Effect pigment dispersion, effect coating composition, and method for forming multilayer coating film

Abstract

An effect pigment dispersion liquid which contains a silica-treated aluminum pigment (A) having an amino group on the surface, a first dispersion resin (B), and water, and wherein: the solid content of the silica-treated aluminum pigment (A) having an amino group on the surface is 90 mass% or more; the first dispersion resin (B) is a polymer of a composition containing a polymerizable unsaturated monomer (b1) containing an acidic functional group, a nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and another polymerizable unsaturated monomer (b3), and the content of water is 90 mass% or more based on the amount of solvent in the effect pigment dispersion.

Description

Technical Field

[0001] The present invention relates to an effect pigment dispersion, an effect coating composition, and a method for forming a multilayer coating film. Background Art

[0002] In recent years, from the viewpoint of global environmental protection, it has been required to reduce volatile organic compounds (VOCs) released from coatings, and in various fields, the replacement from solvent-based coatings to water-based coatings has been rapidly promoted.

[0003] In addition, recently, it has been required to reduce the amount of volatile organic compounds (VOCs) contained in water-based coatings.

[0004] On the other hand, for a coating film formed by coating a coating material, it is required to protect the object to be coated and to impart design (aesthetic appearance) to its appearance at the same time. Among them, metallic coloring is popular because it can create a luxurious feeling.

[0005] However, in metallic coloring, if the amount of organic solvent is reduced in order to reduce the amount of volatile organic compounds (VOCs), the dispersibility of aluminum pigments deteriorates, and it is difficult to obtain a coating film with high effect (brightness).

[0006] Patent Document 1 describes an aluminum pigment composition for water-based coatings, which is characterized in that it contains at least an aluminum pigment, a rheology control agent, and an organic solvent. The organic solvent has a solubility parameter of 6 to 12 and a solubility in water at 20 of 30% by mass or less; with respect to the rheology control agent, when 2.5 parts by mass is added relative to 100 parts by mass of the solid content in the resin emulsion and the viscosity is measured using a B-type viscometer, the viscosity B60 at 60 revolutions and the viscosity B6 at 6 revolutions are both in the range of 0.3 Pa·s to 30 Pa·s, and the thixotropic index as the ratio B6 / B60 of B6 to B60 shows 1 to 60; based on this aluminum pigment composition for water-based coatings, the orientation of the aluminum pigment after coating is improved, whereby the metallic non-uniformity is improved, and thus it is possible to achieve a tone and appearance equivalent to those of solvent-based coatings.

[0007] The above aluminum pigment composition for water-based coatings has good effect, but in recent years, it has been desired to further reduce the amount of volatile organic compounds (VOCs).

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-242457 Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] An object of the present invention is to provide an effect pigment dispersion liquid that can be used for the production of an effect coating composition, the effect coating composition having a low content of volatile organic compounds (VOC) and capable of forming a coating film with excellent effect.

[0013] Means for Solving the Problem

[0014] Based on the present invention, there can be provided an effect pigment dispersion liquid, an effect coating composition, and a method for forming a multilayer coating film including the following embodiments.

[0015] Item 1. An effect pigment dispersion liquid comprising a silica-treated aluminum pigment (A) having an amino group on the surface, a first dispersion resin (B), and water, wherein

[0016] the solid content of the silica-treated aluminum pigment (A) having an amino group on the surface is 90% by mass or more, and

[0017] the first dispersion resin (B) is a polymer of a composition comprising a polymerizable unsaturated monomer (b1) containing an acidic functional group, a nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and other polymerizable unsaturated monomers (b3), and

[0018] based on the amount of the solvent in the effect pigment dispersion liquid, the content of water is 90% by mass or more.

[0019] Item 2. The effect pigment dispersion liquid according to Item 1, wherein the silica-treated aluminum pigment (A) having an amino group on the surface comprises a silica-treated aluminum pigment (A1) having an amino group and an alkyl group on the surface.

[0020] Item 3. The effect pigment dispersion liquid according to Item 1 or 2, wherein the polymerizable unsaturated monomer (b1) containing an acidic functional group comprises a polymerizable unsaturated monomer containing a carboxyl group.

[0021] Item 4. The effect pigment dispersion liquid according to any one of Items 1 to 3, further comprising a second dispersion resin (C), the second dispersion resin (C) being a polymer of a composition comprising a polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group, a nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain, and other polymerizable unsaturated monomers (c3).

[0022] Item 5. An effect coating composition comprising the effect pigment dispersion liquid according to any one of Items 1 to 4 and a film-forming resin.

[0023] Item 6. A method for forming a multilayer coating film, comprising the following steps (1) to (4): Step (1): A step of coating a colored coating composition (X) on an object to be coated to form a colored coating film; Step (2): A step of coating the effect coating composition (Y) described in Item 5 on the colored coating film obtained in Step (1) to form an effect coating film; Step (3): A step of coating a transparent coating composition (Z) on the effect coating film obtained in Step (2) to form a transparent coating film; Step (4): A step of simultaneously curing the multilayer coating film by heating the multilayer coating film including the colored coating film, the effect coating film, and the transparent coating film respectively formed in Steps (1), (2), and (3).

[0024] Effect of the Invention

[0025] When the effect pigment dispersion liquid of the present invention is used, it is possible to manufacture an effect coating composition having a low content of volatile organic compounds (VOC) and capable of forming a coating film with excellent effect properties. Detailed Description of the Invention

[0026] In this specification, "comprise" also includes the concepts of "consist essentially of" and "consist of".

[0027] In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value of a certain numerical range can be arbitrarily combined with the upper limit value or the lower limit value of other numerical ranges. In addition, as the upper limit value or the lower limit value of the numerical range described in this specification including the claims, it can be replaced with the upper limit value or the lower limit value shown in the examples or a value that can be uniquely derived from the examples. Further, in this specification, the numerical values connected by "~" mean a numerical range including the numerical values before and after "~" as the lower limit value and the upper limit value.

[0028] Hereinafter, the effect pigment dispersion liquid of the present invention will be described in further detail.

[0029] Effect pigment dispersion liquid

[0030] The effect pigment dispersion liquid of the present invention is an effect pigment dispersion liquid containing a silica-treated aluminum pigment (A) having an amino group on the surface, a first dispersion resin (B), and water, wherein

[0031] the solid content of the silica-treated aluminum pigment (A) having an amino group on the surface is 90% by mass or more, and

[0032] The first dispersion resin (B) is a polymer of a composition containing a polymerizable unsaturated monomer (b1) having an acidic functional group, a nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and other polymerizable unsaturated monomers (b3), and

[0033] Based on the amount of the solvent in the effect pigment dispersion liquid, the water content is 90% by mass or more.

[0034] Regarding the above water content, from the viewpoint of producing an effect coating composition with a low content of volatile organic compounds (VOCs), based on the amount of the solvent in the effect pigment dispersion liquid, it is preferably 92% by mass or more, and more preferably 94% by mass or more. Examples of the solvent include water and organic solvents. The amount of the solvent in the effect pigment dispersion liquid is the total amount of one or more solvents contained in the effect pigment dispersion liquid.

[0035] Silica-treated aluminum pigment (A) having an amino group on the surface

[0036] The solid content of the silica-treated aluminum pigment (A) having an amino group on the surface is 90% by mass or more. Among them, from the viewpoint of producing an effect coating composition with a low content of volatile organic compounds (VOCs), the solid content is preferably 95% by mass or more, and more preferably 99% by mass or more.

[0037] The silica-treated aluminum pigment (A) having an amino group on the surface can be produced by reacting a silane coupling agent with an aluminum pigment that has been surface-treated with silica. Such an amino-based modification of the silica-treated aluminum pigment is well-known.

[0038] Since the silica-treated aluminum pigment (A) having an amino group on the surface has an amino group on the surface, it interacts with the acidic functional group possessed by the first dispersion resin (B). Therefore, the dispersibility of the above silica-treated aluminum pigment (A) becomes good, and an effect coating composition containing the above silica-treated aluminum pigment (A) can form a coating film with excellent effect.

[0039] From the viewpoint of forming a coating film with excellent effect from the effect coating composition containing the above silica-treated aluminum pigment (A), the average particle diameter of the silica-treated aluminum pigment (A) having an amino group on the surface is preferably in the range of 1 μm to 100 μm, more preferably in the range of 5 μm to 50 μm, and further preferably in the range of 7 μm to 30 μm. In addition, the thickness is preferably in the range of 0.01 μm to 1.0 μm, and more preferably in the range of 0.02 μm to 0.5 μm.

[0040] From the viewpoints of dispersibility and the water resistance and effectiveness of the formed coating film, the silica-treated aluminum pigment (A) having an amino group on the surface preferably includes the silica-treated aluminum pigment (A1) having an amino group and an alkyl group on the surface.

[0041] The silica-treated aluminum pigment (A1) having an amino group and an alkyl group on the surface can be produced by reacting a silane coupling agent with an aluminum pigment that has been surface-treated with silica. Such modification of the silica-treated aluminum pigment based on the amino group and the alkyl group is well-known.

