JP5226272B2 - Aqueous resin composition and aqueous coating composition containing the same - Google Patents

Description

  The present invention relates to an aqueous resin composition capable of forming a coating film excellent in water resistance and corrosion resistance, and an aqueous coating composition containing the same.

  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. . For example, 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. Of these, epoxy resins have been used for a wide range of applications because of their excellent adhesion to various materials. However, when making these epoxy resins water-based, emulsifiers are used, or hydrophilic groups in the resin skeleton are used. In all cases, these properties are sufficiently satisfactory for water-based paint applications, such as reduced corrosion resistance, water resistance, and adhesion to metal materials compared to solvent-based systems. The current situation is that nothing has been obtained.

  As a method for compensating for the deterioration of corrosion resistance and water resistance associated with the aqueousization of such an epoxy resin, for example, a method of introducing a phosphate group having good adhesion to a metal material into an epoxy resin skeleton has been proposed (for example, Patent Documents). 1, Patent Document 2, etc.). However, this method has a limitation that an alcohol solvent or the like cannot be used at the time of synthesis.

  Patent Document 3 proposes a method of using an aqueous epoxy ester resin obtained by modifying an epoxy ester obtained by reacting an unsaturated fatty acid with an epoxy resin with a monomer having a carboxyl group. Although this method shows an improvement in corrosion resistance, it is not sufficient in a field where high corrosion resistance is required.

  Patent Document 4 proposes to use a polyol resin composition obtained by adding a specific isocyanate compound having a polyether structure to an epoxy polyol resin. By using this composition, it is possible to provide a water-based paint that forms a coating film excellent in adhesion, water resistance, corrosion resistance, etc., but there is a problem that gelation tends to occur during the synthesis of the resin.

JP-A-5-14850 JP-A-4-298580 JP 2003-64302 A JP 2004-182867 A

  The objective of this invention is providing the water-based resin composition which can eliminate the said malfunction, and can form the coating film which has high corrosion resistance and water resistance, and the water-based coating composition containing this.

The present invention provides an epoxy prepolymer (I) having an amino group at a terminal obtained by a reaction between a polyepoxy compound (a) and an amine compound (b),
A compound (c) containing two or more hydroxyl groups in one molecule, a polyisocyanate compound (d), and a compound (e) containing two or more active hydrogen groups and containing a tertiary amino group in one molecule; An aqueous resin composition, wherein the polyurethane resin (III) obtained by the reaction with the urethane prepolymer (II) having an isocyanate group at the terminal obtained by the reaction of is dispersed in an aqueous medium, and The present invention relates to an aqueous coating composition containing the same.

  According to the aqueous resin composition of the present invention, a specific epoxy prepolymer and a urethane prepolymer are combined into a composite resin via a urea bond, so that the film formability and adhesion are excellent, and high corrosion resistance and water resistance are achieved. It becomes possible to form the coating film which has.

  In the present invention, the epoxy prepolymer (I) has an amino group at the terminal and is obtained by a reaction between the polyepoxy compound (a) and the amine compound (b).

  The polyepoxy compound (a) is a compound having two or more epoxy groups in one molecule, such as bisphenol A, bisphenol F, bisphenol S, hydrogenated bisphenol A, neopentyl glycol, 1,6-hexanediol, etc. Diglycidyl ethers of polyhydric alcohols; glycidyl ether type epoxy resins such as bisphenol A and bisphenol F, hydrogenated bisphenol A type epoxy resins, glycidyl ester type epoxy resins, alicyclic epoxy resins, polyglycol type epoxy resins; A modified epoxy resin obtained by modifying an epoxy resin with at least one modifier selected from alkylphenols and fatty acids; obtained by reacting an alkylphenol or an alkylphenol novolac resin with epichlorohydrin Epoxy group-introduced alkylphenol or alkylphenol novolak type resins; dibasic acid modified epoxy resins, and the like modified epoxy resin dibasic acid and a carboxyl group-containing phenol.

  The amine compound (b) is a compound having a primary amino group, for example, an aliphatic amine such as propylamine, isopropylamine, butylamine, amylamine, hexylamine, octylamine, decylamine, undecylamine, dodecylamine; Aromatic amines such as aniline, o-toluidine, m-toluidine, and p-toluidine; cycloaliphatic amines such as cyclobutylamine, cyclopentylamine, and cyclohexylamine; and methylaminopropylamine and the like. Can do.

