JP2019516002A - Aqueous resin composition, aqueous paint and article having cured coating of the aqueous paint - Google Patents

Abstract

A self-emulsifying aqueous resin (E) in which a modified epoxy resin (D) is encapsulated in an acrylic resin (C) in which a carboxyl group-containing polymer (A) is neutralized with a basic compound (B) is aqueous An aqueous resin composition dispersed in a medium, wherein the acid value of the polymer (A) is in the range of 40 to 90 mg KOH / g, and the basic compound (B) is 55 mol% of alkylamine (b1) Characterized in that the modified epoxy resin (D) is a reaction product of the epoxy resin (d1), a monocarboxylic acid (d2) and a compound (d3) having a hydroxyl group bonded to a phosphorus atom An aqueous resin composition is provided. The cured coating film obtained from the aqueous resin composition has high hardness and is excellent in substrate adhesion, acid resistance, corrosion resistance and the like, and thus can be suitably used for an aqueous coating.

Description

  The present invention relates to an aqueous resin composition, an aqueous coating and an article having a cured coating of the aqueous coating.

  Conventionally, solvent-based acrylic resin paints, solvent-based alkyd resin paints, and baking paints, which use an amino resin as a curing agent, are used as paints for metal products such as construction materials, steel furniture, small articles and accessories. However, in recent years, from the viewpoint of environmental protection by reducing volatile substances such as organic solvents released from paints, and the non-hazardization of paints, solvent-based paints have been replaced with water-based paints in recent years, Also in the case of baked paint, there is a strong demand for making the paint water-based.

  In addition, although baked coatings are generally cured at a high temperature of 120 ° C. or higher, in recent years, the baking temperature has been reduced from the viewpoint of reducing energy costs and using for substrates where high temperature baking processing of plastics etc is difficult. Reduction is required.

  As such a resin for aqueous baking coating, for example, an aqueous resin composition comprising a modified epoxy resin has been proposed (see, for example, Patent Document 1). However, since this aqueous resin composition contains an emulsifier, for example, in the salt spray test of a steel plate cross-cut so as to reach the base material, there is a problem that rust, swelling and the like occur.

  In addition, an aqueous resin composition in which a self-emulsifying type aqueous acrylic resin containing a modified epoxy resin is dispersed has been proposed (see, for example, Patent Document 2). However, when this aqueous resin composition is cured at less than 120 ° C., the coating film hardness is low and the acid resistance is also poor.

  Therefore, a coating composition capable of obtaining a cured coating having high coating film hardness and excellent coating physical properties such as acid resistance under low temperature curing conditions has been desired.

JP 2003-2950 A JP 2012-92198 A

  The problem to be solved by the present invention is an aqueous resin composition capable of obtaining a cured coating film which is high in coating film hardness and excellent in substrate adhesion, acid resistance, corrosion resistance and the like even under low temperature curing conditions. It is an object to provide an article having a paint and a cured coating of the water-based paint.

  As a result of intensive studies to solve the above problems, the present inventors found that a self-emulsification aqueous solution in which a specific modified epoxy resin is encapsulated in an acrylic resin having a carboxyl group neutralized with a specific basic compound. An aqueous resin composition in which a resin is dispersed in an aqueous medium can be used as a resin for an aqueous coating, and the aqueous coating composition containing the aqueous resin composition and a curing agent has a high coating film hardness, adhesion to a substrate, The inventors have found that a cured coating film excellent in acid resistance and corrosion resistance can be obtained, and completed the present invention.

  That is, the present invention is a self-emulsifying aqueous resin in which a modified epoxy resin (D) is encapsulated in an acrylic resin (C) in which a polymer (A) having a carboxyl group is neutralized with a basic compound (B). An aqueous resin composition in which (E) is dispersed in an aqueous medium, wherein the acid value of the polymer (A) is in the range of 40 to 90 mg KOH / g, and the basic compound (B) is an alkylamine (B1) is contained 55 mol% or more, and the reaction of the modified epoxy resin (D) with a compound (d3) having a hydroxyl group bonded to an epoxy resin (d1), a monocarboxylic acid (d2) and a phosphorus atom The present invention relates to an aqueous resin composition characterized by the above, an aqueous paint containing the composition and a curing agent (F), and an article having a cured coating of the aqueous paint.

  The aqueous resin composition of the present invention can be used as a resin for aqueous coating. Moreover, since the water-based paint containing the water-based resin composition and the curing agent has a high coating film hardness and can obtain a cured coating film excellent in substrate adhesion, acid resistance and corrosion resistance, it can be used as a belt, a fastener or a bag. Metal parts such as key chains and ornaments; Construction members such as steel furniture, outer walls and roofs; Civil engineering members such as guard rails, sound barriers and drainage grooves; Suitable for various metal substrates such as home appliances, industrial machines and automobiles It can be used.

  The aqueous resin composition of the present invention is a self-emulsification in which a modified epoxy resin (D) is contained in an acrylic resin (C) in which a polymer (A) having a carboxyl group is neutralized with a basic compound (B). Type aqueous resin (E) is an aqueous resin composition dispersed in an aqueous medium, wherein the acid value of the polymer (A) is in the range of 40 to 90 mg KOH / g, and the basic compound (B) Is a compound containing 55 mol% or more of alkylamine (b1), and the modified epoxy resin (D) is a compound (d3) having a hydroxyl group bonded to an epoxy resin (d1), a monocarboxylic acid (d2) and a phosphorus atom Is a reaction product with

  First, the polymer (A) having a carboxyl group will be described. The polymer (A) is, for example, copolymerized with an unsaturated monomer (a1) having a carboxyl group and an unsaturated monomer (a2) other than the unsaturated monomer (a1) having the carboxyl group. It is obtained by

  Examples of the unsaturated monomer (a1) include (meth) acrylic acid, crotonic acid, isocrotonic acid, 2- (meth) acryloyloxyethyl succinic acid, and 2- (meth) acryloyloxyhexahydrophthalic acid. Acids, 2- (meth) acroyloxy ethyl glutarate; dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid and anhydrides thereof; monomethylmaleic acid, monoethylmaleic acid, monobutylmaleic acid, monooctylmaleic acid, Monoalkyl esters of dicarboxylic acids such as monomethyl fumaric acid, monoethyl fumaric acid, monobutyl fumaric acid, monooctyl fumaric acid, monomethyl itaconic acid, monoethyl itaconic acid, monobutyl itaconic acid, monobutyl itaconic acid, monooctyl itaconic acid, etc. . Among the unsaturated monomers (a1), (meth) acrylic acid is preferable because a resin with low viscosity and excellent dispersibility can be obtained. Moreover, these unsaturated monomers (a1) can be used alone or in combination of two or more.