[0042] Regarding the content of the silica-treated aluminum pigment (A) having an amino group on the surface in the effect pigment dispersion of the present invention, from the viewpoint of producing an effect coating composition with a low content of volatile organic compounds (VOC) and capable of forming a coating film with excellent effectiveness, based on 100 parts by mass of the solid content in the effect pigment dispersion, it is preferably 60 to 95 parts by mass, more preferably 65 to 93 parts by mass, and further preferably 70 to 90 parts by mass.

[0043] First dispersion resin (B)

[0044] The first dispersion resin (B) is a polymer of a composition containing a polymerizable unsaturated monomer (b1) having an acidic functional group, a nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and other polymerizable unsaturated monomers (b3).

[0045] Examples of the polymerizable unsaturated monomer (b1) having an acidic functional group include polymerizable unsaturated monomers containing a carboxyl group, polymerizable unsaturated monomers containing a phosphoric acid group, polymerizable unsaturated monomers containing a sulfonic acid group, etc. Among them, polymerizable unsaturated monomers containing a carboxyl group are preferably included.

[0046] The polymerizable unsaturated monomer containing a carboxyl group is a compound having one or more carboxyl groups and one polymerizable unsaturated group in one molecule. Examples include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and maleic anhydride. These can be used alone or in combination of two or more.

[0047] The polymerizable unsaturated monomer containing a phosphoric acid group is a compound having one or more phosphoric acid groups and one polymerizable unsaturated group in one molecule. Examples include acid phosphatooxyethyl (meth)acrylate (also called "(meth)acrylic acid acid phosphatooxyethyl ester"), acid phosphatooxypropyl (meth)acrylate (also called "(meth)acrylic acid acid phosphatooxypropyl ester"), acid phosphatooxy poly(oxyethylene) glycol (meth)acrylate, acid phosphatooxy poly(oxypropylene) glycol (meth)acrylate, etc. These can be used alone or in combination of two or more.

[0048] The polymerizable unsaturated monomer containing a sulfonic acid group is a compound having one or more sulfonic acid groups and one polymerizable unsaturated group in one molecule. Examples thereof include 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth)acrylate, allylsulfonic acid, 4-styrenesulfonic acid, etc., and sodium salts and ammonium salts of these sulfonic acids. These may be used alone or in combination of two or more.

[0049] In this specification, the polymerizable unsaturated group means an unsaturated group capable of radical polymerization. Examples of the polymerizable unsaturated group include a vinyl group, a (meth)acryloyl group, etc.

[0050] In addition, in this specification, “(meth)acrylate” means acrylate or methacrylate; “(meth)acrylic acid” means acrylic acid or methacrylic acid; “(meth)acryloyl group” means acryloyl group or methacryloyl group. “(meth)acrylamide” means acrylamide or methacrylamide.

[0051] Regarding the proportion of the polymerizable unsaturated monomer (b1) containing an acidic functional group among the monomers constituting the first dispersion resin (B), based on the total amount of the polymerizable unsaturated monomer (b1) containing an acidic functional group, the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and other polymerizable unsaturated monomers (b3), it is preferably 1% by mass to 30% by mass, more preferably 3% by mass to 25% by mass, and still more preferably 5% by mass to 20% by mass.

[0052] The nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain is a monomer having a polyoxyalkylene chain and a polymerizable unsaturated group in one molecule. Examples of the polyoxyalkylene chain (also referred to as “polyoxyalkene chain”) include a polyoxyethylene chain, a polyoxypropylene chain, a block chain of polyoxyethylene and polyoxypropylene, etc.

[0053] The molecular weight of the above polyoxyalkylene chain is preferably 150 to 3000, and more preferably in the range of 300 to 2500.

[0054] Examples of the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain include, for example, the compound represented by the following formula (1). CH 2 =C(R 3 )COO(C n H 2n O) m -R 4 (1) In the formula, R 3 represents a hydrogen atom or a methyl group, and R 4 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; m is an integer of 4 to 60, preferably 6 to 50; n is 2 or 3, preferably 2; herein, m oxyalkylene units (also referred to as "alkylene oxide units") (C n H 2n O) may be the same or different).

[0055] Specific examples of the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain include, for example, 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. These can be used alone or in combination of two or more.

[0056] Regarding the proportion of the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain in the monomers constituting the first dispersion resin (B), based on the total amount of the polymerizable unsaturated monomer (b1) having an acidic functional group, the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and the other polymerizable unsaturated monomer (b3), it is preferably 50% by mass to 95% by mass, more preferably 55% by mass to 93% by mass, and still more preferably 60% by mass to 90% by mass.

[0057] The other polymerizable unsaturated monomer (b3) is a compound having one polymerizable unsaturated bond in one molecule other than the above monomers (b1) and (b2). Specific examples thereof are listed below.

[0058] (i) Alkyl (meth)acrylate or cycloalkyl (meth)acrylate: 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, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, tricyclodecyl (meth)acrylate, etc.

[0059] (ii) Polymerizable unsaturated monomer having isobornyl: isobornyl (meth)acrylate, etc.

[0060] (iii) Polymerizable unsaturated monomer having adamantyl: adamantyl (meth)acrylate, etc.

[0061] (iv) Polymerizable unsaturated monomer having tricyclodecenyl: tricyclodecenyl (meth)acrylate, etc.

[0062] (v) Polymerizable unsaturated monomer containing aromatic ring: benzyl (meth)acrylate, styrene, α-methylstyrene, vinyltoluene, etc.

[0063] (vi) Polymerizable unsaturated monomer having alkoxysilyl: vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, etc.

[0064] (vii) Polymerizable unsaturated monomer having fluoroalkyl: perfluoroethyl (meth)acrylate, perfluorooctyl (meth)acrylate, etc., perfluoroalkyl (meth)acrylate; fluoroolefin, etc.

[0065] (viii) Polymerizable unsaturated monomer having a photopolymerizable functional group such as maleimide group.

[0066] (ix) Vinyl compound: N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate, etc.

[0067] (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 and amine compounds, etc.

[0068] (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.

[0069] (xii) Polymerizable unsaturated monomers containing an epoxy group: 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.

[0070] (xiii) Polymerizable unsaturated monomers having an ultraviolet-absorbing functional group: 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.

[0071] (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-crotonyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonyloxy-2,2,6,6-tetramethylpiperidine, etc.

[0072] (xv) Polymerizable unsaturated monomers having a carbonyl group: acrolein, diacetone acrylamide, diacetone methacrylamide, acetylacetoxyethyl methacrylate, formylstyrene, vinyl alkyl ketones having 4 to 7 carbon atoms (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), etc.

[0073] (xvi) Polymerizable unsaturated monomers having an acid anhydride group: maleic anhydride, itaconic anhydride, citraconic anhydride, etc.

[0074] (xvii) Polymerizable unsaturated monomers containing a hydroxyl group: 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2,3-dihydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc., monoesterified products of polyhydric alcohols and (meth)acrylic acid [substances other than the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain], compounds obtained by subjecting the monoesterified product between the above polyhydric alcohol and (meth)acrylic acid to ring-opening polymerization with ε-caprolactone, etc.

[0075] As the proportion of the other polymerizable unsaturated monomer (b3) in the monomers constituting the first dispersion resin (B), based on the total amount of the polymerizable unsaturated monomer (b1) having an acidic functional group, the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and the other polymerizable unsaturated monomer (b3), it is preferably 1% by mass to 25% by mass, more preferably 2% by mass to 15% by mass, and further preferably 3% by mass to 10% by mass.

[0076] The polymerization of the monomers constituting the first dispersion resin (B) can be carried out by a method known per se, such as solution polymerization in an organic solvent, emulsion polymerization in water, etc., and solution polymerization is preferred. As the polymerization method based on the solution polymerization method, for example, the following method can be cited: A mixture of the polymerizable unsaturated monomer (b1) having an acidic functional group, the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and the other polymerizable unsaturated monomer (b3) and a radical polymerization initiator is dissolved or dispersed in an organic solvent, and usually at about 80 to about 200 or so, while stirring for about 1 to 10 hours, it is heated to polymerize.

[0077] As the above-mentioned organic solvents, for example, the following can be cited: hydrocarbon solvents such as heptane, toluene, xylene, octane, and petroleum spirit; 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, isopropyl alcohol, 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; aromatic petroleum solvents such as SWASOL 310, SWASOL 1000, and SWASOL 1500 manufactured by COSMO Oil Co., Ltd. These organic solvents can be used alone or in combination of two or more.

[0078] As the radical polymerization initiator, for example, the following can be cited: 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; dialkyl peroxides such as 1,3-bis(tert-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, diisopropylbenzene peroxide, and tert-butyl cumyl peroxide; diacyl peroxides such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, and 2,4-dichlorobenzoyl peroxide; peroxycarbonates such as bis(tert-butylcyclohexyl) peroxydicarbonate; organic peroxide polymerization initiators such as peroxy esters such as tert-butyl peroxybenzoate and 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane; azo polymerization initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 1,1-azobis(cyclohexane-1-carbonitrile), azo cumene, 2,2'-azobis(methylvaleronitrile), and 4,4'-azobis(4-cyanovaleric acid). The amount of use of these radical polymerization initiators is not particularly limited, and is preferably 0.1 to 15 parts by weight, particularly preferably in the range of 0.3 to 10 parts by weight, based on 100 parts by weight of the total amount of the polymerizable monomers.

