be coated to form a colored coating film; Step (2): Applying a glossy coating composition (Y) described in Item 6 to the colored coating film obtained in Step (1) to form a glossy coating film; Step (3): Applying a clear coating composition (Z) to the glossy coating film obtained in Step (2) to form a clear coating film; Step (4): Heating the multilayer coating film, which includes the colored coating film, glossy coating film, and clear coating film formed in Steps (1), (2), and (3), respectively, to simultaneously cure the multilayer coating film.

[0019] By using the lustrous pigment dispersion of the present invention, it is possible to produce a lustrous paint composition that is excellent in gas generation suppression, circulation resistance, and weather resistance, as well as excellent agglomeration resistance of aluminum pigments.

[0020] The lustrous pigment dispersion of the present invention will be described in more detail below.

[0021] The present invention relates to a lustrous pigment dispersion, which contains a silica-treated aluminum pigment (A) having amino groups on its surface, and a dispersion resin (B), wherein the dispersion resin (B) is a polymer of a composition containing a polymerizable unsaturated monomer (b1) containing phosphate groups and other polymerizable unsaturated monomers (b2), and the weight-average molecular weight of the resin is in the range of 100,000 to 500,000.

[0022] Silica-treated aluminum pigment (A) having amino groups on its surface A silica-treated aluminum pigment (A) having amino groups on its surface can be produced by reacting an aluminum pigment whose surface has been silica-treated with a silane coupling agent.

[0023] The silica-treated aluminum pigment (A) having amino groups on its surface, because it coats the aluminum substrate with a silica layer, can form a coating film with particularly excellent gas generation suppression ability when used in a glossy paint composition.

[0024] The silica-treated aluminum pigment (A) having amino groups on its surface, when used in a glossy paint composition, preferably has an average particle diameter of 1 μm or more, more preferably 5 μm or more, even more preferably 7 μm or more, preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less, from the viewpoint of obtaining a paint composition with excellent gas generation suppression ability and weather resistance. The average particle diameter referred to here means the median diameter of the volume-based particle size distribution measured by laser diffraction scattering using a Microtrac particle size distribution analyzer MT3300 (product name, manufactured by Nikkiso Co., Ltd.).

[0025] Furthermore, the thickness is preferably 0.01 μm or more, more preferably 0.02 μm or more, preferably 1.0 μm or less, and more preferably 0.5 μm or less. The thickness is defined as the average value of 100 or more measurements obtained by observing a cross-section of the coating film containing the silica-treated aluminum pigment (A) having amino groups on its surface under a microscope and measuring the thickness of the silica-treated aluminum pigment (A) having amino groups on its surface using image processing software.

[0026] From the viewpoint of dispersibility, the silica-treated aluminum pigment (A) having amino groups on its surface preferably includes a silica-treated aluminum pigment (A1) having amino groups and alkyl groups on its surface.

[0027] The silica-treated aluminum pigment (A1) having amino groups and alkyl groups on its surface can be produced by reacting a silane coupling agent with an aluminum pigment whose surface has been silica-treated.

[0028] In the lustrous pigment dispersion of the present invention, the content of silica-treated aluminum pigment (A) having amino groups on its surface is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, and even more preferably 1 to 40 parts by mass, based on 100 parts by mass of solids in the lustrous pigment dispersion, from the viewpoint of producing a lustrous paint composition that can form a coating film with excellent color development.

[0029] Dispersion resin (B) Dispersion resin (B) is a polymer of a composition containing a polymerizable unsaturated monomer (b1) containing a phosphate group and other polymerizable unsaturated monomers (b2), and is a resin having a weight-average molecular weight in the range of 100,000 to 500,000.

[0030] The polymerizable unsaturated monomer (b1) containing the above-mentioned phosphate group is a compound having one or more phosphate groups and one or more polymerizable unsaturated groups in one molecule. Examples include acid phosphooxyalkyl (meth)acrylates such as acid phosphooxyethyl (meth)acrylate and acid phosphooxypropyl (meth)acrylate, mono(hydroxyalkyl (meth)acrylate) phosphates such as mono(2-hydroxyethyl methacrylate) phosphate and mono(2-hydroxypropyl methacrylate) phosphate, and acid phosphooxypoly(oxyalkylene) glycol (meth)acrylates such as acid phosphooxypoly(oxyethylene) glycol (meth)acrylate and acid phosphooxypoly(oxypropylene) glycol (meth)acrylate. These can be used individually or in combination of two or more.

[0031] Among these, the polymerizable unsaturated monomer (b1) having a phosphate group preferably contains, as at least one type thereof, acid phosphooxyalkyl (meth)acrylate, mono(hydroxyalkyl (meth)acrylate) phosphate and / or acid phosphooxypoly(oxyalkylene) glycol (meth)acrylate, and more preferably contains mono(hydroxyalkyl (meth)acrylate) phosphate and / or acid phosphooxypoly(oxyalkylene) glycol (meth)acrylate.

[0032] In the present specification, the term "polymerizable unsaturated group" means an unsaturated group capable of radical polymerization. Examples of such polymerizable unsaturated groups include a vinyl group, a (meth)acryloyl group, and the like.

[0033] In addition, in the present specification, "(meth)acrylate" means acrylate or methacrylate. "(meth)acrylic acid" means acrylic acid or methacrylic acid. Further, "(meth)acryloyl" means acryloyl or methacryloyl. Further, "(meth)acrylamide" means acrylamide or methacrylamide.

[0034] The content ratio of the polymerizable unsaturated monomer (b1) having a phosphate group in the dispersion resin (B), based on the total amount of the phosphate group-containing polymerizable unsaturated monomer (b1) and the other polymerizable unsaturated monomer (b2), is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more. Further, it is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less.

[0035] The other polymerizable unsaturated monomer (b2) is a compound having one or more polymerizable unsaturated groups per molecule other than the above monomer (b1), and specific examples thereof are listed below.

[0036] (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, tridecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, tricyclodecanyl (meth)acrylate, etc.

[0037] (ii) Polymerizable unsaturated monomers having an isobornyl group: isobornyl (meth)acrylate, etc.

[0038] (iii) Polymerizable unsaturated monomers having an adamantyl group: adamantyl (meth)acrylate, etc.

[0039] (iv) Polymerizable unsaturated monomers having a tricyclodecenyl group: tricyclodecenyl (meth)acrylate, etc.

[0040] (v) Polymerizable unsaturated monomers containing aromatic rings: benzyl (meth)acrylate, styrene, α-methylstyrene, vinyltoluene, etc.

[0041] (vi) Polymerizable unsaturated monomers having an alkoxysilyl group: vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, etc.

[0042] (vii) Polymerizable unsaturated monomers having a fluorinated alkyl group: perfluoroalkyl (meth)acrylates such as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl (meth)acrylate; fluoroolefins, etc.

[0043] (viiii) A polymerizable unsaturated monomer having a photopolymerizable functional group such as a maleimide group.

[0044] (ix) Vinyl compounds: N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate, etc.

[0045] (x) Nitrogen-containing polymerizable unsaturated monomers: (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, adducts of glycidyl (meth)acrylate with amine compounds, etc.

