JP2006052290A - Method for producing aqueous resin dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably producing an aqueous resin dispersion forming a coated film exhibiting a good finish appearance and having excellent water, weather and corrosion resistances. <P>SOLUTION: The method for producing the aqueous resin dispersion is carried out as follows. A mixture (I) comprising a monomer component composed of (A) a polymerizable unsaturated monomer containing a fatty acid (a1), an epoxy group-containing polymerizable unsaturated monomer (a2) and an isocyanate compound (a3) as constituent units and (B) other polymerizable unsaturated monomers is finely dispersed in an aqueous medium so as to afford ≤500 nm average particle diameter. The resultant emulsion is then polymerized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for stably producing an aqueous resin dispersion capable of forming a coating film that exhibits a good finished appearance and is excellent in water resistance and corrosion resistance.

  In recent years, in the fields of paints, inks, adhesives, etc., from the viewpoint of resource saving, environmental hygiene, non-pollution, non-hazardous materials, etc., conversion from organic solvent type compositions to aqueous type compositions has been promoted. . Examples of the vehicle used in the aqueous coating composition include resins such as alkyd resins, acrylic resins, polyester resins, polyurethane resins, and epoxy resins. In these aqueous coating compositions, the alkyd resin can introduce an oxidative curing group into the resin skeleton by using an unsaturated fatty acid as a raw material, and the aqueous coating composition using the alkyd resin can be cured at one room temperature. In addition, due to its oiliness, anti-corrosion properties can be expected when applied to a metal surface, but its soft nature delays drying of the coating and generally has a weak weather resistance. On the other hand, the acrylic resin is inferior in anticorrosion property although it is excellent in quick drying property and weather resistance. As an aqueous resin material having the characteristics of these two types of resins, many graft resins and the like for bonding alkyd resins and acrylic resins by chemical reaction have been developed and proposed. For example, Patent Document 1 discloses a fatty acid-modified monomer obtained by reacting a dry oil fatty acid or semi-dry oil fatty acid with an α, β-ethylenically unsaturated acid glycidyl ester using a surfactant and / or a polymer protective colloid. It is disclosed that an oxidation polymerization type aqueous emulsion is produced by emulsion polymerization of a radically polymerizable monomer mixture.

  By the way, the formation mechanism of the emulsion polymer is that the monomer diffuses in the water from the large monomer droplets in the aqueous phase, and the polymerization proceeds in the micelles made by the surfactant to produce polymer particles (polymerized small particles). It consists of to do. In this case, the monomer used for the polymerization must be supplied by diffusing water from the monomer droplets to the polymer particles under the conditions for polymerization.

  In general, there is a large particle size difference between monomer droplets and polymer particles growing from micelles. This means that there is a large difference between the total surface area of the monomer droplets and the total surface area of the polymer particles, so that the initiator radical and the monomer diffusing in water penetrate the larger surface area, that is, the polymer particles, The polymerization then proceeds. In the emulsion polymerization method, polymer particles grow while the particle diameter gradually increases.

  In the case of emulsion polymerization of a radically polymerizable monomer mixture containing the above fatty acid-modified monomer, the fatty acid-modified monomer having extremely poor solubility in water is left in the monomer droplets in the polymerization stage, and polymerization proceeds in the monomer droplets. Polymer particles containing a large amount of fatty acid-modified monomer units are formed, while monomers other than the fatty acid-modified monomer diffuse in water from the monomer droplets into the micelles, where the polymer contains many monomer units other than the fatty acid-modified monomer units. Since the particles are generated, there is a high possibility that the nonuniform distribution of the hydrophilic polymer particles and the hydrophobic polymer particles is extremely generated in the polymer particles in the finally obtained emulsion. Therefore, in the coating film formed from such an oxidation polymerization type aqueous emulsion, the hydrophobic polymer particles become nuclei and cause repelling, or the surface floats and remains sticky on the surface. Therefore, there is a problem that a transparent film cannot be formed and the finished appearance of the coating film is remarkably deteriorated.

  As a measure for overcoming the above problems, for example, Patent Document 2 proposes an aqueous copolymer containing a copolymer that is a polymerization product of a vinyl monomer and a hydrophobic ester or a partial ester, and a method for producing the same. ing. In this publication, it is proposed to add a hydrophobic ester from a dry oil acid and a polyol to the monomer droplets in order to suppress the formation of second generation particles other than the monomer droplets during the polymerization. The water-based copolymer described in the publication can form a transparent oxide-cured film at room temperature without containing a volatile coalescing aid. However, the dry oil acid and unsaturated α, β- Since a mixed ester of a polymerizable unsaturated carboxylic acid and a polyol generates a hydroxyl group, the water resistance of a coating film formed using the aqueous copolymer may be affected.

JP 59-8773 A JP 2000-319525 A

  An object of the present invention is to provide a method for stably producing an aqueous resin dispersion that exhibits a good finished appearance and can form a coating film excellent in water resistance, weather resistance, and corrosion resistance.

As a result of intensive studies to solve the above problems, the present inventors have determined that specific polymerizable unsaturated monomers and other polymerizable unsaturated monomers having fatty acid, an epoxy group-containing polymerizable unsaturated monomer and an isocyanate compound as structural units. The present invention has been achieved by a production method in which a mixture containing a saturated monomer is finely dispersed in an aqueous medium so as to have a specific average particle diameter, and the resulting emulsion is polymerized.
That is, the present invention
1. (A) A polymerizable unsaturated monomer containing fatty acid (a1), an epoxy group-containing polymerizable unsaturated monomer (a2) and an isocyanate compound (a3) as structural units, and (B) a monomer comprising other polymerizable unsaturated monomer A method for producing an aqueous resin dispersion, wherein the mixture (I) containing the components is finely dispersed in an aqueous medium so that the average particle diameter is 500 nm or less, and the resulting emulsion is polymerized;
2. The other polymerizable unsaturated monomer (B) is a polymerizable unsaturated monomer (b1) containing a linear or branched hydrocarbon group having 6 or more carbon atoms, a cycloalkyl group-containing polymerizable unsaturated monomer ( 2. The production method according to 1, which comprises at least one polymerizable unsaturated monomer selected from the group consisting of b2) and a carbonyl group-containing polymerizable unsaturated monomer (b3);
3. Item 3. The method according to Item 1 or 2, wherein the mixture (I) further contains an epoxy resin (C).
4). An aqueous resin dispersion obtained by the production method according to any one of claims 1 to 3,
5. An aqueous resin composition containing the aqueous resin dispersion according to item 4,
6). The aqueous resin composition according to 5, further comprising an aqueous epoxy resin (D),
7). Item 7. The aqueous resin composition according to Item 5 or 6, further comprising a hydrazine derivative (E),
8). An aqueous coating composition containing the aqueous resin composition according to any one of items 5 to 7,
9. A method for forming a coating film, which comprises applying the water-based coating composition described in item 8 to a surface to be coated,
10. A coated article obtained by the method for forming a coating film according to Item 9,
About.