  In the present invention, “(meth) acrylic acid” refers to one or both of methacrylic acid and acrylic acid, “(meth) acryloyl” refers to one or both of methacryloyl and acryloyl, and “(meth) acrylic acid” The term "acrylate" refers to one or both of methacrylate and acrylate.

  Examples of the unsaturated monomer (a2) other than the unsaturated monomer (a1) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate and iso-propyl (meth) Acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, octadecyl (meth) acrylate, docosanyl (meth) Alkyl (meth) acrylates such as acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cycloalkyl (meth) acrylate Acrylates; Hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, etc., and ε-caprolactone, γ-valerolactone, etc. of the above hydroxyalkyl (meth) acrylates Unsaturated monomers having a hydroxyl group such as adducts of lactone compounds; aromatic vinyl compounds such as styrene, p-tert-butylstyrene, α-methylstyrene and vinyltoluene; 2-methoxyethyl (meth) acrylate, 4- Ω-alkoxyalkyl (meth) acrylates such as methoxybutyl (meth) acrylate; unsaturated monomers having a tertiary amide group such as N, N-dimethyl (meth) acrylamide; methoxy polyethylene glycol (meth) acrylates Unsaturated monomers having a polyalkylene oxide structure such as polyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate; N-methylol (meth) acrylamide, N-methoxymethyl ( N-Alkoxymethyl (meth) acrylamide such as meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-n-butoxymethyl (meth) acrylamide, N-iso-butoxymethyl (meth) acrylamide, etc .; methylaminoethyl (meth) acrylamide ) An unsaturated monomer having a secondary amino group such as acrylate; an unsaturated monomer having an active methylene group such as vinyl acetoacetate, 2-acetoacetoxyethyl (meth) acrylate; vinyl trime Unsaturated monomer having hydrolyzable silyl group such as xysilane, 3- (meth) acryloyloxypropyl trimethoxysilane; unsaturated monomer having silyl ester group such as trimethylsilyl (meth) acrylate; glycidyl (meth) Unsaturated monomers having an epoxy group such as acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, glycidyl vinyl ether, allyl glycidyl ether; 2-isocyanatopropene, 2-isocyanatoethyl vinyl ether And unsaturated monomers having an isocyanate group such as 2-isocyanatoethyl methacrylate and m-isopropenyl-α, α-dimethylbenzyl isocyanate. These unsaturated monomers (a2) can be used alone or in combination of two or more.

  Examples of the method for producing the polymer (A) include the following two solution polymerization methods.

  As the method 1, a method of dropping the unsaturated monomer (a1) and the unsaturated monomer (a2) together with a polymerization initiator in an organic solvent, and heating and stirring to polymerize can be mentioned.

  In addition, as Method 2, a monomer mixture (I) of the unsaturated monomer (a1) and / or the unsaturated monomer (a2) is dropped into an organic solvent together with a polymerization initiator, and heating is performed. After stirring and polymerizing, a monomer mixture (II) containing the above-mentioned unsaturated monomer (a1) as an essential component is further added, heated and stirred for polymerization, and the resulting aqueous resin composition Of the unsaturated monomer (a1) in the mixture (I) of the unsaturated monomer and the mixture of the unsaturated monomer (x A range in which the ratio [(x) / (y)] to the molar ratio (y) of the unsaturated monomer (a1) in II) is less than 1 is preferable, and the range in which it is less than 0.5 is more preferable.

  Further, the mass ratio [(I) / (II)] of the mixture (I) of the unsaturated monomer to the mixture (II) of the unsaturated monomer is in the range of 20/80 to 85/15. Preferably, the range of 30/70 to 75/25 is more preferable.

  As in method 2 above, in the polymer (A), a mixture of two types different in the composition of the unsaturated monomer to be a raw material of the polymer (A) is charged in two stages and copolymerized. Of the polymer (A) which is to be a shell of the self-emulsifying aqueous resin (E) when the carboxyl group of the polymer is localized and dispersed in the aqueous medium simultaneously with the inclusion of the modified epoxy resin (C) Since the carboxyl group is disposed on the aqueous phase side and the hydrophobic portion of the acrylic resin polymer (A) is disposed on the core side of the self-emulsifying aqueous resin (E), stability in an aqueous medium Improve further.

  The organic solvent used in the production of the polymer (A) is preferably a water-miscible organic solvent which is miscible with water without separation, and among them, the solubility in water (the number of grams of the organic solvent dissolved in 100 g of water) is 3 g or more of an organic solvent at 25 ° C. is preferred. As these water-miscible organic solvents, for example, alcohol solvents such as methanol, ethanol, propanol and butanol; ketone solvents such as acetone and methyl ethyl ketone; ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether Ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol Monomethyl ether, triethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, etc. glycol ethers solvents such as dipropylene glycol dimethyl ether. These water-miscible organic solvents can be used alone or in combination of two or more.

  Examples of the polymerization initiator used in the production of the polymer (A) include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2-methylbutyronitrile), azobiscyanovaleric acid, etc. Azo compounds of: tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, t Organic peroxides such as butyl hydroperoxide; and inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate and the like. These polymer initiators can be used alone or in combination of two or more. Moreover, it is preferable to use the said polymerization initiator within the range of 0.1-10 mass% with respect to the sum total of the unsaturated monomer used as the raw material of the said polymer (A).

  Moreover, the range of 30-90 mass% is preferable, and, as for the non volatile matter in the reaction container at the time of manufacturing the said polymer (A), the range of 50-85 mass% is more preferable.

  It is important that the acid value of the polymer (A) be in the range of 40 to 90 mg KOH / g in order to impart excellent low temperature curability.

  The hydroxyl value of the polymer (A) is preferably in the range of 5 to 100 mg KOH / g because the low temperature curability is further improved.

  In addition, the weight average molecular weight of the polymer (A) is preferably in the range of 5,000 to 100,000, since an aqueous resin composition or paint which is excellent in storage stability and does not cause thickening can be obtained. The range of 1,000 to 50,000 is more preferable.

  In the present invention, the acid value and the hydroxyl value are the acid values obtained by calculation from the composition of the unsaturated monomer as the raw material. The weight average molecular weight is determined by gel permeation chromatography (hereinafter abbreviated as "GPC") method.

  It is important that the glass transition temperature of the polymer (A) is in the range of 50 to 100 ° C. from the viewpoint of the coating film hardness.

The glass transition temperature in the present invention is
Formula of FOX: 1 / Tg = W1 / Tg1 + W2 / Tg2 +.
(Tg: glass transition temperature to be determined, W1: weight fraction of component 1, Tg1: glass transition temperature of homopolymer of component 1)
Calculated according to The value of the glass transition temperature of the homopolymer of each component is the value described in “Adhesion technology handbook” of Nikkan Kogyo Shimbun or “Polymer Handbook” of Wiley-Interscience. Hereinafter, this glass transition temperature is abbreviated as "Tg".