[0046] (xi) Polymerizable unsaturated monomers having two or more polymerizable unsaturated groups in one molecule: 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.

[0047] (xi) Epoxy group-containing polymerizable unsaturated monomers: 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.

[0048] (xiiii) Polymerizable unsaturated monomers having UV-absorbing functional groups: 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-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, etc.

[0049] (xiv) Photostable polymerizable unsaturated monomers: 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.

[0050] (xv) Polymerizable unsaturated monomers having a carbonyl group: acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, vinyl alkyl ketones having 4 to 7 carbon atoms (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), etc.

[0051] (xvi) Polymerizable unsaturated monomers having an acid anhydride group: maleic anhydride, itaconic anhydride, citraconic anhydride, etc.

[0052] (xvii) Hydroxyl group-containing polymerizable unsaturated monomers: Monoesters of polyhydric alcohols and (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2,3-dihydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate [excluding the nonionic polymerizable unsaturated monomer (xix) having a polyoxyalkylene chain listed below]; compounds obtained by ring-opening polymerization of the above monoesters of polyhydric alcohols and (meth)acrylic acid with ε-caprolactone, etc.

[0053] (xviii) Polymerizable unsaturated monomers containing acidic functional groups other than phosphate groups: Polymerizable unsaturated monomers containing carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and maleic anhydride; 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth)acrylate, allylsulfonic acid, 4-styrenesulfonic acid, etc.; polymerizable unsaturated monomers containing sulfonic acid groups such as sodium salts and ammonium salts of these sulfonic acids.

[0054] (xix) Nonionic polymerizable unsaturated monomers having polyoxyalkylene chains: (tetraethylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, ethoxytetraethylene glycol (meth)acrylate, n-butoxytetraethylene glycol (meth)acrylate, tetrapropylene glycol (meth)acrylate, methoxytetrapropylene glycol (meth)acrylate, ethoxytetrapropylene glycol (meth)acrylate, n-butoxytetrapropylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, etc.)

[0055] These can be used individually or in combination of two or more types.

[0056] Of the above-mentioned other polymerizable unsaturated monomers (b2), it is preferable to include a hydroxyl group-containing polymerizable unsaturated monomer from the viewpoint of curability and finished appearance.

[0057] The content of the other polymerizable unsaturated monomer (b2) in the dispersed resin (B) is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, based on the total amount of polymerizable unsaturated monomer (b1) containing a phosphate group and the other polymerizable unsaturated monomer (b2). Furthermore, it is preferably 99% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less.

[0058] Furthermore, if the other polymerizable unsaturated monomer (b2) includes a hydroxyl group-containing polymerizable unsaturated monomer, its content is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less, based on the total amount of the phosphate group-containing polymerizable unsaturated monomer (b1) and the other polymerizable unsaturated monomers (b2), from the viewpoint of curability and finished appearance.

[0059] Polymerization of the dispersed resin (B) can be carried out by known methods, such as solution polymerization in an organic solvent or emulsion polymerization in water, but solution polymerization is preferred. As an example of a polymerization method using solution polymerization, a mixture of a polymerizable unsaturated monomer containing a phosphate group (b1) and other polymerizable unsaturated monomers (b2) and a radical polymerization initiator is dissolved or dispersed in an organic solvent, and polymerization is carried out by heating with stirring at a temperature of about 80°C to about 200°C for about 1 to 10 hours.

[0060] Examples of the above-mentioned organic solvents include hydrocarbon solvents such as heptane, toluene, xylene, octane, and mineral spirits; ester solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, and diethylene glycol monobutyl ether acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol, and isobutanol; ether solvents such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monomethyl ether; and aromatic petroleum solvents such as Swazole 310, Swazole 1000, and Swazole 1500 manufactured by Cosmo Oil Co., Ltd. These organic solvents can be used individually or in combination of two or more.

[0061] Examples of the radical polymerization initiators include ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; peroxyketals such as 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, and n-butyl-4,4-bis(tert-butylperoxy)valerate; hydroperoxides such as cumene hydroperoxide and 2,5-dimethylhexane-2,5-dihydroperoxide; 1,3-bis(tert-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide, and tert-butylperoxy. Examples of organic peroxide polymerization initiators include dialkyl peroxides such as tylcumyl peroxide; diacyl peroxides such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, and 2,4-dichlorobenzoyl peroxide; peroxycarbonates such as bis(tert-butylcyclohexyl)peroxydicarbonate; peroxyesters such as tert-butyl peroxybenzoate and 2,5-dimethyl-2,5-di(benzoylperoxy)hexane; and azo polymerization initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropionic acid)dimethyl, 1,1-azobis(cyclohexane-1-carbonitride), azocumene 2,2'-azobismethylvaleronitrile, and 4,4'-azobis(4-cyanovaleric acid). The amount of these radical polymerization initiators used is not particularly limited, but is generally preferably in the range of 0.1 to 15 parts by weight, and especially 0.3 to 10 parts by weight, per 100 parts by weight of the total amount of polymerizable unsaturated monomers.

[0062] The dispersion resin (B) has a weight-average molecular weight of 100,000 or more, from the viewpoint of the agglomeration resistance of the lustrous pigment in the lustrous coating composition of the present invention. In particular, it is preferably 110,000 or more, and more preferably 120,000 or more.

[0063] Furthermore, from the viewpoint of pigment stability, the weight-average molecular weight is 500,000 or less. In particular, it is preferably 400,000 or less, more preferably 350,000 or less, and even more preferably 300,000 or less.

[0064] In this specification, the average molecular weight of the resin is calculated from the chromatogram measured by gel permeation chromatography, using the molecular weight of standard polystyrene as a reference. The gel permeation chromatograph used was "HLC8120GPC" (manufactured by Tosoh Corporation). Four columns were used: "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL", and "TSKgel G-2000HXL" (all product names manufactured by Tosoh Corporation). The measurements were performed under the following conditions: mobile phase; tetrahydrofuran, measurement temperature; 40°C, flow rate; 1 mL / min, detector; RI.

[0065] From the viewpoint of curability and finished appearance, the dispersion resin (B) preferably has a hydroxyl value of 0.0 mg KOH / g or more, more preferably 20.0 mg KOH / g or more, even more preferably 40.0 mg KOH / g or more, preferably 140.0 mg KOH / g or less, more preferably 120.0 mg KOH / g or less, and even more preferably 100.0 mg KOH / g or less. From the viewpoint of interaction with the amino groups of the silica-treated aluminum pigment (A) having amino groups on its surface, the dispersion resin (B) preferably has an acid value of 70 mg KOH / g or more, more preferably 90 mg KOH / g or more, even more preferably 110 mg KOH / g or more, preferably 200 mg KOH / g or less, more preferably 180 mg KOH / g or less, and even more preferably 150 mg KOH / g or less. In the lustrous pigment dispersion of the present invention, the content of the dispersion resin (B) is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, even more preferably 0.3 parts by mass or more, preferably 20.0 parts by mass or less, more preferably 15.0 parts by mass or less, and even more preferably 10.0 parts by mass or less, based on 100 parts by mass of solids in the lustrous pigment dispersion, from the viewpoint of producing a lustrous paint composition that is excellent in gas generation suppression ability, weather resistance, and agglomeration resistance of aluminum pigments.

