JP6410098B2 - Water-based resin composition and water-based paint - Google Patents

Description

  The present invention relates to an aqueous resin composition suitable for an aqueous paint and an aqueous paint containing the same.

  In recent years, due to increasing awareness of environmental issues, in the paint field, the transition from solvent-based paints that frequently use volatile organic compounds (VOC) to environment-friendly paints that reduce VOCs has been promoted. Above all, in general industrial applications such as building exteriors, bridges, vehicles, industrial machinery, gas tanks, construction machinery, ships, etc., it is difficult to heat the object to be coated like powder paint, so it is excellent at room temperature drying method Replacement with water-based paint is the mainstream.

  Conventionally, when designing a water-based paint, a form that imparts solubility and dispersibility in water of a resin by introducing a carboxylic acid into a resin as a binder and neutralizing with ammonia or an organic amine. For example, a water-based paint in which dimethylethanolamine is combined with an acid group-containing acrylic resin has been proposed (see, for example, Patent Document 1). However, when ammonia, triethylamine, dimethylethanolamine or the like is used as the neutralizing agent, the viscosity of the aqueous resin solution decreases over time (hereinafter referred to as “thinning”), and the storage stability is greatly improved. It was an issue. On the other hand, if amine remains in the coating film without volatilizing, water resistance, chemical resistance, etc. deteriorate, so low boiling point volatilization such as ammonia, triethylamine, and dimethylethanolamine can be used as a neutralizing agent that can be used. There was also a problem that it was limited to the sex amine.

  Therefore, there has been a demand for a water-based paint resin with extremely high practicality that can achieve both storage stability and various physical properties of the coating film.

JP 2012-21107 A

  The problem to be solved by the present invention is to provide an aqueous resin composition capable of obtaining a cured coating film having excellent storage stability and excellent coating film properties such as water resistance and chemical resistance, and an aqueous coating material containing the same. It is to be.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained an aqueous resin composition obtained by neutralizing a carboxyl group in an aqueous resin with a specific amine and dissolving or dispersing it in an aqueous medium. The present invention was completed by discovering that the cured film was excellent in storage stability and water resistance and chemical resistance.

  That is, the present invention is obtained by neutralizing a carboxyl group in an aqueous resin with an amine (A) obtained by neutralizing one amino group of the diamine (a) with an acid, and dissolving or dispersing in an aqueous medium. The present invention relates to an aqueous resin composition.

  Since the aqueous resin composition of the present invention is excellent in storage stability and various physical properties of the resulting coating film, it can be used for various general industrial water bases such as building exteriors, bridges, vehicles, industrial machines, gas tanks, construction machinery, and ships. It can be suitably used for paints and the like.

  In the aqueous resin composition of the present invention, the carboxyl group in the aqueous resin is neutralized with an amine (A) obtained by neutralizing one amino group of the diamine (a) with an acid, and dissolved or dispersed in an aqueous medium. Is obtained.

  Examples of the diamine (a) include alkylenediamines such as ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, and 1,6-hexamethylenediamine; xylylenediamine, tetrachloro-p-xylylenediamine, and the like. 1,4-cyclohexanediamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 4,4′-dicyclohexylmethanediamine, 1,3-bis (aminomethyl) cyclohexane, norbornanediamine, etc. Cycloaliphatic polyamines such as: piperazine, 2,5-dimethylpiperazine, N-aminoethylpiperazine, 1,4-diaminoethylpiperazine, 1,4bis (2-amino-2-methylpropyl) piperazine ; JEFFAMINE (D series ED series, such as a diamine having the EDR series) (alkylene oxide chain of HUNTSMAN, Ltd.), and the like. Among these diamines, a diamine having an alkylene oxide chain is preferable because storage stability is further improved, and a diamine represented by the following general formula (1) is particularly preferable.

（一般式（１）中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４はそれぞれ独立して、水素原子又はメチル基であり、ｎは１〜８０の整数である。）

(In general formula (1), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or a methyl group, and n is an integer of 1 to 80.)

  Examples of the acid used for neutralizing the diamine (a) include inorganic acids such as hydrochloric acid and sulfuric acid; organic acids such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, malic acid, malonic acid, and adipic acid. Among these, carboxylic acids such as formic acid, acetic acid, propionic acid, and butyric acid are preferable, and formic acid and acetic acid are particularly preferable because storage stability is further improved.