  The acrylic resin (C) is obtained by neutralizing the polymer (A) with the basic compound (B), but from the viewpoint of acid resistance, the basic compound (B) is an alkylamine (b1). It is important to contain 55 mol% or more, and it is preferable to contain 70 mol% or more.

  Examples of the alkylamine (b1) include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dipropylamine, tripropylamine and the like, but the temperature control of the neutralization step is Triethylamine is preferred in terms of ease. These alkylamines (b1) can be used alone or in combination of two or more.

  Examples of the basic compound (b2) other than the alkylamine (b1) used as the basic compound (B) include monoethanolamine, diethanolamine, monoisopropanolamine, diisopropanolamine, N-methylethanolamine, Alkanolamines such as N, N-dimethylethanolamine, N, N-diethylethanolamine, 2-amino-2-methylpropanol, 2- (dimethylamino) -2-methylpropanol and N-methyldiethanolamine; ethylenediamine, diethylenetriamine, Organic amines such as polyvalent amines such as triethylenetetramine and tetraethylenepentamine, and ammonia (water) can be mentioned. These basic compounds (b2) can be used alone or in combination of two or more.

  The neutralization ratio of the carboxyl group of the acrylic resin (C) is preferably in the range of 50 to 100% because the dispersion stability is further improved.

  The modified epoxy resin (D) is a reaction product of an epoxy resin (d1), a monocarboxylic acid (d2), and a compound (d3) having a hydroxyl group bonded to a phosphorus atom.

  Examples of the epoxy resin (d1) include ethylene glycol, propylene glycol, hexanediol, neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol, glycerin, diglycerin, sorbitol, spiroglycol or hydrogenated bisphenol A and the like. Aliphatic polyol diglycidyl ether type epoxy resin;

  Aromatic epoxy resin such as diglycidyl ether type epoxy resin such as bisphenol A, bisphenol F, bisphenol S or bisphenol AD, novolac type epoxy resin which is glycidyl ale such as phenol novolak resin or cresol novolac resin; aromatic polyhydroxy compound Diglycidyl ether type epoxy resins of polyols such as ethylene oxide or propylene oxide adducts of

  Polyglycidyl ether type epoxy resin of polyether polyol such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; bis (3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxy Cycloaliphatic polyepoxy resins such as cyclohexyl carboxylate;

  Polyglycidyl ester type epoxy resin of polycarboxylic acid such as propanetricarboxylic acid, butanetetracarboxylic acid, adipic acid, phthalic acid, terephthalic acid or trimellitic acid; butadiene, hexadiene, octadiene, dodecadiene, cyclooctadiene, α-pinene or Hydrocarbon-based diene bis-epoxy resins such as vinylcyclohexene;

  Epoxy resins of diene polymers such as polybutadiene or polyisoprene; glycidyl amine type epoxy resins such as tetraglycidyl diaminodiphenylmethane, tetraglycidyl bisaminomethyl cyclohexane, diglycidyl aniline or tetraglycidyl metaxylylene diamine; various compounds such as triazine or hydantoin The epoxy resin etc. which have a heterocyclic ring are mentioned. In addition, these epoxy resins (c1) can be used alone or in combination of two or more.

  Among these epoxy resins, aromatic epoxy resins are preferable, and bisphenol A epoxy resins are more preferable because corrosion resistance is further improved.

  Examples of the monocarboxylic acid (d2) include saturated carboxylic acids such as propionic acid, lactic acid, butyric acid and valeric acid; (meth) acrylic acid, vinylacetic acid, crotonic acid, tiglic acid, 3, 3-dimethylacrylic acid, Ethylenically unsaturated monocarboxylic acids such as pentenoic acid can be mentioned. Among these, ethylenically unsaturated monocarboxylic acid is preferable, the ethylenically unsaturated monocarboxylic acid having 3 to 5 carbon atoms is more preferable, and (meth) acrylic acid is more preferable because the adhesion to a substrate is further improved. preferable. Moreover, these monocarboxylic acids (d2) can be used alone or in combination of two or more.

  Examples of the compound (d3) having a hydroxyl group bonded to a phosphorus atom include phosphoric acid, phosphorous acid, hypophosphorous acid; phosphoric monoesters such as monomethyl phosphate, monoethyl phosphate, monopropyl phosphate, monobutyl phosphate and the like And the like, but from the viewpoint of further improving the corrosion resistance, a compound having two or more hydroxyl groups bonded to a phosphorus atom is preferable, and phosphoric acid is more preferable.

  The reaction of the epoxy resin (d1), the monocarboxylic acid (d2), and the compound (d3) having a hydroxyl group bonded to the phosphorus atom in obtaining the modified epoxy resin (D) is the epoxy resin (d1). The number of moles of the sum of the number of moles of carboxyl groups in the monocarboxylic acid (d2) and the number of moles of hydroxyl groups bonded to phosphorus atoms in the compound (d3) relative to 1 mole of epoxy groups in It is preferable that it is 0.9 to 1 mol.

  Examples of the method for producing the modified epoxy resin (D) include the following methods (1) to (3).

  Method (1): A method in which the epoxy resin (d1), the monocarboxylic acid (d2) and the compound (c3) are charged at one time and reacted.

  Method (2): The epoxy resin (d1) and the monocarboxylic acid (d2) are reacted, and then the compound (d3) is reacted.

  Method (3): The epoxy resin (d1) and the compound (d3) are reacted, and then the monocarboxylic acid (d2) is reacted.

  Among these methods, method (2) is preferable because the reaction efficiency is more excellent.

  In these methods, if necessary, an organic solvent, a catalyst or the like may be used, and it is preferable to use triphenylphosphine, an amine compound or the like as the catalyst.

  The self-emulsifying type aqueous resin (E) is one in which the modified epoxy resin (D) is contained in the acrylic resin (C), and for example, the polymer (A) and the modified epoxy resin ( The solution obtained by mixing D) and the basic compound (B) is obtained by phase inversion emulsification using water.

  The mass ratio [(A) / (D)] of the polymer (A) to the modified epoxy resin (D) in the self-emulsifying aqueous resin (E) is the storage stability and the corrosion resistance of the obtained coating film The range of 70/30 to 97/3 is preferable for further improvement.

  The aqueous resin composition of the present invention is obtained by dispersing the self-emulsifying aqueous resin (E) in an aqueous medium, and as the aqueous medium, water and the polymer (A) are produced. The water miscible organic solvents listed as the organic solvent to be used can be used. These aqueous media can be used alone or in combination of two or more.

  The aqueous resin composition of the present invention is obtained by dispersing the self-emulsifiable aqueous resin (E) in an aqueous medium, and by further blending a curing agent (F), it becomes the aqueous paint of the present invention. Examples of the curing agent (F) include amino resins and blocked isocyanate resins.