[0066] Other Components: The luminous pigment dispersion of the present invention may further contain, as needed, an organic solvent, pigments other than the silica-treated aluminum pigment (A) having amino groups on its surface, a viscosity modifier, a settling inhibitor, an ultraviolet absorber, and a light stabilizer.

[0067] In particular, from the viewpoint of improving the dispersibility of the lustrous pigment, it is preferable that the lustrous pigment dispersion of the present invention contains a nitrogen-containing compound (C) represented by the following general formula (2).

[0068] general formula

[0069]

[0070] [In the formula, R ３represents a monovalent organic group having 4 to 22 carbon atoms. R ４ is a hydrocarbon group having 4 to 22 carbon atoms, an acyl group having 4 to 22 carbon atoms or

[0071]

[0072] (wherein R ６ represents an alkylene group having 2 to 10 carbon atoms, and n represents an integer of 0 to 100. When n is 2 or more, a plurality of R ６ groups may be the same or different from each other. ). R ５ represents an alkylene group having 2 to 10 carbon atoms. m represents an integer of 1 to 100. When m is 2 or more, a plurality of R ５ groups may be the same or different from each other. ].

[0073] As the monovalent organic group having 4 to 22 carbon atoms represented by R ３ , examples thereof include a hydrocarbon group having 4 to 22 carbon atoms, an acyl group having 4 to 22 carbon atoms, and the like.

[0074] The alkylene groups represented by R ５ and R ６ may each be a linear alkylene group or a branched alkylene group. Further, the alkylene group preferably has 2 to 4 carbon atoms, more preferably 2 or 3 carbon atoms, and still more preferably 2 carbon atoms.

[0075] m is preferably an integer of 1 to 50, more preferably an integer of 1 to 25, still more preferably an integer of 2 to 15, and most preferably an integer of 3 to 10. n is preferably an integer of 0 to 50, more preferably an integer of 1 to 25, still more preferably an integer of 2 to 15, and most preferably an integer of 3 to 10.

[0076] When the above viscosity modifier is contained in the luster pigment dispersion, adding the viscosity modifier before the luster pigment during preparation of the luster pigment dispersion can further improve the dispersibility of the luster pigment.

[0077] If the glossy coating composition (Y) of the present invention contains a nitrogen-containing compound (C), the amount of C is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, preferably 7.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less, based on the total amount of solids of the resin component in the glossy coating composition (Y).

[0078] From the viewpoint of producing a glossy paint composition with a low content of volatile organic compounds (VOCs), the solid content of the glossy pigment dispersion of the present invention is preferably in the range of 10 to 50% by mass, and more preferably in the range of 20 to 40% by mass.

[0079] Luminous paint composition (Y) The luminous paint composition (Y) of the present invention is a luminous paint composition containing the luminous pigment dispersion and film-forming resin of the present invention.

[0080] From the viewpoint of producing a glossy coating composition (Y) with a low content of volatile organic compounds (VOCs), the water content in the glossy coating composition (Y) is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more, based on the amount of solvent in the glossy coating composition (Y).

[0081] Examples of the above-mentioned film-forming resins include acrylic resins, polyester resins, epoxy resins, and urethane resins.

[0082] Examples of the acrylic resins mentioned above include (meth)acrylic acid esters having functional groups such as α,β-ethylenically unsaturated carboxylic acids, hydroxyl groups, amide groups, methylol groups, and epoxy groups, as well as resins obtained by copolymerizing other (meth)acrylic acid esters, styrene, and the like.

[0083] As the polyester resin, for example, a polyester resin obtained by a condensation reaction between a polyhydric alcohol such as ethylene glycol, propylene glycol, butylene glycol, 1,6-hexanediol, trimethylolpropane, or pentaerythritol and a polyhydric carboxylic acid component such as adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride, hexahydrophthalic anhydride, or trimellitic anhydride can be used.

[0084] Examples of the epoxy resin include so-called bisphenol A type epoxy resins, which are produced by a condensation reaction between bisphenol A and epichlorohydrin.

[0085] Examples of the urethane resin include compounds obtained by an addition reaction between a diisocyanate compound and a polyhydric alcohol, and compounds obtained by reacting the above-mentioned acrylic resin, polyester resin, or epoxy resin with a diisocyanate compound to increase its molecular weight.

[0086] The aforementioned film-forming resin preferably has a sufficient amount of hydrophilic groups in order to be water-soluble or water-dispersible.

[0087] Examples of the hydrophilic groups mentioned above include carboxyl groups, hydroxyl groups, methylol groups, amino groups, sulfonic acid groups, and polyoxyethylene bonds, with carboxyl groups being particularly preferred.

[0088] The hydrophilic group described above is preferably neutralized with sodium hydroxide, an amine compound, or the like to form an alkali salt.

[0089] Furthermore, the aqueous dispersion of the above resin can also be carried out by emulsion polymerization of the polymerizable component in the presence of a surfactant or a water-soluble resin. Alternatively, the resin can be obtained by dispersing it in water in the presence of, for example, an emulsifier. In this aqueous dispersion, the base resin does not necessarily need to contain the hydrophilic group.

[0090] The aforementioned film-forming resins can be used alone or in combination of two or more types.

[0091] In the glossy coating composition (Y) of the present invention, the content of the above-mentioned film-forming resin is preferably in the range of 30 to 85 parts by mass, and more preferably in the range of 35 to 80 parts by mass, based on 100 parts by mass of the total solid content in the glossy coating composition (Y), from the viewpoint of forming a coating film with excellent gloss.

[0092] The glossy coating composition (Y) of the present invention preferably further contains a curing agent.

[0093] Examples of the curing agents mentioned above include amino resins, polyisocyanate compounds, and blocked polyisocyanate compounds. The curing agents can be used alone or in combination of two or more types.

[0094] When the glossy coating composition (Y) of the present invention contains the curing agent, the ratio of the film-forming resin to the curing agent is preferably within the range of 50 to 90% by mass, particularly 60 to 85% by mass, and 10 to 50% by mass, particularly 15 to 40% by mass, based on the total mass of both components.

[0095] In addition to the above components, the glossy coating composition (Y) of the present invention may optionally contain a coloring pigment, an extender pigment, a glossy pigment other than the silica-treated aluminum pigment (A) having an amino group on its surface, a curing catalyst, an ultraviolet absorber, an antifoaming agent, a viscosity modifier, a surface modifier, an organic solvent, and the like.

[0096] Examples of the above-mentioned coloring pigments include titanium dioxide, zinc oxide, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, surene pigments, perylene pigments, dioxazine pigments, and diketopyrrolopyrrole pigments, among which carbon black is preferred.

[0097] If the glossy coating composition (Y) of the present invention contains the above-mentioned coloring pigment, the content of the coloring pigment is preferably 0.1 to 30 parts by mass, and more preferably 0.5 to 20 parts by mass, based on 100 parts by mass of resin solids in the glossy coating composition (Y). In this specification, resin solids refer to the total solids of the resin and curing agent (if present).