[0079] From the viewpoints of the curability and water resistance of the obtained coating film, the hydroxyl value of the first dispersion resin (B) is preferably in the range of 0.1 to 20 mgKOH / g, more preferably in the range of 0.5 to 15 mgKOH / g, and still more preferably in the range of 1 to 10 mgKOH / g.

[0080] From the viewpoint of the interaction with the amino group of the silica-treated aluminum pigment (A) having an amino group on the surface, the acid value of the first dispersion resin (B) is preferably in the range of 5 to 200 mgKOH / g, more preferably in the range of 15 to 180 mgKOH / g, and still more preferably in the range of 30 to 150 mgKOH / g.

[0081] From the viewpoint of dispersion stability and the like, the weight average molecular weight of the first dispersion resin (B) is preferably in the range of 1000 to 50000, more preferably in the range of 2000 to 40000, and still more preferably in the range of 3000 to 30000.

[0082] Regarding the content of the first dispersion resin (B) in the effect pigment dispersion liquid of the present invention, from the viewpoint of manufacturing an effect coating composition having a low content of volatile organic compounds (VOC) and capable of forming a coating film with excellent effect, based on 100 parts by mass of the solid content in the effect pigment dispersion liquid, it is preferably 0.1 part by mass to 20.0 parts by mass, more preferably 0.2 part by mass to 15.0 parts by mass, and still more preferably 0.3 part by mass to 10.0 parts by mass.

[0083] From the viewpoint of manufacturing an effect coating composition having a low content of volatile organic compounds (VOC) and capable of forming a coating film with excellent effect, the effect pigment dispersion liquid of the present invention preferably further contains a second dispersion resin (C).

[0084] Second dispersion resin (C)

[0085] The second dispersion resin (C) is a polymer of a composition containing: a polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group, a nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain, and another polymerizable unsaturated monomer (c3).

[0086] In the present invention, when the dispersion resin belongs to both the first dispersion resin (B) and the second dispersion resin (C) at the same time, it is included in the first dispersion resin (B).

[0087] Examples of the polymerizable unsaturated monomer containing a tertiary amino group include: N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N,N-di-tert-butylaminoethyl (meth)acrylate, N,N-dimethylaminobutyl (meth)acrylate and other N,N-dialkylaminoalkyl (meth)acrylates; N,N-dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide and other N,N-dialkylaminoalkyl (meth)acrylamides, etc.

[0088] Examples of the polymerizable unsaturated monomer containing a quaternary ammonium salt group include: 2-(methacryloyloxy)ethyl trimethylammonium chloride, 2-(methacryloyloxy)ethyl trimethylammonium bromide, 2-(methacryloyloxy)ethyl trimethylammonium dimethyl phosphate (salt) and other (meth)acryloyloxyalkyl trialkylammonium salts; methacryloylaminopropyl trimethylammonium chloride, methacryloylaminopropyl trimethylammonium bromide and other (meth)acryloylaminoalkyl trialkylammonium salts, etc.

[0089] As the polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group, from the viewpoint of producing an effect coating composition with a low content of volatile organic compounds (VOC) and capable of forming a coating film with excellent effects, a polymerizable unsaturated monomer containing a tertiary amino group is preferably included.

[0090] Regarding the proportion of the polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group in the monomers constituting the second dispersion resin (C), based on the total amount of the polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group, the nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain, and the other polymerizable unsaturated monomer (c3), it is preferably 0.1% by mass to 20% by mass, more preferably 0.5% by mass to 15% by mass, and further preferably 1% by mass to 10% by mass.

[0091] As the nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain, the compounds described in the description column of the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain can be used.

[0092] Regarding the proportion of the nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain among the monomers constituting the second dispersion resin (C), based on the total amount of the polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group, the nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain, and the other polymerizable unsaturated monomer (c3), it is preferably 1% by mass to 50% by mass, more preferably 3% by mass to 40% by mass, and still more preferably 5% by mass to 30% by mass.

[0093] As the other polymerizable unsaturated monomer (c3), it is a compound having one polymerizable unsaturated bond in one molecule other than the above monomers (c1) and (c2), and specific examples thereof are listed below.

[0094] (i) Alkyl (meth)acrylate or cycloalkyl (meth)acrylate: 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, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, tricyclodecyl (meth)acrylate, etc.

[0095] (ii) Polymerizable unsaturated monomer having an isobornyl group: Isobornyl (meth)acrylate, etc.

[0096] (iii) Polymerizable unsaturated monomer having an adamantyl group: Adamantyl (meth)acrylate, etc.

[0097] (iv) Polymerizable unsaturated monomer having a tricyclodecenyl group: Tricyclodecenyl (meth)acrylate, etc.

[0098] (v) Polymerizable unsaturated monomer containing an aromatic ring: Benzyl (meth)acrylate, styrene, α-methylstyrene, vinyltoluene, etc.

[0099] (vi) Polymerizable unsaturated monomer having an alkoxysilyl group: Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, etc.

[0100] (vii) Polymerizable unsaturated monomers having a fluoroalkyl group: perfluorobutylethyl (meth)acrylate, perfluorooctylethyl (meth)acrylate and other perfluoroalkyl (meth)acrylates, fluoroolefins; and the like.

[0101] (viii) Polymerizable unsaturated monomers having a photopolymerizable functional group such as a maleimide group.

[0102] (ix) Vinyl compounds: N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate and the like.

[0103] (x) Polymerizable unsaturated monomers containing a carboxyl group: (meth)acrylic acid, maleic acid, crotonic acid, β-carboxyethyl (meth)acrylate and the like.

[0104] (xi) Polymerizable unsaturated monomers containing a hydroxyl group: 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2,3-dihydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate and the like, monoesterified products of polyhydric alcohols and (meth)acrylic acid [substances other than the nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain], compounds obtained by ring-opening polymerization of the monoesterified product between the above polyhydric alcohol and (meth)acrylic acid and ε-caprolactone, and the like.

[0105] (xii) 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 and the like.

[0106] (xiii) Polymerizable unsaturated monomers containing an epoxy group: 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 and the like.

[0107] (xiv) Polymerizable unsaturated monomers having a sulfonic acid group: 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth)acrylate, allyl sulfonic acid, 4-styrenesulfonic acid and the like; sodium salts and ammonium salts of these sulfonic acids and the like.

[0108] (xv) Polymerizable unsaturated monomers containing a phosphoric acid group: acid phosphatooxyethyl (meth)acrylate, acid phosphatooxypropyl (meth)acrylate, acid phosphatooxypoly(oxyethylene) glycol (meth)acrylate, acid phosphatooxypoly(oxypropylene) glycol (meth)acrylate and the like.

[0109] (xvi) Polymerizable unsaturated monomers having an ultraviolet absorbing functional group: 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.

[0110] (xvii) 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-crotonyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonyl-4-crotonyloxy-2,2,6,6-tetramethylpiperidine, etc.

[0111] (xviii) Polymerizable unsaturated monomers having a carbonyl group: acrolein, diacetone acrylamide, diacetone methacrylamide, acetylacetoxyethyl methacrylate, formylstyrene, vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), etc.

[0112] (xix) Polymerizable unsaturated monomers having an acid anhydride group: maleic anhydride, itaconic anhydride, citraconic anhydride, etc.

[0113] Regarding the proportion of the above-mentioned other polymerizable unsaturated monomer (c3) in the monomers constituting the second dispersion resin (C), based on the total amount of the polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group, the nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain, and the other polymerizable unsaturated monomer (c3), it is preferably 45% by mass to 90% by mass, more preferably 55% by mass to 87% by mass, and still more preferably 65% by mass to 85% by mass.

[0114] The monomer constituting the second dispersion resin (C) can be polymerized by a conventionally known method. From the viewpoint of the dispersibility of the silica-treated aluminum pigment (A) having an amino group on the surface, etc., the second dispersion resin (C) is preferably an AB block polymer obtained by an addition-fragmentation chain transfer polymerization method using an addition-fragmentation chain transfer agent. Specifically, in the presence of the above addition-fragmentation chain transfer agent, the monomer components constituting the block are subjected to addition-fragmentation chain transfer polymerization to produce a block polymer. This addition-fragmentation chain transfer polymerization can be carried out, for example, by a solution polymerization method in an organic solvent, an emulsion polymerization method in water, etc. In addition, during the polymerization, in addition to this addition-fragmentation chain transfer agent, a known radical polymerization initiator can be optionally used in combination.

[0115] As the above addition-fragmentation chain transfer agent, for example, 2,4-diphenyl-4-methyl-1-pentene (sometimes simply referred to as "α-methylstyrene dimer", "MSD") can be preferably used. MSD is preferably used in the first polymerization.

[0116] The AB block polymer preferably consists of the following A block and B block. The A block contains the above polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group and other polymerizable unsaturated monomers (c3), and the B block contains a nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain and other polymerizable unsaturated monomers (c3).