  The amine (A) can be used alone or in combination of two or more.

  Moreover, other neutralizing agents other than the said amine (A) can also be used together as a neutralizing agent which neutralizes the said aqueous resin. Other neutralizers include alkylamines such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropyllamine, dipropyllaminetripropyllamine; monoethanolamine, diethanolamine, monoisopropanolamine, diisopropanol Amine, N-methylethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, 2-amino-2-methylpropanol, 2- (dimethylamino) -2-methylpropanol, N-methyldiethanolamine, etc. Organic amines such as alkanolamines, ammonia (water), and the like. Among these, N, N-dimethylethanolamine, Ethylamine, ammonia (water) is preferred.

  Examples of the aqueous resin used in the present invention include an acrylic resin having a carboxyl group, a vinyl-modified epoxy ester resin, a polyester resin, a urethane resin, an epoxy resin, and an alkyd resin. Among these, the storage stability is included. From the viewpoint of further improvement, an acrylic resin, a vinyl-modified epoxy ester resin, or a polyester resin having a carboxyl group is preferable.

  Examples of the acrylic resin having a carboxyl group include resins obtained by polymerizing unsaturated carboxylic acids and other vinyl polymerizable monomers.

  Examples of the unsaturated carboxylic acid include ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid, ethylenically unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid, and maleic acid and itaconic acid. And the like, and monoesterified products of these acid anhydrides. Among these, (meth) acrylic acid is preferable. Moreover, these unsaturated carboxylic acids 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) acrylate” refers to one or both of methacrylate and acrylate, and “(meta) “) Acrylamide” refers to one or both of methacrylamide and acrylamide.

  Examples of the other vinyl polymerizable monomers include styrene and / or styrene derivatives such as styrene, tert-butylstyrene, α-methylstyrene, vinyltoluene; methyl (meth) acrylate, and (meth) acrylic. (Meth) acrylic such as ethyl acrylate, (meth) acrylic n-butyl, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate Acid alkyl esters; (meth) acrylic acid 2-hydroxyalkyl esters such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; glycidyl (meth) acrylates such as glycidyl (meth) acrylate Esters; saturated aliphatic carbonates such as vinyl acetate and vinyl propionate Vinyl esters of Bonn acid; (meth) acrylamide, N- methylol acrylamide include monomers having an amide group such as N- methoxy-butylacrylamide. These monomers can be used alone or in combination of two or more.

  When the acrylic resin is cured by reacting with a curing component such as isocyanate, a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, etc. It is preferable to use a monomer having

  As a method for copolymerizing these monomers, various methods can be used. For example, after adding a polymerization initiator in an organic solvent and raising the temperature to a predetermined temperature, the monomer is added dropwise. Examples include a polymerization method.

  Examples of the polyester resin having a carboxyl group include those obtained by reacting a polyol and a polycarboxylic acid under the condition that the carboxyl group is excessive.

  Examples of the polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neo Pentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, aliphatic glycols such as 2-ethyl-2-butylpropanediol, 1,4-cyclohexanedimethanol Aliphatic glycols such as glycerin, trimethylol ethane, trimethylol propane, pentaerythritol, and other aliphatic trifunctional or higher functional polyols, diethylene glycol, triethylene glycol, dipropylene glycol, polytetramethylene glycol, polyethylene glycol, polypro Polyoxyalkylene glycols such as glycol may be used in combination. Further, ethylene oxide adducts of bisphenols (bisphenol A) such as 2,2-bis [4- (hydroxyethoxy) phenyl] propane and bisphenols (bisphenol S) such as bis [4- (hydroxyethoxy) phenyl] sulfone. ) Ethylene oxide adduct and the like. These polyols can be used alone or in combination of two or more.

  Examples of the polycarboxylic acid include polybasic acids having two or more carboxyl groups at the ends, such as aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and trifunctional or higher carboxylic acids. .

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, naphthalene dicarboxylic acid, and biphenyl dicarboxylic acid. Examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, succinic anhydride, Saturated aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, eicosane diacid, hydrogenated dimer acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, And unsaturated aliphatic dicarboxylic acids such as citraconic anhydride and dimer acid.

  Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornenedicarboxylic acid and its anhydride, tetrahydrophthalic acid and its anhydride. Such as things.

  The trifunctional or higher functional carboxylic acids include trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, trimesic acid, ethylene glycol bis (anhydro). Trimellitate), glycerol tris (anhydro trimellitate), 1,2,3,4-butanetetracarboxylic acid and the like.

  These polycarboxylic acids described above can be used alone or in combination of two or more.

  Although there is no restriction | limiting in particular about the method of manufacturing the said polyester resin, The various manufacturing method by the esterification reaction of polyhydric carboxylic acid and a polyhydric alcohol, for example, a melting method or a solvent method can be used.

  Regarding the melting method, for example, the acid component (polycarboxylic acid) and the alcohol component (polyol) as raw materials are heated in a nitrogen stream at 150 to 250 ° C., and the esterification reaction is performed while sequentially removing the generated water. A polyester resin having a predetermined hydroxyl value and acid value can be obtained.

  Regarding the solvent method, for example, an acid component (polycarboxylic acid) and an alcohol component (polyhydric alcohol) are esterified in a solvent such as xylene, and then the solvent is distilled off to obtain a polyester resin. Can do. Moreover, the hydrophilic organic solvent mentioned later can be used as a solvent, and the above-mentioned polyhydric carboxylic acid and polyhydric alcohol can also be esterified in this hydrophilic organic solvent. Thereby, the aqueous solution or water dispersion of a polyester resin can be obtained by adding the basic compound mentioned later following the above-mentioned esterification reaction.

  Examples of the vinyl-modified epoxy ester resin having a carboxyl group include resins obtained by polymerizing an unsaturated fatty acid ester of an epoxy resin, an unsaturated carboxylic acid, and another vinyl polymerizable monomer.

  Examples of the epoxy resin include bisphenol type epoxy resin, alicyclic epoxy resin, phenol novolac type epoxy resin, polyethylene glycol type epoxy resin, epoxidized polybutadiene resin, and the like. More than one species can be used in combination. Among the epoxy resins, it is preferable to use a bisphenol type epoxy resin because a coating film having excellent corrosion resistance can be formed.

  Examples of the bisphenol type epoxy resin include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol AD type epoxy resin, and a bisphenol S type epoxy resin. Among them, a bisphenol A type epoxy resin may be used. It is preferable because a coating film that is superior in corrosion resistance can be obtained. Examples of the bisphenol A type epoxy resin include Epicron 850, 1050, 3050, 4050, 7050, HM-091, HM-101 (all of which are manufactured by DIC Corporation). Examples of the bisphenol F type epoxy resin include Epicron 830 (manufactured by DIC Corporation).

  Examples of the alicyclic epoxy resin include Yunox 201 and 289 (all of which are manufactured by Union Carbide, USA).

  Examples of the phenol novolac type epoxy resin include Epicron N-740 and 775 (all of which are manufactured by DIC Corporation).

  Examples of the polyethylene glycol-based epoxy resin include Epicoat 812 (manufactured by Shell, The Netherlands), Epolite 40E, 200E, 400E (all of which are manufactured by Kyoei Co., Ltd.).

  Examples of the epoxidized polybutadiene resin include BF-1000 (manufactured by Adeka Argas).

  As the epoxy resin, it is preferable to use an epoxy resin having an epoxy equivalent in the range of 400 to 1000 (g / equivalent), since an aqueous paint excellent in film forming property at room temperature can be obtained. It is more preferable to use those having an epoxy equivalent weight of, and it is more preferable to use those having an epoxy equivalent weight in the range of 400 to 600.

  The structure derived from the epoxy resin is preferably contained in the vinyl-modified epoxy ester resin used in the present invention in the range of 15 to 75% by mass because it can form a coating film excellent in film forming property and corrosion resistance. However, it is more preferably included in the range of 20 to 70% by mass, and further preferably included in the range of 25 to 60% by mass.

  Examples of the unsaturated fatty acids include various kinds of (semi) drying oils and non-drying oils such as tung oil, linseed oil, soybean oil, safflower oil, castor oil, dehydrated castor oil, tall oil, rice bran oil, cottonseed oil, and palm oil. Is mentioned. These unsaturated fatty acids can be used alone or in combination of two or more.