  As the amino resin, for example, an amino resin having an alkylol group obtained by reacting a compound having an amino group such as melamine, benzoguanamine, acetoguanamine or urea with an aldehyde compound such as formaldehyde or acetaldehyde; An amino resin having an alkoxyalkyl group obtained by reacting an amino resin having a group with a lower alcohol such as methanol, ethanol, n-butanol or iso-butanol may, for example, be mentioned.

  As the block isocyanate resin, for example, an adduct of an organic diisocyanate compound and a polyhydric alcohol, a low molecular weight hydroxyl group-containing polyester resin, a low molecular weight hydroxyl group-containing alkyd resin, water or the like, and a polymer of the organic diisocyanate compounds (isocyanurate) Block isocyanate obtained by blocking type polyisocyanate compounds and uretdione compounds with various blocking agents such as oxime compounds, phenol compounds, alcohol compounds, and diketone compounds.

  Examples of the organic diisocyanate compound include: alicyclic diisocyanates such as isophorone diisocyanate; aromatic diisocyanates such as xylylene diisocyanate, tolylene diisocyanate or 4,4-diphenylmethane diisocyanate; and aliphatics such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate Diisocyanate is mentioned.

  As the compounding amount of the curing agent (F), the curability of the aqueous paint of the present invention and the coating appearance and durability of the cured coating film are further improved, so that the mass ratio [self-emulsifying type aqueous resin (E) / The curing agent (F)) is preferably in the range of 50/50 to 95/5, and more preferably in the range of 70/30 to 90/10.

  Furthermore, in the water-based paint of the present invention, if necessary, as other ingredients, inorganic pigments, organic pigments, extender pigments, waxes, surfactants, stabilizers, flow control agents, dyes, leveling agents, rheology control Additives, such as UV absorbers, UV absorbers, antioxidants, plasticizers, antistatic agents, antifoaming agents, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, pigment dispersants, etc. be able to.

  The method of coating the coating composition of the present invention varies depending on the article to be coated, but, for example, a gravure coater, a roll coater, a comma coater, a knife coater, an air knife coater, a curtain coater, a kiss coater, a shower coater, a wheel coater, a spin coater, Methods such as dipping, screen printing, spraying, an applicator, a bar coater and the like can be mentioned.

  The water-based paint of the present invention can impart a cured coating film excellent in acid resistance to the surface of various articles.

  The coating composition of the present invention may be directly applied to an article to be coated, or a primer coating material compatible with the article to be coated may be applied before the coating composition of the present invention is applied. Good.

  Materials of articles to be coated include various metals such as iron, copper, zinc, aluminum, magnesium and alloys thereof; polycarbonate (PC), acrylonitrile-butadiene-styrene copolymer (ABS), PC-ABS Various resins such as polymer alloy, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyamide (PA), polypropylene (PP); Fiber reinforced plastic (FRP) in which filler such as glass fiber is added to these resins; etc. Can be mentioned.

  Articles which can be coated with the water-based paint of the present invention include: fittings such as belts, bags and ornaments; steel furniture; building members such as outer walls and roofs; civil engineering members such as guard rails, sound barriers, drainage grooves; Metal substrates such as products, industrial machines, parts of automobiles, etc. may be mentioned.

  Hereinafter, the present invention will be described in more detail by way of specific examples. The viscosity of the aqueous resin composition is a value measured with a BM viscometer "TVB 10 type viscometer" manufactured by Toki Sangyo Co., Ltd., and the average particle diameter of the resin particles in the aqueous resin composition is "Nikkiso Co., Ltd." It is the value measured using Nanotrac UPA-150. Moreover, the weight average molecular weight (Mw) was measured on the following measurement conditions.

[Measurement conditions of weight average molecular weight]
Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were used in series connection.
"TSKgel G5000" (7.8 mm ID × 30 cm) × 1 "TSK gel G 4000" (7.8 mm ID × 30 cm) × 1 "TSK gel G 3000" (7.8 mm ID × 30 cm) × 1 This "TSKgel G2000" (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
Tosoh Corporation "TSKgel standard polystyrene A-500"
Tosoh Corporation "TSKgel standard polystyrene A-1000"
Tosoh Corporation "TSKgel standard polystyrene A-2500"
Tosoh Corporation "TSKgel standard polystyrene A-5000"
Tosoh Corporation "TSKgel standard polystyrene F-1"
Tosoh Corporation "TSKgel standard polystyrene F-2"
Tosoh Corporation "TSKgel standard polystyrene F-4"
Tosoh Corporation "TSKgel standard polystyrene F-10"
Tosoh Corporation "TSKgel standard polystyrene F-20"
Tosoh Corporation "TSKgel standard polystyrene F-40"
Tosoh Corporation "TSKgel standard polystyrene F-80"
Tosoh Corporation "TSKgel standard polystyrene F-128"
Tosoh Corporation "TSKgel standard polystyrene F-288"
Tosoh Corporation "TSKgel standard polystyrene F-550"

Synthesis Example 1: Synthesis of Modified Epoxy Resin (D-1)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction pipe, 545.5 parts by mass of bisphenol A epoxy resin ("Epicoat 1001" manufactured by Mitsubishi Chemical Corporation) and 259.0 parts of diethylene glycol dimethyl ether The temperature was raised to 80 ° C. while heating and dissolving. After dissolution, 59.7 parts by mass of acrylic acid was charged at 80 ° C., and the mixture was stirred while raising temperature to 110 ° C. over 1 hour. The reaction is allowed to continue at 110 ° C. for 3 hours, and when the acid value is 1.0 mg KOH / g or less, the temperature is lowered to 80 ° C., 12.1 parts by mass of 85% by mass phosphoric acid and diethylene glycol dimethyl ether 70 The mixture consisting of 2 parts by mass was continuously dropped over 1 hour. After completion of the dropwise addition, the reaction is continued at 80 ° C. for 4 hours, and then 50.5 parts by mass of diethylene glycol dimethyl ether is charged to obtain a modified epoxy resin having a nonvolatile content of 64.0% by mass and an acid value of 9.0 mg KOH / g (D -1) was obtained.

