JP2006056973A - Method for producing aqueous resin dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an aqueous resin dispersion usable as a binder or adhesive for coatings on metallic, plastic and inorganic material base surfaces. <P>SOLUTION: The method for producing the aqueous resin dispersion comprises the following process: A mixture (I) comprising a polyurethane resin (A) obtained by reaction between a polyol (a), a polyisocyanate compound (b) and a hydroxy-containing ethylenically unsaturated monomer (c), a polymerizable unsaturated monomer (B) and an emulsifier (C) is microdispersed in an aqueous medium so as to be ≤500 nm in average particle size, and the resultant emulsion is subjected to polymerization into a dispersion, which is then incorporated with a monomer component (II) comprising a carboxy-containing polymerizable unsaturated monomer and a carbonyl-containing polymerizable unsaturated monomer followed by carrying out a further polymerization. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing an aqueous resin dispersion that can be used for paints, adhesives, and the like on metal surfaces, plastic surfaces, and inorganic substrate surfaces, and specifically, features such as elasticity of urethane resins and acrylics. The present invention relates to an aqueous dispersion of urethane-acrylic resin composite particles that have characteristics such as weather resistance of a resin, and can also impart rheology control ability and low-temperature curability.

  In recent years, in the fields of paints, inks, adhesives, and the like, conversion from organic solvents to water has been promoted from the viewpoints of resource saving, environmental sanitation, no pollution, non-hazardous materials, and the like. For example, even in paint systems used for automobile outer plates and parts, water-based coatings are rapidly promoted from the solvent type, and an inexpensive and multifunctional water-based paint is desired. As water-based paints used in these fields, acrylic-melamine-curing water-based paints that are generally excellent in weather resistance and hardness dominate. If an aqueous polyurethane resin is added to the aqueous paint containing the aqueous acrylic resin and the melamine resin for the purpose of further imparting elasticity, the compatibility between the aqueous polyurethane resin and the aqueous acrylic resin is poor, and the desired elasticity is imparted. However, there is a problem that a large amount of expensive water-based urethane resin has to be blended and the entire water-based paint has a low solid content.

  As means for solving the above-described problems, various techniques for combining a urethane component and an acrylic component have been proposed. For example, Patent Document 1 and Patent Document 2 disclose ethylenic unsaturation in the presence of a polymerizable polyurethane resin. An aqueous resin dispersion obtained by polymerizing a monomer mixture is disclosed. A water-based paint combining this with a melamine resin can form a cured coating film with high gloss and excellent mechanical stability. However, the former radically uses a polyurethane resin that can be polymerized with an ethylenically unsaturated monomer in an organic solvent. Since it is a production method in which water is dispersed after polymerization, there is a tendency that the urethane resin cannot be sufficiently grafted onto the acrylic, and as a result, the elasticity unique to the urethane component cannot be expressed in the resulting coating film. In the latter case, the polymerized polyurethane resin is used as a polymer emulsifier, and this is a process for emulsion polymerization of ethylenically unsaturated monomers in water. there were.

Japanese National Patent Publication No. 5-501124 JP 2003-105258 A

  The object of the present invention is an aqueous dispersion of urethane-acrylic resin composite particles that combines the elasticity of a urethane resin and the weather resistance of an acrylic resin, and can also impart rheology control ability and low-temperature curability. To provide a body.

  The present invention relates to a polyurethane resin (A), a polymerizable unsaturated monomer (B) and a polyurethane resin (A) obtained by reaction with a polyol (a), a polyisocyanate compound (b) and a hydroxyl group-containing ethylenically unsaturated monomer (c). The mixture (I) containing the emulsifier (C) is finely dispersed in an aqueous medium so as to have an average particle size of 500 nm or less, and the resulting emulsion is polymerized to obtain a carboxyl group-containing polymerization. A method for producing an aqueous resin dispersion, wherein the monomer component (II) containing a polymerizable unsaturated monomer and a carbonyl group-containing polymerizable unsaturated monomer is further polymerized, and the aqueous resin dispersion produced by the method An aqueous resin composition comprising the aqueous resin dispersion, a coating method for coating the coated surface with the aqueous coating composition, a coated article formed by the method, About.

  According to the method of the present invention, the urethane-acrylic resin composite particles that have both the elasticity and the like of the urethane resin and the weather resistance of the acrylic resin, and can also impart rheology control ability and low temperature curability are obtained. Dispersions can be produced. The aqueous resin dispersion produced by the method of the present invention can be used for paints, adhesives, etc. on metal surfaces, plastic surfaces, and inorganic substrate surfaces, and particularly the rheology of aqueous base coat paints for automotive outer panels and parts. Very useful as a control agent and binder.

  The polyurethane resin (A) used in the method of the present invention is obtained by reaction with the polyol (a), the polyisocyanate compound (b), and the hydroxyl group-containing ethylenically unsaturated monomer (c).

  The polyol (a) may have at least two hydroxyl groups in one molecule, for example, low molecular weight glycols, high molecular weight glycols, polyester polyols, polycarbonate polyols, etc. may be used alone, or polyester A low molecular weight glycol may be used in combination with a polyol or a high molecular weight glycol.

  Examples of the low molecular weight glycols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, octanediol, and tricyclodecanedi. There are methylol, hydrogenated bisphenol A, cyclohexanedimethanol, bisphenol A polyethylene glycol ether, bisphenol A polypropylene glycol ether, and the like. These may be used alone or in combination of two or more.

  Examples of the high molecular weight glycols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polycarbonate glycol. Polyester polyols include those obtained by reacting a glycol component with a dicarboxylic acid component. It can manufacture easily by this, and it can manufacture not only by esterification but also by transesterification. Moreover, the polyester diol obtained by ring-opening reaction of cyclic ester compounds, such as (epsilon) -caprolactone, and these cocondensation polyesters can also be included.

  The polyol (a) contains, as at least a part of its components, the fatty acid ester (a1) containing two or more hydroxyl groups in one molecule, the dispersion stability of the emulsion and the water resistance of the formed coating film. It is preferable from the viewpoint of finish and finish.

  The fatty acid ester (a1) contains two or more hydroxyl groups in one molecule and usually has a structural unit derived from a fatty acid via an ester bond, particularly from low molecular weight to high molecular weight. Without limitation, it can be appropriately selected depending on the use of the aqueous resin dispersion obtained by the method of the present invention.

  As the fatty acid ester (a1), glycerin monofatty acid ester can be used first. Examples of the glycerin monofatty acid ester include glycerin monolaurate, glycerin monooleate, and glycerin monostearate, and further esterification reaction between glycerin and a fatty acid having 10 or more carbon atoms, and transesterification reaction between fats and oils and glycerin. And the like obtained by the above. Moreover, the reaction product of a glycidol and a fatty acid may be sufficient.

  Examples of the fatty acid include those having a structure in which a carboxyl group is bonded to the end of a hydrocarbon chain, and examples thereof include dry oil fatty acids, semi-dry oil fatty acids, and non-dry oil fatty acids. Dry oil fatty acids and semi-dry oil fatty acids having saturated groups are preferred. Dry oil fatty acids and semi-dry oil fatty acids are not strictly distinguishable, but usually dry oil fatty acids are unsaturated fatty acids that are iodinated 130 or more, and semi-dry oil fatty acids are iodinated 100 or more and less than 130. Of unsaturated fatty acids. On the other hand, non-drying oil fatty acids are usually fatty acids having an iodine value of less than 100.

  Examples of the dry oil fatty acid and the semidry oil fatty acid include fish oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, poppy oil fatty acid, eno oil fatty acid, hemp oil fatty acid, grape Examples include nuclear oil fatty acid, corn oil fatty acid, tall oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid, and hydienoic acid fatty acid. These can be used alone or in combination of two or more. Furthermore, these fatty acids can be used in combination with caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid and the like.

  The reaction between glycerin and the fatty acid is such that the equivalent ratio of the hydroxyl group in glycerin to the carboxyl group in the fatty acid is from 1: 0.17 to 1: 0.5, preferably from 1: 0.23 to 1: 0.43. It is suitable to mix by mixing at a ratio within the range, and usually by heating at a temperature of about 100 to about 180 ° C. for about 0.5 to about 10 hours in the presence of an esterification catalyst. Examples of the esterification catalyst include sulfuric acid, aluminum sulfate, potassium hydrogen sulfate, alkyl-substituted benzene, hydrochloric acid, methyl sulfate, and phosphoric acid. On the other hand, the reaction between fats and oils (fatty acid triglyceride) and glycerin is usually preferably carried out by a method known per se in the presence of a transesterification catalyst such as zinc acetate, lisurge, dibutyltin oxide, calcium naphthenate and the like. it can.

  As the fatty acid ester (a1), for example, a reaction product of an epoxy resin containing two or more epoxy groups in one molecule and a fatty acid can be used.