  As the unsaturated carboxylic acid used as the raw material for the vinyl-modified epoxy ester resin having a carboxyl group, the unsaturated carboxylic acid exemplified as the raw material for the acrylic resin having a carboxyl group can be used. These unsaturated carboxylic acids can be used alone or in combination of two or more.

  In addition, as the other vinyl polymerizable monomer that is a raw material of the vinyl-modified epoxy ester resin having a carboxyl group, the other vinyl polymerizable monomers exemplified as the raw material of the acrylic resin having a carboxyl group are used. be able to. These monomers can be used alone or in combination of two or more.

  Examples of the aqueous medium used in the present invention include water, a hydrophilic organic solvent, and a mixture thereof. The hydrophilic organic solvent is preferably a water-miscible organic solvent that is miscible without being separated from water, and more preferably an organic solvent having a solubility in water (grams of organic solvent dissolved in 100 g of water) of 3 g or more at 25 ° C. . Examples of these water-miscible organic solvents include methanol, ethanol, propanol, butanol, 1,3-butylene glycol-3-monomethyl ether (generic name: 3-methoxybutanol), 3-methyl-3-methoxybutanol (product) Name: Solvent, manufactured by Kuraray Co., Ltd.); 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 And glycol ether solvents such as glycol monomethyl ether and dipropylene glycol dimethyl ether. These water-miscible organic solvents may be used alone or in combination of two or more.

  Various methods can be applied as a method for dissolving or dispersing the aqueous resin in an aqueous medium, and examples thereof include a phase inversion emulsification method.

As a method of making the resin aqueous by the phase inversion emulsification method, for example, the amine (A) and, if necessary, a neutralizing agent other than the amine (A) and a hydrophilic organic solvent are added to the resin. Then, a method of dissolving or dispersing in water by neutralizing some or all of the acid groups in the resin and then adding water.

  The neutralization rate of the carboxyl group in the aqueous resin is preferably in the range of 40 to 120 mol%, more preferably in the range of 60 to 100 mol%, since the storage stability of the aqueous resin composition is further improved.

  In the aqueous resin composition of the present invention, for example, a curing agent can be blended when blending a paint. The curing agent is not particularly limited as long as it can undergo a crosslinking reaction with the hydroxyl group of the aqueous resin, but for example, amino resins, polyisocyanates, blocked isocyanates and the like are preferably used.

  Here, the amino resin is, for example, a methylolated amino resin obtained by a reaction of one or more of melamine, urea, benzoguanamine and the like with formaldehyde, a methylolated amino resin having an imino group, and the like. Those obtained by etherifying all or part of the methylol group with a monohydric alcohol having 1 to 8 carbon atoms are preferable. Examples thereof include butoxymethylated melamine resin, methoxymethylated melamine resin, and methoxybutoxy mixed methylated melamine resin. .

  Examples of the polyisocyanate include resins having an isocyanate group obtained by reacting an active hydrogen-containing compound such as a polyol with a polyisocyanate in an excess ratio of isocyanate groups.

  Examples of the polyol include polyester polyol, polyether polyol, and polycarbonate polyol.

  Examples of the polyether polyol include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, cyclohexylene, using as an initiator one or more compounds having two or more active hydrogen atoms. Those obtained by addition polymerization of alkylene oxides such as the above can be used.

  As the polycarbonate polyol, those obtained by reacting glycols such as 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and cyclohexanedimethanol with diphenyl carbonate, phosgene and the like can be used. .

  Examples of the isocyanate compound include aromatic diisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, Aliphatic or alicyclic diisocyanates such as tetramethylxylylene diisocyanate and the like can be mentioned.

  Among these polyisocyanates, the use of a water-dispersible polyisocyanate composition is excellent in stability and curability when blended with the aqueous polyester resin of the present invention, and further has a high degree of freedom in pot life. preferable. Examples of the water-dispersible polyisocyanate composition include a polyisocyanate composition (p) obtained by modifying a part of a polyisocyanate with a polyoxyalkylene glycol having one end blocked with an alkoxy group, and an isocyanate contained in the polyisocyanate. A water-dispersible polyisocyanate composition (q) obtained by modifying a part of a group with a polyoxyalkylene glycol having one end blocked with an alkoxy group with a fatty acid ester, or a polymer having a hydrophobic polyisocyanate compound and a hydrophilic functional group The composition (r) containing an isocyanate compound is mentioned. Examples of the composition (r) include a composition containing a hydrophobic polyisocyanate and a vinyl polymer containing a polyoxyalkylene structure and an isocyanate group.