  According to the production method of the present invention, a large amount of an organic solvent or an auxiliary surfactant is obtained by using a specific polymerizable unsaturated monomer having a fatty acid, an epoxy group-containing polymerizable unsaturated monomer and an isocyanate compound as structural units. Even if it does not use etc., the aqueous resin dispersion containing a fatty-acid component and a urethane component can be manufactured stably. In addition, since the polymerizable unsaturated monomer has a hydroxyl group partially or completely modified with a urethane bond, the resulting aqueous resin dispersion is excellent in the finish, adhesion, and water resistance of the formed coating film. It has the advantage of having elasticity and toughness due to the urethane component. In addition, the aqueous resin dispersion is excellent in storage stability, can form a coating film excellent in performance such as water resistance and weather resistance at room temperature, and can be used in a wide range of fields such as vehicles such as automobiles and coatings of buildings. Can be applied to.

  The aqueous resin dispersion of the present invention comprises (A) a polymerizable unsaturated monomer having a fatty acid (a1), an epoxy group-containing polymerizable unsaturated monomer (a2) and an isocyanate compound (a3) as structural units, and (B) other The mixture (I) containing a monomer component composed of a polymerizable unsaturated monomer is finely dispersed in an aqueous medium so that the average particle diameter is in the range of 500 nm or less, and the resulting emulsion is polymerized. When the average particle diameter exceeds 500 nm, the hydrophilic-hydrophobic non-uniformity of the aqueous resin dispersion particles becomes extreme, storage stability is inferior, and the finish and practicality of the formed coating film are deteriorated. In this specification, the average particle size is “SALD-3100” (trade name, manufactured by Shimadzu Corporation, laser diffraction particle size distribution analyzer), and the sample is diluted with deionized water to 20 ° C. The measurement of the average particle size of the emulsion or resin dispersion of the finely divided mixture (I) is performed at the time when 30 minutes have elapsed after the production, respectively.

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

Polymerizable unsaturated monomer (A)
In the present invention, the polymerizable unsaturated monomer (A) facilitates atomization during the emulsification of the mixture (I), and stabilizes the emulsion after atomization in the polymerization stage. In order to suppress the diffusion of the unsaturated monomer (B) into the aqueous medium, and to improve the finish of the coating film formed using the produced water dispersion, to give flexibility and toughness, In addition, in the case of imparting oxidative curability to a coating film formed using an aqueous resin dispersion, it is used for introducing an oxidatively hardened group, and includes fatty acid (a1) and epoxy group-containing polymerizability. It is a polymerizable unsaturated monomer containing an unsaturated monomer (a2) and an isocyanate compound (a3) as structural units.

  Examples of the fatty acid (a1) include those having a structure in which a carboxyl group is bonded to the end of a hydrocarbon chain, and examples thereof include a dry oil fatty acid, a semi-dry oil fatty acid, and a non-dry oil fatty acid. Dry oil fatty acids and semi-dry oil fatty acids are not strictly distinguishable, but usually dry oil fatty acids are unsaturated fatty acids that are iodinated 130 or more, and semi-dry oil fatty acids are iodinated 100 or more and less than 130. Of unsaturated fatty acids. On the other hand, non-drying oil fatty acids are usually fatty acids having an iodine value of less than 100.

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

  In the present invention, for the purpose of improving the oxidative curability of the formed coating film, the fatty acid (a1) is preferably a dry oil fatty acid and / or a semi-dry oil fatty acid.

  The epoxy group-containing polymerizable unsaturated monomer (a2) includes a compound having one epoxy group and one polymerizable unsaturated group in one molecule, and specifically, for example, glycidyl (meth) acrylate. , Β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, allyl glycidyl ether, etc. Is mentioned. These can be used alone or in combination of two or more.

  The isocyanate compound (a3) contains one or more, preferably two or more isocyanate groups in one molecule. Specific examples thereof include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, Aliphatic diisocyanate compounds such as lysine diisocyanate; burette-type adducts and isocyanurate cycloadducts of these polyisocyanates; isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4- (or − 2,6-) diisocyanate, 1,3- (or 1,4-) di (isocyanatomethyl) cyclohexane, 1,4-cyclohexane diisocyanate, 1,3-cyclopentane diisocyanate Alicyclic diisocyanate compounds such as 1,2-cyclohexane diisocyanate; bullet type adducts of these diisocyanates, isocyanurate cycloadducts; xylylene diisocyanate, metaxylylene diisocyanate, tetramethyl xylylene diisocyanate , Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether isocyanate, (m- Or p-) phenylene diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, bis (4-isocyanatophenyl) sulfone Aromatic diisocyanate compounds such as isopropylidenebis (4-phenylisocyanate); burette type adducts and isocyanurate ring adducts of these diisocyanate compounds; triphenylmethane-4,4 ′, 4 ″ — In one molecule such as triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate A polyisocyanate compound having three or more isocyanate groups; a burette-type adduct of these polyisocyanates, an isocyanurate cycloadduct; ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylolpropionic acid, polyalkylene Glycol, trimethylo Urethane adducts obtained by reacting a polyisocyanate compound in an excess ratio of isocyanate groups to the hydroxyl groups of polyols such as rupropane and hexanetriol; bullet type adducts of these urethanized adducts, isocyanurates A cycloadduct etc. can be mentioned. Among these, aliphatic diisocyanate compounds and / or alicyclic diisocyanate compounds are preferred from the viewpoint of the weather resistance of the formed coating film.