  Examples of the epoxy resin include glycidyl ether type epoxy resins such as bisphenol A and bisphenol F, hydrogenated bisphenol A type epoxy resins, glycidyl ester type epoxy resins, alicyclic epoxy resins, and polyglycol type epoxy resins; A modified epoxy resin obtained by modifying at least one modifier selected from alkylphenols and fatty acids; an epoxy group-introduced alkylphenol or alkylphenol novolac resin obtained by reacting an alkylphenol or an alkylphenol novolak resin with epichlorohydrin; a dibasic acid modification Examples include epoxy resins, epoxy resins modified with dibasic acid and carboxyl group-containing phenols. Phenol A type epoxy resins, aliphatic glycidyl ester type epoxy resin, aliphatic glycidyl ether type epoxy resins, aliphatic epoxy resins such as alicyclic epoxy resin is preferable. It is preferred that the epoxy resin has a weight average molecular weight in the range of about 200 to about 3,000, preferably in the range of about 300 to about 2,000. In this specification, the weight average molecular weight is a value obtained by converting the weight average molecular weight measured by gel permeation chromatography using tetrahydrofuran as a solvent based on the weight average molecular weight of polystyrene. “HLC8120GPC” (trade name, manufactured by Tosoh Corporation) can be used for the gel permeation chromatography apparatus, and columns used for gel permeation chromatography include “TSKgel G-4000H × L” and “TSKgel G-”. “3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (all manufactured by Tosoh Corporation).

  As said fatty acid, it can select from the thing listed by description of the said glycerol mono fatty acid ester suitably, and can use it.

  In the reaction between the epoxy resin and the fatty acid, the equivalent ratio of the epoxy group in the epoxy resin to the carboxyl group in the fatty acid is 1: 0.6 to 1: 1.4, preferably 1: 0.8 to 1: 1. .2 in a ratio within the range of, for example, usually in the presence of an epoxy group / carboxyl group reaction catalyst for about 1 to 10 hours. Examples of epoxy group / carboxyl group reaction catalysts include quaternary salt catalysts such as tetraethylammonium bromide, tetrabutylammonium bromide, tetraethylammonium chloride, tetrabutylphosphonium bromide, triphenylbenzylphosphonium chloride; triethylamine, tributylamine And the like. The reaction temperature is suitably about 120 to 150 ° C.

  As the fatty acid ester (a1), a reaction product of a compound containing two or more carboxyl groups in one molecule and a monoepoxy compound containing a long-chain hydrocarbon group is used to improve the water resistance and finish of the formed coating film. It can be preferably used from the viewpoint of properties.

  Examples of the compound containing two or more carboxyl groups in one molecule include, for example, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, naphthalenedicarboxylic acid, 4,4-diphenyl Dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, het acid, maleic acid, fumaric acid, itaconic acid, trimellitic acid, pyromellitic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid Hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, tetrahydrophthalic acid, hexahydrotrimellitic acid, methylhexahydrophthalic acid, malic acid, citric acid and other polycarboxylic acids and their anhydrides These can be used alone or in combination of two or more. It can be.

  The above-mentioned monoepoxy compound containing a long-chain hydrocarbon group is a monoepoxide compound having a chain or cyclic hydrocarbon group having 4 or more carbon atoms, preferably 6 to 20 carbon atoms. , Pivalic acid glycidyl ester, hexanoic acid glycidyl ester, cyclohexanecarboxylic acid glycidyl ester, 2-ethylhexanoic acid glycidyl ester, isononanoic acid glycidyl ester, undecanoic acid glycidyl ester, lauric acid glycidyl ester, myristic acid glycidyl ester, Glycidyl esters such as glycidyl palmitate, glycidyl stearate, and Cardura E10 (manufactured by Japan Epoxy Resin, Neodecanoic acid monoglycidyl ester); butyl glycidyl ester Ether, phenyl glycidyl ether, glycidyl ethers such as decyl glycidyl ether; styrene oxide, AOEX24 (manufactured by Daicel Chemical Industries, alpha-olefin monoepoxide mixture) include alpha-olefin monoepoxide such like. The hydrocarbon group having 4 or more carbon atoms may have, for example, a substituent such as a hydroxyl group. Specifically, as a monoepoxide compound having a hydrocarbon group having such a substituent, for example, 1,2-epoxyoctanol, hydroxyoctyl glycidyl ether, and the like. These can be used alone or in combination of two or more.

  In the reaction of the carboxyl group-containing compound and the monoepoxy compound, the equivalent ratio of the carboxyl group in the former to the epoxy group in the latter is 1: 0.6 to 1: 1.4, preferably 1: 0.8 to What is necessary is just to make it heat-react for about 1 to 10 hours normally, for example in the presence of an epoxy group / carboxyl group reaction catalyst. The epoxy group / carboxyl group reaction catalyst can be appropriately selected from the above.

  The fatty acid ester (a1) obtained as described above has a water resistance and finish of 5% by weight or more, preferably 10% by weight or more, more preferably 20% by weight or more in the polyol (a). From the point of view, it is preferable.

  The polyisocyanate compound (b) contains two or more isocyanate groups in one molecule. Specific examples thereof include aliphatic groups such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, and lysine diisocyanate. Polyisocyanates; burette type adducts, isocyanurate cycloadducts of these polyisocyanates; isophorone diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4- (or -2,6-) Diisocyanate, 1,3- (or 1,4-) di (isocyanatomethyl) cyclohexane, 1,4-cyclohexane diisocyanate, 1,3-cyclopentane diisocyanate, 1,2-cyclohex Alicyclic diisocyanates such as diisocyanates; bullet type adducts and isocyanurate cycloadducts of these diisocyanates; xylylene diisocyanate, metaxylylene diisocyanate, tetramethyl xylylene diisocyanate, tolylene diisocyanate, 4, 4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether isocyanate, (m- or p-) phenylene diisocyanate, 4,4′-biphenylene diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, bis (4-isocyanatophenyl) sulfone, isopropylidenebis (4-phenyl) Aromatic diisocyanate compounds such as phenyl isocyanate); bullet type adducts of these diisocyanate compounds, isocyanurate cycloadducts; triphenylmethane-4,4 ′, 4 ″ -triisocyanate, 1,3, Three or more isocyanate groups in one molecule such as 5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate Polyisocyanates having these: burette-type adducts, isocyanurate cycloadducts of these polyisocyanates; ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylolpropionic acid, polyalkylene glycol, trimethylolpropane, hexane Trial Urethane adducts obtained by reacting a polyisocyanate compound in an excess ratio of the isocyanate groups to the hydroxyl groups of the polyols; burette type adducts, isocyanurate ring adducts, etc. of these urethanized adducts Can do.

The hydroxyl group-containing polymerizable unsaturated monomer (c) is used for the purpose of introducing a radical polymerizable unsaturated group into the polyurethane resin (A). As the hydroxyl group-containing polymerizable unsaturated monomer (c), Compounds having one hydroxyl group and one polymerizable unsaturated group in one molecule are included. Specifically, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate DOO, 3-hydroxypropyl (meth) acrylate, _C 2 -C ₈ hydroxyalkyl (meth) acrylate (meth) acrylic acid such as hydroxybutyl (meth) acrylate, allyl alcohol - le, the _C 2 -C ₈ hydroxyalkyl ( (Meth) acrylate having a hydroxyl group such as a modified ε-caprolactone of meth) acrylate; the molecular terminal is a hydroxyl group Having a polyoxyethylene chain (meth) acrylate, and the like. These may be used singly or in combination of two or more.

  The polyurethane resin (A) contains the above components (a), (b), and (c) as constituent components, and a carboxyl group-containing diol can be used as necessary. Examples of the carboxyl group-containing diol include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, and a polyester polyol obtained by condensing these. Examples include polyether polyols. These can be used in combination with hydroxycarboxylic acids such as 12-hydroxystearic acid, paraoxybenzoic acid, 2,2-dimethyl-3-hydroxypropionic acid, and salicylic acid.

  The production of the polyurethane resin (A) is not particularly limited, and a conventionally known method can be employed. For example, the above-described components (a), (b) and (c) may be reacted at once, You may make it react. The production of the polyurethane resin (A) may be carried out in an organic solvent inert to the isocyanate group, but from the point of eliminating the introduction of the solvent, the isocyanate group in the polymerizable unsaturated monomer (B) described later is used. It is preferable to produce the polyurethane resin (A) using a monomer which is inert to the solvent as a diluent component. The proportions of the components (a) and (b) can be variously changed, but the equivalent ratio of isocyanate groups to hydroxyl groups in all components is generally 1: 1 to 1: 3, preferably 1: 1 to 1: It is desirable to make it 2.5. If the ratio is less than 1: 1, the terminal end becomes isocyanate, which is not preferable for this purpose. If the ratio is more than 1: 3, an excessive hydroxyl component that does not react increases, and stability during the production of the aqueous resin dispersion is decreased. Moreover, you may mix | blend monohydric alcohol as needed in order to block an excess isocyanate group. Furthermore, the amount of component (c) used is suitably in the range of 0.01 to 1, preferably 0.02 to 0.8 equivalents per equivalent of isocyanate group.

  The reaction is usually carried out at a temperature of 40 to 180 ° C, preferably 60 to 130 ° C. In order to promote this reaction, an amine catalyst such as triethylamine, N-ethylmorpholine, or triethylenediamine used in a normal urethanization reaction, or a tin catalyst such as dibutyltin dilaurate or dioctyltin dilaurate is used as necessary. It may be used. Also, hydroquinone, hydroquinone monomethyl ether, p-benzoquinone, etc. are used in order to prevent polymerization of the polymerizable unsaturated monomer (B) used as component (c) or, optionally, a diluting component during the urethanization reaction. can do.