[0098] Examples of the aforementioned extender pigments include barium sulfate, talc, clay, kaolin, barium carbonate, calcium carbonate, silica, and alumina white.

[0099] When the glossy coating composition (Y) of the present invention contains the above-mentioned extender pigment, the content of the extender pigment is preferably 0.1 to 30 parts by mass, and more preferably 0.5 to 20 parts by mass, based on 100 parts by mass of resin solids in the glossy coating composition (Y).

[0100] Examples of luminous pigments other than the silica-treated aluminum pigment (A) having amino groups on its surface include aluminum other than the silica-treated aluminum pigment (A) having amino groups on its surface (including vapor-deposited aluminum), copper, zinc, brass, nickel, glass flakes, aluminum oxide, mica, aluminum oxide coated with titanium oxide and / or iron oxide, mica coated with titanium oxide and / or iron oxide, etc.

[0101] If the glossy coating composition (Y) of the present invention contains a glossy pigment other than the silica-treated aluminum pigment (A) having amino groups on its surface, the content of the glossy pigment is preferably 0.1 to 30 parts by mass, and more preferably 0.5 to 20 parts by mass, based on 100 parts by mass of resin solids in the glossy coating composition (Y).

[0102] Examples of the curing catalysts include tin octoate, dibutyltin diacetate, dibutyltin di(2-ethylhexanoate), dibutyltin dilaurate, dioctyltin diacetate, dioctyltin di(2-ethylhexanoate), dibutyltin oxide, dibutyltin sulfide, dioctyltin oxide, dibutyltin fatty acid salts, lead 2-ethylhexanoate, zinc octoate, zinc naphthenate, zinc fatty acid derivatives, bismuth octanoate, bismuth 2-ethylhexanoate, bismuth oleate, bismuth neodecanoate, and bismuth versatate. Organometallic compounds such as smus, bismuth naphthenate, cobalt naphthenate, calcium octylate, copper naphthenate, and tetra(2-ethylhexyl) titanate; sulfonic acid group-containing compounds such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and dinonylnaphthalenesulfonic acid; and phosphate group-containing compounds such as monobutyl phosphate, dibutyl phosphate, mono-2-ethylhexyl phosphate, di-2-ethylhexyl phosphate, alkyl ether phosphate, polyoxyethylene alkyl ether phosphate, and phosphate group-containing resins can be used.

[0103] In the glossy coating composition (Y) of the present invention, it is preferable to include a phosphate group-containing compound, particularly from the viewpoint of improving resistance to circulation.

[0104] As a phosphate group-containing compound, a phosphate group-containing compound (D) represented by the following general formula (1) (which may be abbreviated as "phosphate group-containing compound (D)" in this specification) can be preferably used.

[0105]

[0106] (In the formula, m is 1 or 2, n is 0 or an integer from 1 to 20, R 1 is a hydrocarbon group having 2 to 20 carbon atoms, which may have substituents, and when m is 2, each R 1 They may be the same or different, R 2 This is an alkylene group having 2 to 4 carbon atoms, and when n is 2 or more, it consists of n oxyalkylene units (R 2 O) may be the same as each other or different from each other, and if they are different, (R 2O)n may be added in any of the following ways: random addition, block addition, or alternating addition.

[0107] Also, if m is 2, (R 2 O)n may be the same or different.

[0108] Furthermore, the phosphate group-containing compound (D) may be a neutralized salt.

[0109] The phosphate group-containing compound (D) having the structure of the general formula (1) above is a compound having a phosphate group and a hydrocarbon group, and preferably further having a (poly)oxyalkylene group. It is a compound that has the action of an acid compound due to the phosphate group and the action of a surfactant due to having both a hydrophilic group (phosphate group, preferably further having a nonionic group, a (poly)oxyalkylene group) and a hydrophobic group, a hydrocarbon group.

[0110] Due to its surfactant properties, the emulsifying properties of the resin component of the lustrous coating composition (Y) of the present invention can be improved.

[0111] As a result, effects such as wettability and viscosity are also exhibited, thereby improving the storage stability of the glossy coating composition (Y) of the present invention, as well as the finished appearance (smoothness, vividness).

[0112] Furthermore, since the phosphate group also has the effect of suppressing the reaction between metal powders such as aluminum and water, the storage stability of the glossy coating composition (Y) of the present invention, which has a flake-shaped metal powder pigment such as aluminum pigment, can be improved. Also, due to its surfactant properties, the orientation of the glossy pigment in the coating film is good, making it possible to obtain a coating film with excellent metallic feel and a finish appearance free from metallic unevenness.

[0113] Furthermore, in the case of a glossy coating composition (Y) in which the base resin has hydroxyl groups as crosslinking functional groups and the crosslinking agent is such that its reactivity is promoted by an acid catalyst such as melamine resin, the acid catalytic effect of the phosphate group improves curability, thus making it possible to obtain a coating film with excellent properties such as water resistance.

[0114] In the above general formula (1), R １R is a hydrocarbon group which may have substituents, and from the viewpoint of the appearance of the resulting coating film, such as brightness and metallic feel, and water resistance, １ The hydrocarbon group is preferably having 2 to 20 carbon atoms, more preferably 4 to 20 carbon atoms, even more preferably 7 to 20 carbon atoms, and even more preferably 7 to 16 carbon atoms.

[0115] The above R 1 When the alkyl group is a branched alkyl group, a coating film with excellent brightness can be formed even when the glossy coating composition (Y) is stored for a relatively long period of time before being applied.

[0116] The phosphate group-containing compound (D) can be obtained, for example, by reacting a phosphorylating agent such as orthophosphoric acid, phosphorus pentoxide (phosphoric anhydride), polyphosphoric acid, or phosphorus oxychloride with an alcohol or an alcohol alkylene oxide adduct obtained by the addition reaction of an alkylene oxide to an alcohol.

[0117] The reaction between a phosphorylating agent and an alcohol or an alcohol alkylene oxide adduct can be carried out by methods known in themselves, in which the alcohol and the alcohol alkylene oxide adduct can be used individually or in combination of two or more.

[0118] Generally, the phosphate group-containing compound (D) represented by general formula (1) is obtained as a mixture of monoesters and diesters.

[0119] Examples of the alkylene oxides mentioned above include alkylene oxides having 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide, and butylene oxide, and one or more of these can be used. Among these, ethylene oxide can be suitably used. Therefore, in general formula (1), the oxyalkylene unit (R ２ Examples of O) include oxyethylene groups, oxypropylene groups, oxybutylene groups, etc., and multiple oxyalkylene units may be the same or different from each other. Also, oxyalkylene units (R) ２ For O), an oxyethylene group is preferred.

[0120] In the above general formula (1), n ​​is the number of moles of alkylene oxide added, and n is preferably in the range of 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. In a preferred embodiment, the phosphate group-containing compound (D) may be a mixture of a phosphate compound in which n is 0 in general formula (1) and a phosphate compound in which n is an integer from 1 to 20.

[0121] Furthermore, the number-average molecular weight of the phosphate group-containing compound (D) is preferably in the range of 100 to 3000, more preferably 100 to 2500, and even more preferably 100 to 2000. The number-average molecular weight of the phosphate group-containing compound (D) can be calculated based on information regarding the molecular weight of the raw materials used and the synthesis conditions.