  The production of the polymerizable unsaturated monomer (A) is not particularly limited. For example, the above-described components (a1), (a2) and (a3) may be reacted at once, or may be reacted in multiple stages. You may let them. For example, the carboxyl group of the fatty acid (a1) and the epoxy group of the epoxy group-containing polymerizable unsaturated monomer (a2) are reacted, and the isocyanate compound (a3) is reacted with the secondary hydroxyl group of the resulting fatty acid-modified polymerizable unsaturated monomer. be able to.

  In the fatty acid-modified polymerizable unsaturated monomer, the fatty acid (a1) and the epoxy group-containing polymerizable unsaturated monomer (a2) are a carboxyl group in the fatty acid (a1) and an epoxy group-containing polymerizable unsaturated monomer (a2). The reaction can be carried out in such a ratio that the equivalent ratio with the epoxy group is in the range of 0.75: 1 to 1.25: 1, preferably 0.8: 1 to 1.2: 1.

  The reaction between the fatty acid (a1) and the epoxy group-containing polymerizable unsaturated monomer (a2) is usually carried out in the presence of a polymerization inhibitor without causing a reaction problem such as gelation. And the epoxy group in the epoxy group-containing polymerizable unsaturated monomer can be carried out under conditions that allow smooth reaction, and usually by heating at a temperature of about 100 to about 180 ° C. for about 0.5 to about 10 hours. Suitable to do.

  In this reaction, an esterification reaction catalyst such as a tertiary amine such as N, N-dimethylaminoethanol, a quaternary ammonium salt such as tetraethylammonium bromide or tetrabutylammonium bromide can be used. An inert organic solvent may be used.

  Examples of the polymerization inhibitor include hydroxy compounds such as hydroquinone, hydroquinone monomethyl ether, pyrocatechol and p-tert-butylcatechol; nitrobenzene, nitrobenzoic acid, o-, m- or p-dinitrobenzene, 2,4- Nitro compounds such as dinitrotoluene, 2,4-dinitrophenol, trinitrobenzene, and picric acid; quinone compounds such as p-benzoquinone, dichlorobenzoquinone, chloranil, anthraquinone, and phenanthroquinone; nitrosobenzene, nitroso-β-naphthol, and the like Examples thereof include radical polymerization inhibitors known per se such as nitroso compounds, and these can be used alone or in combination of two or more.

  In the present invention, the proportion of the fatty acid-modified polymerizable unsaturated monomer and the isocyanate compound (a3) used can be variously changed. From the viewpoint of the water resistance of the formed coating film and the production stability of the aqueous resin dispersion, the fatty acid-modified The equivalent ratio of the hydroxyl group contained in the polymerizable unsaturated monomer to the isocyanate group is generally 1: 0.2 to 1: 1.2, preferably 1: 0.3 to 1: 1.1. Is desirable.

  The reaction is usually carried out at a temperature of 40 to 180 ° C, preferably 60 to 130 ° C. In order to promote this reaction, an amine catalyst such as triethylamine, N-ethylmorpholine, or triethylenediamine used in a normal urethanization reaction, or a tin catalyst such as dibutyltin dilaurate or dioctyltin dilaurate is used as necessary. It may be used.

Other polymerizable unsaturated monomers (B)
In the present invention, the other polymerizable unsaturated monomer (B) is a polymerizable unsaturated monomer other than the monomer (A) copolymerizable with the polymerizable unsaturated monomer (A), and has at least 1 in the molecule. And preferably one compound containing one polymerizable unsaturated group such as vinyl group, (meth) acryloyl group and the like. Specific examples of such other polymerizable unsaturated monomer (B) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n -Butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate , Tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (manufactured by Osaka Organic Chemical Co., Ltd.), cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t -Butyl Alkyl or cycloalkyl (meth) acrylates such as hexyl (meth) acrylate and cyclododecyl (meth) acrylate; isobornyl group-containing polymerizable unsaturated monomers such as isobornyl (meth) acrylate; adamantyl (meth) acrylate and the like Adamantyl group-containing polymerizable unsaturated monomer; glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3, Epoxy group-containing polymerizable unsaturated monomers such as 4-epoxycyclohexylpropyl (meth) acrylate and allyl glycidyl ether; aromatic vinyl monomers such as styrene, α-methylstyrene and vinyltoluene; Alkoxysilyl group-containing polymerizable unsaturated monomers such as xylsilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane A polydimethylsiloxane macromonomer; a perfluoroalkyl (meth) acrylate such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; an alkyl fluorine group-containing polymerizable unsaturated monomer such as a fluoroolefin; N- ((Meth) acryloxyethyl) -N, N′-ethyleneurea, N- (acrylamidoethyl) -N, N′-ethyleneurea and other copolymerizable ethyleneurea derivatives; photopolymerizable functional groups such as maleimide groups Have Compatible unsaturated monomers; vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate; (meth) acrylic acid, fumaric acid, itaconic acid, maleic acid, crotonic acid, β-carboxyethyl Carboxyl group-containing polymerizable unsaturated monomers such as acrylate; unsaturated carboxylic anhydrides such as maleic anhydride and itaconic anhydride; (meth) acrylonitrile, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl ( Nitrogen-containing polymerizable unsaturated monomers such as meth) acrylate and adducts of glycidyl (meth) acrylate and amines; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3 -Hydroxypropyl (meta Hydroxyl groups such as hydroxyalkyl (meth) acrylates having 2 to 8 carbon atoms such as acrylate and hydroxybutyl (meth) acrylate, allyl alcohol, and ε-caprolactone modified products of the above hydroxyalkyl (meth) acrylates having 2 to 8 carbon atoms Containing (meth) acrylate; hydroxyl group-containing polymerizable unsaturated monomer such as (meth) acrylate having a polyoxyethylene chain having a hydroxyl group at the molecular end: polyoxyethylene chain-containing (meth) acrylate having an alkoxy group at the molecular end; 2 -Sulphonic acid group-containing polymerizable unsaturated monomers such as acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, styrene sulfonic acid sodium salt, sulfoethyl methacrylate and its sodium salt and ammonium salt; 2-hydroxy-4- (3 -Metak Liloyloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone, 2,2′-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, Hydroxybenzophenones such as 2,2'-dihydroxy-4- (3-acryloxy-2-hydroxypropoxy) benzophenone, 2,4-dihydroxybenzophenone, 2,2 ', 4-trihydroxybenzophenone and glycidyl (meth) acrylate Or a polymerizable unsaturated monomer having an ultraviolet-absorbing functional group such as 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl) -2H-benzotriazole; 4- (meth) acryloyl Oxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4- (meth) acryloylamino-2, 2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (Meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6- Polymerizable unsaturation having UV-stable functional groups such as tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine Monomers: Carbonyl such as acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrene, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) Group-containing polymerizable unsaturated monomer: allyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate G, 1,6-hexane Orange (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1- Trishydroxymethylethanedi (meth) acrylate, 1,1,1-trishydroxymethylethanetri (meth) acrylate, 1,1,1-trishydroxymethylpropanetri (meth) acrylate, triallyl Polyvinyl compounds having at least two polymerizable unsaturated groups in one molecule such as isocyanurate, diallyl terephthalate, divinylbenzene, etc .; the fatty acid (a1) and the epoxy group-containing polymerizable unsaturated monomer (A2) / or a reaction product with the above hydroxyl group-containing polymerizable unsaturated monomer, etc., and these may be used alone depending on the desired performance. It is appropriately used or two or more kinds.