  The polyurethane resin (A) thus produced preferably has an acid value of 30 mgKOH / g or less, preferably 20 mgKOH / g or less from the viewpoint of the water resistance of the formed coating.

  As the polymerizable unsaturated monomer (B) used in the method of the present invention, conventionally known monomers can be exemplified without any particular limitation. Usually, at least one, preferably one polymerizable unsaturated group in the molecule, for example, , Vinyl groups, (meth) acryloyl groups and the like are included.

Specific examples of the polymerizable unsaturated monomer (B) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) ) Acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) ) Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methyl cyclohexyl (meth) acrylate, t-butyl cyclohexyl (meth) acrylate, An alkyl or cycloalkyl (meth) acrylate such as clododecyl (meth) acrylate; a polymerizable unsaturated compound having an isobornyl group such as isobornyl (meth) acrylate; a polymerizable unsaturated having an adamantyl group such as adamantyl (meth) acrylate Compound: Vinyl aromatic compound such as styrene, α-methylstyrene, vinyltoluene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ -Polymerizable unsaturated compounds having an alkoxysilyl group such as (meth) acryloyloxypropyltriethoxysilane; such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate Perfluoroalkyl (meth) acrylate; polymerizable unsaturated compound having a fluorinated alkyl group such as fluoroolefin; polymerizable unsaturated compound having a photopolymerizable functional group such as maleimide group; N-vinylpyrrolidone, ethylene, butadiene, Vinyl compounds such as chloroprene, vinyl propionate and vinyl acetate; compounds having a carboxyl group such as (meth) acrylic acid, maleic acid, crotonic acid and β-carboxyethyl acrylate; (meth) acrylonitrile, (meth) acrylamide, dimethylamino Nitrogen-containing polymerizable unsaturated compounds such as propyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, adducts of glycidyl (meth) acrylate and amines; 2-hydroxyethyl (meth) acrylate, 2-hydroxy Propyl Meth) acrylate - DOO, 3-hydroxypropyl (meth) acrylate, _C 2 -C ₈ hydroxyalkyl (meth) acrylate (meth) acrylic acid such as hydroxybutyl (meth) acrylate, allyl alcohol - le, the _C 2 -C (Meth) acrylate having a hydroxyl group such as an ε-caprolactone modified form of ₈ -hydroxyalkyl (meth) acrylate; a polymerizable unsaturated compound having a hydroxyl group such as (meth) acrylate having a polyoxyethylene chain having a molecular terminal hydroxyl group; (Meth) acrylate having a polyoxyethylene chain whose molecular terminal is an alkoxy group; 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, styrenesulfonic acid sodium salt, sulfoethyl methacrylate, and sodium and ammonium salts thereof A polymerizable unsaturated compound having a sulfonic acid group: 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone, Hydroxybenzophenones such as 2,2'-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone and 2,2'-dihydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone and glycidyl An addition reaction product with (meth) acrylate, or a polymerizable unsaturated compound having an ultraviolet-absorbing functional group such as 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl) -2H-benzotriazole; (Meta) acryloil Ci-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4- (meth) acryloylamino-2, 2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (Meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6- UV-stable polymerizable unsaturated compounds such as tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine; Carbonyl groups such as vinylacetone, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) Polymerizable unsaturated compounds having the following: allyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate 1,6-hexanediol (meta ) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethane (Meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl isocyanurate, Examples thereof include polyvinyl compounds having at least two polymerizable unsaturated groups in one molecule such as diallyl terephthalate and divinylbenzene, and these are used alone depending on the performance desired for the obtained aqueous resin dispersion. Or in combination of two or more.

  When the polymerizable unsaturated monomer (B) contains a carboxyl group-containing polymerizable unsaturated monomer as at least a part of its components, the stability and mechanical stability of the resulting aqueous resin dispersion particles in an aqueous medium It is preferable from the point that can be secured. Examples of the carboxyl group-containing polymerizable unsaturated monomer include (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, etc., and acrylic acid, methacrylic acid, and crotonic acid are particularly preferable. It is.

  The carboxyl group-containing polymerizable unsaturated monomer is used in an amount of 0.1 to 5% by weight, preferably 0.5% by weight or more and less than 3% by weight, based on the total weight of component (B). It is desirable to comprise within.

  The polymerizable unsaturated monomer (B) also contains a polymerizable unsaturated monomer containing a linear or branched hydrocarbon group having 6 or more carbon atoms as at least a part of its components. This is preferable from the viewpoint of polymerization stability of the emulsion and water resistance of the formed coating film. Examples of the polymerizable unsaturated monomer containing a hydrocarbon group having 6 or more carbon atoms include, for example, n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) ) Acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (manufactured by Osaka Organic Chemical Co., Ltd.) and the like. These may be used alone or in combination of two or more. Can be used.

  The amount of the polymerizable unsaturated monomer containing a linear or branched hydrocarbon group having 6 or more carbon atoms is 1 to 40% by weight, preferably based on the total weight of the component (B). It is desirable to contain in the range of 5 to 30% by weight.

  In the present invention, the use ratio of the polyurethane resin (A) and the polymerizable unsaturated monomer (B) is in the range of 5:95 to 80:20, preferably 10:90 to 70:30 in terms of solid content weight ratio. It is preferable from the viewpoint of the flexibility and elasticity of the formed coating film and the rheology control ability of the coating liquid.

  As the emulsifier (C) used in the method of the present invention, an anionic emulsifier and a nonionic emulsifier are suitable. Examples of the anionic emulsifier include sodium salts and ammonium salts such as alkyl sulfonic acid, alkyl benzene sulfonic acid, and alkyl phosphoric acid. Nonionic emulsifiers include, for example, polyoxyethylene oleyl ether and polyoxyethylene. Stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, Polyoxyethylene monooleate, sorbitan monolaurate, sorbitan monostearate, sorbitan monostearate, sorbitan trioleate, poly Polyoxyethylene sorbitan monolaurate, and the like.

  Also, a polyoxyalkylene group-containing anionic emulsifier having an anionic group and a polyoxyalkylene group such as a polyoxyethylene group or a polyoxypropylene group in one molecule, or the anionic group and polymerizable unsaturated in one molecule Reactive anionic emulsifiers having groups may be used.

  The emulsifier (C) can be used in the range of 0.1 to 15% by weight, preferably 0.5 to 12% by weight, based on the total amount of all monomers used.

  In the method of the present invention, the mixture (I) containing the polyurethane resin (A), the polymerizable unsaturated monomer (B) and the emulsifier (C) is finely dispersed in an aqueous medium so that the average particle size is 500 nm or less. The resulting emulsion is polymerized.

  In the method of the present invention, when the average particle diameter of the mixture (I) particles in the emulsion exceeds 500 nm, sedimentation during storage of the emulsion and the hydrophilic-hydrophobic composition distribution of the resulting aqueous resin dispersion particles are not satisfactory. The uniformity becomes extreme, which may cause a cloudiness of a coating film formed using the same, which is not preferable.

  In the present specification, the average particle size is obtained by diluting a sample with deionized water and using “SALD-3100” (trade name, manufactured by Shimadzu Corporation, laser diffraction particle size distribution measuring device) at room temperature (20 ° C. The average particle size is measured within 24 hours after the production of the finely divided monomer emulsion or aqueous resin dispersion.

  Moreover, as an aqueous medium used at the time of superposition | polymerization, the water-organic solvent mixed solution etc. which mix water and organic solvents, such as a water-soluble organic solvent, can be mentioned to this.

  The mixture (I) contains the polyurethane resin (A), the polymerizable unsaturated monomer (B) and the emulsifier (C) described above as essential components, but the mixture (I) is further substantially polymerized. The compound which does not contain an ionic unsaturated group can also be contained.

  By using the mixture (I) containing the above-mentioned compound that does not substantially contain a polymerizable unsaturated group, aqueous resin dispersion particles enclosing the compound can be produced.

  Examples of the compound that does not substantially contain a polymerizable unsaturated group include, for example, UV absorbers, UV stabilizers, paint additives such as metal dryers; resins such as acrylic resins, polyester resins, alkyd resins; pigments, dyes, etc. These can be used alone, or these can be used alone or in combination and used in combination of two or more.

  The mixture (I) may contain a chain transfer agent for the purpose of adjusting the molecular weight of the obtained aqueous resin dispersion. Examples of the chain transfer agent include compounds having a mercapto group. Specifically, for example, lauryl mercaptan, t-dodecyl mercaptan, octyl mercaptan, 2-ethylhexyl thioglycolate, 2-methyl-5-tert- Examples thereof include butylthiophenol, mercaptoethanol, thioglycerol, mercaptoacetic acid (thioglycolic acid), mercaptopropionate, and n-octyl-3-mercaptopropionate. In general, the chain transfer agent is preferably used in an amount of 0.05 to 10% by weight, particularly 0.1 to 5% by weight, based on the total amount of all monomers.