[0122] Furthermore, the number-average molecular weight and weight-average molecular weight of the phosphate group-containing compound (D) can also be measured using the same method as described above for the dispersion resin (B).

[0123] The phosphate group-containing compound (D) may be used alone or in combination of two or more types. Furthermore, the phosphate group-containing compound (D) may be either a commercially available product or a synthetic product.

[0124] When the glossy coating composition (Y) of the present invention contains a phosphate group-containing compound (D), its content is preferably in the range of 0.1 to 10% by mass, more preferably 0.3 to 7% by mass, and even more preferably 0.5 to 5% by mass, relative to the total amount of solids of the resin component in the glossy coating composition (Y).

[0125] The glossy coating composition (Y) of the present invention can be applied by diluting it with water and / or an organic solvent as needed and adjusting it to an appropriate viscosity.

[0126] The appropriate viscosity varies depending on the paint composition, but it is preferable to adjust it appropriately using water and / or an organic solvent so that, for example, the viscosity measured using a B-type viscometer at 20°C and a rotation speed of 6 rpm is in the range of 2000 to 7000 mPa·s. Furthermore, the solid content concentration of the coating of the glossy paint composition (Y) is preferably 3 to 30% by mass, and more preferably about 5 to 25% by mass. The solid content concentration of the coating of the glossy paint composition (Y) refers to the solid content concentration of the glossy paint composition (Y) at the time of application, and in this specification, solid content means the residue remaining after removing volatile components such as resin, hardener, and pigment. For example, solid content refers to the residue remaining after removing volatile components by treating the sample at 105°C for 3 hours.

[0127] The glossy coating composition (Y) of the present invention may be either a one-component coating or a multi-component coating, but it is preferable to be a one-component coating from the viewpoint of having no coating mixing step and having excellent productivity, and simplifying the maintenance of coating machinery.

[0128] The glossy coating composition (Y) of the present invention can be applied to an object by known methods, such as air spray coating, airless spray coating, rotary atomization coating, curtain coating coating, etc., and electrostatic application may be performed during coating. Of these, air spray coating and rotary atomization coating methods are preferred. Furthermore, such coating methods can be carried out in one to several stages until the desired film thickness is obtained.

[0129] The amount of the glossy coating composition (Y) of the present invention applied is preferably 0.5 to 20 μm as a cured film thickness, more preferably 1 to 15 μm, and more preferably 2 to 10 μm.

[0130] The glossy coating composition (Y) of the present invention is particularly suitable as an aqueous base coat coating used in metallic specifications containing aqueous glossy pigments.

[0131] Method for forming a multilayer coating The method for forming a multilayer coating of the present invention comprises the following steps (1) to (4): Step (1): A step of applying a colored coating composition (X) to an object to be coated to form a colored coating film; Step (2): A step of applying the glossy coating composition (Y) of the present invention to the colored coating film obtained in step (1) to form a glossy coating film; Step (3): A step of applying a clear coating composition (Z) to the glossy coating film obtained in step (2) to form a clear coating film; Step (4): A step of heating the multilayer coating film, which includes the colored coating film, glossy coating film and clear coating film formed in steps (1), (2), and (3), respectively, to simultaneously cure the multilayer coating film.

[0132] The objects to be coated are not particularly limited, but examples include the exterior panels of automobile bodies such as passenger cars, trucks, motorcycles, and buses; automobile parts; and the exterior panels of household electrical appliances such as mobile phones and audio equipment. Of these, the exterior panels of automobile bodies and automobile parts are preferred.

[0133] The materials of these objects to be coated are not particularly limited. Examples include metallic materials such as iron, aluminum, brass, copper, tinplate, stainless steel, galvanized 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, epoxy resin, and various FRP plastic materials; inorganic materials such as glass, cement, and concrete; wood; and fibrous materials such as paper and cloth. Of these, metallic and plastic materials are preferred.

[0134] Furthermore, the surfaces to which the multi-layer coating is applied may include metal surfaces such as the exterior panels of automobile bodies, automobile parts, household electrical appliances, and metal substrates such as steel plates that make up these, which may have been subjected to surface treatments such as phosphate treatment, chromate treatment, or composite oxide treatment.

[0135] A coating film may be formed on an object that has been surface-treated or not. For example, the substrate (the object to be coated) may be surface-treated as needed, and then a primer film and / or intermediate coating film may be formed thereon. The primer film and / or intermediate coating film can be formed, for example, if the object to be coated is an automobile body, using a known primer and / or intermediate coating composition that is commonly used in the painting of automobile bodies.

[0136] As the primer coating composition for forming the above-mentioned primer coating film, for example, an electrodeposition coating, preferably a cationic electrodeposition coating, can be used. Furthermore, as the intermediate coating coating composition for forming the above-mentioned intermediate coating film, a coating can be made by combining a base resin such as an acrylic resin, polyester resin, alkyd resin, urethane resin, or epoxy resin having crosslinkable functional groups such as carboxyl groups or hydroxyl groups, with a crosslinking agent such as an amino resin such as a melamine resin or urea resin, or a polyisocyanate compound that may be blocked, together with a pigment, a thickener, and other optional components.

[0137] As the colored paint composition (X), a thermosetting colored paint composition known for use in painting automobile bodies and the like can be used. For example, a thermosetting paint composition containing a base resin having a crosslinkable functional group, a crosslinking agent, a coloring pigment, and an extender pigment can be suitably used. Furthermore, a glossy pigment may also be included.

[0138] Examples of crosslinkable functional groups in the above-mentioned base resin include carboxyl groups, hydroxyl groups, and epoxy groups.

[0139] Examples of the substrate resins mentioned above include acrylic resin, polyester resin, alkyd resin, and urethane resin.

[0140] Examples of the crosslinking agent include melamine resin, polyisocyanate compounds, and blocked polyisocyanate compounds.

[0141] The aforementioned colored paint composition (X) may be either an aqueous paint composition or an organic solvent-based paint composition, but an aqueous paint composition is preferred from the viewpoint of reducing environmental impact.

[0142] The method of applying the colored paint composition (X) is not particularly limited, but a wet coating can be formed by coating methods such as air spray coating, airless spray coating, rotary atomization coating, and curtain coating. Electrostatic application may be performed as needed in these coating methods. Of these, air spray coating or rotary atomization coating is particularly preferred. The amount of colored paint composition (X) applied is usually preferably such that the cured film thickness is 5 to 30 μm, more preferably 7 to 20 μm.

[0143] Furthermore, when performing air spray painting, airless spray painting, or rotary atomization painting, it is preferable to adjust the viscosity of the colored paint composition (X) using a solvent such as water or an organic solvent so that it is within a viscosity range suitable for the painting, typically a viscosity range of about 15 to 60 seconds at 20°C, and particularly about 20 to 50 seconds, using a Ford Cup No. 4 viscometer.

[0144] As the clear coating composition (Z), any thermosetting clear coating composition known for use in painting automobile bodies and the like can be used. Examples include organic solvent-type thermosetting coating compositions containing a base resin having a crosslinkable functional group and a curing agent, aqueous thermosetting coating compositions, powder thermosetting coating compositions, and the like.