Example 1 Synthesis of Aqueous Resin Composition (1)
In a reaction vessel equipped with a reflux condenser, a stirrer and a nitrogen inlet tube, 766.8 parts by mass of diethylene glycol dimethyl ether and 27.0 parts by mass of fumaric acid were charged and stirring was started, and the temperature was raised to 135 ° C. Under nitrogen stream, 637.2 parts by mass of styrene, 145.8 parts by mass of methyl methacrylate, 62.6 parts by mass of n-butyl acrylate, 108.0 parts by mass of 2-hydroxyethyl methacrylate, 16.2 parts by mass of acrylic acid The monomer mixture consisting of and 39.6 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, a single amount consisting of 424.8 parts by mass of styrene, 97.2 parts by mass of methyl methacrylate, 41.8 parts by mass of n-butyl acrylate, 72.0 parts by mass of 2-hydroxyethyl methacrylate, and 145.8 parts by mass of acrylic acid The body mixture and 30.6 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (A-1) having a Tg of 80 ° C., an acid value of 85 mg KOH / g and a hydroxyl value of 43 mg KOH / g. 149.4 parts by mass of a modified epoxy resin (D-1) is mixed with this solution, followed by neutralization with 117.0 parts by mass of triethylamine, and phase inversion emulsification using 2105.0 parts by mass of ion-exchanged water, An aqueous resin composition (1) in which a self-emulsifying aqueous resin was dispersed in an aqueous medium was obtained. The aqueous resin composition (1) had a nonvolatile content of 44.0% by mass and a pH of 7.5.

Example 2 Synthesis of Aqueous Resin Composition (2)
In a reaction vessel equipped with a reflux condenser, a stirrer and a nitrogen inlet tube, 234.4 parts by mass of diethylene glycol dimethyl ether was charged, stirring was started, and the temperature was raised to 135 ° C. Under nitrogen stream, 227.2 parts by mass of styrene, 58.5 parts by mass of methyl methacrylate, 21.6 parts by mass of n-butyl acrylate, 38.5 parts by mass of 2-hydroxyethyl methacrylate, 5.0 parts by mass of acrylic acid The monomer mixture consisting of and 14.1 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3.5 hours. Subsequently, a single amount consisting of 97.4 parts by mass of styrene, 25.1 parts by mass of methyl methacrylate, 9.2 parts by mass of n-butyl acrylate, 16.5 parts by mass of 2-hydroxyethyl methacrylate, 44.5 parts by mass of acrylic acid The body mixture and 7.7 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 1.5 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (A-2) having a Tg of 80 ° C., an acid value of 70 mg KOH / g and a hydroxyl value of 43 mg KOH / g. In this solution, 45.8 parts by mass of modified epoxy resin (D-1) is mixed, followed by neutralization with 34.7 parts by mass of triethylamine, and phase inversion emulsification is performed using 485.7 parts by mass of ion exchanged water. An aqueous resin composition (2) was obtained in which the self-emulsifying aqueous resin was dispersed in an aqueous medium. The aqueous resin composition (2) had a nonvolatile content of 47.0% by mass and a pH of 7.5.

Example 3 Synthesis of Aqueous Resin Composition (3)
In a reaction vessel equipped with a reflux condenser, a stirrer and a nitrogen inlet tube, 255.8 parts by mass of diethylene glycol dimethyl ether and 9.0 parts by mass of fumaric acid were charged and stirring was started, and the temperature was raised to 135 ° C. Under a nitrogen stream, 212.4 parts by mass of styrene, 64.9 parts by mass of methyl methacrylate, 23.4 parts by mass of n-butyl acrylate, 36.0 parts by mass of 2-hydroxyethyl methacrylate, 1.5 parts by mass of acrylic acid A monomer mixture consisting of 0.7 parts by mass of methacrylic acid and 13.6 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, 141.6 parts by mass of styrene, 43.3 parts by mass of methyl methacrylate, 15.6 parts by mass of n-butyl acrylate, 24.0 parts by mass of 2-hydroxyethyl methacrylate, 13.9 parts by mass of acrylic acid, methacrylic acid 6 A monomer mixture consisting of 5 parts by mass and 9.8 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (A-3) having a Tg of 80 ° C., an acid value of 42 mg KOH / g, and a hydroxyl value of 43 mg KOH / g. 50.0 parts by mass of a modified epoxy resin (D-1) is mixed with this solution, followed by neutralization with 30.1 parts by mass of triethylamine, and phase inversion emulsification using 725.0 parts by mass of ion-exchanged water, An aqueous resin composition (3) in which a self-emulsifying aqueous resin was dispersed in an aqueous medium was obtained. The aqueous resin composition (3) had a non-volatile content of 36.5% by mass and a pH of 7.4.

Example 4 Synthesis of Aqueous Resin Composition (4)
In a reaction vessel equipped with a reflux condenser, a stirrer, and a nitrogen inlet tube, 255.0 parts by mass of diethylene glycol dimethyl ether and 9.0 parts by mass of fumaric acid were charged and stirring was started, and the temperature was raised to 135 ° C. Under a nitrogen stream, 212.4 parts by mass of styrene, 60.8 parts by mass of methyl methacrylate, 21.6 parts by mass of n-butyl acrylate, 36.0 parts by mass of 2-hydroxyethyl methacrylate, 3.3 parts by mass of acrylic acid The monomer mixture consisting of and 13.3 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, a single amount consisting of 141.6 parts by mass of styrene, 40.2 parts by mass of methyl methacrylate, 14.4 parts by mass of n-butyl acrylate, 24.0 parts by mass of 2-hydroxyethyl methacrylate, and 29.7 parts by mass of acrylic acid The body mixture and 10.0 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (A-4) having a Tg of 80 ° C., an acid value of 57 mg KOH / g and a hydroxyl value of 43 mg KOH / g. 50.0 parts by mass of a modified epoxy resin (D-1) is mixed with this solution, followed by neutralization with 39.0 parts by mass of triethylamine, and phase inversion emulsification using 735.0 parts by mass of ion-exchanged water, An aqueous resin composition (4) in which a self-emulsifying aqueous resin was dispersed in an aqueous medium was obtained. This aqueous resin composition (4) had a non-volatile content of 40.5% by mass and a pH of 7.5.

Example 5 Synthesis of Aqueous Resin Composition (5)
In a reaction vessel equipped with a reflux condenser, a stirrer and a nitrogen inlet tube, 256.5 parts by mass of diethylene glycol dimethyl ether and 9.0 parts by mass of fumaric acid were charged and stirring was started, and the temperature was raised to 135 ° C. Under a nitrogen stream, 212.4 parts by mass of styrene, 67.0 parts by mass of methyl methacrylate, 22.0 parts by mass of n-butyl acrylate, 36.0 parts by mass of 2-hydroxyethyl methacrylate, 2.1 parts by mass of acrylic acid The monomer mixture consisting of and 13.6 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, a single amount consisting of 141.6 parts by mass of styrene, 44.6 parts by mass of methyl methacrylate, 14.8 parts by mass of n-butyl acrylate, 24.0 parts by mass of 2-hydroxyethyl methacrylate, and 19.1 parts by mass of acrylic acid The body mixture and 10.0 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (A-5) having a Tg of 80 ° C., an acid value of 42 mg KOH / g and a hydroxyl value of 43 mg KOH / g. 50.0 parts by mass of a modified epoxy resin (D-1) is mixed with this solution, followed by neutralization with 29.8 parts by mass of triethylamine, and phase inversion emulsification using 725.0 parts by mass of ion-exchanged water, An aqueous resin composition (5) was obtained in which the self-emulsifying aqueous resin was dispersed in an aqueous medium. The aqueous resin composition (5) had a nonvolatile content of 32.0% by mass and a pH of 7.6.