  Furthermore, you may mix | blend organic solvents, such as long-chain saturated hydrocarbon solvents, such as hexadecane, and long-chain alcohol solvents, such as hexadecanol, with mixture (I) as needed.

  According to the present invention, the mixture (I) described above is finely dispersed in an aqueous medium to form an emulsion.

  The concentration of the mixture (I) in the aqueous medium is generally 10 to 70% by weight from the viewpoint of atomization suitability of the emulsion to be formed, stability in the polymerization stage, practicality when applied to an aqueous paint, and the like. The preferred range is 20 to 60% by weight.

  The fine dispersion of the mixture (I) in the aqueous medium can be usually performed using a disperser having a high energy shearing ability. Examples of the disperser that can be used in this case include a high-pressure emulsifier, an ultrasonic emulsifier, a high-pressure colloid mill, and a high-pressure homogenizer. These dispersers can usually be operated under a high pressure of about 10 to 1000 MPa, preferably about 50 to 300 MPa. In addition, the monomer mixture may be pre-emulsified with a disper or the like in advance before being dispersed by the machine.

  The average particle size of the dispersed particles in the emulsion obtained by finely dispersing the mixture (I) in an aqueous medium by the above method is 500 nm or less, preferably from the viewpoint of the transparency and water resistance of the formed coating film. A range of 80 to 400 nm, more preferably 100 to 300 nm is suitable.

  Polymerization of the emulsion thus obtained is carried out by, for example, charging the entire amount of the finely dispersed emulsion into a reactor equipped with a stirrer, adding a polymerization initiator, and heating with stirring according to the miniemulsion polymerization method. be able to.

  The polymerization initiator may be either oil-soluble or water-soluble, and examples of the oil-soluble polymerization initiator include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide. Organic peroxides such as oxides; azo compounds such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile); and water-soluble initiators such as cumene hydroperoxide , Organic peroxides such as tert-butyl peroxide, tert-butyl peroxylaurate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxyacetate, diisopropylbenzene hydroperoxide; azobis (2-methylpropiononitrile) A Bis (2-methylbutyronitrile), 4,4'-azobis (4-cyanobutanoic acid), dimethylazobis (2-methylpropionate), azobis [2-methyl-N- (2-hydroxyethyl)- Azo compounds such as propionamide] and azobis {2-methyl-N- [2- (1-hydroxybutyl)]-propionamide}; and persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate. . These can be used alone or in combination of two or more. Further, if necessary, a reducing agent such as sugar, sodium formaldehyde sulfoxylate, or iron complex may be used in combination with the polymerization initiator to form a redox polymerization system.

  In general, the polymerization initiator is preferably used in an amount of 0.1 to 5% by weight, particularly 0.2 to 3% by weight, based on the total weight of the components (A) and (B). The method for adding the polymerization initiator is not particularly limited, and can be appropriately selected according to the type and amount thereof. For example, it may be previously contained in the mixture (I) or the aqueous medium, or may be added all at once during the polymerization, or may be added dropwise.

  According to the method described above, it is possible to produce a resin dispersion having an average particle diameter of 500 nm or less, particularly preferably in the range of 100 to 300 nm.

  In the method of the present invention, a monomer component (II) containing a carboxyl group-containing polymerizable unsaturated monomer and a carbonyl group-containing polymerizable unsaturated monomer is added to the resin dispersion obtained as described above, and further polymerized. It is characterized by this.

  Examples of the carboxyl group-containing polymerizable unsaturated monomer include (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate, etc., and acrylic acid, methacrylic acid, and crotonic acid are particularly preferable. It is.

  It is obtained aqueous that the carboxyl group-containing polymerizable unsaturated monomer is contained in the range of 0.5 to 50% by weight, preferably 1 to 40% by weight, based on the total weight of the monomer component (II). This is desirable from the viewpoint of rheology control by the development of alkali thickening of the resin dispersion.

  The carbonyl group-containing polymerizable unsaturated monomer includes a compound having one carbonyl group and one polymerizable unsaturated bond in one molecule, and specifically includes, for example, acrolein, diacetone acrylamide, dye Examples include acetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrene, vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), and these are used alone or as 2 It can be used in combination of more than one species. Of these, diacetone (meth) acrylamide is particularly preferred.

  The coating film formed is that the carbonyl group-containing polymerizable unsaturated monomer is contained in the range of 0.1 to 20% by weight, preferably 1 to 15% by weight, based on the total weight of the monomer component (II). It is desirable from the viewpoint of curability.

  For the monomer component (II), other polymerizable unsaturated monomers other than the above carboxyl group-containing polymerizable unsaturated monomers and carbonyl group-containing polymerizable unsaturated monomers can be used, and such other polymerizable unsaturated monomers. Can be appropriately selected from the polymerizable monomers listed in the description of the polymerizable unsaturated monomer (B). The amount used is suitably in the range of 30 to 99.4% by weight, preferably 45 to 98% by weight, based on the total weight of the monomer component (II).

  The other polymerizable unsaturated monomer described above contains a hydroxyl group-containing polymerizable unsaturated monomer as at least a part of its components, and a curing agent capable of reacting the resulting aqueous dispersion with a hydroxyl group, such as isocyanate-based or melamine From the viewpoint of crosslinkability with the curing agent when used together with a curing agent such as a system, and from the viewpoint of improving the adhesion of the formed coating film to the substrate surface.

Examples of the hydroxyl group-containing polymerizable unsaturated monomer include compounds having one hydroxyl group and one polymerizable unsaturated group in one molecule. Specifically, for example, 2-hydroxyethyl (meth) acrylate. , 2-hydroxypropyl (meth) acrylate - DOO, 3-hydroxypropyl (meth) acrylate, _C 2 -C ₈ hydroxyalkyl (meth) acrylate (meth) acrylic acid such as hydroxybutyl (meth) acrylate, allyl alcohol - Le , (Meth) acrylate having a hydroxyl group such as an ε-caprolactone modified product of the above C ₂ -C ₈ hydroxyalkyl (meth) acrylate; (meth) acrylate having a polyoxyethylene chain having a hydroxyl group at the molecular end, and the like. These can be used alone or in combination of two or more.

  The hydroxyl group-containing polymerizable unsaturated monomer is used in an amount of 0.5 to 25% by weight, preferably 1 to 20% by weight, based on the total weight of the monomer component (II).

  The monomer component (II) can appropriately contain components such as a polymerization initiator, a chain transfer agent, a reducing agent, and an emulsifier as listed above, if necessary.

  In the method of the present invention, the monomer component (II) can be dropped as it is, but it is desirable to disperse the monomer component (II) in an aqueous medium and drop it as a monomer emulsion obtained. In this case, the average particle size of the monomer emulsion is not particularly limited.

  Examples of the polymerization method of the monomer component (II) include a method in which the monomer component (II) which may be emulsified is added to the resin dispersion in a batch or dropwise and heated to an appropriate temperature while stirring. Can be mentioned.

  The aqueous resin dispersion obtained as described above has a (co) polymer complex (I) composed of the polyurethane resin (A) and the polymerizable unsaturated monomer (B) as a core, and is co-polymerized with the monomer component (II). It can have a core-shell type multilayer structure with the polymer (II) as a shell.

  In the present invention, the ratio of the composite (I) to the copolymer (II) is such that the rheology control of the resulting aqueous resin dispersion and the water resistance of the formed coating film are compatible, It is generally desirable that the solid content weight ratio of the polymer (II) is in the range of 40/60 to 95/5, particularly 50/50 to 90/10.

  The aqueous resin dispersion obtained as described above can generally have an average particle size in the range of 100 to 1000 nm, particularly 100 to 500 nm.

  In the present invention, in order to improve the mechanical stability of the particles of the obtained aqueous resin dispersion, it is desirable to neutralize the carboxyl group or the like of the aqueous resin dispersion with a neutralizing agent. The neutralizing agent is not particularly limited as long as it can neutralize acidic groups. For example, sodium hydroxide, potassium hydroxide, trimethylamine, dimethylaminoethanol, 2-methyl-2-amino-1-propanol, Examples thereof include triethylamine and aqueous ammonia, and these neutralizing agents are desirably used in such an amount that the pH of the aqueous resin dispersion after neutralization is about 6.5 to 9.0.

  The aqueous resin composition provided by the present invention comprises the aqueous resin dispersion obtained as described above.

  In addition to the water-based resin dispersion, the water-based resin composition includes a water-soluble or water-dispersible polyurethane resin, a polyester resin, an acrylic resin, an alkyd resin, a silicon resin, a fluororesin, and an epoxy resin. In particular, it is desirable to include a polyurethane dispersion from the viewpoint of the flexibility of the formed coating film. From the viewpoints of film formability, finish, weather resistance, etc., water-soluble polyester resins and water-soluble acrylic resins can be included.

  The above polyurethane dispersion is usually a dispersion obtained by forcibly or self-emulsifying while dispersing a urethane prepolymer obtained by previously reacting a diol with diisocyanate and further dimethylolalkanoic acid in the presence of an emulsifier. It is. In the case of using the polyurethane dispersion, the blending amount thereof is 5 to 400 parts by weight, particularly 10 to 300 parts per 100 parts by weight of the resin solid content of the aqueous resin dispersion from the viewpoint of improving the physical properties of the coating film. It is desirable to be within the range of parts by weight.

