JP2000230146A - Aqueous resin composition for high damping coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having excellent adhesiveness to an electro-deposited steel plate, or the like, in the case of being used as a high damping coating material and also excellent in storage stability of the coating material by including an epoxy-modified acrylic emulsion. SOLUTION: This resin composition contains an epoxy-modified acrylic emulsion in an amount of preferably 0.005-600 pts.wt., more preferably 0.01-50 pts.wt. based on 100 pts.wt. of the resin composition. The emulsion is obtained, e.g. by polymerizing a radically polymerizable monomer [e.g. styrene, (n)-butyl acrylate, or the like] by a known emulsion polymerization technique in the presence of an epoxy resin (e.g. diglycidyl ether of bisphenol-A). Preferably, the composition contains a synthetic rubber latex such as a styrene-butadiene- based copolymer latex and/or a synthetic resin emulsion such as an acrylic emulsion. The composition is useful for reduction, or the like, of vibration of automobiles, or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous resin composition used for reducing vibration or noise caused by vibration of automobiles, precision machines, home appliances, construction machines, building structures, and other various devices and structures. About. More specifically, the present invention relates to an aqueous resin composition having good adhesion to an electrodeposited steel sheet or the like used for an automobile or the like.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of environmental problems, the development of materials that are resource-saving and environmentally friendly has been promoted. For example, desolvation from solvent-based paints and solvent-based adhesives, and treatment after disposal are considered. Material selection is being actively conducted. Specifically, for solvent-based paints and solvent-based adhesives, conversion to water-based materials can be mentioned. In addition, in terms of disposal, there is a method of converting a PVC polymer, which is said to generate toxic gas during combustion and damage the incinerator, to another material.

[0003] In this trend, the same is progressing for peripheral materials surrounding automobiles. For example, where a conventionally used asphalt-based damping sheet or damping steel sheet is used, a water-based damping paint responds to the movement,
There is also a trend to change chipping paint, which mainly used PVC sol, to water-based paint. However, it has been found that the conventional water-based paint has poor adhesion to an adherend such as an electrodeposited steel sheet. On the other hand, JP-A-63-165462 discloses that the adhesion is improved by blending a urethane emulsion. Although the disclosed technology significantly improves the adhesion, it is not satisfactory from the level currently required.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous resin composition having good adhesion to an electrodeposited steel sheet or the like when used as a damping coating. that time,
It is another object of the present invention to provide an aqueous resin composition that can exhibit performance without impairing the storage stability of a paint.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and surprisingly found that an aqueous resin dispersion containing an epoxy-modified acrylic emulsion can solve the problems, and arrived at the present invention. . That is, the present invention is an aqueous resin composition for vibration damping paint containing an epoxy-modified acrylic emulsion, or the above-mentioned aqueous resin composition containing a synthetic rubber latex and / or a synthetic resin emulsion.

Hereinafter, the present invention will be described in detail. The aqueous resin composition of the present invention needs to contain an epoxy-modified acrylic emulsion. The epoxy-modified acrylic emulsion is not particularly limited as long as it is an acrylic emulsion, but preferably has two or more epoxy groups in one molecule.

As a method for producing an epoxy-modified acrylic emulsion, for example, a method in which a radical polymerizable monomer is obtained by a conventionally known emulsion polymerization technique in the presence of an epoxy resin can be used. Emulsion polymerization can be performed in the presence of a radically polymerizable monomer, a radical polymerization initiator, water, and a surfactant. For example, an epoxy resin and a radical polymerizable monomer are uniformly dissolved in advance by sufficiently stirring at room temperature or under heating, and a surfactant, a dispersant, a protective colloid, a water-soluble polymer, and water and A method in which a radical polymerization initiator is added to form an emulsified dispersion, followed by polymerization. Other than this method, for example, a method of separately emulsifying and dispersing an epoxy resin and a radical polymerizable monomer for polymerization, a method of emulsifying and dispersing only the epoxy resin and directly polymerizing the radical polymerizable monomer, and the like, The initiator may be added together with the emulsified dispersion or separately. The epoxy resin exemplified in the epoxy modification is preferably a compound containing two or more epoxy groups in one molecule, for example, glycidyl ethers, glycidyl esters, glycidylamines, alicyclic epoxides, alicyclics Trioxide epoxide, and the like.