Example 6 Synthesis of Aqueous Resin Composition (6)
In a reaction vessel equipped with a reflux condenser, a stirrer, and a nitrogen inlet tube, 256.4 parts by mass of diethylene glycol dimethyl ether and 9.0 parts by mass of fumaric acid were charged, stirring was started, and the temperature was raised to 135 ° C. Under a nitrogen stream, 212.4 parts by mass of styrene, 67.0 parts by mass of methyl methacrylate, 22.0 parts by mass of n-butyl acrylate, 36.0 parts by mass of 2-hydroxyethyl methacrylate, 2.1 parts by mass of acrylic acid The monomer mixture consisting of and 13.6 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, a single amount consisting of 141.6 parts by mass of styrene, 44.6 parts by mass of methyl methacrylate, 14.8 parts by mass of n-butyl acrylate, 24.0 parts by mass of 2-hydroxyethyl methacrylate, and 19.1 parts by mass of acrylic acid The body mixture and 10.0 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (A-6) having a Tg of 80 ° C., an acid value of 43 mg KOH / g, and a hydroxyl value of 43 mg KOH / g. This solution is mixed with 50.0 parts by mass of a modified epoxy resin (D-1) and then neutralized with 22.3 parts by mass of triethylamine and 7.2 parts by mass of 25% by mass ammonia water, and ion-exchanged water 835.0 Phase inversion emulsification was carried out using parts by mass to obtain an aqueous resin composition (6) in which a self-emulsifying aqueous resin was dispersed in an aqueous medium. The aqueous resin composition (6) had a nonvolatile content of 32.0% by mass and a pH of 7.6.

Comparative Example 1: Preparation of Aqueous Resin Composition (R1)
In a reaction vessel equipped with a reflux condenser, a stirrer, and a nitrogen inlet tube, 255.6 parts by mass of diethylene glycol dimethyl ether and 9.0 parts by mass of fumaric acid were charged, stirring was started, and the temperature was raised to 135 ° C. Under a nitrogen stream, 212.4 parts by mass of styrene, 48.6 parts by mass of methyl methacrylate, 20.9 parts by mass of n-butyl acrylate, 36.0 parts by mass of 2-hydroxyethyl methacrylate, 5.4 parts by mass of acrylic acid The monomer mixture consisting of and 13.0 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, a single amount consisting of 141.6 parts by mass of styrene, 32.4 parts by mass of methyl methacrylate, 13.9 parts by mass of n-butyl acrylate, 24.0 parts by mass of 2-hydroxyethyl methacrylate, and 48.6 parts by mass of acrylic acid The body mixture and 10.4 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (RA-1) having a Tg of 80 ° C., an acid value of 85 mg KOH / g and a hydroxyl value of 43 mg KOH / g. Neutralization is performed by adding 38.8 parts by mass of triethylamine to this solution, phase inversion emulsification is performed using 870.0 parts by mass of ion-exchanged water, and an aqueous resin composition in which a self-emulsifiable aqueous resin is dispersed in an aqueous medium An object (R1) was obtained. The aqueous resin composition (R1) had a non-volatile content of 36.5% by mass and a pH of 7.5.

Comparative Example 2 Preparation of Aqueous Resin Composition (R2)
In a reaction vessel equipped with a reflux condenser, a stirrer and a nitrogen inlet tube, 766.8 parts by mass of diethylene glycol dimethyl ether and 27.0 parts by mass of fumaric acid were charged and stirring was started, and the temperature was raised to 135 ° C. Under nitrogen stream, 637.2 parts by mass of styrene, 145.8 parts by mass of methyl methacrylate, 62.6 parts by mass of n-butyl acrylate, 108.0 parts by mass of 2-hydroxyethyl methacrylate, 16.2 parts by mass of acrylic acid The monomer mixture consisting of and 39.6 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, a single amount consisting of 424.8 parts by mass of styrene, 97.2 parts by mass of methyl methacrylate, 41.8 parts by mass of n-butyl acrylate, 72.0 parts by mass of 2-hydroxyethyl methacrylate, and 145.8 parts by mass of acrylic acid The body mixture and 30.6 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (RA-2) having a Tg of 80 ° C., an acid value of 85 mg KOH / g and a hydroxyl value of 43 mg KOH / g. 149.4 parts by mass of a modified epoxy resin (D-1) is mixed with this solution, followed by neutralization with 103.0 parts by mass of dimethylethanolamine, and phase inversion emulsification using 2105.0 parts by mass of ion exchanged water. To obtain an aqueous resin composition (R2) in which the self-emulsifying aqueous resin is dispersed in an aqueous medium. The aqueous resin composition (R2) had a nonvolatile content of 44.0% by mass and a pH of 7.5.

Comparative Example 3 Preparation of Aqueous Resin Composition (R3)
In a reaction vessel equipped with a reflux condenser, a stirrer and a nitrogen introduction tube, 327.7 parts by mass of diethylene glycol dimethyl ether was charged, stirring was started, and the temperature was raised to 135 ° C. Under nitrogen stream, 212.8 parts by mass of styrene, 83.7 parts by mass of methyl methacrylate, 390.9 parts by mass of n-butyl acrylate, 129.8 parts by mass of 2-hydroxyethyl methacrylate, unsaturated fatty acid hydroxyalkyl ester modification A monomer mixture consisting of 243.0 parts by mass of epsilon-caprolactone ("Placel FM1" manufactured by Daicel Chemical Industries, Ltd.) and 33.6 parts by mass of t-butylperoxy-2-ethylhexanoate It dripped continuously over time. Subsequently, 91.2 parts by mass of styrene, 35.8 parts by mass of methyl methacrylate, 167.5 parts by mass of n-butyl acrylate, 55.6 parts by mass of 2-hydroxyethyl methacrylate, unsaturated fatty acid hydroxyalkyl ester modified epsilon-caprolactone ( 104.2 parts by mass of "Placel FM1" manufactured by Daicel Chemical Industries, Ltd., 39.0 parts by mass of acrylic acid, 16.0 parts by mass of methoxypolyethylene glycol methacrylate ("NK ester M-230G" manufactured by Shin-Nakamura Chemical Co., Ltd.) The monomer mixture consisting of and 14.4 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 1.5 hours. After stirring for 1 hour at the same temperature, the temperature is lowered to 120 ° C., 16.0 parts by mass of styrene and 5.9 parts by mass of t-butylperoxybenzoate are charged, and after stirring for 2 hours, the reaction is terminated. A solution of a polymer (RA-3) having a value of 20 mg KOH / g and a hydroxyl value of 100 mg KOH / g was obtained. 302.4 parts by mass of modified epoxy resin (D-1) is mixed with this solution, followed by neutralization with 44.6 parts by mass of dimethylethanolamine, and phase inversion emulsification using 1856.3 parts by mass of ion exchanged water. To obtain an aqueous resin composition (R3) in which the self-emulsifying aqueous resin is dispersed in an aqueous medium. The aqueous resin composition (R3) had a nonvolatile content of 44.0% by mass and a pH of 8.3.