  The water-soluble polyester resin is an oil-free or oil-modified product prepared by esterification using a polyhydric alcohol and a polybasic acid, and if necessary, a monobasic acid or an oil component (including this fatty acid). It is obtained by neutralizing the polyester resin. The polyester resin has a weight average molecular weight of about 1000 to 100,000, preferably 2000 to 80000. A basic substance can be used for neutralizing the carboxyl group of the polyester resin. The basic substance is preferably water-soluble, such as ammonia, methylamine, ethylamine, propylamine, butylamine, dimethylamine, trimethylamine, triethylamine, ethylenediamine, morpholine, methylethanolamine, dimethylethanolamine, diethanolamine, triethanol. An amine, diisopropanolamine, 2-amino-2-methylpropanol, etc. are mentioned, These can use 1 type (s) or 2 or more types. When the water-soluble polyester resin is used, the blending amount thereof is in the range of 5 to 400 parts by weight, particularly 10 to 300 parts by weight with respect to 100 parts by weight of the resin solid content of the aqueous resin dispersion. It is desirable.

  As the water-soluble acrylic resin, a mixture comprising a water-soluble group-containing polymerizable unsaturated monomer such as a carboxyl group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomers is copolymerized by a solution polymerization method or the like. An acrylic copolymer having a weight average molecular weight of 3,000 to 100,000, preferably 5,000 to 80,000 may be mentioned. The carboxyl group of the acrylic copolymer can be neutralized, and neutralization can be performed using the above-mentioned basic substance.

  When the water-soluble acrylic resin is used, the blending amount thereof is in the range of 5 to 400 parts by weight, particularly 10 to 300 parts by weight with respect to 100 parts by weight of the resin solid content of the aqueous resin dispersion. It is desirable.

  The aqueous resin composition may further comprise a hydrazine derivative. Specific examples of the hydrazine derivative include saturated dicarboxylic acid dihydrazides having 2 to 18 carbon atoms such as oxalic acid dihydrazide, malonic acid dihydrazide, glutaric acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide and the like. Monoolefinic unsaturated dicarboxylic acid dihydrazide such as maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide; phthalic acid dihydrazide, terephthalic acid dihydrazide or isophthalic acid dihydrazide; pyromellitic acid dihydrazide, trihydrazide or tetrahydrazide; nitrilotrihydride Citric acid trihydrazide, 1,2,4-benzenetrihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, 1,4,5,8-naphthoic acid Polyhydrazide obtained by reacting a low polymer having a carboxylic acid lower alkyl ester group with hydrazine or a hydrazine hydrate (hydrazine hydride); a hydrazide group-containing compound such as carbonic dihydrazide; bissemicarbazide; hexamethylene diisocyanate Polyfunctional semicarbazide obtained by excessively reacting N, N-substituted hydrazine such as N, N-dimethylhydrazine or the above-mentioned hydrazide with a diisocyanate such as chlorobenzene or isophorone diisocyanate or a polyisocyanate compound derived therefrom, and the polyisocyanate compound Dihydrazide as exemplified above for the isocyanate group in the reaction product of an active hydrogen compound containing a hydrophilic group such as a polyether and a polyol or a polyethylene glycol monoalkyl ether Excessively reacted with the resulting aqueous polyfunctional semicarbazide; compound having a semicarbazide group, such as a mixture of polyfunctional semicarbazide and aqueous polyfunctional semicarbazide; compound having a hydrazone group such as bis-acetyl-di hydrazone and the like.

  When the aqueous resin composition contains the hydrazine derivative, it can act as a crosslinking agent that crosslinks with the carbonyl group in the aqueous resin dispersion, and the formed coating film is a harmful substance in the air, such as formaldehyde. It is useful for the removal of these harmful substances.

  In general, the blending amount of the hydrazine derivative is desirably in the range of 0.01 to 10% by weight, particularly 0.1 to 8% by weight, based on the resin solid content of the aqueous resin dispersion.

  In addition, when the aqueous resin dispersion has a crosslinkable functional group such as a hydroxyl group, the aqueous resin composition includes a curing agent having a crosslinkable functional group capable of reacting with the functional group, such as an isocyanate-based curing agent or a melamine type. A curing agent or the like can be contained.

  The aqueous resin composition further comprises an ultraviolet absorber, an ultraviolet stabilizer, a wetting agent, an antifoaming agent, a plasticizer, a film-forming aid, an organic solvent, a thickener, an antiseptic, an antifungal agent, if necessary. Additives such as a pH adjusting agent, a curing catalyst, and a surface adjusting agent can be appropriately selected and contained in combination.

  Thus, the water-based resin composition is used for coatings for automotive outer panels, automotive parts, inorganic building materials, coating materials such as printing inks, additives for coatings, bonding agents for nonwovens, adhesives, fillers, etc. It can be used for various applications such as molding materials and resists.

  The present invention also provides an aqueous coating composition comprising the above aqueous resin composition.

  The aqueous coating composition can be used as a clear coating or as an enamel coating. When used as an enamel paint, a color pigment, a luster pigment, an extender pigment or the like known in the paint field can be blended as a pigment component.

  In addition to the above components, the above-mentioned aqueous coating composition is composed of a pigment dispersant, a surfactant, a dispersant, an antifoaming agent, a thickening agent, a film-forming aid, an antiseptic, an antifungal agent, an antifreezing agent, and a pH adjuster. In addition, additives such as a low-staining agent such as polyalkylene glycol-modified alkyl silicate can be contained alone or in combination of two or more.

  The surface to be coated with the aqueous coating composition is not particularly limited, and examples thereof include metals such as iron and aluminum; organic base materials such as plastics; concrete, mortar, slate plate, PC plate, ALC. Substrates such as boards, cement calcium silicate boards, concrete blocks, wood, stones, and other inorganic substrates, acrylic resins, acrylic urethane resins, polyurethane resins, fluororesins, silicon provided on these substrates Examples of the coating surface include acrylic resin, vinyl acetate resin, epoxy resin, and alkyd resin.

  In the present invention, the above-mentioned aqueous coating composition is suitably used as the aqueous base coat coating in a method in which an aqueous base coat coating containing a glittering pigment and / or a colored pigment is applied onto the surface to be coated, and then a clear coating is applied. it can.

  The water-based coating composition is usually known on the surface to be coated such that it has a dry film thickness of 5 to 40 μm, preferably 10 to 30 μm, such as air spray coating, airless spray coating, electrostatic coating, etc. Painted in the way. The obtained coating surface can be set at room temperature for 1 to 60 minutes as necessary, or preheated at about 40 to 80 ° C. for 1 to 60 minutes, or about 50 to 140 ° C., preferably about It can be cured by heating at a temperature of about 60 to 100 ° C. for 20 to 40 minutes.

  The clear coating mainly contains a resin component such as a base resin and a crosslinking agent, an organic solvent, water and the like, and further contains an organic solvent system or an aqueous system in which an ultraviolet absorber, a light stabilizer and the like are blended as necessary. This is a thermosetting paint having transparency that allows the lower layer coating film to be visually recognized through the clear coating film.

  Examples of the base resin include acrylic resins, polyester resins, alkyd resins, fluororesins, urethane resins, and silicon-containing resins containing at least one crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, and an epoxy group. Of these, hydroxyl group-containing resins, particularly hydroxyl group-containing acrylic resins are preferred. Examples of the crosslinking agent include (block) polyisocyanate compounds, melamine resins, urea resins, epoxy compounds, carboxyl group-containing compounds, acid anhydrides, and alkoxysilane group-containing compounds that can react with these functional groups. Block) polyisocyanate compounds are preferred.

  If necessary, the clear paint may further contain paint additives such as a curing catalyst, a coating surface preparation agent, a rheology control agent, an antioxidant, an antifoaming agent, and a wax.

  The clear coating is applied electrostatically so that the dry film thickness is in the range of 20 to 70 μm, preferably 25 to 60 μm, and the obtained coating surface is applied at room temperature for 1 to 60 minutes as necessary. After setting or preheating at about 40 to 80 ° C. for 1 to 60 minutes, it can be cured by heating at about 50 to 140 ° C., preferably about 60 to 100 ° C. for 20 to 40 minutes.

  As described above, when the aqueous paint composition of the present invention is used as an aqueous base coat paint, and further a clear paint containing a hydroxyl group-containing resin and a polyisocyanate compound is applied, a crosslinking reaction between the hydroxyl group-containing resin and the polyisocyanate compound occurs in the clear coating film. On the other hand, if the resin component has a hydroxyl group in the base coat film, the hydroxyl group undergoes a crosslinking reaction with the isocyanate group of the polyisocyanate compound penetrating from the clear coating film, thereby crosslinking by the carbonyl group and the hydrazide group. In view of low temperature curability, it can be cured. The crosslinking reaction can be promoted by adding a catalyst such as an organic tin compound to one or both of the aqueous base coat paint and the clear paint, or by adding a carboxyl group to the resin component.

  Hereinafter, the present invention will be described in more detail with reference to examples. “Part” and “%” indicate “part by weight” and “% by weight” unless otherwise specified.