The above-mentioned polymerizable unsaturated monomer (A) and other polymerizable unsaturated monomer (B) are used in proportions from the viewpoint of film-forming property, drying property, finishing property, and polymerization stability. Based on the total weight of monomer (B),
The polymerizable unsaturated monomer (A) is 5 to 50% by weight, preferably 10 to 40% by weight, and the other polymerizable unsaturated monomer (B) is 50 to 95% by weight, preferably 60 to 90% by weight. Can be within the range.

  In the present invention, the other polymerizable unsaturated monomer (B) includes a polymerizable unsaturated monomer (b1) containing a linear or branched hydrocarbon group having 6 or more carbon atoms, and a cycloalkyl group-containing polymerizable property. It is desirable to include at least one polymerizable unsaturated monomer selected from the group consisting of an unsaturated monomer (b2) and a carbonyl group-containing polymerizable unsaturated monomer (b3).

  Examples of the polymerizable unsaturated monomer (b1) containing a linear or branched hydrocarbon group having 6 or more carbon atoms include n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl ( And (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (manufactured by Osaka Organic Chemical Co., Ltd.), etc. Or in combination of two or more.

  By using the polymerizable unsaturated monomer (b1) containing a linear or branched hydrocarbon group having 6 or more carbon atoms as at least a part of the other polymerizable unsaturated monomer (B), Polymerization stability of emulsion of mixture (I) after atomizing mixture (I) containing monomer component comprising polymerizable unsaturated monomer (A) and other polymerizable unsaturated monomer (B) in an aqueous medium In addition, it is possible to produce an aqueous resin dispersion that forms a coating film excellent in water resistance.

  The polymerizable unsaturated monomer (b1) containing a linear or branched hydrocarbon group having 6 or more carbon atoms is 1 to 30% by weight based on the total weight of the monomer (A) and the monomer (B). , Preferably 5 to 25% by weight.

  As the cycloalkyl group-containing polymerizable unsaturated monomer (b2), a compound having one cycloalkyl group having 6 or more carbon atoms and one polymerizable unsaturated bond in one molecule is preferable. Examples include cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, and the like. These can be used in combination.

  When the other polymerizable unsaturated monomer (B) contains the cycloalkyl group-containing polymerizable unsaturated monomer (b2) as a part of the component, the weather resistance of the formed coating film can be improved. The polymerizable unsaturated monomer (b2) is desirably contained in the range of 1 to 70% by weight, preferably 10 to 60% by weight, based on the total weight of the monomer (A) and the monomer (B). .

  Examples of the carbonyl group-containing polymerizable unsaturated monomer (b3) include compounds having one carbonyl group and one polymerizable unsaturated bond in one molecule. Specific examples thereof include acrolein and diacetone acrylamide. , Diacetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrene, vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) and the like. Or it can be used in combination of two or more. Of these, diacetone (meth) acrylamide is particularly preferred. As the at least part of the monomer (B), a carbonyl group-containing polymerizable unsaturated monomer (b3) is used, and a hydrazine derivative described later is added to the resulting dispersion to contain a carbonyl group. The carbonyl group derived from the polymerizable unsaturated monomer (b3) and the hydrazine derivative can be cross-linked, the drying property of the coating film can be further improved, and the physical properties such as weather resistance and water resistance can be improved. A composition that forms an excellent coating film can be prepared. The proportion of the monomer (b3) used is suitably in the range of 0.5 to 35% by weight, preferably 2 to 20% by weight, based on the total weight of the monomer (A) and the monomer (B).

  In the case where the other polymerizable unsaturated monomer (B) comprises a polymerizable unsaturated monomer (b3) containing a carbonyl group, the type of the fatty acid (a1) is not particularly limited, It can also consist of drying oil fatty acids and / or non-drying oil fatty acids. Semi-drying oil fatty acids and / or non-drying oil fatty acids are generally fatty acids with low oxidative curability, and those exemplified above can be used.