Comparative Example 4 Preparation of Aqueous Resin Composition (R4)
In a reaction vessel equipped with a reflux condenser, a stirrer and a nitrogen introduction tube, 329.6 parts by mass of diethylene glycol dimethyl ether was charged, stirring was started, and the temperature was raised to 135 ° C. Here, under nitrogen stream, 214.1 parts by mass of styrene, 240.8 parts by mass of methyl methacrylate, 396.3 parts by mass of n-butyl acrylate, 78.3 parts by mass of 2-hydroxyethyl methacrylate, unsaturated fatty acid hydroxyalkyl ester modification 3. A monomer mixture consisting of 47.0 parts by mass of epsilon-caprolactone ("Placel FM1" manufactured by Daicel Chemical Industries, Ltd.) and 39.4 parts by mass of t-butylperoxy-2-ethylhexanoate. It dripped continuously over 5 hours. Subsequently, 91.7 parts by mass of styrene, 103.2 parts by mass of methyl methacrylate, 169.8 parts by mass of n-butyl acrylate, 33.6 parts by mass of 2-hydroxyethyl methacrylate, unsaturated fatty acid hydroxyalkyl ester modified epsilon-caprolactone ( Monomer mixture consisting of 63.0 parts by mass of "Placel FM1" manufactured by Daicel Chemical Industries, Ltd., 39.3 parts by mass of acrylic acid, and 16.1 parts by mass of "NK ester M-230G", and t-butylperoxy 16.9 parts by mass of -2-ethylhexanoate was continuously added dropwise over 1.5 hours. After stirring for 1 hour at the same temperature, the temperature is lowered to 120 ° C., 16.1 parts by mass of styrene and 4.8 parts by mass of t-butylperoxybenzoate are charged, and after stirring for 2 hours, the reaction is completed. A solution of a polymer (RA-4) having an acid value of 20 mg KOH / g and a hydroxyl value of 49 mg KOH / g was obtained. 307.2 parts by mass of a modified epoxy resin (D-1) is mixed with this solution, followed by neutralization with 41.4 parts by mass of dimethylethanolamine, and phase inversion emulsification using 1891.2 parts by mass of ion exchanged water. Thus, an aqueous resin composition (R4) was obtained in which the self-emulsifying aqueous resin was dispersed in an aqueous medium. The aqueous resin composition (R4) had a nonvolatile content of 44.0% by mass and a pH of 7.8.

Comparative Example 5 Preparation of Aqueous Resin Composition (R5)
In a reaction vessel equipped with a reflux condenser, a stirrer, and a nitrogen inlet tube, 255.6 parts by mass of diethylene glycol dimethyl ether and 9.0 parts by mass of fumaric acid were charged, stirring was started, and the temperature was raised to 135 ° C. Under a nitrogen stream, 212.4 parts by mass of styrene, 38.9 parts by mass of methyl methacrylate, 20.1 parts by mass of n-butyl acrylate, 36.0 parts by mass of 2-hydroxyethyl methacrylate, 5.4 parts by mass of acrylic acid The monomer mixture consisting of and 12.6 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, a single amount consisting of 141.6 parts by mass of styrene, 25.9 parts by mass of methyl methacrylate, 13.4 parts by mass of n-butyl acrylate, 24.0 parts by mass of 2-hydroxyethyl methacrylate, and 66.0 parts by mass of acrylic acid The body mixture and 10.8 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (RA-5) having a Tg of 80 ° C., an acid value of 107 mg KOH / g and a hydroxyl value of 43 mg KOH / g. 50.0 parts by mass of a modified epoxy resin (D-1) is mixed with this solution, followed by neutralization with 37.8 parts by mass of triethylamine, and phase inversion emulsification using 835.0 parts by mass of ion-exchanged water, An aqueous resin composition (R5) was obtained in which a self-emulsifying aqueous resin was dispersed in an aqueous medium. The aqueous resin composition (R5) had a nonvolatile content of 40.0% by mass and a pH of 7.4.

Comparative Example 6: Preparation of Aqueous Resin Composition (R6)
In a reaction vessel equipped with a reflux condenser, a stirrer, and a nitrogen inlet tube, 255.4 parts by mass of diethylene glycol dimethyl ether and 9.0 parts by mass of fumaric acid were charged, stirring was started, and the temperature was raised to 135 ° C. Under a nitrogen stream, 212.4 parts by mass of styrene, 70.2 parts by mass of methyl methacrylate, 22.4 parts by mass of n-butyl acrylate, 36.0 parts by mass of 2-hydroxyethyl methacrylate, 1.6 parts by mass of acrylic acid The monomer mixture consisting of and 13.7 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3 hours. Subsequently, a single amount consisting of 141.6 parts by mass of styrene, 46.8 parts by mass of methyl methacrylate, 14.9 parts by mass of n-butyl acrylate, 24.0 parts by mass of 2-hydroxyethyl methacrylate, 13.8 parts by mass of acrylic acid The body mixture and 9.4 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (RA-6) having a Tg of 80 ° C., an acid value of 43 mg KOH / g and a hydroxyl value of 43 mg KOH / g. This solution was mixed with 50.0 parts by mass of a modified epoxy resin (D-1), then neutralized with 21.5 parts by mass of triethylamine, and phase inversion emulsification was performed using 500.0 parts by mass of ion-exchanged water However, an aqueous resin composition in which a self-emulsifying aqueous resin was dispersed in an aqueous medium was not obtained.