[0117] In the above AB block polymer, from the viewpoint of the dispersibility of the silica-treated aluminum pigment (A) having an amino group on the surface, etc., the ratio (mass ratio) of the total amount of the monomers constituting the A block to the total amount of the monomers constituting the B block is preferably 10 / 90 to 60 / 40, more preferably in the range of 20 / 80 to 50 / 50.

[0118] From the viewpoint of the curability and water resistance of the resulting coating film, etc., the hydroxyl value of the second dispersion resin (C) is preferably in the range of 10 to 100 mgKOH / g, more preferably in the range of 20 to 80 mgKOH / g, and further preferably in the range of 30 to 60 mgKOH / g.

[0119] From the viewpoint of the interaction with the silica-treated aluminum pigment (A) having an amino group on the surface and the first dispersion resin (B), the amine value of the second dispersion resin (C) is preferably in the range of 1 to 30 mgKOH / g, more preferably in the range of 3 to 25 mgKOH / g, and further preferably in the range of 5 to 20 mgKOH / g.

[0120] From the viewpoints of dispersion stability and the like, the weight-average molecular weight of the second dispersion resin (C) is preferably in the range of 1,000 to 50,000, more preferably in the range of 2,000 to 40,000, and still more preferably in the range of 3,000 to 30,000.

[0121] Regarding the content of the second dispersion resin (C) in the effect pigment dispersion liquid of the present invention, from the viewpoint of manufacturing an effect coating composition with a low content of volatile organic compounds (VOC) and capable of forming a coating film with excellent effect, based on 100 parts by mass of the solid content in the effect pigment dispersion liquid, it is preferably 1 to 25 parts by mass, more preferably 3 to 23 parts by mass, and still more preferably 5 to 20 parts by mass.

[0122] Other components

[0123] In the effect pigment dispersion liquid of the present invention, organic solvents, pigments other than the above-mentioned silica-treated aluminum pigment (A) having an amino group on the surface, viscosity modifiers, anti-settling agents, ultraviolet absorbers, light stabilizers, etc. can be further appropriately blended as needed.

[0124] From the viewpoint of manufacturing an effect coating composition with a low content of volatile organic compounds (VOC) and capable of forming a coating film with excellent effect, the solid content of the effect pigment dispersion liquid of the present invention is preferably in the range of 10% to 50% by mass, and still more preferably in the range of 20% to 40% by mass.

[0125] Effect coating composition (Y)

[0126] The effect coating composition (Y) of the present invention is an effect coating composition containing the effect pigment dispersion liquid of the present invention and a film-forming resin.

[0127] Regarding the content of water in the effect coating composition (Y) of the present invention, from the viewpoint of manufacturing an effect coating composition (Y) with a low content of volatile organic compounds (VOC), based on the amount of the solvent in the effect coating composition (Y), it is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 85% by mass or more. Examples of the solvent include water and organic solvents. The amount of the solvent in the effect coating composition (Y) is the total amount of one or more solvents contained in the effect coating composition (Y).

[0128] Examples of the above-mentioned film-forming resin include acrylic resin, polyester resin, epoxy resin, polyurethane resin, etc.

[0129] As the above acrylic resin, for example, resins obtained by copolymerizing α,β-ethylenically unsaturated carboxylic acids, (meth)acrylates having functional groups such as hydroxyl group, amide group, hydroxymethyl group, epoxy group, and other (meth)acrylates, styrene, etc. can be cited.

[0130] As the above polyester resin, for example, polyester resins obtained by the condensation reaction of polyhydric alcohols (ethylene glycol, propylene glycol, butylene glycol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, etc.) and polycarboxylic acid components (adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, etc.) can be used.

[0131] As the above epoxy resin, for example, so-called bisphenol A type epoxy resin manufactured by the condensation reaction of bisphenol A and epichlorohydrin can be cited.

[0132] As the above polyurethane resin, for example, compounds obtained by the addition reaction of diisocyanate compounds and polyhydric alcohols, and substances obtained by polymerizing diisocyanate compounds with the above acrylic resin, polyester resin or epoxy resin to increase the molecular weight can be cited.

[0133] Regarding the film-forming resin, in order to make it water-soluble or water-dispersible, it preferably has a sufficient amount of hydrophilic groups.

[0134] As the above hydrophilic groups, for example, carboxyl group, hydroxyl group, hydroxymethyl group, amino group, sulfonic acid group, polyoxyethylene bond, etc. can be cited, and among them, carboxyl group is preferred.

[0135] The above hydrophilic groups are preferably neutralized with sodium hydroxide, amine compounds, etc. to form alkali salts.

[0136] In addition, the water-dispersion of the above resin can also be carried out by emulsion polymerization of polymerizable components in the presence of surfactants and water-soluble resins. In addition, it can also be obtained by dispersing the above resin in water in the presence of, for example, emulsifiers. In this water-dispersion, the matrix resin may not contain the above hydrophilic groups.

[0137] The above film-forming resin can be used alone or in combination of two or more.

[0138] Regarding the content of the above film-forming resin in the effect coating composition (Y) of the present invention, from the viewpoint of forming a film with excellent effect, based on 100 parts by mass of the total solid components in the effect coating composition (Y), it is preferably in the range of 30 parts by mass to 85 parts by mass, and more preferably in the range of 35 parts by mass to 80 parts by mass.

[0139] The effect coating composition (Y) of the present invention preferably further contains a curing agent.

[0140] As the above-mentioned curing agent, for example, amino resins, polyisocyanate compounds, blocked polyisocyanate compounds, etc. can be cited. The curing agent can be used alone or in combination of two or more.

[0141] When the effect coating composition (Y) of the present invention contains the above-mentioned curing agent, in terms of the content ratio of the film-forming resin and the curing agent, based on the total mass of the two components, the former is preferably in the range of 50% by mass to 90% by mass, particularly preferably in the range of 60% by mass to 85% by mass, and the latter is preferably in the range of 10% by mass to 50% by mass, particularly preferably in the range of 15% by mass to 40% by mass.

[0142] In addition to containing the above-mentioned components, the effect coating composition (Y) of the present invention can also appropriately contain coloring pigments, extender pigments, effect pigments other than the silica-treated aluminum pigment (A) having an amino group on the surface, curing catalysts, ultraviolet absorbers, defoamers, viscosity regulators, surface regulators, organic solvents, etc. according to the need.

[0143] As the above-mentioned coloring pigment, for example, 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. can be cited, and among them, carbon black is preferably included.

[0144] When the effect coating composition (Y) of the present invention contains the above-mentioned coloring pigment, based on 100 parts by mass of the resin solid content in the effect coating composition (Y), the content of the coloring pigment is preferably 0.1 part by mass to 30 parts by mass, and more preferably 0.5 part by mass to 20 parts by mass.

[0145] As the above-mentioned extender pigment, for example, barium sulfate, talc, clay, kaolin, barium carbonate, calcium carbonate, silica, alumina white, etc. can be cited.

[0146] When the effect coating composition (Y) of the present invention contains the above-mentioned extender pigment, based on 100 parts by mass of the resin solid content in the effect coating composition (Y), the content of the extender pigment is preferably 0.1 part by mass to 30 parts by mass, and more preferably 0.5 part by mass to 20 parts by mass.

[0147] As the above-mentioned effect pigment other than the silica-treated aluminum pigment (A) having an amino group on the surface, for example, aluminum (including vapor-deposited aluminum), copper, zinc, brass, nickel, glass flakes, alumina, mica, alumina coated with titanium oxide and / or iron oxide, mica coated with titanium oxide and / or iron oxide, etc. other than the silica-treated aluminum pigment (A) having an amino group on the surface can be cited.

[0148] When the effect coating composition (Y) of the present invention contains an effect pigment other than the silica-treated aluminum pigment (A) having an amino group on the surface, based on 100 parts by mass of the resin solid content in the effect coating composition (Y), the content of the effect pigment is preferably 0.1 part by mass to 30 parts by mass, more preferably 0.5 part by mass to 20 parts by mass.

[0149] As the above-mentioned curing catalyst, for example, the following can be used: organometallic compounds such as tin octoate, dibutyltin diacetate, dibutyltin bis(2-ethylhexanoate), dibutyltin dilaurate, dioctyltin diacetate, dioctyltin bis(2-ethylhexanoate), dibutyltin oxide, dibutyltin sulfide, dioctyltin oxide, dibutyltin fatty acid salts, lead 2-ethylhexanoate, zinc octoate, zinc naphthenate, fatty acid zincs, bismuth octoate, bismuth 2-ethylhexanoate, bismuth oleate, bismuth neodecanoate, bismuth versatate, bismuth naphthenate, cobalt naphthenate, calcium octoate, copper naphthenate, tetra(2-ethylhexyl) titanate, etc.; compounds containing a sulfonic acid group such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, etc.; compounds containing a phosphoric acid group such as monobutyl phosphate, dibutyl phosphate, mono(2-ethylhexyl) phosphate, bis(2-ethylhexyl) phosphate, alkyl ether phosphoric acid, polyoxyethylene alkyl ether phosphoric acid, resin containing a phosphoric acid group, etc.