  Examples of the blocked isocyanate include various aromatic diisocyanates such as xylene diisocyanate and isophorone diisocyanate (alicyclic diisocyanate), tolylene diisocyanate and 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, and trimethyl. Organic diisocyanate compounds such as aliphatic diisocyanates such as hexamethylene diisocyanate, adducts of these compounds with polyhydric alcohols, low molecular weight hydroxyl group-containing polyester resins, low molecular weight hydroxyl group-containing alkyd resins or water; Polymers (including isocyanurate type polyisocyanate compounds and uretdione compounds) are converted into oxime compounds, Lumpur compounds, alcohol compounds, and blocked isocyanate obtained by blocking a known conventional blocking agent such as diketone compounds. Among these, one end of the isocyanate group is modified with, for example, polyoxyethylene glycol, and the other end is blocked with an alkoxy group, or one end is modified with a polyoxyalkylene compound having an active hydrogen-containing group. Those are preferred.

  The aqueous resin composition of the present invention can be prepared into a paint by blending a pigment, a solvent, and, if necessary, other resins, a dispersion aid, a basic neutralizer, other additives, and the like. .

  Examples of the pigment include bright pigments such as aluminum powder, copper powder, nickel powder, stainless steel powder, chromium powder, mica-like iron oxide, titanium oxide-coated mica powder, iron oxide-coated mica powder, and bright graphite; Pink EB Organic red pigments such as azo and quinacridone, organic blue pigments such as cyanine blue and cyanine green, organic yellow pigments such as benzimidazolone, isoindoline and quinophthalone; titanium oxide, titanium yellow, bengara Inorganic color pigments such as carbon black, yellow lead, iron oxide, and various fired pigments. Further, extender pigments may be included. These pigments may be subjected to a known surface treatment such as acid / base treatment, coupling agent treatment, plasma treatment, oxidation / reduction treatment and the like.

  The blending ratio of these pigments is not particularly limited, but is 10 to 3,000 parts by weight, particularly 15 to 2,000 parts by weight, and more particularly 15 to 1,500 parts per 100 parts by weight of the pigment dispersing resin. It is preferable that it is in the range of parts by mass in terms of pigment dispersibility, dispersion stability, and coloring power of the resulting pigment dispersion.

  Examples of the solvent include water, organic solvents, and mixtures thereof. Examples of the organic solvent used here include methyl alcohol, ethyl alcohol, isopropyl alcohol, propylene glycol monopropyl ether, ethylene glycol monoble ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol. Water-soluble organic solvents such as monobutyl ether, tripropylene glycol monomethyl ether, and 3-methyl 3-methoxybutanol; poorly soluble or insoluble organic solvents such as xylene, toluene, cyclohexanone, hexane, and pentane. These organic solvents can be used alone or in combination of two or more. As the organic solvent, those mainly composed of a water-soluble organic solvent are suitable. Further, the mixing ratio of water and the organic solvent is not particularly limited, but the content of the organic solvent is desirably 50% by mass or less, particularly 35% by mass or less of the mixed solution. The blending ratio of the solvent in the paint is not particularly limited, but the viscosity at the time of pigment dispersion, pigment dispersibility, dispersion stability, and production efficiency are improved, so 50 to 5 per 100 parts by mass of the aqueous resin. The range of 1,000 parts by mass is preferable, the range of 100 to 3,000 parts by mass is particularly preferable, and the range of 100 to 2,000 parts by mass is more preferable.

  Examples of the dispersion aid include Disperbyk 184 and Disperbyk 190 of Big Chemie Japan, and other additives include antifoaming agents, antiseptics, rust preventives, plasticizers, and the like. Can do. These compounding amounts are 50 parts by mass or less with respect to 100 parts by mass of the pigment dispersing resin because the dispersibility of the pigment, the stability of the paste, the letdown stability, and the coating film performance are further improved. Is preferred.