  In addition, the other polymerizable unsaturated monomer (B) is an acid group-containing polymerizable unsaturated monomer of 10% by weight or less, preferably 0.1%, based on the total weight of the monomer (A) and the monomer (B). It can comprise within a range of ˜5% by weight.

  Examples of the acid group-containing polymerizable unsaturated monomer include (meth) acrylic acid, fumaric acid, itaconic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate and other carboxyl group-containing polymerizable unsaturated monomers; 2-acrylamide -2-Methylpropane sulfonic acid, allyl sulfonic acid, styrene sulfonic acid sodium salt, sulfoethyl methacrylate and sulfonic acid group-containing polymerizable unsaturated monomers such as sodium salt and ammonium salt thereof can be mentioned, in particular, carboxyl group Containing polymerizable unsaturated monomers are preferred.

  By using an acid group-containing polymerizable unsaturated monomer as at least a part of the other polymerizable unsaturated monomer (B), the stability and mechanical stability of the obtained aqueous resin dispersion particles in an aqueous medium are ensured. In addition, when the aqueous resin composition containing the same is applied to an enamel paint, the toning property of the paint can be improved.

Aqueous Resin Dispersion In the present invention, the mixture (I) contains a monomer component composed of a polymerizable unsaturated monomer (A) and other polymerizable unsaturated monomers as essential components, and further includes an epoxy resin (C). Can be contained.

  By using a mixture in which the epoxy resin (C) is further added to the monomer component as the mixture (I), aqueous resin dispersion particles encapsulating the resin (C) can be produced. The anticorrosion property can be improved. As a result, the epoxy resin (C) is uniformly dispersed in the coating film formed using the resulting aqueous dispersion, and the effect can be stably exhibited over a long period of time after the coating film is formed. it can.

  Specific examples of the epoxy resin (C) include polyphenols such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A / F type epoxy resin, and novolac type phenol resin, and epihalohydrins such as epichlorohydrin. An aromatic epoxy resin obtained by reacting with glycidyl group and reacting polyphenols with this glycidyl group-introduced reaction product to increase molecular weight; aliphatic epoxy resin, alicyclic epoxy resin Epoxy resins such as: epoxy group-containing acrylic copolymers obtained by copolymerizing an epoxy group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomers; polybutadiene resins having an epoxy group; polyurethane resins having an epoxy group Epoxy group-containing resins such as 1); the epoxy group-containing resin (c1) modified epoxy resin obtained by modifying the like.

  The epoxy group-containing resin (c1) is generally in the range of 200 to 6000, particularly 300 to 2000, more particularly 350 to 2000, and generally 100 to 3000, especially 150 to 1000, more particularly 175 to 1000. It is preferable to have an epoxy equivalent of In this specification, the weight average molecular weight is a value obtained by converting the weight average molecular weight measured by gel permeation chromatography using tetrahydrofuran as a solvent based on the weight average molecular weight of polystyrene.

  The epoxy group-containing resin (c1) can be used alone or in combination of two or more depending on the purpose, and particularly preferable epoxy group-containing resin (c1) is an aromatic epoxy resin. be able to.

  From the viewpoint of compatibility with the polymerizable unsaturated monomer (A) and other polymerizable unsaturated monomers (B), production stability, and finish of the formed coating film, the epoxy resin (C) is a modified epoxy resin. It is desirable that it is a fatty acid-modified epoxy resin obtained by reacting the epoxy group-containing resin (c1) with a fatty acid. By modifying with a fatty acid, the epoxy resin (C) can have a secondary hydroxyl group, and the adhesion of the formed coating film can be improved. As this fatty acid, the thing similar to what was listed by description of the said fatty acid (a1) can be used.

  The reaction between the epoxy group-containing resin (c1) and the fatty acid usually occurs in the presence of a polymerization inhibitor without causing a reaction problem such as gelation and the epoxy group in the epoxy group-containing resin (c1). The reaction can be carried out under conditions such that the carboxyl group in the fatty acid reacts smoothly, and it is usually suitable to heat at a temperature of about 140 to about 170 ° C. for about 7 to about 15 hours.

  In this reaction, an esterification reaction catalyst such as a tertiary amine such as N, N-dimethylaminoethanol, a quaternary ammonium salt such as tetraethylammonium bromide or tetrabutylammonium bromide can be used. An inert organic solvent may be used.

  As content in the mixture (I) of the said epoxy resin (C), the polymerizable unsaturated monomer (A) and other polymerizable unsaturated monomer (B) from the point of the weather resistance of a formed coating film, and corrosion resistance The epoxy resin (C) can be in the range of 3 to 60% by weight, preferably 5 to 50% by weight, based on the total weight.

  The mixture (I) is a resin such as an acrylic resin, a polyester resin, an alkyd resin, a polyorganosiloxane, or a urethane resin; an additive for coating materials such as an ultraviolet absorber, an ultraviolet stabilizer, and a metal dryer; Agents and the like.

  The mixture (I) may contain an emulsifier, if necessary, when finely dispersed in an aqueous medium. As the emulsifier, an anionic emulsifier and a nonionic emulsifier are suitable. Examples of the anionic emulsifier include sodium salts and ammonium salts such as alkylsulfonic acid, alkylbenzenesulfonic acid, and alkylphosphoric acid. Nonionic emulsifiers include, for example, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octyl Phenyl ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, sorbitan monolaurate, sorbitan monos Areto, sorbitan monostearate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, and the like.

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

  The emulsifier can be used in the range of 0.1 to 15% by weight, preferably 0.5 to 12% by weight, based on the total weight of the monomer (A) and monomer (B) used.

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

  The aqueous resin dispersion of the present invention can suppress diffusion from the finely dispersed particles in which the monomer (B) or the like is a polymerization field in the polymerization stage due to the above-described polymerizable unsaturated monomer (A) and the like. In general, the mixture (I) is generally used in miniemulsion polymerization such as a long-chain saturated hydrocarbon solvent such as hexadecane or a long-chain alcohol solvent such as hexadecanol as needed. A hydrophobic organic solvent may be blended.