[0150] When the effect coating composition (Y) of the present invention is used, water and / or an organic solvent can be added as needed for dilution and adjusted to a suitable viscosity, and then painting can be carried out.

[0151] The suitable viscosity varies depending on the coating composition. For example, it is preferably adjusted appropriately using water and / or an organic solvent so that the viscosity measured at a rotation speed of 6 rpm using a B-type viscometer at 20 is in the range of 2000 to 7000 mPa･s. In addition, in the above, the coating solid content concentration of the effect coating composition (Y) is preferably 3% by mass to 30% by mass, more preferably about 5% by mass to 25% by mass.

[0152] The effect coating composition (Y) of the present invention can be either a one-component type coating or a multi-component type coating. From the viewpoints of excellent productivity without a coating mixing process and the ability to simplify the maintenance of painting machinery, etc., a one-component type coating is preferred.

[0153] The effect coating composition (Y) of the present invention can be applied to an object to be coated by a known method (such as air spraying, airless spraying, rotary atomization spraying, curtain coating, etc.). Electrostatic charges can be applied during painting. Among these, methods such as air spraying and rotary atomization spraying are preferred. In addition, the painting method can be carried out once or several times until the desired film thickness is obtained.

[0154] Regarding the coating amount of the effect coating composition (Y) of the present invention, in terms of the cured film thickness, it is preferably an amount of 0.5 μm to 20 μm, more preferably 1 μm to 15 μm, and still more preferably 2 μm to 10 μm.

[0155] Method for forming a multilayer coating film

[0156] The method for forming a multilayer coating film of the present invention is a method for forming a multilayer coating film including the following steps (1) to (4): Step (1): A step of coating a colored coating composition (X) on an object to be coated to form a colored coating film, Step (2): A step of coating the effect coating composition (Y) of the present invention on the colored coating film obtained in step (1) to form an effect coating film, Step (3): A step of coating a transparent coating composition (Z) on the effect coating film obtained in step (2) to form a transparent coating film, Step (4): A step of heating the multilayer coating film including the colored coating film, the effect coating film, and the transparent coating film respectively formed in steps (1), (2), and (3) to simultaneously cure the multilayer coating film.

[0157] The object to be coated is not particularly limited. For example, it may include: the outer panel part of an automobile body such as a passenger car, a truck, a motorcycle, a bus, etc.; automobile parts; the outer panel part of household appliances such as a mobile phone, an audio device, etc. Among these, the outer panel part of an automobile body and automobile parts are preferred.

[0158] The material of these objects to be coated is not particularly limited. For example, it may include: metal materials such as iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel, galvanized alloy (Zn - Al, Zn - Ni, Zn - Fe, etc.) steel; resin materials such as polyethylene resin, polypropylene resin, acrylonitrile - butadiene - styrene (ABS) resin, polyamide resin, acrylic resin, polyvinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin; plastic materials such as various FRPs; inorganic materials such as glass, cement, concrete; wood; fiber materials such as paper, cloth, etc. Among these, metal materials and plastic materials are preferred.

[0159] In addition, as the surface of the object to be coated applicable to the multilayer coating film, it may be a surface of an object obtained by subjecting a metal surface such as the outer panel part of an automobile body, automobile parts, household appliances, and metal substrates such as steel plates constituting them to surface treatments such as phosphate treatment, chromate treatment, and composite oxide treatment.

[0160] On an object that may or may not be subjected to surface treatment, a coating film can be further formed. For example, the object to be coated as a substrate can be subjected to surface treatment as needed, and a primer coating film and / or an intermediate coating film can be formed thereon. For example, when the object to be coated is an automobile body, the primer coating film and / or the intermediate coating film can be formed using known primer coating and / or intermediate coating paint compositions commonly used in the painting of automobile bodies.

[0161] 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. In addition, as the intermediate coating composition for forming the above-mentioned intermediate coating film, a substance obtained by coating a matrix resin (such as an acrylic resin, a polyester resin, an alkyd resin, a polyurethane resin, an epoxy resin, etc.) having crosslinkable functional groups such as carboxyl groups and hydroxyl groups, a crosslinking agent such as an amino resin (such as a melamine resin and a urea resin) and a blocked or unblocked polyisocyanate compound, together with a pigment, a thickener, and optionally other components, can be used.

[0162] As the colored coating composition (X), a known thermosetting colored coating composition for coating an automobile body or the like can be used. For example, a thermosetting coating composition containing a matrix resin having crosslinkable functional groups, a crosslinking agent, a coloring pigment, and an extender pigment can be preferably used. In addition, an effect pigment can also be included.

[0163] Examples of the crosslinkable functional groups possessed by the above-mentioned matrix resin include carboxyl groups, hydroxyl groups, and epoxy groups.

[0164] Examples of the types of the above-mentioned matrix resin include acrylic resins, polyester resins, alkyd resins, and polyurethane resins.

[0165] Examples of the crosslinking agent include melamine resins, polyisocyanate compounds, and blocked polyisocyanate compounds.

[0166] As the colored coating composition (X), either an aqueous coating composition or an organic solvent-based coating composition can be used; from the viewpoint of reducing the environmental load and the like, an aqueous coating composition is preferred.

[0167] The coating method of the colored coating composition (X) is not particularly limited. For example, a wet coating film can be formed by using coating methods such as air spray coating, airless spray coating, rotary atomization coating, and curtain coating. In these coating methods, static electricity can be applied as needed. Among them, air spray coating or rotary atomization coating is particularly preferred. Regarding the coating amount of the colored coating composition (X), it is preferably an amount that reaches 5 μm to 30 μm in terms of the cured film thickness, and more preferably an amount that reaches 7 μm to 20 μm.

[0168] In addition, in the case of air spray coating, airless spray coating, and rotary atomization coating, the viscosity of the colored coating composition (X) is appropriately adjusted to a viscosity range suitable for the coating in advance using a solvent such as water or an organic solvent. Preferably, in a Ford No. 4 cup viscometer, at 20 it becomes a viscosity range of about 15 seconds to 60 seconds, particularly preferably about 20 seconds to 50 seconds.

[0169] As the transparent coating composition (Z), a known thermosetting transparent coating composition used for coating automotive bodies or the like can be arbitrarily used. For example, an organic solvent-based thermosetting coating composition, an aqueous thermosetting coating composition, a powder thermosetting coating composition, etc. containing a matrix resin having a crosslinkable functional group and a curing agent can be cited.

[0170] Examples of the crosslinkable functional group possessed by the above matrix resin include a carboxyl group, a hydroxyl group, an epoxy group, a silanol group, etc. Examples of the type of matrix resin include an acrylic resin, a polyester resin, an alkyd resin, a polyurethane resin, an epoxy resin, a fluororesin, etc. Examples of the curing agent include a polyisocyanate compound, a blocked polyisocyanate compound, a melamine resin, a urea resin, a compound containing a carboxyl group, a resin containing a carboxyl group, a resin containing an epoxy group, a compound containing an epoxy group, etc.

[0171] As the combination of the matrix resin / curing agent of the transparent coating composition (Z), a resin containing a carboxyl group / a resin containing an epoxy group, a resin containing a hydroxyl group / a polyisocyanate compound, a resin containing a hydroxyl group / a blocked polyisocyanate compound, a resin containing a hydroxyl group / a melamine resin, etc. are preferred.

[0172] In addition, the above transparent coating composition (Z) can be a one-component type coating or a multi-component type coating such as a two-component type polyurethane resin coating.

[0173] In addition, in the above transparent coating composition (Z), a coloring pigment, an effect pigment, a dye, etc. can be contained as needed within the extent that does not impair transparency, and a extender pigment, an ultraviolet absorber, a light stabilizer, an antifoaming agent, a thickener, a rust inhibitor, a surface conditioner, etc. can also be appropriately contained.

[0174] As the coating method of the transparent coating composition (Z), there is no particular limitation. For example, a wet coating film can be formed using coating methods such as air spray coating, airless spray coating, rotary atomization coating, curtain coating, etc. In these coating methods, static electricity can be applied as needed. Among them, air spray coating or rotary atomization coating is particularly preferred. Regarding the coating amount of the transparent coating composition (Z), a cured film thickness of 10 μm to 50 μm is preferred, and more preferably 20 μm to 40 μm.

[0175] In addition, in the case of air spray coating, airless spray coating, and rotary atomization coating, the viscosity of the transparent coating composition (Z) is appropriately adjusted to a viscosity range suitable for the coating in advance using a solvent such as an organic solvent. Preferably, the viscosity becomes about 15 seconds to 60 seconds, particularly preferably about 20 seconds to 50 seconds, at 20 in a Ford No. 4 cup viscometer.

[0176] The above heating can be carried out by known means. For example, drying furnaces such as hot blast furnaces, electric furnaces, and infrared induction heating furnaces can be applied. The heating temperature is preferably in the range of 70 to 160 and more preferably in the range of 90 to 150 . There is no particular limitation on the heating time, and it is preferably in the range of 10 minutes to 60 minutes, and more preferably in the range of 20 minutes to 40 minutes.