  The paint containing the aqueous resin composition of the present invention is obtained by uniformly mixing and dispersing the above-described components using a dispersing machine such as a paint shaker, a sand mill, a ball mill, an LMZ mill, or a DCP pearl mill. Can be prepared.

  Next, the present invention will be specifically described with reference to examples and comparative examples.

(Synthesis Example 1: Production of acrylic resin (M-1))
In a four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen introduction tube, 132 parts by mass of diethylene glycol dimethyl ether was charged and heated to 135 ° C. while stirring. After reaching 135 ° C., a mixture of 18 parts by mass of styrene, 71 parts by mass of methyl methacrylate, 237 parts by mass of butyl methacrylate, 104 parts by mass of 2-hydroxyethyl methacrylate, and 20 parts by mass of t-butylperoxy-2-ethylhexanoate Was added dropwise over 3.5 hours. After maintaining at the same temperature for 30 minutes from the end of dropping, 8 parts by mass of styrene, 30 parts by mass of methyl methacrylate, 102 parts by mass of butyl methacrylate, 44 parts by mass of 2-hydroxyethyl methacrylate, 15 parts by mass of acrylic acid, and t-butyl A mixture of 9 parts by mass of peroxy-2-ethylhexanoate was added dropwise over 1.5 hours. The acrylic resin (M-1) was obtained by maintaining at the same temperature for 3 hours.

(Synthesis Example 2: Production of vinyl-modified epoxy ester resin (M-2))
In a four-necked flask equipped with a stirrer, thermometer and nitrogen introduction tube, 100 parts by mass of dehydrated castor oil fatty acid, 300 parts by mass of linseed oil fatty acid, 500 parts by mass of bisphenol A type epoxy resin (“Epiclon 1050” manufactured by DIC Corporation) Was charged. Furthermore, 0.05 part by mass of N, N-dimethylbenzylamine was charged into the reaction vessel, and the temperature was raised to 180 ° C. while stirring. Dehydration began when the inside reached around 180 ° C., and the temperature was raised to 220 ° C. while observing the dehydrated state, and esterification proceeded. The contents were reacted for about 3 hours until the solid acid value of the content became 4 or less, and 263 parts by mass of butyl cellosolve was further added to obtain a 77% non-volatile solution of fatty acid ester of epoxy resin. Next, while maintaining the internal temperature at 120 ° C., a mixture of 340 parts by mass of styrene and 45 parts by mass of acrylic acid and 5 parts by mass of t-butylperoxy-2-ethyhexanoate are dropped over 1 hour. Furthermore, 5 parts by mass of di-t-butyl peroxide was added and held at the same temperature for 5 hours to conduct a vinylation reaction on the fatty acid ester of the epoxy resin to obtain a vinyl-modified epoxy ester resin (M-2). Obtained.

(Synthesis Example 3: Production of polyester resin (M-3))
In a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and reflux condenser with a dehydration trap, 248 parts of isophthalic acid, 536 parts of hexahydrophthalic anhydride, 484 parts of 1,6 hexanediol, and trimethylolpropane 195 The temperature was raised to 240 ° C. and a dehydration condensation reaction was performed. The reaction was continued until the acid value became 8 or less, and when it was cooled to 165 ° C., 38 parts of trimellitic anhydride was added and reacted for 1 hour. After cooling for 1 hour, 154 parts of dipropylene glycol monomethyl ether was added at 150 ° C. or lower and mixed well to obtain a polyester resin (M-3).

(Synthesis Example 4: Production of amine (A-1))
In a four-necked flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, polyoxypropylenediamine (“Jeffamine D-230” manufactured by HUNTSMAN, R ^{1 in the} general formula (1) is a methyl group, R ² is hydrogen, R ³ is hydrogen, ^{R 4} is a methyl group, the average number of repeating propylene oxide 2.5) was stirred charged with 180 parts. At 30 ° C., 47 parts of acetic acid was added dropwise over 1 hour. After completion of dropping, the mixture was stirred for 1 hour to obtain an amine (A-1) obtained by neutralizing one terminal amine of polyoxypropylenediamine with acetic acid.