Production Example 1 of aqueous resin dispersion
The following components were charged in a reaction vessel and heated to 80 ° C.

Fatty acid ester (a-1) (Note 1) 22.69 parts Etacol UH-50 (Note 2) 9.23 parts Hydroquinone 0.0126 parts n-Butyl methacrylate 22.5 parts i-Butyl methacrylate 14.7 parts Dibutyltin 0.0189 parts of dilaurate

  Next, 15.19 parts of isophorone diisocyanate was dropped into this over 1 hour, and the mixture was reacted to an NCO value of 13.6. Thereafter, 0.506 parts of n-butanol and 0.0126 parts of hydroquinone were added and reacted to an NCO value of 10.2. Then, 4.88 parts of 2-hydroxyethyl acrylate was added and reacted to an NCO value of 1 or less. It was. After completion of the reaction, the reaction mixture is cooled to a temperature of 40 ° C., and 0.0126 part of hydroquinone, 10 parts of 2-ethylhexyl methacrylate, and 0.25 part of methacrylic acid are put into the reaction vessel, and a polyurethane resin solution diluted with monomers is added. Got.

  In a beaker, add 100 parts of the polyurethane resin solution diluted with the monomer obtained above, 10 parts “New Coal 707SF” (manufactured by Nippon Emulsifier Co., Ltd., anionic emulsifier, 30% active ingredient), 90 parts water and mix with a disper. The mixture was stirred at 2000 rpm for about 15 minutes to prepare a preliminary emulsion. This preliminary emulsified liquid was subjected to a high pressure treatment of 100 MPa with a high pressure emulsifying apparatus that applied high pressure energy to collide fluids to obtain an emulsified liquid having an average particle diameter of dispersed particles of 236 nm.

  This emulsion was transferred to a flask and heated to 80 ° C. A polymerization initiator aqueous solution in which 0.24 part of ammonium persulfate was dissolved in 10 parts of water was dropped into the flask over 1 hour, and a polymerization reaction was carried out while maintaining the temperature. Thereafter, the temperature was further maintained at 80 ° C. for 2 hours, and the reaction was proceeded, followed by cooling and cooling by adding 96 parts of deionized water. At this time, a resin dispersion (I-1) having an average particle diameter of 247 nm of the dispersion resin was obtained.

  Next, the following components were put into another beaker, and stirred for about 15 minutes at 2000 rpm with a disper to produce a monomer emulsion (II-1). Then, the temperature of the previous resin dispersion was 50 ° C. or less. Then, it was dropped into the flask and stirred for 30 minutes. Thereafter, the temperature was raised to 80 ° C., and the reaction was allowed to proceed for 2 hours while maintaining the temperature, followed by cooling to obtain an aqueous resin dispersion (1) having an average particle diameter of 255 nm and a solid content concentration of 35%. .

Composition of monomer emulsion (II-1) “New Coal 707SF” 2 parts Deionized water 45 parts Ammonium persulfate 0.015 parts Methyl methacrylate 12 parts N-butyl acrylate 12 parts Diacetone acrylamide 3 parts Methacrylic acid 3 parts

(Note 1) Fatty acid ester (a-1): 292 parts of adipic acid, “Cardura E10P” (trade name, glycidyl ester of thiodecanoic acid) manufactured by Japan Epoxy Resin Co., Ltd., 1.25 parts of tetraethylammonium bromide The mixture was heated to 150 ° C. with stirring and reacted to an acid value of 1 mgKOH / g or less.
(Note 2) Etacol UH-50: Ube Industries, trade name, polycarbonate diol

Example 2
In the method of Example 1, according to the method of Example 1, except that the following monomer emulsion (II-2) is used instead of the monomer emulsion (II-1), the average particle size of the dispersed resin is 245 nm, the solid content concentration A 35% aqueous resin dispersion (2) was obtained.

Composition of monomer emulsion (II-2) “New Coal 707SF” 2 parts Deionized water 45 parts Ammonium persulfate 0.015 parts Methyl methacrylate 12 parts N-butyl acrylate 9 parts 2-hydroxyethyl acrylate 3 parts Diacetone acrylamide 3 parts Methacrylic acid 3 parts

Example 3
The following components were charged in a reaction vessel and heated to 80 ° C.

Fatty acid ester (a-2) (Note 3) 16.11 parts Etacol UH-50 (Note 2) 11.46 parts Hydroquinone 0.0126 parts n-butyl methacrylate 22.5 parts i-butyl methacrylate 14.75 parts Dibutyl tin 0.0189 parts of dilaurate

  Next, 18.85 parts of isophorone diisocyanate was dropped into this over 1 hour, and the mixture was reacted to an NCO value of 17.1. Thereafter, 0.628 parts of n-butanol and 0.0126 parts of hydroquinone were added and reacted until an NCO value of 12.7, and then 5.45 parts of 2-hydroxyethyl acrylate was added and reacted until the NCO value was 1 or less. It was. After completion of the reaction, the reaction mixture is cooled to a temperature of 40 ° C., and 0.0126 part of hydroquinone, 10 parts of 2-ethylhexyl methacrylate, and 0.25 part of methacrylic acid are put into the reaction vessel, and a polyurethane resin solution diluted with monomers is added. Got.

  In a beaker, add 100 parts of the polyurethane resin solution diluted with the monomer obtained above, 10 parts “New Coal 707SF” (manufactured by Nippon Emulsifier Co., Ltd., anionic emulsifier, 30% active ingredient), 90 parts water and mix with a disper. The mixture was stirred at 2000 rpm for about 15 minutes to prepare a preliminary emulsion. This preliminary emulsified liquid was subjected to a high pressure treatment of 100 MPa with a high pressure emulsifying apparatus that applied high pressure energy to collide fluids to obtain an emulsified liquid having an average particle size of dispersed particles of 248 nm.

  This emulsion was transferred to a flask and heated to 80 ° C. A polymerization initiator aqueous solution in which 0.24 part of ammonium persulfate was dissolved in 10 parts of water was dropped into the flask over 1 hour, and a polymerization reaction was carried out while maintaining the temperature. Thereafter, the temperature was further maintained at 80 ° C. for 2 hours, and the reaction was proceeded, followed by cooling and cooling by adding 96 parts of deionized water. At this time, a resin dispersion (I-2) having an average particle diameter of 256 nm of the dispersion resin was obtained.

  Subsequently, the following components were put into another beaker, and stirred for about 15 minutes at 2000 rpm with a disper to produce the monomer emulsion (II-1) described in Example 1, and then the monomer emulsion was added to the previous resin dispersion. When the temperature of (I-2) became 50 ° C. or lower, it was dropped into the flask and stirred for 30 minutes. Thereafter, the temperature was raised to 80 ° C., and the reaction was allowed to proceed for 2 hours while maintaining the temperature, followed by cooling to obtain an aqueous resin dispersion (3) having an average particle diameter of the dispersed resin of 262 nm and a solid content concentration of 35%. .

(Note 3) Fatty acid ester (a-2): “Limaker S-100P”, manufactured by Riken Vitamin Co., Ltd., glycerin monostearate (monoester content of 95% or more)

Example 4
The following components were charged in a reaction vessel and heated to 80 ° C.

Fatty acid ester (a-3) (Note 4) 26.97 parts Etacol UH-50 (Note 2) 7.79 parts Hydroquinone 0.0126 parts n-butyl methacrylate 22.5 parts i-butyl methacrylate 14.75 parts dibutyl tin 0.0189 parts of dilaurate

  Next, 12.81 parts of isophorone diisocyanate was dropped into this over 1 hour, and the mixture was reacted to an NCO value of 11.4. Thereafter, 0.628 parts of n-butanol and 0.0126 parts of hydroquinone were added and reacted until the NCO value was 8.5, and then 4.51 parts of 2-hydroxyethyl acrylate was charged and reacted until the NCO value was 1 or less. It was. After completion of the reaction, the reaction mixture is cooled to a temperature of 40 ° C., and 0.0126 part of hydroquinone, 10 parts of 2-ethylhexyl methacrylate, and 0.25 part of methacrylic acid are put into the reaction vessel, and a polyurethane resin solution diluted with monomers is added. Got.

  In a beaker, add 100 parts of the polyurethane resin solution diluted with the monomer obtained above, 10 parts “New Coal 707SF” (manufactured by Nippon Emulsifier Co., Ltd., anionic emulsifier, 30% active ingredient), 90 parts water and mix with a disper. The mixture was stirred at 2000 rpm for about 15 minutes to prepare a preliminary emulsion. This preliminary emulsified liquid was subjected to a high pressure treatment of 100 MPa with a high pressure emulsifying apparatus that applied high pressure energy to collide fluids to obtain an emulsified liquid having an average particle diameter of dispersed particles of 223 nm.

  This emulsion was transferred to a flask and heated to 80 ° C. A polymerization initiator aqueous solution in which 0.24 part of ammonium persulfate was dissolved in 10 parts of water was dropped into the flask over 1 hour, and a polymerization reaction was carried out while maintaining the temperature. Thereafter, the temperature was further maintained at 80 ° C. for 2 hours, and the reaction was proceeded, followed by cooling and cooling by adding 96 parts of deionized water. At this time, a resin dispersion (I-3) having an average particle diameter of 232 nm of the dispersion resin was obtained.