[0177] Examples

[0178] Hereinafter, the present invention will be described more specifically by giving production examples, examples, and comparative examples. It should be noted that these production examples, examples, and comparative examples are merely examples and are not intended to limit the scope of the present invention. In the production examples, examples, and comparative examples, unless otherwise specified, "parts" and "%" are based on mass. In addition, the film thickness of the coating film is based on the cured coating film.

[0179] 1. Production of the object to be coated

[0180] The cationic electrodeposition coating "Elecron GT-10" (trade name: manufactured by Kansai Paint Co., Ltd., a substance obtained by using a blocked polyisocyanate compound as a curing agent in an epoxy resin polyamine-based cationic resin) was electrodeposition-coated on a degreased and zinc phosphate-treated steel plate (JIS G3141, size 400 mm × 300 mm × 0.8 mm) so that the film thickness based on the cured coating film became 20 μm, and heated at 170 for 20 minutes to crosslink and cure it, forming an electrodeposition coating film.

[0181] By air spraying, "WP-523H" (trade name: Kansai Paint Co., Ltd., an acrylic / melamine resin-based aqueous intermediate coating) was coated on the electrodeposition-coated surface of the above steel plate so that the film thickness based on the cured coating film became 20 μm. After standing for 3 minutes, it was preheated at 80 for 3 minutes to form an uncured intermediate coating film, thereby producing the object to be coated.

[0182] 2. Production of the coating

[0183] Manufacture of hydroxyl group-containing acrylic resin emulsion (1)

[0184] Production Example 1

[0185] Into a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, and a dropping device, 70.7 parts of deionized water and 0.52 parts of "AQUALON KH-10" (trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., emulsifier, active ingredient 97%) were charged, and the mixture was stirred and mixed in a nitrogen stream, and the temperature was raised to 80 . Then, 1% of the total amount of the following monomer emulsion and 5 parts of 6% ammonium persulfate aqueous solution were introduced into the reaction vessel, and the temperature was maintained at 80 for 15 minutes. Then, the remaining monomer emulsion was added dropwise to the reaction vessel maintained at this temperature over 3 hours. After the addition was completed, the mixture was aged for 1 hour. Then, while gradually adding 40 parts of 5% 2-(dimethylamino)ethanol aqueous solution to the reaction vessel, the temperature was cooled to 30 , and while filtering through a 100-mesh nylon cloth, the mixture was discharged to obtain a hydroxyl group-containing acrylic resin emulsion (1) having a solid content concentration of 45%. The hydroxyl value of the obtained hydroxyl group-containing acrylic resin emulsion (1) was 43 mgKOH / g, and the acid value was 12 mgKOH / g.

[0186] Monomer emulsion: 50 parts of deionized water, 10 parts of styrene, 40 parts of methyl methacrylate, 35 parts of ethyl acrylate, 3.5 parts of n-butyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate, 1.5 parts of acrylic acid, 1.0 part of "Aqualon KH-10", and 0.03 part of ammonium persulfate were mixed and stirred to obtain a monomer emulsion.

[0187] Manufacture of hydroxyl group-containing polyester resin (2)

[0188] Production Example 2

[0189] Into a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, and a water separator, 174 parts of trimethylolpropane, 327 parts of neopentyl glycol, 352 parts of adipic acid, 109 parts of isophthalic acid, and 101 parts of 1,2-cyclohexanedicarboxylic anhydride were charged, and the temperature was raised from 160 to 230 over 3 hours, and while distilling off the generated condensation water using the water separator, the temperature was maintained at 230 until the acid value became 3 mgKOH / g or less. 59 parts of trimellitic anhydride were added to the reaction product, and an addition reaction was carried out at 170 for 30 minutes, and then the temperature was cooled to 50 Next, 2-(dimethylamino)ethanol was added in an amount equivalent to the acid groups for neutralization, and then deionized water was gradually added to obtain a solution of a hydroxyl group-containing polyester resin (2) having a solid content concentration of 45% and a pH of 7.2. The hydroxyl value of the obtained hydroxyl group-containing polyester resin (2) was 128 mgKOH / g, the acid value was 35 mgKOH / g, and the weight average molecular weight was 13,000.

[0190] Manufacture of colored pigment dispersion paste

[0191] Production Example 3

[0192] 56 parts (25 parts of solid content) of the hydroxyl group-containing polyester resin (2) solution obtained in Production Example 2, 60 parts of "JR-806" (trade name, rutile titanium dioxide, manufactured by TAYCA Corporation), 1 part of "Carbon MA-100" (trade name, carbon black, manufactured by Mitsubishi Chemical Corporation), 15 parts of "BARIACE B-35" (trade name, barium sulfate powder, manufactured by Sakai Chemical Industry Co., Ltd.) and 5 parts of deionized water were mixed, and the pH was adjusted to 8.0 with 2-(dimethylamino)ethanol. Then, the obtained mixture was put into a wide-mouth glass bottle, glass beads with a diameter of about 1.3 mm were added as a dispersion medium, sealed, and dispersed with a paint stirrer for 30 minutes to obtain a colored pigment dispersion slurry (P-1).

[0193] Manufacture of colored coating composition (X)

[0194] Production Example 4

[0195] 137 parts of the colored pigment dispersion slurry (P-1) obtained in Production Example 3, 25 parts (11 parts of solid content) of the hydroxyl group-containing acrylic resin emulsion (1) obtained in Production Example 1, 20 parts (9 parts of solid content) of the polyester resin solution (2) obtained in Production Example 2, 78 parts (30 parts of solid content) of "BAYHYDUR VPLS2310" (trade name, blocked polyisocyanate compound, manufactured by Sumika Covestro Urethane Co., Ltd., solid content 38%) and 72 parts (25 parts of solid content) of "UCOAT UX-8100" (trade name, urethane emulsion, manufactured by Sanyo Chemical Industries, Ltd., solid content 35%) were uniformly mixed. Then, "UH-752" (trade name, thickener, manufactured by ADEKA Corporation), 2-(dimethylamino)ethanol and deionized water were added to the obtained mixture to obtain a colored coating composition (X-1) having a pH of 8.0, a coating solid content of 48%, and a viscosity of 30 seconds based on Ford No. 4 cup at 20 °C.

[0196] Manufacture of first dispersion resin (B)

[0197] Production Example 5

[0198] 75 parts of propylene glycol monomethyl ether was charged into a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, a nitrogen inlet tube, and a dropping device, and the temperature was raised to 95 After that, a mixture of 2 parts of styrene, 1.5 parts of n-butyl methacrylate, 1.5 parts of 2-hydroxyethyl methacrylate, 12 parts of methacrylic acid, 83 parts of methoxypolyethylene glycol methacrylate (molecular weight: about 496), 120 parts of propylene glycol monomethyl ether, and 10 parts of 2,2'-azobis(2-methylbutyronitrile) was added dropwise over 4 hours. After the addition was completed, the mixture was aged for 30 minutes. Then, a mixture of 10 parts of propylene glycol monomethyl ether and 0.5 part of 2,2'-azobis(2-methylbutyronitrile) was further added dropwise over 1 hour. After the addition was completed, the mixture was aged for 1 hour. Then, desolvation was carried out under reduced pressure to remove propylene glycol monomethyl ether until the solid content reached 90% by mass. The resulting first dispersion resin (B-1) had a weight-average molecular weight of 5000, an acid value of 78 mgKOH / g, and a hydroxyl value of 6.5 mgKOH / g.

[0199] Production Examples 6 to 13

[0200] In Production Example 5, the composition was made as shown in Table 1, and otherwise, the same operation as in Production Example 5 was carried out to obtain solutions of first dispersion resins (B-2) to (B-9) having a solid content of 90% by mass. The weight-average molecular weight, acid value, and hydroxyl value of each first dispersion resin are shown in Table 2.

[0201] [Table 1]

[0202] [Table 2]

[0203] Manufacture of second dispersion resin (C)

[0204] Production Example 14

[0205] 18.2 parts of ethylene glycol monobutyl ether and 11.8 parts of 2,4-diphenyl-4-methyl-1-pentene were charged into a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, and a dropping device, and stirred and mixed in a nitrogen stream until the temperature reached 120 After that, the following monomer mixture I was added dropwise over 6 hours, and the mixture was aged for 30 minutes at 120 Aged for 30 minutes.

[0206] <Composition of monomer mixture I>

[0207] 87 parts of methyl methacrylate

[0208] 12 parts of N,N-dimethylaminoethyl methacrylate

[0209] 0.5 part of tridecyl methacrylate

[0210] 0.5 part of lauryl methacrylate

[0211] 3 parts of 2,2’-azobis(2-methylbutyronitrile)

[0212] 6 parts of ethylene glycol monobutyl ether

[0213] Next, the following additional catalyst mixture was added dropwise to the above-mentioned cured product over 1 hour, and at 120 After curing for 1 hour, 18 parts of ethylene glycol monobutyl ether and 22.7 parts of propylene glycol monobutyl ether were added to make the solid content concentration 60%, and a polymer A solution as a macromonomer was obtained. The weight-average molecular weight of the obtained polymer A was about 3000.