Comparative Example 7 Preparation of Aqueous Resin Composition (R7)
In a reaction vessel equipped with a reflux condenser, a stirrer, and a nitrogen inlet tube, 255.0 parts by mass of diethylene glycol dimethyl ether and 9.0 parts by mass of fumaric acid were charged and stirring was started, and the temperature was raised to 135 ° C. Under a nitrogen stream, 212.4 parts by mass of styrene, 60.8 parts by mass of methyl methacrylate, 21.6 parts by mass of n-butyl acrylate, 36.0 parts by mass of 2-hydroxyethyl methacrylate, 3.3 parts by mass of acrylic acid The monomer mixture consisting of and 13.3 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 3.0 hours. Subsequently, a single amount consisting of 141.6 parts by mass of styrene, 40.2 parts by mass of methyl methacrylate, 14.4 parts by mass of n-butyl acrylate, 24.0 parts by mass of 2-hydroxyethyl methacrylate, and 29.7 parts by mass of acrylic acid The body mixture and 10.0 parts by mass of t-butylperoxy-2-ethylhexanoate were continuously added dropwise over 2 hours. After stirring for 2 hours at the same temperature, the reaction was terminated to obtain a solution of a polymer (RA-7) having a Tg of 80 ° C., an acid value of 57 mg KOH / g and a hydroxyl value of 43 mg KOH / g. This solution was mixed with 50.0 parts by mass of a modified epoxy resin (D-1), then neutralized with 19.5 parts by mass of triethylamine, and phase inversion emulsification was performed using 500.0 parts by mass of ion-exchanged water However, an aqueous resin composition in which a self-emulsifying aqueous resin was dispersed in an aqueous medium was not obtained.

  The property values of the aqueous resin compositions (1) to (6) and (R1) to (R5) obtained above are shown in Tables 1 and 2. In the table, "TEA" represents triethylamine, and "DMEA" represents dimethylethanolamine. In Comparative Examples 6 and 7, since the aqueous resin composition in which the self-emulsifying aqueous resin was dispersed in the aqueous medium was not obtained, the property value is not measured.

Examples 7 to 12 Preparation and Evaluation of Water-Based Paints (1) to (6)
[Preparation of water-based paint]
Each aqueous resin composition (1) to (6) obtained in Examples 1 to 6 and a curing agent (melamine resin) are compounded as shown in Table 3 below, stirred and mixed to obtain an aqueous paint (1 ) To (6) were obtained. Subsequently, the following coating-film evaluation was performed using the obtained water-based paint (1)-(6).

[Preparation of coating film for evaluation]
Each water-based paint (1) to (6) obtained above was coated on a tin plate with a bar coater so that the film thickness after drying was 30 μm. After painting, it was aged at 25 ° C. for 20 minutes and then dried at 110 ° C. for 25 minutes to prepare evaluation coatings (1) to (6).

[Evaluation of coating film hardness (pencil hardness)]
About the surface of the cured coating film for evaluation obtained above, according to JIS K 5600-5-4: 1999 scratch hardness (pencil method), the hardness of the hardest pencil which did not produce a scar was measured as pencil hardness. The coating film hardness was evaluated according to the following criteria.
A: 2H or more B: H
C: F or less

[Evaluation of substrate adhesion]
The coating film for evaluation obtained above was measured based on the adhesiveness (cross-cut method) of JIS K 5600-5-6: 1999. A 1 mm wide incision is made on the cured coating with a cutter, the number of grids is 100, and cellophane tape (manufactured by Nichiban Co., Ltd.) is pasted so as to cover all grids and quickly peeled off. The adhesion of the substrate was evaluated based on the following criteria from the percentage of the grids remaining adhering.
A: Coating peeling is less than 5% of the whole B: Coating peeling is 5% to less than 15% of the whole C: Coating peeling is 15% or more of the whole

[Evaluation of acid resistance]
After 2 ml of 50 mass% nitric acid was dropped on the coating film for evaluation obtained above and the nitric acid was wiped off after 90 seconds, the coating film surface was observed and the acid resistance was evaluated according to the following criteria.
A: No change before and after the test B: Traces, blisters, slight yellowing etc. C: Traces, blisters, yellowing etc are large

[Evaluation of corrosion resistance]
The coating film for evaluation obtained above was measured based on the salt water spray resistance test of JIS K 5600-7-9: 2006. The hardened film is scratched with a cutter knife to a depth reaching the substrate (cross cut part), and a salt spray test is carried out with a salt spray tester made by Suga Test Instruments Co., Ltd. Were visually evaluated according to the following criteria.
A: No occurrence of rust was observed at the periphery of the cross cut portion or occurrence of a very small amount of rust was found, but no peeling or swelling of the coating film due to it was found.
B: The occurrence of rust was widely observed at the periphery of the cross cut portion, and peeling and swelling of the coating film due to it were observed, but no flow rust was observed.
C: Occurrence of rust was widely observed at the periphery of the cross cut portion, and peeling and swelling of the coating film due to it were observed, and further, contamination of the coating film due to flowing rust was observed.

Comparative Examples 8 to 12 Preparation and Evaluation of Water-Based Paints (R1) to (R5)
After obtaining water-based paints (R1) to (R5) by operating in the same manner as in Examples 7 to 12 except for changing to the formulations shown in Table 4 below, each coating film was evaluated.

  Table 3 shows the compositions and evaluation results of the water-based paints (1) to (6) obtained above.

  Table 4 shows the compositions and evaluation results of the water-based paints (R1) to (R5) obtained above.

  It was confirmed that the water-based paint using the water-based resin composition of the present invention of Examples 1 to 6 is excellent in various film physical properties.

  On the other hand, Comparative Example 1 was an example in which the modified epoxy resin was not contained, but it was confirmed that the base material adhesion, acid resistance and corrosion resistance were inferior.

  Comparative Examples 2 to 4 are examples using dimethylethanolamine as the basic compound, but it was confirmed that the acid resistance was inferior.

  Comparative Example 5 is an example in which the acid value of the polymer is 107 mg KOH / g, which is greater than 90 mg KOH / g, which is the upper limit of the present invention, but it was confirmed that the substrate adhesion and corrosion resistance were poor.

  Comparative Example 6 is an example in which the acid value of the polymer is 35 mg KOH / g, which is smaller than 40 mg KOH / g, which is the lower limit of the present invention, but an aqueous dispersion could not be obtained.

  Comparative Example 7 is an example where an alkylamine and ammonia water are used in combination as the basic compound, and the alkylamine is 50 mol% less than the lower limit of 55 mol% of the present invention, but an aqueous dispersion could not be obtained.

Claims (4)

  A self-emulsifying aqueous resin (E) in which a modified epoxy resin (D) is encapsulated in an acrylic resin (C) in which a carboxyl group-containing polymer (A) is neutralized with a basic compound (B) is aqueous An aqueous resin composition dispersed in a medium, wherein the acid value of the polymer (A) is in the range of 40 to 90 mg KOH / g, and the basic compound (B) is 55 mol% of alkylamine (b1) Characterized in that the modified epoxy resin (D) is a reaction product of the epoxy resin (d1), a monocarboxylic acid (d2) and a compound (d3) having a hydroxyl group bonded to a phosphorus atom Aqueous resin composition.   The aqueous resin composition according to claim 1, wherein the monocarboxylic acid (d2) is an ethylenically unsaturated carboxylic acid.   An aqueous paint comprising the aqueous resin composition according to claim 1 and a curing agent (F).   An article having a cured coating of the water-based paint according to claim 3.