[0145] Examples of crosslinkable functional groups in the above-mentioned base resin include carboxyl groups, hydroxyl groups, epoxy groups, and silanol groups. Examples of base resin types include acrylic resins, polyester resins, alkyd resins, urethane resins, epoxy resins, and fluororesins. 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.

[0146] Preferred combinations of base resin / curing agent for the clear coating composition (Z) include carboxyl group-containing resin / epoxy group-containing resin, hydroxyl group-containing resin / polyisocyanate compound, hydroxyl group-containing resin / blocked polyisocyanate compound, and hydroxyl group-containing resin / melamine resin.

[0147] Furthermore, the clear coating composition (Z) may be a one-component coating or a multi-component coating such as a two-component urethane resin coating.

[0148] Furthermore, the clear coating composition (Z) may optionally contain coloring pigments, luminescence pigments, dyes, etc., to an extent that does not impair transparency, and may also appropriately contain extender pigments, ultraviolet absorbers, light stabilizers, defoamers, thickeners, rust inhibitors, surface modifiers, etc.

[0149] The method of applying the clear coating composition (Z) is not particularly limited, but a wet coating can be formed by methods such as air spray coating, airless spray coating, rotary atomization coating, and curtain coat coating. Electrostatic application may be performed as needed in these coating methods. Of these, air spray coating or rotary atomization coating is particularly preferred. The amount of clear coating composition (Z) applied is usually such that the cured film thickness is 10 to 50 μm, preferably 20 to 40 μm.

[0150] Furthermore, when performing air spray painting, airless spray painting, or rotary atomization painting, it is preferable to adjust the viscosity of the clear coating composition (Z) using an organic solvent or other solvent to a viscosity range suitable for the painting method, typically a viscosity range of about 15 to 60 seconds at 20°C, particularly about 20 to 50 seconds, using a Ford Cup No. 4 viscometer.

[0151] The above heating can be carried out by known means, for example, drying furnaces such as hot air furnaces, electric furnaces, and infrared induction heating furnaces can be used. The heating temperature is preferably in the range of 70 to 160°C, more preferably in the range of 90 to 150°C. The heating time is not particularly limited, but is preferably in the range of 10 to 60 minutes, more preferably in the range of 20 to 40 minutes.

[0152] The present invention will be described in more detail below with reference to manufacturing examples, embodiments, and comparative examples. These manufacturing examples, embodiments, and comparative examples are merely illustrative and are not intended to limit the scope of the present invention. In the manufacturing examples, embodiments, and comparative examples, "parts" and "%" are based on mass unless otherwise specified. Furthermore, the film thickness of the coating is based on the cured coating.

[0153] [1] Preparation of the workpiece A degreased and zinc phosphate treated steel plate (JIS G3141, size 400 mm x 300 mm x 0.8 mm) was electrodeposited with cationic electrodeposition paint "Elecron GT-10" (product name: manufactured by Kansai Paint Co., Ltd., which uses a blocked polyisocyanate compound as a hardener in an epoxy resin polyamine-based cationic resin) based on the cured coating film to a thickness of 20 μm, and was heated at 170°C for 20 minutes to crosslink and harden, forming an electrodeposited coating film, thus creating the workpiece.

[0154] [2] Preparation of paints Production of phosphate group-containing dispersion resin (B-1) Production example 1 40 parts of propylene glycol monomethyl ether were added to a reaction vessel and heated to 115°C under a nitrogen atmosphere. Maintaining the temperature at 115°C, a mixture of 20 parts styrene, 10 parts n-butyl acrylate, 20 parts lauryl methacrylate / tridecane methacrylate mixture, 10 parts hydroxyethyl acrylate, 10 parts epsilon caprolactone-modified hydroxyethyl methacrylate, 30 parts mono(2-hydroxyethyl methacrylate) phosphate and 3.0 parts t-butyl peroxy-2-ethylhexanoate was added to the reaction vessel over 4 hours. After the addition was complete, the mixture was aged at 115°C for 30 minutes, and a mixture of 0.5 parts t-butyl peroxy-2-ethylhexanoate and 5 parts propylene glycol monomethyl ether was added over 1 hour, followed by stirring and aging for another 1 hour to obtain a phosphate group-containing dispersion resin (B-1) with a solid content of 50%. The acid value due to the phosphate group of this resin was 140 mg KOH / g, the hydroxyl value was 60 mg KOH / g, and the weight-average molecular weight was 150,000.

[0155] Production Examples 2-13 Solutions of each dispersion resin (B-2) to (B-13) with a solid content of 50% by mass were obtained in the same manner as in Production Example 1, except that the compound composition was as shown in Table 1. The weight-average molecular weight, acid value, and hydroxyl value of each dispersion resin are also shown in accordance with Table 1.

[0156]

[0157]

[0158] Production Example 1 of Luminous Pigment Dispersion (P-1) In a stirring mixing vessel, 44.4 parts (20 parts solids) of aluminum pigment A (silica-treated aluminum pigment having amino groups and alkyl groups on its surface, average particle size (d50) 8.8 μm, solid content concentration 45%), 35 parts of 2-ethyl-1-hexanol, and 2 parts (1 part solids) of a solution of the phosphate group-containing dispersion resin (B-1) obtained in Production Example 1 were uniformly mixed to obtain Luminous Pigment Dispersion (P-1).

[0159] Examples 2-18 and Comparative Examples 1-4 In Example 1, the luminous pigment dispersions (P-2) to (P-22) were obtained in the same manner as in Example 1, except that the formulation composition was as shown in Table 2.

[0160] (*1) Aluminum pigment B (silica-treated aluminum pigment having amino groups and alkyl groups on the surface, average particle size (d50) 15.1 μm, solid content concentration 45%) (*2) Aluminum pigment C (silica-treated aluminum pigment having amino groups and alkyl groups on the surface, average particle size (d50) 17.9 μm, solid content concentration 59%) (*3) Aluminum pigment D (silica-treated aluminum pigment having amino groups and alkyl groups on the surface, average particle size (d50) 21.0 μm, solid content concentration 60%) (*4) Aluminum pigment paste (aluminum pigment paste, GX180A, manufactured by Asahi Kasei Corporation, average particle size (d50) 17.0 μm, solid content concentration 74%) (*5) Viscosity modifier nitrogen-containing compound (C): In the above general formula (2), R ３ is an alkyl group having 8 carbon atoms, R ４ is R ６ This is an alkylene group with 2 carbon atoms, R ５A nitrogen-containing compound in which the alkylene group has 2 carbon atoms and the sum of m and n is 7, with a molecular weight of 437.