(Example 1: Preparation of aqueous resin composition (1))
Into a flask equipped with a stirrer and a thermometer, 1000 parts by mass of the acrylic resin (M-1) having a carboxyl group obtained in Synthesis Example 1 was added, and the temperature was raised to 80 ° C. Next, 20 parts by mass of dimethylethanolamine was added and mixed with sufficient stirring. Subsequently, 6.8 parts by mass of the amine (A-1) obtained in Synthesis Example 4 was added and mixed with sufficient stirring. Furthermore, 900 parts by mass of ion-exchanged water was added and sufficiently stirred to obtain an aqueous resin composition (1) having a nonvolatile content of 43% by mass. The viscosity of the aqueous resin composition (1) at 25 ° C. was 780 mPa · s.

(Example 2: Preparation of aqueous resin composition (2))
Into a flask equipped with a stirrer and a thermometer, 1000 parts by mass of the vinyl-modified epoxy ester resin (M-2) having a carboxyl group obtained in Synthesis Example 2 was added, and the temperature was raised to 80 ° C. Next, 26 parts by mass of dimethylethanolamine was added and mixed with sufficient stirring. Subsequently, 18 parts by mass of the amine (A-1) obtained in Synthesis Example 4 was added and mixed with sufficient stirring. Furthermore, 1070 parts by mass of ion-exchanged water was added and sufficiently stirred to obtain an aqueous resin composition (2) having a nonvolatile content of 40% by mass. The viscosity of the aqueous resin composition (2) at 25 ° C. was 900 mPa · s.

(Example 3: Preparation of aqueous resin composition (3))
To a flask equipped with a stirrer and a thermometer, 1000 parts by mass of the polyester resin (M-3) having a carboxyl group obtained in Synthesis Example 3 was added, and the temperature was raised to 80 ° C. Next, 26 parts by mass of dimethylethanolamine was added and mixed with sufficient stirring. Subsequently, 18 parts by mass of the amine (A-1) obtained in Synthesis Example 4 was added and mixed with sufficient stirring. Further, 1000 parts by mass of ion-exchanged water was added and sufficiently stirred to obtain an aqueous resin composition (3) having a nonvolatile content of 45% by mass. The viscosity of the aqueous resin composition (3) at 25 ° C. was 450 mPa · s.

(Comparative Example 1: Preparation of aqueous resin composition (R-1))
Into a flask equipped with a stirrer and a thermometer, 1000 parts by mass of the acrylic resin (M-1) having a carboxyl group obtained in Synthesis Example 1 was added, and the temperature was raised to 80 ° C. Next, 25 parts by mass of dimethylethanolamine was added and mixed with sufficient stirring. Furthermore, 861 parts by mass of ion-exchanged water was added and sufficiently stirred to obtain an aqueous resin composition (R-1) having a nonvolatile content of 43% by mass. The viscosity of the aqueous resin composition (R-1) at 25 ° C. was 710 mPa · s.

(Comparative Example 2: Preparation of aqueous resin composition (R-2))
Into a flask equipped with a stirrer and a thermometer, 1000 parts by mass of the vinyl-modified epoxy ester resin (M-2) having a carboxyl group obtained in Synthesis Example 2 was added, and the temperature was raised to 80 ° C. Next, 32 parts by mass of dimethylethanolamine was added and mixed with sufficient stirring. Furthermore, 1043 parts by mass of ion-exchanged water was added and sufficiently stirred to obtain an aqueous resin composition (R-2) having a nonvolatile content of 40% by mass. The viscosity of this aqueous resin composition (R-2) at 25 ° C. was 875 mPa · s.

(Comparative Example 3: Preparation of aqueous resin composition (R-3))
To a flask equipped with a stirrer and a thermometer, 1000 parts by mass of the polyester resin (M-3) having a carboxyl group obtained in Synthesis Example 3 was added, and the temperature was raised to 80 ° C. Next, 33 parts by mass of dimethylethanolamine was added and mixed with sufficient stirring. Furthermore, 967 parts by mass of ion-exchanged water was added and sufficiently stirred to obtain an aqueous resin composition (R-3) having a nonvolatile content of 46% by mass. The viscosity of the aqueous resin composition (R-3) at 25 ° C. was 150 mPa · s.