(A) The glycidyl ethers include aromatic glycidyl ethers and aliphatic glycidyl ethers. Examples of the aromatic glycidyl ethers include diglycidyl ether of bisphenol, polyglycidyl ether of phenol novolak, and diglycidyl ether of biphenol. Is mentioned. Examples of the diglycidyl ether of bisphenol include diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, and tetrabromobisphenol A. Examples of the polyglycidyl ether of phenol novolak include: Examples include polyglycidyl ethers such as phenol novolak, cresol novolak, and brominated phenol novolak. Examples of the diglycidyl ether of biphenol include diglycidyl ether of biphenol and tetramethylbiphenol.

Examples of the aliphatic glycidyl ether include glycidyl ethers such as polyethylene glycol, polypropylene glycol, sorbitol, sorbitan, glycerol, polyglycerol, pentaerythritol, tetramethylene glycol, hexamethylene glycol, and trimethylolpropane. (Ii) Examples of the glycidyl esters include aromatic glycidyl esters and alicyclic glycidyl esters. As the aromatic glycidyl ester, for example, diglycidyl esters such as phthalic acid, terephthalic acid, and isophthalic acid, and as the alicyclic glycidyl ester, for example, hexahydrophthalic acid, tetrahydrophthalic acid,
Glycidyl esters such as dimer acid are exemplified.

(C) Examples of glycidylamines include tetraglycidyldiaminodiphenylmethane, tetraglycidyl meta-xylylenediamine, and triglycidylaminophenol. (D) Examples of the linear aliphatic epoxides include epoxidized polybutadiene and epoxidized soybean oil. (E) Examples of the alicyclic epoxide include 3,4 epoxy-6-methylcyclohexylmethyl carboxylate and 3,4 epoxy cyclohexylmethyl carboxylate.

These epoxy resins may be used alone or in combination of two or more. Preferred epoxy resins are glycidyl ethers from the viewpoint of adhesion, more preferably diglycidyl ether of bisphenol, and particularly preferably biphenol A and biphenol F.
Of diglycidyl ether. The epoxy equivalent of the epoxy resin is preferably from 150 to 3,000, more preferably from 170 to 1,000.

The following can be used as the radical polymerizable monomer in the production of the epoxy-modified acrylic emulsion. For example, aromatic unsaturated compounds,
α, β-unsaturated monocarboxylic acid alkyl esters, unsaturated carboxylic acids, and the like. Examples of the aromatic unsaturated compound include styrene, α-methylstyrene, and vinyl toluene. Examples of the alkyl ester of α, β-unsaturated monocarboxylic acid include alkyl esters of acrylic acid or methacrylic acid. Can be Examples of the alkyl ester of acrylic acid or methacrylic acid include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, and ethyl methacrylate. , Propyl methacrylate, isopropyl acrylate, butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate and the like.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, monoalkyl itaconate and the like. Radical polymerizable monomers other than those described above may be combined as necessary. For example, a hydroxyl-containing monomer such as 2
-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate,
Hydroxypropyl methacrylate, polyethylene glycol acrylate; amide group-containing monomer, for example,
Acrylamide, methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, maleic amide, maleimide; methylol group-containing monomers such as N-methylol acrylamide, N-methylol methacrylamide, dimethylol acrylamide, dimethylol methacrylamide; Epoxy group-containing monomers, such as N-methoxymethyl acrylamide, N-methoxymethyl methacrylamide, N-butoxymethyl acrylamide, N-butoxymethyl methacrylamide; epoxy group-containing monomers, such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether , Methyl glycidyl acrylate, methyl glycidyl methacrylate; polyfunctional monomers such as divinyl Benzene, polyoxyethylene diacrylate, polyoxyethylene dimethacrylate,
Polyoxypropylene diacrylate, polyoxypropylene dimethacrylate, butanediol diacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate;
mono- or diesters of α, β-ethylenically unsaturated dicarboxylic acids, such as mono- or dibutyl maleate, mono- or dioctyl fumarate; vinyl esters, such as vinyl acetate, vinyl propionate; unsaturated nitriles, such as acrylonitrile, methacrylic acid Lonitrile;
Olefins, for example, butadiene, isoprene; chlorine-containing vinyl monomers, for example, vinyl chloride, vinylidene chloride, chloroprene and the like.