[0161]

[0162]

[0163]

[0164] Production Example 14 of Hydroxyl Group-Containing Acrylic Resin Emulsion (3) 130 parts of deionized water and 0.52 parts of "Aqualon KH-10" were charged into a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, and dropping device, and stirred and mixed in a nitrogen atmosphere, and the temperature was raised to 80°C. Next, 1% of the total amount of the monomer emulsion (1) described below and 5.3 parts of a 6% ammonium persulfate aqueous solution were introduced into the reaction vessel and maintained at 80°C for 15 minutes. Then, the remaining monomer emulsion (1) was added dropwise over 3 hours into the reaction vessel maintained at the same temperature, and the mixture was allowed to mature for 1 hour after the completion of the dropwise addition. Then, the monomer emulsion (2) described below was added dropwise over 1 hour, and after maturation for 1 hour, 40 parts of a 5% dimethylethanolamine aqueous solution were gradually added to the reaction vessel while cooling to 30°C, and the mixture was discharged while filtering through a 100-mesh nylon cloth to obtain a hydroxyl group-containing acrylic resin emulsion (3) with a solid content of 30%. The obtained hydroxyl group-containing acrylic resin emulsion (3) had a hydroxyl value of 25 mg KOH / g and an acid value of 33 mg KOH / g.

[0165] 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 monomer emulsion (1).

[0166] Monomer emulsion (2): 18 parts deionized water, 0.31 parts "Aqualon KH-10", 0.03 parts ammonium persulfate, 5.1 parts methacrylic acid, 5.1 parts 2-hydroxyethyl acrylate, 3 parts styrene, 6 parts methyl methacrylate, 1.8 parts ethyl acrylate, and 9 parts n-butyl acrylate were mixed and stirred to obtain monomer emulsion (2).

[0167] Production Example 15 of Acrylic Resin for Dispersing Colored Pigments (4) In a conventional acrylic resin reaction vessel equipped with a stirrer, thermometer, and reflux condenser, 48 parts of ethylene glycol monobutyl ether were charged and heated and stirred, and maintained at 110°C. To this, a mixture consisting of 10 parts styrene, 40 parts methyl methacrylate, 25 parts n-butyl methacrylate, 10 parts 2-hydroxyethyl methacrylate, 3 parts methacrylic acid, 5 parts N,N-dimethylaminoethyl methacrylate (solid content, dissolved in 10 parts deionized water), 10 parts polyethylene glycol monomethacrylate (molecular weight approximately 350), 4 parts azobisisobutyronitrile, and 20 parts isobutyl alcohol was added dropwise over 3 hours. After the dropwise addition was complete, the mixture was aged at 110°C for 30 minutes, and then an additional catalyst mixture consisting of 25 parts ethylene glycol monobutyl ether and 0.5 parts azobisisobutyronitrile was added dropwise over 1 hour. Next, the mixture was aged at 110°C for 1 hour and then cooled to obtain a solution of acrylic resin (4) for dispersing colored pigments with a solid content of 50%. The acrylic resin (4) for dispersing colored pigments had a hydroxyl value of 43 mgKOH / g and a weight-average molecular weight of approximately 20,000.

[0168] Production Example 16 of Hydroxyl Group-Containing Polyester Resin (5) In a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, and water separator, 109 parts of trimethylolpropane, 141 parts of 1,6-hexanediol, 126 parts of hexahydrophthalic anhydride, and 120 parts of adipic acid were charged and heated, and the temperature was raised from 160°C to 230°C over 3 hours, after which the condensation reaction was carried out at 230°C for 4 hours. Next, in order to add carboxyl groups to the obtained condensation reaction product, 38.3 parts of trimellitic anhydride were added and the reaction was carried out at 170°C for 30 minutes, and then diluted with 2-ethyl-1-hexanol to obtain a hydroxyl group-containing polyester resin (5) solution with a solid content of 70%. The obtained hydroxyl group-containing polyester resin (5) had a hydroxyl value of 150 mg KOH / g, an acid value of 46 mg KOH / g, and a weight-average molecular weight of 6400.

[0169] Production Example 17 of Colored Pigment Dispersion Paste (6) 16 parts (8 parts solids) of the acrylic resin (4) solution for colored pigment dispersion obtained in Production Example 15, 5 parts of "RAVEN 5000 ULTRA III BEADS" (product name, carbon black pigment, manufactured by COLUMBIAN CARBON CO.) and 70 parts of deionized water were mixed and dispersed in a paint shaker for 2 hours to obtain a colored pigment dispersion paste (6) with a solids content of 14.3%.

[0170] Production of Activated Methylene Block Polyisocyanate Compound (7) Production Example 18 A reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, dropping device, and simple removal solvent trap was charged with 360 parts of "Sumijoule N-3300", 60 parts of "Uniox M-550" (manufactured by NOF Corporation, polyethylene glycol monomethyl ether, average molecular weight approximately 550) and 0.2 parts of 2,6-di-tert-butyl-4-methylphenol, mixed well, and heated at 130°C for 3 hours under a nitrogen stream. Next, 110 parts of ethyl acetate and 252 parts of diisopropyl malonate were charged, and while stirring under a nitrogen stream, 3 parts of a 28% methanol solution of sodium methoxide were added, and the mixture was stirred at 65°C for 8 hours. The amount of isocyanate in the obtained resin solution was 0.12 mol / kg. 683 parts of 4-methyl-2-pentanol were added to this, and the solvent was removed by distillation under reduced pressure for 3 hours while maintaining the system temperature at 80-85°C to obtain 1010 parts of the activated methylene-blocked polyisocyanate compound solution. The simple solvent removal trap contained 95 parts of isopropanol. The solid content concentration of the obtained activated methylene-type blocked polyisocyanate compound (7) solution was approximately 60%.

[0171] Production Example 19 of the Luminous Paint Composition (Y-1): 81.4 parts (21.0 parts solids) of the luminous pigment dispersion (P-1) obtained in Example 1, 6.4 parts (0.92 parts solids) of the colored pigment dispersion paste (6) obtained in Production Example 17, 121.3 parts (36.4 parts solids) of the hydroxyl group-containing acrylic resin emulsion (3) obtained in Production Example 14, 14.3 parts (10 parts solids) of the hydroxyl group-containing polyester resin (5) solution obtained in Production Example 16, and a phosphate group-containing compound (D1) (*6 Two parts (2 parts solids), 31.3 parts (25 parts solids) of "Cymel 325" (trade name, manufactured by Ornex, melamine resin, 80% solids), 28.6 parts (10 parts solids) of "U-Coat UX-8100" (trade name, manufactured by Sanyo Chemical Industries, urethane emulsion, 35% solids), and 25 parts (15 parts solids) of the activated methylene block polyisocyanate compound (7) obtained in Production Example 18 were uniformly mixed. Next, "Primal ASE-60" (trade name, manufactured by Rohm & Haas, thickener, 28% solids), 2-(dimethylamino)ethanol and deionized water were added to the resulting mixture to obtain a glossy paint composition (Y-1) with a pH of 7.8, a paint solids content of 26%, and a viscosity of 2000 mPa·s when measured using a B-type viscometer at 20°C and a rotation speed of 6 rpm. The water content in the glossy coating composition (Y-1) was 81% by mass, based on the amount of solvent in the glossy coating composition (Y-1).

[0172] (*6) Phosphate group-containing compound (D1): In the above general formula (1), R １ R is a linear alkyl group having 3 carbon atoms, ２ A compound in which the ethylene group is and n is 1. Molecular weight 227. Note that m is 1 or 2, and the ratio of the monoester with m=1 to the diester with m=2 is 1:1.