  The storage stability of the aqueous resin compositions (1) to (3) and (R-1) to (R-3) obtained above was evaluated.

<Evaluation of storage stability>
The aqueous resin composition obtained above was stored in a constant temperature bath at 40 ° C., the viscosity was measured after one month, and the storage stability was evaluated according to the following criteria.
Viscosity change rate (%) = 100− [viscosity after one month storage (mPa · s) / initial viscosity (mPa · s) × 100]
Good: Viscosity change rate of less than 20% Poor: Viscosity change rate of 20% or more

  Table 1 shows the compositions and evaluation results of the aqueous resin compositions (1) to (3) and (R-1) to (R-3) obtained above.

(Example 4: Preparation and evaluation of water-based paint (1))
[Preparation of water-based paint]
100 parts by mass of the aqueous resin composition (1) obtained in Example 1 as the main component of the aqueous paint and a curing agent (“Bernock DNW-5500” manufactured by DIC Corporation, water-dispersible polyisocyanate having a nonvolatile content of 80% by mass) 28 .6 parts by mass are mixed with stirring, diluted with ion-exchanged water so that the viscosity is 18 to 20 seconds (23 ° C.) using “Viscosity Cup NK-2” manufactured by Anest Iwata Co., Ltd. Obtained. DNW-5500 was mixed immediately before coating. Subsequently, the following coating film evaluation was performed using the obtained water-based paint (1).

[Preparation of coating film for evaluation]
The water-based paint (1) obtained above was applied to an aluminum plate (manufactured by Engineering Test Service Co., Ltd.) subjected to a chromate treatment with an air spray so that the film thickness after drying was 40 μm. After coating, the film was cured for 1 week under conditions of 23 ° C. and 50% relative humidity to prepare a coating film for evaluation.

[Evaluation of water resistance]
After the coating film for evaluation obtained above was immersed in water at 40 ° C. for 1 week, the appearance was observed and water resistance was evaluated according to the following evaluation criteria.
Good: No change from before test.
Bad: Whitening or blistering occurs.

[Evaluation of acid resistance]
The coating film for evaluation obtained above was immersed in a 5% sulfuric acid aqueous solution at 25 ° C. for 24 hours, then the appearance was observed, and acid resistance was evaluated according to the following evaluation criteria.
Good: No change from before test.
Bad: Whitening or blistering occurs.

[Evaluation of alkali resistance]
The coating film for evaluation obtained above was immersed in a 5% aqueous sodium hydroxide solution at 25 ° C. for 24 hours, then the appearance was observed, and the alkali resistance was evaluated according to the following evaluation criteria.
Good: No change from before test.
Bad: Whitening or blistering occurs.

(Examples 5 to 6: Preparation and evaluation of water-based paints (2) to (3))
Except having changed into the mixing | blending shown in following Table 2, after obtaining water-based paint (2)-(3) by operating like Example 4, coating-film evaluation was performed similarly.

(Comparative Examples 4 to 6: Preparation and evaluation of water-based paints (R-1) to (R-3))
Except having changed into the mixing | blending shown in the following Table 2, by operating like Example 4, after obtaining water-based paint (R-1)-(R-3), the coating-film evaluation was performed similarly.

  It was confirmed that the aqueous resin compositions of Examples 1 to 3 were excellent in storage stability and the water resistance, acid resistance and alkali resistance of the resulting coating film were good.

  Although the aqueous resin composition of Comparative Examples 1-3 is an example which does not use an amine (A) for neutralization of aqueous resin, it was confirmed that the storage stability is unsatisfactory.

Claims (3)

An aqueous resin composition obtained by neutralizing a carboxyl group in an aqueous resin with an amine (A) obtained by neutralizing one amino group of the diamine (a) with an acid, and dissolving or dispersing in an aqueous medium. The diamine (a) is represented by the following general formula (1) .

(In general formula (1), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or a methyl group, and n is an integer of 1 to 80.) It said aqueous resin is an acrylic resin, a vinyl-modified epoxy ester resin, and an aqueous resin composition according to claim 1 Symbol placement is one or more resin selected from the group consisting of polyester resins. The aqueous coating composition characterized by containing the claims 1 or 2 aqueous resin composition.