  Next, the following components were put into another beaker and stirred for about 15 minutes at 2000 rpm with a disper to produce the monomer emulsion (II-2) described in Example 2, and then the monomer emulsion was added to the previous resin dispersion. When the temperature of (I-3) became 50 ° C. or lower, it was dropped into the flask and stirred for 30 minutes. Thereafter, the temperature was raised to 80 ° C., and the reaction was allowed to proceed for 2 hours while maintaining the temperature, followed by cooling to obtain an aqueous resin dispersion (4) having an average particle diameter of 240 nm and a solid content concentration of 35%. .

(Note 4) Fatty acid ester (a-3): "ST-3000" (manufactured by Tohto Kasei Co., Ltd., hydrogenated bisphenol A type epoxy resin, epoxy equivalent 231) in a flask, 500 parts, coconut oil fatty acid 454.5 parts, and tetraethyl 1.5 parts of ammonium bromide was added, the temperature was raised to 150 ° C. with stirring, and the acid value was reacted to 1 mgKOH / g or less to obtain a fatty acid ester.

Comparative Example 1
The flask was charged with 100 parts of deionized water and 3 parts of “New Coal 707SF” and heated to 80 ° C.

  In a beaker, 5 parts "New Coal 707SF", 86 parts deionized water, 0.1 part ammonium persulfate, 50 parts n-butyl methacrylate, 27 parts n-butyl acrylate, 20 parts 2-ethylhexyl methacrylate and 3 parts allyl methacrylate 5 parts from the monomer emulsion prepared by stirring at 2000 rpm for about 15 minutes with a disper, and put into the flask together with a solution of 0.1 part ammonium persulfate in 10 parts deionized water in advance. For 20 minutes. Subsequently, the remainder of the monomer emulsion was added dropwise over 2 hours and held at 80 ° C. for 30 minutes.

  Then in another beaker, 2 parts "New Coal 707SF", 45 parts deionized water, 0.015 parts ammonium persulfate, 12 parts methyl methacrylate, 12 parts n-butyl acrylate, 3 parts 2-hydroxyethyl acrylate and 3 methacrylic acid 3 The monomer emulsion prepared in advance by stirring for about 15 minutes at 2000 rpm with a disper is dropped into the flask having the internal temperature of 80 ° C. over 1 hour, and further maintained at 80 ° C. for 1 hour. Then, the reaction was proceeded and then cooled to obtain an aqueous resin dispersion (5) having an average particle diameter of the dispersed resin of 120 nm and a solid content concentration of 35%.

Preparation Examples 5 to 8 and Comparative Example 2 of aqueous resin composition
An aqueous resin composition was obtained according to the composition shown in Table 1 below. Each aqueous resin composition was subjected to the following performance test and evaluated. The results are also shown in Table 1.

Performance Test Method (* 1) Curability: Each aqueous resin composition was applied to a glass plate with a doctor blade so that the dry film thickness was 20 μm, dried and heated at 80 ° C. for 30 minutes, The dried film was peeled off from the glass plate and cut into a size of 4 × 4 cm to obtain a test piece.

The obtained test piece was immersed in acetone for 6 hours under reflux conditions. The coating film extraction residue was calculated as follows from the coating film weight before and after extraction.
Paint film extraction residue (%) = (weight of film after extraction / weight of film before extraction) × 100 (%)

(* 2) Flex resistance: Each aqueous resin composition was spray-coated on a steel plate so that the dry film thickness was about 20 μm, and dried and heated at 80 ° C. for 30 minutes to prepare each test plate.

  The obtained test coated plate was placed in a constant temperature and humidity room at room temperature 20 ± 1 ° C. and humidity 75 ± 2% for 24 hours, and then bent 180 ° in 1-2 seconds.

◎: No abnormality on both front and back sides of the folded part ○: There is no problem at least on either side of the folded part, but there is no problem △: Cracking, peeling, etc. on the front and back of the folded part Yes, practically difficult ×: Abnormalities such as cracks and peelings are significant on at least one of the folded parts

(* 3) Water resistance: Each aqueous resin composition was spray-coated on a steel plate so that the dry film thickness was about 20 μm, and dried and heated at 80 ° C. for 30 minutes to prepare each test plate.
The obtained test coating plate was immersed in a constant temperature water bath at room temperature of 20 ° C. for 7 days, and the state of the coating film was visually observed.

◎: No abnormality ○: Slight swelling and discoloration, but in good condition △: Swelling and discoloration, difficult to use ×: Significant swelling and discoloration

Preparation of water-soluble acrylic resin solution 57 parts of propylene glycol monopropyl ether was placed in a reaction apparatus equipped with a thermometer, thermostat, stirrer, reflux condenser, dropping pump, etc., heated to 120 ° C. under a nitrogen stream, and then 15 parts of styrene 20 parts of methyl methacrylate, 25 parts of ethyl acrylate, 20 parts of n-butyl acrylate, 15 parts of hydroxyethyl acrylate, 5 parts of acrylic acid and “Perbutyl O” (manufactured by NOF Corporation, t-butyl peroxy 2-ethylhexanoate ) 3 parts of the mixture was added dropwise over 3 hours. After completion of dropping, the mixture was kept at 120 ° C. for 1 hour, and then a mixed solution of 10 parts of propylene glycol monopropyl ether and 0.5 part of “perbutyl O” was dropped over 1 hour, and further aged at 120 ° C. for 1 hour. Thereafter, the mixture was cooled to 40 ° C., 6 parts of dimethylaminoethanol was added, and the mixture was further stirred for 30 minutes to obtain an acrylic resin solution (P-1) having a solid content of 60%. The acid value of the obtained resin was 38 mgKOH / g, the hydroxyl value was 72 mgKOH / g, and the weight average molecular weight was 30,000.

Preparation of water-soluble acrylic resin solution for clear paints A reactor equipped with a thermometer, thermostat, stirrer, reflux condenser, dripping pump, etc. was charged with 50 parts of diethylene glycol monoethyl ether and heated to 120 ° C under nitrogen flow. Then, a monomer mixture of 50 parts of styrene, 25 parts of n-butyl acrylate, 20 parts of 2-hydroxyethyl methacrylate, 5 parts of acrylic acid and 6 parts of azobisisobutyronitrile was dropped over 3 hours. After completion of the dropwise addition of the monomer mixture, the mixture was further maintained at 120 ° C. for 1 hour, and then a mixture of 5 parts of azobisisobutyronitrile and 10 parts of diethylene glycol monoethyl ether was added dropwise over 1 hour. Thereafter, the mixture was kept at 120 ° C. for 1 hour and then cooled to 40 ° C. or less. Then, 6 parts of dimethylaminoethanol was added and stirred for another 30 minutes to obtain an acrylic resin solution (P-2) having a solid content of 62%. Obtained. The acrylic resin had a weight average molecular weight of 9,000, an acid value of 39 mgKOH / g, and a hydroxyl value of 86 mgKOH / g.

Preparation of acrylic resin aqueous dispersion for clear paints A reactor equipped with a thermometer, thermostat, stirrer, reflux condenser, dripping pump, etc., and 67 parts of deionized water and an emulsifier "New Coal 562SF" (Emulsifier, active ingredient 60%) 0.2 part), heated and stirred under a nitrogen stream to reach 80 to 85 ° C., then 3 parts of the following monomer premix and 0.15 g of ammonium persulfate were removed beforehand. A solution dissolved in 2.5 parts of ionic water was added and stirred for 20 minutes. Subsequently, the remainder of the following monomer premix was added dropwise over 3 hours, held at 80 to 85 ° C. for 2 hours, and then cooled to 40 ° C. Therefore, a mixed solution of 15 parts of deionized water and 1 part of dimethylaminoethanol was added to obtain an acrylic resin aqueous dispersion (E-1) having a solid content of 40% and a particle size of 100 nm.

Monomer pre-mixed styrene 50 parts n-butyl acrylate 26 parts 2-hydroxyethyl methacrylate 20 parts acrylic acid 4 parts n-octanethiol 0.8 parts "New Coal 562SF" 1 part "Emulgen 840S" (Note 5) 1 part ammonium persulfate 0.35 parts Deionized water 60 parts (Note 5) "Emulgen 840S": product name, nonionic emulsifier manufactured by Kao Corporation

Example 9 of Preparation of Aqueous Coating Composition for Base Coat Paint
A water-soluble acrylic resin solution (P-1) 16.6 parts (solid content 10 parts) was placed in a container, and 33 parts of deionized water was gradually added under stirring to replace the aqueous system. Thereafter, 257 parts of the aqueous resin dispersion (1) prepared in Example 1 (90 parts of solid content), 0.75 part of adipic acid dihydrazide, 2 parts of dimethylethanolamine, 49.18 parts of aluminum paste (Note 6), and removal 50 parts of ionic water was added and further stirred and mixed. Further, 80 parts of “Primal ASE-60” (manufactured by Rohm and Haas Co., Ltd., alkali swelling type thickener) diluted to 5% is put in this, and the viscosity (25 ° C .; B type with dimethylethanolamine and deionized water) The viscosity was adjusted so that the viscometer, the No. 3 rotor, and the rotational speed of 6 rpm were 2000 mPa · s and pH 8 to obtain an aqueous coating composition.