The radically polymerizable monomers may be used alone or as a mixture of two or more. Preferably, a combination of an aromatic unsaturated compound, an alkyl ester of an α, β-unsaturated monocarboxylic acid, and an unsaturated monocarboxylic acid is an essential component. More preferably,
Examples of the aromatic unsaturated compound include styrene, and α,
As alkyl esters of β-unsaturated monocarboxylic acids, ethyl acrylate, butyl acrylate, 2-
Ethylhexyl acrylate is exemplified, and unsaturated monocarboxylic acid is exemplified by acrylic acid and methacrylic acid.

The preferred composition ratios of the aromatic unsaturated compound, the α, β-unsaturated monocarboxylic acid alkyl ester and the unsaturated monocarboxylic acid are 20 to 80% by weight of the aromatic unsaturated compound, α, β-
20 to 80 alkyl esters of unsaturated monocarboxylic acid
% By weight, and 0.1 to 20% by weight of unsaturated monocarboxylic acid.

The Tg of the acrylic polymer may be set according to the purpose, but is preferably from -60 ° C to 30 ° C. At -60 ° C or higher, there is no problem in adhesion, and at 30 ° C or lower, there is no problem in the state of the coating film. More preferably, the temperature is from -40 ° C to 0 ° C.
° C. In addition, Tg here means the calculated value from all the monomers except the epoxy resin. In the production of the epoxy-modified acrylic emulsion used in the present invention, the ratio of the epoxy resin to the radical polymerizable monomer is such that the epoxy resin is 0.5 to 60% by weight and the radical polymerizable monomer is 40 to 99.5% by weight. Desirably. When the epoxy resin content is 0.5% by weight or more, there is no problem in adhesion, and when it is 60% by weight or less, there is no problem in polymerization stability of the epoxy-modified emulsion. More preferably, the radical polymerizable monomer is 45 to 99% by weight based on 1 to 55% by weight of the epoxy resin.

The surfactant used is ionic,
There are nonionic surfactants, which include anionic, cationic and amphoteric surfactants. Examples of the anionic surfactant include a carboxylic acid type, a sulfate ester type, a sulfonic acid type, a phosphate ester type, and the like.Examples of the carboxylic acid type include a fatty acid soap and a naphthenic acid soap. Examples thereof include long-chain alcohol sulfate, polyoxyethylene alkyl phenyl ether sulfate, fatty acid monoglyceride sulfate, fatty acid monoalkanolamide sulfate, and the like.Examples of the sulfonic acid type include alkanesulfonic acid salts and α-sulfofatty acid salts. , Dialkyl sulfosuccinate, polyoxyethylene alkyl phenyl ether sulfonate, alkylbenzene sulfonate, formalin condensed naphthalene sulfonate, and the like. Examples of the phosphate ester type include polyoxyethylene alkyl E alkenyl ether phosphate salts, polyoxyethylene alkyl ether phosphate salts, and the like.

Examples of the cationic surfactant include quaternary ammonium type, aliphatic amine type and heterocyclic amine type. Examples of the quaternary ammonium type include long-chain primary amine salts and dialkyldimethylammonium. salt,
Long-chain tertiary amine salts, alkyltrimethylammonium salts, alkylpyridinium salts and the like are mentioned, examples of the aliphatic amine type include polyoxyethylene alkylamines, and examples of the heterocyclic amine type include alkylimidazoline and the like. Can be

Examples of the amphoteric surfactant include N-alkylamino acid type and imidazoline type. Examples of the N-alkylamino acid type include N-alkyl-β-aminopropionate and N-alkyl-β-imino. Examples include dipropionate salts, and the imidazoline type includes, for example, 2-alkylimidazoline derivatives.
As the nonionic surfactant, for example, ether type,
Ester type, alkanolamide type and the like, and examples of the ether type include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether,
Polyoxyethylene alkyl thioethers and the like, and examples of the ester type include polyoxyethylene monofatty acid ester, polyoxyethylene difatty acid ester, polyoxyethylene propylene glycol fatty acid ester, polyoxyethylene sorbitan monofatty acid ester, glycerin monofatty acid ester, Examples include sucrose fatty acid esters, and examples of the alkanolamide type include fatty acid diethanolamide and polyoxyethylene alkylamide.

A reactive surfactant may be used in combination with the non-reactive surfactants mentioned above. The reactive surfactant has a radical polymerizable double bond in one molecule and has one or more functional groups selected from sulfonic acid groups, sulfonic acid ester groups, sulfonic acid groups, sulfonic acid ester bases, or It has a radical polymerizable double bond functional group in one molecule and has polyoxyethylene, polyoxypropylene, polyoxyethylene polyoxypropylene composite type alkyl ether or alcohol. Here, the salt refers to a sodium salt, a potassium salt, and an ammonium salt.