[0214] <Additional catalyst mixture>

[0215] 0.5 part of 2,2’-azobis(2-methylbutyronitrile)

[0216] 9 parts of ethylene glycol monobutyl ether

[0217] Next, 41.7 parts of the above polymer A as a macromonomer was charged into a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, and a dropping device, and stirred and mixed in a nitrogen stream until it reached 95 After that, the following monomer mixture II and monomer mixture III were added dropwise over 3 hours, and cured at 95 for 30 minutes.

[0218] <Composition of monomer mixture II>

[0219] 45 parts of methyl methacrylate

[0220] 10 parts of 2-hydroxyethyl methacrylate

[0221] 0.9 part of 2,2’-azobis(2-methylbutyronitrile)

[0222] 5 parts of propylene glycol monobutyl ether

[0223] <Composition of monomer mixture III>

[0224] 20 parts of methoxypolyethylene glycol methacrylate (molecular weight about 2080)

[0225] 20 parts of deionized water

[0226] 5 parts of ethylene glycol monobutyl ether

[0227] Next, the following additional catalyst mixture was added dropwise to the above-mentioned matured product over a period of 1 hour at 95 After aging for 1 hour, 36 parts of propylene glycol monobutyl ether was added so that the solid content concentration became 53%, thereby obtaining a second dispersion resin (C-1) solution as an AB block polymer. The obtained polymer had a weight average molecular weight of about 15,000, an amine value of 9.5 mgKOH / g, and a hydroxyl value of 43 mgKOH / g.

[0228] <Addition of catalyst mixture>

[0229] 2,2'-Azobis(2-methylbutyronitrile) 0.375 parts

[0230] 6 parts of propylene glycol monobutyl ether

[0231] Manufacture of carboxylic acid group-containing dispersion resin (3)

[0232] Production Example 15

[0233] 35 parts of propylene glycol monopropyl ether were placed in a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a nitrogen inlet tube and a dropping device, and the temperature was raised to 85 Then, a mixture of 30 parts of methyl methacrylate, 20 parts of 2-ethylhexyl acrylate, 29 parts of n-butyl acrylate, 15 parts of 2-hydroxyethyl acrylate, 6 parts of acrylic acid, 15 parts of propylene glycol monopropyl ether and 2.3 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) was added dropwise over 4 hours, and the mixture was aged for 1 hour after the addition was completed. Then, a mixture of 10 parts of propylene glycol monopropyl ether and 1 part of 2,2'-azobis(2,4-dimethylvaleronitrile) was added dropwise over 1 hour, and the mixture was aged for 1 hour after the addition was completed. Further, 7.4 parts of diethanolamine was added to obtain a carboxylic acid group-containing dispersion resin (3) solution having a solid content of 55%. The obtained carboxylic acid group-containing dispersion resin (3) had an acid value of 47 mgKOH / g, a hydroxyl value of 72 mgKOH / g, and a weight average molecular weight of 58,000.

[0234] Manufacture of dispersion resin (4) containing a phosphoric acid group

[0235] Production Example 16

[0236] A mixed solvent of 27.5 parts of methoxypropanol and 27.5 parts of isobutyl alcohol was added to a reaction vessel equipped with a thermostat, a stirrer, a reflux condenser and a dropping device, and heated to 110 , over 4 hours, 121.5 parts of a mixture containing 25 parts of styrene, 27.5 parts of n-butyl methacrylate, 20 parts of “isostearyl acrylate” (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., branched higher alkyl acrylate), 7.5 parts of 4-hydroxybutyl acrylate, 15 parts of the following polymerizable monomer containing a phosphate group, 12.5 parts of 2-methacryloyloxyethyl acid phosphate (also known as “2-methacryloyloxyethyl acid phosphate”), 10 parts of isobutanol, and 4 parts of tert-butyl peroxyoctanoate were added to the above mixed solvent, and further, over 1 hour, a mixture containing 0.5 part of tert-butyl peroxyoctanoate and 20 parts of isopropanol was added dropwise. Then, it was stirred and aged for 1 hour to obtain a solution of a phosphate group-containing dispersion resin (4) with a solid content concentration of 50%. The acid value of this resin based on the phosphate group was 83 mgKOH / g, the hydroxyl value was 29 mgKOH / g, and the weight average molecular weight was 10,000.

[0237] Polymerizable monomer containing a phosphate group: Into a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, and dropping device, 57.5 parts of monobutyl phosphate and 41 parts of isobutanol were added, and the temperature was raised to 90 After that, 42.5 parts of glycidyl methacrylate were added dropwise over 2 hours, and then it was further stirred and aged for 1 hour. Then, 59 parts of isopropanol were added to obtain a polymerizable monomer solution containing a phosphate group with a solid content of 50%. The acid value of the obtained monomer based on the phosphate group was 285 mgKOH / g.

[0238] Manufacture of dispersion resin (5) containing a nonionic polymerizable unsaturated monomer having an amino group and a polyoxyalkylene chain

[0239] Production Example 17

[0240] 20 parts of ethylene glycol monobutyl ether were charged into a four-necked flask equipped with a stirring device, thermometer, cooling tube, and nitrogen inlet, and the temperature was raised to 95 under nitrogen gas flow . When it reached 95 After that, the nitrogen gas flow was stopped, and a mixture containing 10 parts of styrene, 40 parts of methyl methacrylate, 10 parts of 2-hydroxyethyl acrylate, 10 parts of dimethylaminoethyl methacrylate, 30 parts of methoxypolyethylene glycol methacrylate (molecular weight of about 1000), 65 parts of ethylene glycol monobutyl ether, and 1 part of 2,2’-azobisisobutyronitrile was added dropwise over 3 hours. While passing nitrogen gas, it was aged for 2 hours, and then cooled to 60 ​, diluted with 15 parts of ethylene glycol monobutyl ether, whereby a dispersion resin (5) solution containing a nonionic polymerizable unsaturated monomer having an amino group and a polyoxyalkylene chain with a solid content of 50% was obtained. The resulting dispersion resin (5) containing a nonionic polymerizable unsaturated monomer having an amino group and a polyoxyalkylene chain had an amine value of 35.5 mgKOH / g, a hydroxyl value of 48.4 mgKOH / g, and a number average molecular weight of 6500.

[0241] Manufacture of effect pigment dispersion liquid

[0242] Example 1

[0243] In a stirring and mixing container, 30 parts (30 parts of solid content) of aluminum pigment A (silica-treated aluminum pigment having an amino group and an alkyl group on the surface, average particle diameter (d50) 19 μm, average thickness 0.40 μm, solid content concentration 100%), 80 parts of deionized water, and 2 parts (1.8 parts of solid content) of the first dispersion resin (B-1) obtained in Production Example 5 were uniformly mixed to obtain an effect pigment dispersion (P-2).

[0244] Examples 2 to 10 and Comparative Examples 1 to 4

[0245] Except for setting the formulation as described in Table 2, all operations were carried out in the same manner as in Example 1 to obtain effect pigment dispersions (P-3) to (P-15).

[0246] [Table 3]

[0247] [Table 4]

[0248] Manufacture of hydroxyl group-containing acrylic resin emulsion (6)

[0249] Production Example 18

[0250] Into a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, and dropping device, 130 parts of deionized water and 0.52 part of "Aqualon KH-10" were charged, stirred and mixed in a nitrogen stream, and heated to 80 . Then, 1% of the total amount of the following monomer emulsion (1) and 5.3 parts of a 6% aqueous ammonium persulfate solution were introduced into the reaction vessel and maintained at 80 for 15 minutes. Then, the remaining monomer emulsion (1) was added dropwise to the reaction vessel maintained at this temperature over 3 hours, and after the addition was completed, it was aged for 1 hour. Then, the following monomer emulsion (2) was added dropwise over 1 hour, and after aging for 1 hour, while gradually adding 40 parts of a 5% aqueous dimethylethanolamine solution to the reaction vessel, it was cooled to 30 , while filtering with a 100-mesh nylon cloth and discharging, an acrylic resin emulsion (6) containing hydroxyl groups with a solid component concentration of 30% is obtained. The hydroxyl value of the obtained acrylic resin emulsion (6) containing hydroxyl groups is 25 mgKOH / g, and the acid value is 33 mgKOH / g.

[0251] Monomer emulsion (1): 42 parts of deionized water, 0.72 part of "Aqualon KH-10", 2.1 parts of methylene bisacrylamide, 2.8 parts of styrene, 16.1 parts of methyl methacrylate, 28 parts of ethyl acrylate, and 21 parts of n-butyl acrylate are mixed and stirred to obtain monomer emulsion (1).

[0252] Monomer emulsion (2): 18 parts of deionized water, 0.31 part of "Aqualon KH-10", 0.03 part 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 are mixed and stirred to obtain monomer emulsion (2).