  (Note 6) Aluminum paste: An aluminum paste was obtained by mixing 17 parts of aluminum pigment paste “MG-51” (manufactured by Asahi Kasei Co., Ltd., metal content 66.3%) and 20 parts of butyl cellosolve in a container and stirring.

Example 10
In Example 9, an aqueous coating composition was obtained in the same manner as in Example 9 except that the same amount of the aqueous resin dispersion (2) prepared in Example 2 was used instead of the aqueous resin dispersion (1). .

Example 11
In a container, put 25 parts of Superflex 410 (Daiichi Kogyo Seiyaku Co., Ltd., polycarbonate urethane dispersion, solid content 40%) (solid content 10 parts) and gradually add 24.6 parts of deionized water with stirring. I put it in. Thereafter, 257 parts of the aqueous resin dispersion (2) prepared in Example 2 (90 parts of solid content), 0.75 part of adipic acid dihydrazide, 2 parts of dimethylethanolamine, 49.18 parts of aluminum paste (Note 6) and removal 50 parts of ionic water was added and further stirred and mixed. Furthermore, 80 parts of “Primal ASE-60” diluted to 5% is put in this, and the viscosity (25 ° C .; condition of B-type viscometer, No3 rotor, rotational speed 6 rpm) is 2000 mPas with dimethylethanolamine and deionized water. -It adjusted so that it might become s and pH8, and the water-based coating composition was obtained.

Example 12
In Example 9, an aqueous coating composition was obtained in the same manner as in Example 9 except that the same amount of the aqueous resin dispersion (3) prepared in Example 3 was used instead of the aqueous resin dispersion (1). .

Example 13
In Example 11, an aqueous coating composition was obtained in the same manner as in Example 11 except that the same amount of the aqueous resin dispersion (4) prepared in Example 4 was used instead of the aqueous resin dispersion (2). .

Comparative Example 3
A water-soluble acrylic resin solution (P-1) 16.6 parts (solid content 10 parts) was placed in a container, and 33 parts of deionized water was gradually added under stirring to replace the aqueous system. Thereafter, 257 parts of the aqueous resin dispersion (5) prepared in Comparative Example 1 (90 parts of solid content), 2 parts of dimethylethanolamine, 49.18 parts of aluminum paste (Note 6) and 50 parts of deionized water were further added. Stir and mix. Furthermore, 80 parts of “Primal ASE-60” diluted to 5% is put in this, and the viscosity (25 ° C .; condition of B-type viscometer, No3 rotor, rotational speed 6 rpm) is 2000 mPas with dimethylethanolamine and deionized water. -It adjusted so that it might become s and pH8, and the water-based coating composition was obtained.

Water- soluble acrylic resin solution (P-2) 64.5 parts (solid content 40 parts), “BYK-307” (by BIC Chemie, surface conditioner) 0.1 part, 1130 "(manufactured by Ciba Specialty Chemicals Co., Ltd., UV absorber) and 150 parts of acrylic resin aqueous dispersion (E-1) (60 parts in solids) were mixed with stirring, and then deionized water was added. The paint viscosity was adjusted to 35 seconds (Ford Cup # 4/25 ° C.). Immediately before coating, 57 parts (NCO / OH = 1.5 / 1) of “Bihijur 3100” (manufactured by Sumika Bayer Urethane Co., Ltd., water-based polyisocyanate curing agent) were added and stirred well. 1) was created.

Preparation Example 14 of Painted Plate
Amine-modified epoxy resin-based cationic electrodeposition paint is applied to a treated steel sheet that has been chemically treated with a zinc phosphate-based treatment agent “Palbond # 3020” (trade name, manufactured by Nihon Parkerizing Co., Ltd.) on a cold-rolled dull steel sheet so that the dry film thickness is 25 μm The film was electrodeposited and cured at 170 ° C. for 30 minutes. A polyester melamine resin-based organic solvent-type intermediate coating for automobiles was applied onto the electrodeposited steel sheet so as to have a dry film thickness of 30 μm, and baked at 140 ° C. for 30 minutes to obtain an article to be coated.

  The aqueous paint composition prepared in Example 9 was used as the aqueous base coat paint, and this was applied to the object to be coated by air spray coating so that the dry film thickness was 15 μm. Next, it is dried at 80 ° C. for 10 minutes, and a two-component acrylic resin-based organic solvent diluted clear coating “Soflex-500TL” (manufactured by Kansai Paint Co., Ltd., using a polyisocyanate curing agent) is continuously applied on the coated surface. Spray coating was performed so that the dry film thickness was 30 μm, and then heating was performed at 100 ° C. for 30 minutes to cure both coating films at the same time to prepare a test coating plate.

Example 15
In Example 14, a test coated plate was prepared in the same manner as in Example 14 except that the aqueous coating composition prepared in Example 10 was used as the aqueous base coat coating.

Example 16
In Example 14, a test coating plate was prepared in the same manner as in Example 14 except that the aqueous coating composition prepared in Example 11 was used as the aqueous base coat coating.

Example 17
In Example 14, a test coated plate was prepared in the same manner as in Example 14 except that the aqueous coating composition prepared in Example 12 was used as the aqueous base coat coating.

Example 18
In Example 14, a test coated plate was prepared in the same manner as in Example 14 except that the aqueous coating composition prepared in Example 13 was used as the aqueous base coat coating.

Comparative Example 4
In Example 14, a test coated plate was prepared in the same manner as in Example 14 except that the aqueous coating composition prepared in Comparative Example 3 was used as the aqueous base coat coating.

Example 19
The aqueous coating composition prepared in Example 9 was used as the aqueous base coat coating, and this was applied to the same coating as in Example 14 so that the dry film thickness was 15 μm by air spray coating. Next, it was dried at 80 ° C. for 10 minutes, and the aqueous clear paint (S-1) prepared as described above was spray-coated on the coated surface so as to have a dry film thickness of 30 μm. After preheating for 30 minutes, heating was performed at 100 ° C. for 30 minutes, and both coating films were simultaneously cured to prepare a test coating plate.

Example 20
In Example 19, a test coated plate was prepared in the same manner as in Example 19 except that the aqueous coating composition prepared in Example 10 was used as the aqueous base coat coating.

Comparative Example 5
In Example 19, a test coating plate was prepared in the same manner as in Example 19 except that the aqueous coating composition prepared in Comparative Example 3 was used as the aqueous base coat coating.

  About each coating board for a test obtained by the said Example and comparative example, the chipping resistance and finishing property were evaluated in accordance with the following test method. The obtained results are shown in Table 2.

(* 4) Chipping resistance: A test plate was placed on a test piece holder of a “QGR gravelometer” (manufactured by US Q-PANEL, chipping test apparatus), and 0.392 MPa at −20 ° C. ( 4 gf / cm ² ) compressed air of 50 g of granite crushed stone was sprayed onto the coating surface, and the degree of scratches on the coating film was visually observed and evaluated.

◎: Small scratch size, few scratches, intermediate coating film exposed ○: Small scratch size, many scratches, intermediate coating film exposed △: Scratch size Small, many scratches, bare steel plate is exposed ×: large scratches, many scratches, bare steel plate is exposed

(* 5) Finishing property: The coating film was visually evaluated according to the following criteria.

◎: Concavity and convexity is not recognized, smoothness is good, metallic feeling and sharpness are excellent ○: metallic feeling and sharpness are excellent, but smoothness is slightly inferior ×: metallic feeling, sharpness Inferior in smoothness and smoothness

Claims (10)

Polyurethane resin (A), polymerizable unsaturated monomer (B) and emulsifier (C) obtained by reaction with polyol (a), polyisocyanate compound (b) and hydroxyl group-containing ethylenically unsaturated monomer (c) In a dispersion liquid obtained by finely dispersing a mixture (I) containing an aqueous medium so that the average particle diameter is 500 nm or less and polymerizing the resulting emulsion, a carboxyl group-containing polymerizable unsaturated monomer And a monomer component (II) containing a carbonyl group-containing polymerizable unsaturated monomer, and further polymerizing the monomer component (II). The method for producing an aqueous resin dispersion according to claim 1, wherein the polyol (a) contains a fatty acid ester (a1) containing two or more hydroxyl groups in one molecule as at least a part of the component. An aqueous resin dispersion produced by the method according to claim 1. An aqueous resin composition comprising the aqueous resin dispersion according to claim 3. Furthermore, the aqueous resin composition of Claim 4 containing a polyurethane dispersion. The aqueous resin composition according to claim 4 or 5, further comprising a hydrazine derivative. An aqueous coating composition comprising the aqueous resin composition according to any one of claims 4 to 6. A coating method comprising applying the aqueous coating composition according to claim 7 to a surface to be coated. The water-based coating composition according to claim 7 is used as the water-based base coat paint in a method of applying a water-based base coat paint containing a glitter pigment and / or a color pigment on a surface to be coated and then applying a clear paint. Painting method. A coated article formed by the method according to claim 8 or 9.