As the polymerization initiator, water-soluble and oil-soluble polymerization initiators can be used. As the water-soluble polymerization initiator,
For example, persulfates, peroxides, water-soluble azobis compounds,
Peroxide-reducing agent redox system and the like, and examples of the persulfate include ammonium persulfate, potassium persulfate, sodium persulfate, and the like, and examples of the peroxide include hydrogen peroxide, t-butylhydrogen, and the like. Peroxide, t-butylperoxymaleic acid, and succinic peroxide are exemplified. Examples of the water-soluble azobis compound include 2,2′-azobis (N-hydroxyethylisobutylamide) and 2,2′-azobis (2- Amidinopropane) dihydrochloride, 4,4′-azobis (4-cyanopentanoic acid) and the like. As the redox system of the peroxide-reducing agent, for example, sodium sulfooxylate formaldehyde, Sodium bisulfite, sodium thiosulfate, sodium hydroxymethanesulfinate, L-ascor Phosphate, and salts thereof, cuprous salts, addition of a reducing agent such as ferrous salts.

Examples of the oil-soluble polymerization initiator include peroxides and oil-soluble azobis compounds. Examples of the peroxide include dibutyl peroxide, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide. And the like. Examples of the oil-soluble azobis compound include, for example, 2,2 ′
-Azobisisobutyronitrile, 2,2'-azobis-
2-methylbutyronitrile, 2,2'-azobis-2,
4-dimethylvaleronitrile and the like.

In the polymerization of the epoxy-modified acrylic emulsion used in the present invention, if necessary, a pH adjuster such as sodium hydrogen phosphate and sodium hydrogen carbonate, n-hexyl mercaptan, n-octyl mercaptan, t-dodecyl mercaptan, n -Addition of mercaptans such as dodecyl mercaptan and thioglycolic acid, molecular weight regulators such as α-methylstyrene dimer and low molecular weight halogen compounds, chelating agents, plasticizers, organic solvents, etc. before, during and after emulsion polymerization. Can be. The polymerization temperature is, for example, 0 to 150.
The temperature is particularly preferably in the range of 30 to 90 ° C., and the reaction is carried out in an inert atmosphere under normal pressure or, if necessary, under pressure.

Examples of the dispersant, protective colloid, and water-soluble polymer that can be used during or after the production include polyphosphates, polyacrylates, styrene-maleic acid copolymer salts, and styrene-acrylic acid copolymer salts. , Styrene-methacrylic acid copolymer salt, water-soluble acrylate copolymer salt, water-soluble methacrylic acid ester copolymer salt,
Examples thereof include polyvinyl alcohol, polyacrylamide, polymethacrylamide, polyacrylamide copolymer, and polymethacrylamide copolymer.

The epoxy-modified acrylic emulsion used in the present invention may have a uniform structure or a core-shell structure. For example, there is a case where the core portion is made of an epoxy resin and an acrylic polymer and the shell portion is made of only an acrylic polymer, and a case where the core portion is made of only an acrylic polymer and the shell portion is made of an epoxy resin and an acrylic polymer.

The epoxy-modified acrylic emulsion is preferably contained in an amount of 0.005 to 60 parts by weight based on 100 parts by weight of the aqueous resin composition. If it is 0.005 parts by weight or more, there is no problem in adhesion, and if it is 60 parts by weight or less, there is no problem in storage stability. More preferably, it is 0.01 to 50 parts by weight. Although the aqueous resin composition of the present invention contains an epoxy-modified acrylic emulsion, it may be used as it is, or may contain a curing agent as needed to cure the epoxy resin. Examples of the curing agent include polyamines, tertiary amines, acid anhydrides, and polymercaptans.

The aqueous resin composition of the present invention may contain a synthetic rubber latex. The synthetic rubber latex referred to herein is a latex obtained by emulsion copolymerization of a conjugated diene monomer and a radical polymerizable monomer copolymerizable therewith. For example, styrene-butadiene-based copolymer latex, methyl methacrylate-butadiene-based copolymer latex, acrylonitrile-butadiene-based copolymer latex, polybutadiene-based copolymer latex, and the like can be given.

Preferred is a styrene-butadiene copolymer latex. The glass transition temperature of the synthetic rubber latex is preferably −60 to 60 ° C., more preferably −40 to 30 ° C. The method for producing the synthetic rubber latex may be a conventionally known emulsion polymerization method. Examples of conjugated diene monomers that can be used include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, chloroprene, and the like. .