[0253] Manufacture of acrylic resin for colored pigment dispersion (7)

[0254] Production Example 19

[0255] 48 parts of ethylene glycol monobutyl ether are charged into a common acrylic resin reaction tank equipped with a stirrer, a thermometer, and a reflux condenser, heated and stirred, and maintained at 110 . Into it, a mixture containing 10 parts of styrene, 40 parts of methyl methacrylate, 25 parts of n-butyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate, 3 parts of methacrylic acid, 5 parts of N,N-dimethylaminoethyl methacrylate (solid component amount, dissolved in 10 parts of deionized water for formulation), 10 parts of polyethylene glycol monomethacrylate (molecular weight of about 350), 4 parts of azobisisobutyronitrile, and 20 parts of isobutanol is added dropwise over 3 hours. After the addition is completed, it is aged at 110 for 30 minutes, and then a supplementary catalyst mixture containing 25 parts of ethylene glycol monobutyl ether and 0.5 part of azobisisobutyronitrile is added dropwise over 1 hour. Then, it is aged at 110 for 1 hour, and then cooled to obtain an acrylic resin (7) solution for coloring pigment dispersion with a solid component of 50%. The hydroxyl value of the acrylic resin (7) for coloring pigment dispersion is 43 mgKOH / g, and the weight average molecular weight is about 20,000.

[0256] Manufacture of hydroxyl group-containing polyester resin (8)

[0257] Production Example 20

[0258] Into a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, and a 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. It was heated from 160 to 230 over 3 hours. After that, a condensation reaction was carried out at 230 for 4 hours. Then, in order to add a carboxyl group to the obtained condensation reaction product, 38.3 parts of trimellitic anhydride were further added. After reacting for 30 minutes at 170 it was diluted with 2 - ethyl - 1 - hexanol to obtain a solution of a hydroxyl - containing polyester resin (8) with a solid component concentration of 70%. The hydroxyl value of the obtained hydroxyl - containing polyester resin (8) was 150 mgKOH / g, the acid value was 46 mgKOH / g, and the weight - average molecular weight was 6400.

[0259] Manufacture of colored pigment dispersion paste (P-16)

[0260] Production Example 21

[0261] 16 parts (8 parts in terms of solid component) of the acrylic resin (7) solution for dispersing coloring pigments obtained in Production Example 19, 5 parts of "RAVEN 5000 ULTRA III BEADS" (trade name, carbon black pigment, manufactured by COLUMBIAN CARBON CO.), and 70 parts of deionized water were mixed and dispersed with a paint stirrer for 2 hours to obtain a coloring pigment - dispersed slurry (P - 16) with a solid component of 14.3%.

[0262] Manufacture of effect coating composition (Y)

[0263] Example 11

[0264] 112 parts (31.8 parts of solid content) of the effect pigment dispersion liquid (P-2) obtained in Example 1, 91 parts (13 parts of solid content) of the colored pigment dispersion slurry (P-16) obtained in Production Example 21, 83.3 parts (25 parts of solid content) of the hydroxyl group-containing acrylic resin emulsion (6) obtained in Production Example 18, 35.7 parts (25 parts of solid content) of the solution of the hydroxyl group-containing polyester resin (8) obtained in Production Example 20, 37.5 parts (30 parts of solid content) of "CYMEL 325" (trade name, manufactured by Allnex Co., melamine resin, solid content 80%), and 20.4 parts (10.2 parts of solid content) of the solution of the phosphate group-containing dispersion resin (4) obtained in Production Example 16 were uniformly mixed. Then, to the obtained mixture, "PRIMAL ASE-60" (trade name, manufactured by Rohm and Haas Co., thickener, solid content 28%), 2-(dimethylamino)ethanol, and deionized water were added to obtain an effect coating composition (Y-1) having a pH of 7.8, a coating solid content of 14%, and a viscosity of 2000 mPa·s when measured at a rotational speed of 6 rpm using a B-type viscometer. Based on the solvent amount of the effect coating composition (Y), the water content in the effect coating composition (Y-1) was 89% by mass. The viscosity was 2000 mPa･s when measured at a rotational speed of 6 rpm using a B-type viscometer. Based on the solvent amount of the effect coating composition (Y), the water content in the effect coating composition (Y-1) was 89% by mass.

[0265] Examples 12 to 21, Comparative Examples 5 to 8

[0266] Except that the compounding composition was as shown in Table 3 below, the same operation as in Example 11 was carried out to obtain each effect coating composition (Y-2) to (Y-15).

[0267] [Table 5]

[0268] [Table 6]

[0269] 3. Production of test panels

[0270] Example 22

[0271] Using a rotary atomization type bell coater, the colored coating composition (X-1) obtained in Production Example 4 was electrostatically coated on the object to be coated produced in the above "1. Production of object to be coated" so that the cured film thickness became 12 μm, and left for 2 minutes to form a colored coating film. Further, on this colored coating film, using a robot bell (Robobell) manufactured by ABB Co., Ltd., at a spraying booth temperature of 23 and a humidity of 68%, the effect coating composition (Y-1) obtained in Example 11 was coated so that the dry coating film became 4 μm. Left for 3 minutes, and then at 80 Preheat for 3 minutes to form an effect coating film. Then, using a robot bell (Robobell) manufactured by ABB Ltd., on this effect coating film, under the conditions of a spraying booth temperature of 23 and a humidity of 68%, a transparent coating composition (Z-1) "MAGICRON KINO-1210TW" (trade name, manufactured by Kansai Paint Co., Ltd., an acrylic resin-based organic solvent-type transparent coating composition containing a resin with a carboxyl group and a resin with an epoxy group) was applied in such a way that the dry coating film became 35 μm to form a transparent coating film. After coating, it was left at room temperature for 7 minutes, and then using a hot air circulation drying furnace, it was heated at 140 for 30 minutes while drying the multi-layer coating film to produce a test panel.

[0272] Examples 23 to 32, Comparative Examples 9 to 12

[0273] Except for using the coatings described in Table 4, all operations were carried out in the same manner as in Example 22 to obtain test panels.

[0274] [Table 7]

[0275] [Table 8]

[0276] [Table 9]

[0277] Coating film evaluation

[0278] For each of the test panels obtained in the above manner, the following items were evaluated. The results are also shown in Table 4.

[0279] Gloss level Sg(15°) value: In the direction perpendicular to the plane direction of the measurement object surface of each test panel, a CCD chip for photographing the measurement object surface was arranged, and the measurement object surface was irradiated with light at an angle of 15° from the perpendicular direction. Through this CCD chip, images of the measurement object surface were respectively photographed, and the obtained images were analyzed by an image analysis algorithm using a histogram of brightness levels to evaluate the gloss level Sg(15°) value. During the measurement, a multi-angle colorimeter (manufactured by BYK Co., trade name BYK-mac i) was used. The smaller the value, the less particle-like. A value of 10 or less was considered qualified.

[0280] FF value: Using a multi-angle colorimeter BYK-mac i (trade name, manufactured by BYK-Gardner Co.), the L value at a light-receiving angle of 15 degrees (L 15 value) and the L value at a light-receiving angle of 110 degrees 15 value) were measured. Value (L value), which is calculated by the following formula. The larger the value, the greater the change in brightness with the viewing angle and the better the sense of brightness. A value of 50 or more is considered qualified.

[0281] FF value = L value (L 15 value) - L value (L 110 value).

[0282] The lightness grade Sg values and FF values of the test panels of Examples 22 to 32 are all qualified, and the effectiveness of the multilayer coating film is excellent. In contrast, the lightness grade Sg values of the test panels of Comparative Examples 9 and 10 are unqualified, and the FF values of Comparative Examples 11 and 12 are unqualified.

Claims

1. An effect pigment dispersion comprising a silica-treated aluminum pigment (A) having an amino group on the surface, a first dispersing resin (B) and water, wherein The solid content of the silica-treated aluminum pigment (A) having an amino group on the surface is 90% by mass or more, and The first dispersing resin (B) is a polymer of a composition comprising a polymerizable unsaturated monomer (b1) containing an acidic functional group, a nonionic polymerizable unsaturated monomer (b2) having a polyoxyalkylene chain, and other polymerizable unsaturated monomers (b3), and The water content is 90% by mass or more based on the amount of the solvent in the effect pigment dispersion.

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

3. The effect pigment dispersion according to claim 1 or 2, wherein: The acidic functional group-containing polymerizable unsaturated monomer (b1) includes a carboxyl group-containing polymerizable unsaturated monomer.

4. The effect pigment dispersion according to any one of claims 1 to 3, further comprising a second dispersing resin (C), wherein the second dispersing resin (C) is a polymer of a composition comprising a polymerizable unsaturated monomer (c1) containing at least one functional group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group, a nonionic polymerizable unsaturated monomer (c2) having a polyoxyalkylene chain, and other polymerizable unsaturated monomers (c3).

5. An effect coating composition comprising the effect pigment dispersion according to any one of claims 1 to 4 and a film-forming resin.

6. A method for forming a multilayer coating film, comprising the following steps (1) to (4): Step (1): a step of applying a colored coating composition (X) to a coating object to form a colored coating film; Step (2): a step of applying the effect coating composition (Y) according to claim 5 on the colored coating film obtained in step (1) to form an effect coating film; Step (3): a step of applying a clear coating composition (Z) on the effect coating film obtained in step (2) to form a clear coating film; Step (4): a step of simultaneously curing the multilayer coating film by heating the multilayer coating film including the color coating film, the effect coating film and the clear coating film formed in the steps (1), (2) and (3).

Images