  The mixture (I) described above is finely dispersed in an aqueous medium to form an emulsion (hereinafter sometimes referred to as “emulsion”) which is a particle dispersion containing the mixture (I). .

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

  The fine dispersion of the mixture (I) in the aqueous medium is not particularly limited as long as the average particle diameter of the emulsion can be within the above-mentioned range, but it has a high energy shearing ability. This can be done using a disperser. Examples of the disperser that can be used in this case include a high-pressure emulsifier, an ultrasonic emulsifier, a high-pressure colloid mill, and a high-pressure homogenizer. These dispersers can usually be operated under a high pressure of about 10 to 1000 MPa, preferably about 50 to 300 MPa. Further, the mixture may be pre-emulsified with a disper or the like in advance before being dispersed by the machine.

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

  The polymerization of the emulsion thus obtained is performed by, for example, charging the entire amount of the monomer emulsion after fine dispersion into a reactor equipped with a stirrer, adding a polymerization initiator, and heating with stirring according to the miniemulsion polymerization method. It can be carried out.

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

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

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

  In the aqueous resin dispersion obtained as described above, the average particle diameter of the dispersed resin particles can be 500 nm or less, particularly 80 to 400 nm, more particularly 100 to 300 nm.

Aqueous resin composition The aqueous resin composition of the present invention contains the aqueous resin dispersion described above.

  Moreover, the aqueous resin composition of this invention can contain a water-based epoxy resin (D) from the point which improves sclerosis | hardenability and corrosion resistance, maintaining the finishing property of a formed coating film.

  The water-based epoxy resin (D) is a resin obtained by making the epoxy resin (C) water-based, and in particular, the storage stability of the aqueous resin composition and the finish of the formed coating film among the epoxy resins (C). Therefore, it is desirable to use a modified epoxy resin, and it is desirable to use a fatty acid-modified epoxy resin obtained by reacting the epoxy group-containing resin (c1) with a fatty acid. The method of making the aqueous solution is not particularly limited. However, when the epoxy resin (C) has a carboxyl group, the epoxy resin (C) is mixed with an emulsifier and dispersed in an aqueous medium. And a method in which the carboxyl group is neutralized with a basic substance and then dispersed in an aqueous medium.

  When the water-based epoxy resin (D) is blended, the amount of the water-based epoxy resin dispersion (D) is 97 / 3-50 / 50, preferably 95 / 5-60 / solid-solid weight ratio. It is desirable to be within the range of 40.

  The aqueous resin composition of the present invention can further contain a hydrazine derivative (E).

  Specific examples of the hydrazine derivative (E) include saturated oxalic acid dihydrazide, malonic acid dihydrazide, glutaric acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide and the like. Carboxylic acid dihydrazides; monoolefinic unsaturated dicarboxylic acid dihydrazides such as maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide; phthalic acid dihydrazide, terephthalic acid dihydrazide or isophthalic acid dihydrazide, pyromellitic acid dihydrazide, trihydrazide or tetrahydrazide Nitrilotrihydrazide, citric acid trihydrazide, 1,2,4-benzenetrihydrazide, ethylenediaminetetraacetic acid tetrahydrazide, 1,4,5,8-naphtho Acid tetrahydrazide; polyhydrazide obtained by reacting a low polymer having a carboxylic acid lower alkyl ester group with hydrazine or hydrazine hydrate (hydrazine hydride); compound having hydrazide group such as carbonic acid dihydrazide; bissemicarbazide; hexamethylene diisocyanate Polyfunctional semicarbazide obtained by excessively reacting N, N-substituted hydrazine such as N, N-dimethylhydrazine or the above-mentioned hydrazide with a diisocyanate such as benzene or isophorone diisocyanate and a polyisocyanate compound derived therefrom; The dihydrazide exemplified above is added to an isocyanate group in a reaction product of a compound, a polyether, and an active hydrogen compound containing a hydrophilic group such as a polyol or a polyethylene glycol monoalkyl ether. Reacted obtained aqueous polyfunctional semicarbazide in linseed; compound having a semicarbazide group, such as a mixture of polyfunctional semicarbazide and aqueous polyfunctional semicarbazide, compounds and the like having a hydrazone group such as bis-acetyl-di hydrazone.

  By including the hydrazine derivative (E), the formed coating film is useful because it can adsorb and remove harmful substances in the air, such as formaldehyde, and reacts when the dispersion has a carbonyl group. It is also possible to act as a crosslinking agent.

  The amount of the hydrazine derivative (E) is generally 0.01 to 10% by weight, particularly preferably 0.1 to 5% by weight, based on the solid content of the aqueous resin dispersion.

  The aqueous resin composition preferably contains a metal dryer in order to accelerate the curing of the coating film. Examples of the metal dryer include salts of at least one metal selected from the group consisting of aluminum, calcium, cerium, cobalt, iron, lithium, magnesium, manganese, zinc, and zirconium with an acid. Examples include capric acid, caprylic acid, isodecanoic acid, linolenic acid, naphthenic acid, neodecanoic acid, octenoic acid, oleic acid, palmitic acid, resin acid, ricinoleic acid, soybean oil fatty acid, stearic acid, tall oil fatty acid and the like. . The use rate of the metal dryer is 0.1 to 10% by weight, preferably 0.5 to 7% by weight based on the resin solid content of the aqueous resin composition.

  In addition, when the aqueous resin dispersion has a crosslinkable functional group such as a hydroxyl group, the aqueous resin composition has a curing agent having a crosslinkable functional group capable of reacting with the functional group, such as an isocyanate-based curing agent and / or Or a melamine type hardening | curing agent etc. can be contained.

  In addition to the above components, the aqueous resin composition of the present invention comprises a water-soluble or emulsion-type acrylic resin, alkyd resin, silicone resin, fluororesin, urethane resin, polyester resin, amino resin, or other modified resin; It contains appropriate combinations of additives such as antifoaming agents, plasticizers, film-forming aids, organic solvents, thickeners, preservatives, fungicides, pH adjusters, curing catalysts, and surface adjusters. Can do.