Examples of the radical polymerizable monomer copolymerizable with the conjugated diene monomer include the above-mentioned aromatic unsaturated compounds, α, β-unsaturated monocarboxylic acid alkyl esters, unsaturated carboxylic acids, hydroxyl-containing monomers, amides Group-containing monomer, methylol group-containing monomer, alkoxymethyl group-containing monomer, epoxy group-containing monomer, polyfunctional monomer, α, β-ethylenically unsaturated dicarboxylic acid mono- or diester, vinyl ester, unsaturated nitrile, chlorine-containing vinyl And monomers.

The aqueous resin composition of the present invention may contain a synthetic resin emulsion. The synthetic resin emulsion referred to herein is an emulsion obtained by emulsion-copolymerizing a radically polymerizable monomer containing no conjugated diene monomer according to a conventional method. For example, a (meth) acrylate-based copolymer emulsion, a styrene- (meth) acrylate-based copolymer emulsion, a vinyl acetate-based copolymer emulsion, and an ethylene-vinyl acetate-based copolymer emulsion are exemplified.

Preferred are (meth) acrylate copolymer emulsions and styrene- (meth) acrylate copolymer emulsions. The (meth) acrylic acid ester has the same meaning as the above-mentioned α, β-unsaturated monocarboxylic acid alkyl ester. The glass transition temperature of the synthetic resin emulsion is usually -60 to 60C.
And preferably −40 to 30 ° C.

In the production of a synthetic resin emulsion,
The radically polymerizable monomers mentioned above except for the conjugated diene monomer can be used. Also in the emulsion polymerization, the above-mentioned method of emulsion polymerization of the epoxy-modified acrylic emulsion can be used. It is desirable that the aqueous resin composition of the present invention contains a synthetic rubber emulsion and a synthetic resin emulsion.

In the present invention, (1) an epoxy-modified acrylic emulsion and (2) a synthetic rubber latex and / or
Alternatively, as for the weight ratio with the synthetic resin emulsion, (1) / (2) is preferably 1/999 or more at each solid content. Adhesion is good at 1/999 or more. There is no problem in storage stability. More preferably (1) /
(2) = 1/99 to 70/30.

In the aqueous resin composition of the present invention, when the epoxy-modified acrylic emulsion is epoxy-modified using an epoxy resin, a total of 100 parts by weight of the epoxy-modified acrylic emulsion, synthetic rubber latex and synthetic resin emulsion (solid %), The amount of the epoxy resin used for the epoxy modification of the epoxy-modified acrylic emulsion is preferably 0.1 to 10 parts by weight. When the amount is 0.1 part by weight or more, there is no problem in adhesion, and when it is 10 parts by weight or less, there is no problem in storage stability. More preferably, 0.
5 to 8 parts by weight. The amount of the epoxy resin can be determined by the amount of the epoxy resin in the epoxy-modified acrylic emulsion and the combination of the synthetic rubber latex and the synthetic resin emulsion.

In the present invention, the epoxy-modified acrylic emulsion, the synthetic rubber latex, and the synthetic resin emulsion may be blended with a thermosensitive gel. The term "thermal gelation" as used herein means that the latex gels when heated to a certain temperature or higher. To the aqueous resin composition of the present invention, if necessary, other latexes, tackifiers and rubber components, inorganic fillers, coloring pigments, extender pigments, pigments such as rust preventive pigments may be added for improving the performance. Good. Further, a bactericide, a preservative, an antifoaming agent, a plasticizer, a flow regulator, a thickener, a pH regulator, a surfactant, a thermosensitive gelling agent, a solvent and the like may be added.

Examples of the latex for improving the performance include urethane latex and epoxy emulsion. Examples of the tackifier include rosin, rosin derivative, terpene resin, natural tackifier such as terpene derivative, petroleum resin, styrene resin, coumarone indene resin, phenol resin, and xylene resin. And a synthetic resin-based tackifier. These tackifiers are preferably added in the form of an aqueous dispersion or an aqueous solution. Examples of the rubber component include liquid nitrile rubber, silicone rubber, and powder rubber.

Examples of the inorganic filler include calcium carbonate, magnesium carbonate, aluminum hydroxide, calcium silicate, barium sulfate, kaolin, clay, diatomaceous earth, alumina, gypsum, cement, converter slag powder, glass powder and the like. Examples of the pigment include titanium oxide, carbon black, phosphate-based rust preventive pigments, molybdate-based rust preventive pigments, and the like.