[0173] Examples 20-41 and Comparative Examples 5-8 In Example 20, the glossy coating compositions (Y-2) to (Y-27) were obtained in the same manner as in Example 19, except that the formulation was changed as shown in Table 3 below.

[0174]

[0175]

[0176]

[0177] [3] Preparation of Test Panel Example 42 On the substrate prepared in [1] above, the colored paint composition (X-1) "WP-523H" (product name: Kansai Paint Co., Ltd., water-based intermediate coating paint) was electrostatically applied using a rotary atomizing bell-type coating machine to a hardened film thickness of 15 μm, and left for 5 minutes to form a colored coating film. Furthermore, the glossy paint composition (Y-1) obtained in Example 19 was applied on the colored coating film using an ABB robot bell under booth temperature of 23°C and humidity of 68% to a dry coating film thickness of 12 μm. It was left for 3 minutes, and then preheated at 80°C for 3 minutes to form a glossy coating film. Next, a clear coating composition (Z-1) "Magiclon KINO-1210TW" (product name, manufactured by Kansai Paint Co., Ltd., an acrylic resin-based organic solvent type clear coating composition containing carboxyl group-containing resin and epoxy group-containing resin) was applied to this glossy coating film using an ABB robot bell under booth temperature of 23°C and humidity of 68% to form a clear coat film with a thickness of 35 μm. After application, the surface was left at room temperature for 7 minutes, and then heated in a hot air circulating drying oven at 140°C for 30 minutes to simultaneously dry the multi-layer coating film and prepare a test panel.

[0178] Examples 43-64 and Comparative Examples 9-12: Each test plate was obtained in the same manner as in Example 42, except that the paint composition was as described in Table 4.

[0179]

[0180]

[0181]

[0182] Coating Film Evaluation: Each glossy coating composition and test panel obtained in the above examples and comparative examples were evaluated for the following items. The results are also shown in Table 4.

[0183] 1. Weather resistance: Accelerated weathering tests were conducted using a super xenon weatherometer (product name, manufactured by Suga Test Instruments Co., Ltd.) as specified in JIS B 7754. One cycle consisted of 2 hours, with 1 hour and 42 minutes of irradiation with a xenon arc lamp followed by 18 minutes of irradiation under rainfall conditions. After 500 cycles of repeated testing, the results were evaluated by comparing them with the corresponding initial coated panels. (1) Appearance [After weather resistance test (visual inspection)] S: No abnormalities were observed in the coating. A: Slight yellowing was observed in the coating, but no cracks occurred, and there were no problems when used as a product. B: Yellowing was observed in the coating. C: Significant yellowing was observed in the coating, or cracks occurred. S and A are at the acceptable level. (2) Appearance [After weather resistance test (color difference)] The color difference ΔE in accordance with JIS Z 8730 was measured on the test panels in the initial and post-tested states. A smaller ΔE value indicates better performance, and a ΔE of less than 2.0 is considered practical. (3) Appearance [After weathering test (gloss retention rate)] The gloss of each painted surface was measured for the paint film before and after the test in accordance with the specular gloss (60 degrees) of JIS K5600-4-7 (1999). The gloss after the test was calculated as the gloss retention rate (%) relative to the gloss before the test and evaluated according to the following criteria. A gloss retention rate of 80% or more is considered practical. (4) Adhesion [After weathering test] 100 2mm x 2mm pores were made on the paint film of each painted board after the weathering test in accordance with JIS K 5600-5-6 (1990), adhesive tape was applied to the surface, and after rapidly peeling it off, the number of pores remaining on the painted surface was evaluated.

[0184] S: Number of remaining pieces / Total number of pieces = 100 / 100 with no chipping edges A: Number of remaining pieces / Total number of pieces = 100 / 100 with chipping edges B: Number of remaining pieces / Total number of pieces = 99 to 90 / 100 C: Number of remaining pieces / Total number of pieces = 89 or less / 100 S and A are at a passing level

[0185] 2. Gas generation suppression ability: After preparing each glossy paint composition (Y-1) to (Y-27) and letting it stand for one day, 200g of the paint was placed in a dedicated glass container (internal volume 500ml), and the container was immersed in a constant temperature bath at 40°C without a stopper for one hour. Then the stopper of the glass container was put on to start (hour 0), and the cumulative amount of gas generated over 7 days was measured.

[0186] 3. Aggregation Resistance (Heated Magnetic Stirrer Test) As a substitute test for circulation resistance, an heated magnetic stirrer test with temperature load, which is correlated with circulation resistance, was performed to evaluate agglomeration resistance.

[0187] 300 g each of the glossy paint compositions (Y-1) to (Y-27) was transferred to a 500 mL beaker, and the contents of the beaker were stirred from top to bottom to make a homogeneous mixture. Then, the mixture was stirred using a magnetic stirrer at a temperature of 40°C and 800 rpm for 18 hours. The mouth of the beaker was sealed with Parafilm to prevent evaporation of water during stirring. The stirred glossy paint compositions were then left to stand at a temperature of 23°C for 6 hours.

[0188] 4. Appearance [After Testing (Color Difference)] (Evaluation of Anti-Agglomeration) The color difference ΔE was measured in accordance with JIS Z 8730 for the test boards in the initial and post-tested state. A smaller ΔE value indicates better performance, and a ΔE of less than 2.0 is considered to be at a practical level.

Claims

1. A lustrous pigment dispersion containing a silica-treated aluminum pigment (A) having amino groups on its surface, and a dispersion resin (B), wherein the dispersion resin (B) is a polymer of a composition containing a polymerizable unsaturated monomer (b1) containing phosphate groups and other polymerizable unsaturated monomers (b2), and the weight-average molecular weight of the resin is in the range of 100,000 to 500,000.

2. The luminous pigment dispersion according to claim 1, wherein the silica-treated aluminum pigment (A) having an amino group on its surface comprises a silica-treated aluminum pigment (A1) having an amino group and an alkyl group on its surface.

3. The luminous pigment dispersion according to claim 1 or 2, wherein the polymerizable unsaturated monomer (b1) containing the phosphate group is at least one selected from the group consisting of acid phosphooxyalkyl (meth)acrylate, mono(hydroxyalkyl (meth)acrylate) phosphate, and acid phosphooxypoly(oxyalkylene) glycol (meth)acrylate.

4. The luminous pigment dispersion according to claim 1 or 2, wherein the other polymerizable unsaturated monomer (b2) comprises a polymerizable unsaturated monomer containing a hydroxyl group.

5. The luminous pigment dispersion according to claim 1 or 2, further comprising a nitrogen-containing compound (C).

6. A glossy paint composition containing the glossy pigment dispersion and film-forming resin described in claim 1 or 2.

7. A method for forming a multilayer coating, comprising the following steps (1) to (4): Step (1): Applying a colored coating composition (X) to an object to be coated to form a colored coating film; Step (2): Applying the glossy coating composition (Y) described in claim 6 to the colored coating film obtained in step (1) to form a glossy coating film; Step (3): Applying a clear coating composition (Z) to the glossy coating film obtained in step (2) to form a clear coating film; Step (4): Heating the multilayer coating film, which includes the colored coating film, glossy coating film, and clear coating film formed in steps (1), (2), and (3), respectively, to simultaneously cure the multilayer coating film.

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