  Thus, the above-mentioned aqueous resin composition is used for coatings such as automotive outer panels, automotive parts, automotive repairs, cans, PCMs, architectural coatings, printing inks, non-woven fabrics, etc. It can be used for various applications such as an agent, a filler, a molding material, and a resist.

Aqueous coating composition The aqueous coating composition of the present invention comprises the aqueous resin composition described above.

  When the aqueous resin composition is applied to an aqueous coating composition, it can be applied to either a clear coating or an enamel coating.

  When applied as an enamel paint, conventionally known color pigments, extender pigments, rust preventive pigments and the like can be blended as the pigment component.

  In the aqueous coating composition, pigment dispersant, surfactant, surface conditioner, plasticizer, anti-settling agent, antistatic agent, antibacterial agent, fragrance, ultraviolet absorber, ultraviolet stabilizer, curing catalyst, dispersant, Antifoaming agent, thickener, film-forming aid, preservative, antifungal agent, antifreezing agent, pH adjuster, flash last inhibitor, aldehyde scavenger, layered viscosity mineral, powdered or fine particle activated carbon, photocatalyst Additives such as low-contaminating agents such as titanium oxide and alkylene glycol-modified alkyl silicate can be appropriately selected and contained in combination.

  The present invention is a coating method characterized by coating the surface to be coated with the water-based coating composition.

  The surface to be coated is not particularly limited. Metals such as iron and aluminum; Organic base materials such as plastics; Base materials such as inorganic base materials such as concrete blocks, wood and stones; A coating film can be mentioned. Examples of the old coating film include acrylic resin, acrylic urethane resin, polyurethane resin, fluororesin, silicon acrylic resin, vinyl acetate resin, epoxy resin, alkyd resin, and the like. Further, these coated surfaces may be subjected to chemical conversion treatment, undercoating, intermediate coating, or the like. It is also possible to apply a known paint after applying the aqueous paint composition of the present invention.

  The aqueous coating composition can be applied using a conventionally known method such as roller, air spray, airless spray, lysine gun, universal gun, brush, electrostatic coating, or the like. Moreover, as a drying method, any of heat drying, forced drying, and normal temperature drying may be sufficient, and it can adjust suitably according to a composition. In this specification, the drying condition of less than 40 ° C. is normal temperature drying, the drying condition of 40 ° C. or more and less than 80 ° C. is forced drying, and the drying condition of 80 ° C. or more is heat drying.

  Hereinafter, the present invention will be described more specifically with reference to examples. “Parts” and “%” are “parts by weight” and “% by weight”.

Production of fatty acid-modified polymerizable unsaturated monomer Production Example 1
280 parts of safflower oil fatty acid and 142 parts of glycidyl methacrylate were placed in a reaction vessel and reacted with stirring at a reaction temperature of 140 ° C. until the acid value became 1 or less to obtain a fatty acid-modified polymerizable unsaturated monomer. Next, the temperature of the internal solution was set to 90 ° C., and 0.11 part of dibutyltin dilaurate was added and stirred. 111 parts of isophorone diisocyanate was dropped into the reaction vessel over 1 hour, and the NCO value was reacted to 1 or less to obtain a fatty acid-modified polymerizable unsaturated monomer (a-1) modified with urethane. The hydroxyl value of the monomer was less than 1.

Production Example 2
In a reaction vessel, 280 parts of soybean oil fatty acid and 142 parts of glycidyl methacrylate were allowed to react with stirring at a reaction temperature of 140 ° C. until the acid value became 1 or less to obtain a fatty acid-modified polymerizable unsaturated monomer. Next, the temperature of the internal solution was set to 90 ° C., and 0.10 parts of dibutyltin dilaurate was added and stirred. 84 parts of hexamethylene diisocyanate was added dropwise to the reaction vessel over 1 hour and reacted until the NCO value was 1 or less to obtain a fatty acid-modified polymerizable unsaturated monomer (a-2) modified with urethane. . The hydroxyl value of the monomer was less than 1.

Production Example 3
In a reaction vessel, 210 parts of coconut oil fatty acid and 142 parts of glycidyl methacrylate are stirred and reacted at a reaction temperature of 140 ° C. until the acid value becomes 1 or less, and a fatty acid-modified polymerizable unsaturated monomer having a hydroxyl value of 159 mgKOH / g ( a-3) was obtained.
Production Example 4
280 parts of soybean oil fatty acid and 142 parts of glycidyl methacrylate are placed in a reaction vessel and reacted with stirring at a reaction temperature of 140 ° C. until the acid value becomes 1 or less, and a fatty acid-modified polymerizable unsaturated monomer having a hydroxyl value of 133 mg KOH / g ( a-4) was obtained.

Production of fatty acid-modified epoxy resin Production Example 5
In a reaction vessel, put 598 parts of “Epicoat 828EL” (trade name, manufactured by Japan Epoxy Resin, bisphenol A type epoxy resin, epoxy equivalent 185), 905 parts of linseed oil fatty acid, 1.5 parts of tetraethylammonium bromide, and heated to 150 ° C. The mixture was heated and reacted until the acid value became 1 or less to obtain a fatty acid-modified epoxy resin (C-1).

Production of aqueous fatty acid-modified epoxy resin Production Example 6
300 parts of the fatty acid-modified epoxy resin (C-1) obtained in Production Example 5 and 12 parts of “Solpol 7425” (trade name, manufactured by Toho Chemical Co., Ltd., phosphate emulsifier) were mixed in a container. The mixture was dispersed while adding 355 parts of water to obtain an aqueous fatty acid-modified epoxy resin (D-1) having a solid content of 46% and an average particle size of 300 nm.