The aqueous resin composition of the present invention is dried after being applied to an adherend. As an application method, for example, an airless spray method, a brush application method, a roll application method, a spatula application method, or the like can be used. Examples of the drying method include a baking drying method and a room temperature drying method. As the adherend,
A typical example is an electrodeposited steel plate for an automobile, but is not limited thereto. For example, wood, plywood, particle board, gypsum board, iron, metal such as aluminum, plastic film, plastic foam, non-woven fabric of plastic, leather, cotton, linen, glass fiber, glass cloth, FRP, painted steel sheet, paper, Various plastics such as a PVC tile, a PVC sheet, and a polyolefin sheet are exemplified.

Examples of applications include packaging materials, processed paper, decorative boards, fiber processing agents, building materials, building materials, and the like, in addition to the coating applications of the present invention.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but they do not limit the scope of the present invention. Parts are by weight unless otherwise specified. Also,
The evaluation method is as follows. Each characteristic was obtained as follows. (1) Storage stability: The composition containing the epoxy-modified acrylic emulsion shown in Table 2 was left at 40 ° C. for 7 days.
The viscosity before standing and the viscosity after standing were measured, and the viscosity change rate was 5%.
0% or less was regarded as a pass.

The numbers in Table 2 represent solid contents. Further, the composition is adjusted with water so that the solid content is 65%,
Thereafter, the viscosity was adjusted with a thickener so as to become 2000 to 3000 mPa · s. (2) Adhesion: The composition shown in Table 2 was coated with an electrodeposition paint.
It is applied to a cured commercially available cationic electrodeposition coated plate (manufactured by Test Piece Co., Ltd.) using a bar coater so that the thickness becomes 300 μm after drying. Thereafter, the coating was heated at 60 ° C. for 30 minutes and further at 140 ° C. for 20 minutes to form a coating film.

The composition used was prepared in the same manner as in the above (1). Cross cut the coating surface with a cutter knife. In this case, a knife is inserted into the electrodeposition coating film. Next, a cellophane tape is attached to the center of the cross cut portion, and vigorously peeled off. When the cross cut portion did not come off, it was judged as passed.

[0043]

Reference Examples 1 to 4 (Preparation of Epoxy-Modified Acrylic Emulsion) 25 parts of Emulgen 950 [polyoxyethylene nonyl phenyl ether] manufactured by Kao Corporation were added to 1000 parts of a mixture of a radical polymerizable monomer and an epoxy resin shown in Table 1. 80 parts of a 25% aqueous solution, 40 parts of a 25% aqueous solution of Revenol WZ [Kao Corporation, sodium polyoxyethylene nonylphenyl ether sulfate], 2 parts of ammonium persulfate, and 430 parts of distilled water are added, and the mixture is stirred with a homomixer. An emulsion was prepared. Separately, 400 parts of distilled water and 20 parts of a 25% aqueous solution of Emulgen 950 are charged into a flask equipped with a stirrer, the temperature is raised to 80 ° C., and 1 part of ammonium persulfate dissolved in 50 parts of water is added. To this, the pre-emulsion is continuously dropped over 4 hours. Next, a solution prepared by dissolving 0.5 part of ammonium persulfate in 50 parts of water was added, and polymerization was continued at the same temperature for 1 hour. afterwards,
Cool to 30 ° C or less, and add 25% ammonia water
H was adjusted to 7 to obtain an emulsion having a solid content of 50%.
Table 1 also shows Tg calculated from the radical polymerizable monomer.

[0044]

Examples 1 to 9 Aqueous resin compositions shown in Table 2 were prepared.
The storage stability and adhesion were evaluated.

[0045]

Comparative Examples 1 to 4 Aqueous resin compositions shown in Table 3 were prepared.
Evaluation of storage stability and adhesion was performed in the same manner as in the examples. The numbers in Table 3 represent the solid content, and the composition was adjusted in the same manner as in the examples.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

According to the present invention, when used as a damping paint, it has good adhesion to an electrodeposited steel sheet or the like. Also, the storage stability of the paint is good.

Claims (2)

[Claims] 1. An aqueous resin composition for a vibration damping paint containing an epoxy-modified acrylic emulsion. 2. The aqueous resin composition according to claim 1, comprising a synthetic rubber latex and / or a synthetic resin emulsion.