Production of aqueous resin dispersion Example 1
The following components are put in a container, stirred at 2000 rpm with a disper for 15 minutes to produce a preliminary emulsion, and then the preliminary emulsion is subjected to a high pressure treatment at 100 MPa in a high pressure emulsifier that collides the fluids by applying high pressure energy. As a result, a monomer emulsion having an average particle size of the dispersed particles of 170 nm was obtained.
Monomer emulsion composition Fatty acid-modified polymerizable unsaturated monomer (a-1) modified with urethane
30 parts n-butyl methacrylate 25 parts i-butyl methacrylate 27 parts 2-ethylhexyl acrylate 17 parts methacrylic acid 1 part “Newcol 707SF” (Note 1) 10 parts deionized water 85 parts The above monomer emulsion 546 parts is transferred to a flask and degassed. Diluted with 95 parts of ionic water. This was heated to 85 ° C. while stirring, and an initiator aqueous solution in which 1 part of ammonium persulfate was dissolved in 64.7 parts of deionized water was added to the flask and stirred for 3 hours while maintaining the temperature. Further, an initiator aqueous solution in which 0.25 parts of ammonium persulfate was dissolved in 16.2 parts of deionized water was added to the flask, stirred for 3 hours while maintaining the temperature, and then cooled to 40 ° C. The pH was adjusted to 8.0 with dimethylaminoethanol to obtain an aqueous resin dispersion (A-1) having a solid content concentration of 40% and an average particle diameter of the dispersion resin of 174 nm.
(Note 1) “Newcol 707SF”: trade name, manufactured by Nippon Emulsifier Co., Ltd., an anionic emulsifier having a polyoxyethylene chain, 30% active ingredient.

Examples 2-5 and Comparative Examples 1-3
Aqueous resin dispersions (A-2) to (A-8) were obtained in the same manner as in Example 1 except that the composition of the monomer emulsion and the average particle size were changed as shown in Table 1. About dispersion (A-8), there were very many filtration residues. The average particle size of the dispersion excluding the residue was 150 nm.

Production of aqueous resin composition Example 6
In a container, put 250 parts of 40% aqueous resin dispersion (A-1), 2.5 parts of “DICNATE 1000W” (Note 2) and 10 parts of “TEXNOL” (Note 3), and stir and mix to obtain an aqueous resin composition (B -1) was obtained.

Examples 7-11 and Comparative Examples 4-6
In the said Example 6, each aqueous resin composition (B-2)-(B-9) was obtained like the said Example 6 except a compounding composition being set to following Table 2.

Preparation of test coated plate Each aqueous resin composition was spray-coated on a steel plate to a dry film thickness of 40 µm, dried at 20 ° C for 1 week, and then subjected to each test. The results are shown in Table 2.

（注２）「ＤＩＣＮＡＴＥ１０００Ｗ」：商品名、大日本インキ社製、水性金属ドライヤー、Ｃｏ含有率３．６％
（注３）「ＴＥＸＮＯＬ」：商品名、イーストマンケミカル社製、２，２，４−トリメチル−１，３−ペンタンジオールモノイソブチレート、造膜助剤。

(Note 2) “DICnate 1000W”: trade name, manufactured by Dainippon Ink Co., Ltd., aqueous metal dryer, Co content 3.6%
(Note 3) “TEXNOL”: trade name, manufactured by Eastman Chemical Co., Ltd., 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, film-forming aid.

(* 1) Water resistance:
Each obtained test coating plate was immersed in a constant temperature water bath at room temperature of 20 ° C. for 7 days, and the state of the coating film was visually observed.
◎: No abnormality ○: Slightly blistered and discolored, but in good condition ○ △: Slightly bluffed and discolored, but practically no hindrance △: Swelled and discolored, difficult to use ×: Swelled and discolored remarkably ( * 2) Curability:
The free film was peeled off from each test coated plate obtained above, and the coating film cut to a size of 4 × 4 cm was immersed in acetone for 6 hours under reflux conditions. The coating film extraction residue is calculated from the coating film weight before and after extraction.
Paint film extraction residue (%) = (weight of film after extraction / weight of film before extraction) × 100 (%)
(* 3) Corrosion protection:
Each test coated plate was cross-cut with a knife so as to reach the substrate, and this was subjected to a salt spray resistance test for 240 hours in accordance with JISZ-2371. It was evaluated with.
○: The maximum width of rust and blisters is less than 2 mm from the cut part (one side)
Δ: The maximum width of rust and blisters is 2 mm or more and less than 3 mm (one side) from the cut part, and blisters are observed on the entire coating surface. ×: The maximum width of rust and blisters is 3 mm or more from the cut part and the coating surface Blistering is observed throughout (* 4) Finishing property Each test coated plate was visually evaluated.
○: Finishing property is very good, △: Finishing property is slightly good, ×: Finishing property is poor

Claims (10)

(A) A polymerizable unsaturated monomer containing fatty acid (a1), an epoxy group-containing polymerizable unsaturated monomer (a2) and an isocyanate compound (a3) as structural units, and (B) a monomer comprising other polymerizable unsaturated monomer A method for producing an aqueous resin dispersion, comprising: finely dispersing a mixture (I) containing components in an aqueous medium so as to have an average particle diameter of 500 nm or less, and polymerizing the resulting emulsion. The other polymerizable unsaturated monomer (B) is a polymerizable unsaturated monomer (b1) containing a linear or branched hydrocarbon group having 6 or more carbon atoms, a cycloalkyl group-containing polymerizable unsaturated monomer ( The production method according to claim 1, comprising at least one polymerizable unsaturated monomer selected from the group consisting of b2) and a carbonyl group-containing polymerizable unsaturated monomer (b3). The production method according to claim 1 or 2, wherein the mixture (I) further contains an epoxy resin (C). The aqueous resin dispersion obtained by the manufacturing method of any one of Claims 1 thru | or 3. An aqueous resin composition containing the aqueous resin dispersion according to claim 4. The aqueous resin composition according to claim 5, further comprising an aqueous epoxy resin (D). The aqueous resin composition according to claim 5 or 6, further comprising a hydrazine derivative (E). An aqueous coating composition containing the aqueous resin composition according to any one of claims 5 to 7. A method of forming a coating film, comprising applying the aqueous coating composition according to claim 8 to a surface to be coated. The coated article obtained by the coating-film formation method of Claim 9.