  Further, as the amine compound (b), an alkanolamine can be used when a highly reactive active hydrogen group is left in the resin (III). Examples of the alkanolamine include monoethanolamine and monoisopropanolamine. N-methylethanolamine, N-ethylethanolamine, N-benzylethanolamine, diethanolamine, diisopropanolamine and the like can be used in combination with these as required.

  Furthermore, aminosilane can be used as the amine compound (b) from the viewpoint of improving the water resistance of the formed coating film. The aminosilane contains an amino group and an alkoxysilyl group in one molecule, and specific examples thereof include, for example, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldisilane. Examples include ethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) aminopropyltrimethoxysilane, and N-β- (aminoethyl) aminopropyltriethoxysilane.

  The production of the epoxy prepolymer (I) is not particularly limited, and a conventionally known method can be adopted, and it is usually performed by heating at 50 to 250 ° C. for 1 to 24 hours. The proportions of the components (a) and (b) can be variously changed, but the equivalent ratio of the epoxy group in the component (a) and the amino group in the component (b) is generally 1: 0.5 to 1 : 2, preferably 1: 0.5 to 1: 0.9.

  In the present invention, the urethane prepolymer (II) contains a compound (c) containing two or more hydroxyl groups in one molecule, a polyisocyanate compound (d) and two or more active hydrogen groups in one molecule, and 3 It is obtained by reaction with a compound (e) containing a secondary amino group.

  The compound (c) has two or more hydroxyl groups in one molecule, and examples thereof include low molecular weight glycols, high molecular weight glycols, polyester polyols, polycarbonate polyols and the like. For example, a low molecular weight glycol can be used in combination with a polyester polyol or a high molecular weight glycol.

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

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

  The said compound (c) can contain a bisphenol skeleton containing diol compound as at least one part of the component from the point of the corrosion-resistant improvement of a formation coating film.

  Examples of the bisphenol skeleton-containing diol compound include ethylene oxide and / or propylene oxide adducts of bisphenols. Examples of bisphenols include bisphenol A, bisphenol F, and bisphenol S.

  When the bisphenol skeleton-containing diol compound is used, the content in the compound (c) is 10 to 98% by weight, preferably 50 to 95% by weight.

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

  Compound (e) contains two or more active hydrogen groups in one molecule and contains a tertiary amino group. For example, a diol compound, a triol compound, a diamine compound and a triamine compound having a tertiary amino group These may be used alone or in combination of two or more.

  Examples of the diol compound having a tertiary amino group include N-methyldiethanolamine, N-ethyldiethanolamine, and N-isobutyldiethanolamine. Examples of the triol compound having a tertiary amino group include triethanolamine. . Examples of the diamine compound having a tertiary amino group include methyliminobispropylamine and butyliminobispropylamine. Examples of the triamine compound having a tertiary amino group include tri (2-aminoethyl) amine. Etc.

  In addition to the above (c), (d) and (e), a fatty acid ester (f) containing two or more active hydrogen groups in one molecule as necessary, as a raw material for producing the urethane prepolymer (II). From the viewpoint of improving the drying property, curability, water resistance and the like of the formed coating film.

  The fatty acid ester (f) usually has a structural unit derived from a fatty acid via an ester bond, and there is no particular limitation from low molecular weight to high molecular weight, and the use of the aqueous resin composition of the present invention It is possible to select appropriately according to, for example.

  For example, glycerin monofatty acid ester can be used as the fatty acid ester (f). Examples of the glycerin monofatty acid ester include glycerin monolaurate, glycerin monooleate, and glycerin monostearate, and further esterification reaction between glycerin and a fatty acid having 10 or more carbon atoms, and transesterification reaction between fats and oils and glycerin. And the like obtained by the above. Moreover, the reaction product of a glycidol and a fatty acid may be sufficient. The glycerin monofatty acid ester is a weather resistant, anticorrosive, water resistant, such as an undercoat paint applied to a building exterior top coat or a metal building material, or a one coat finish paint applied to a metal surface. When used in applications requiring quick drying properties, finish properties, etc., it can be suitably selected as the fatty acid ester (f).

  Examples of the fatty acid include those having a structure in which a carboxyl group is bonded to the end of a hydrocarbon chain, and examples include dry oil fatty acids, semi-dry oil fatty acids, and non-dry oil fatty acids. Dry oil fatty acids and semi-dry oil fatty acids are not strictly distinguishable. Usually, dry oil fatty acids are unsaturated fatty acids having an iodine value of 130 or more, and semi-dry oil fatty acids have an iodine value of 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 semi-dry 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.

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

  As the fatty acid ester (f), a reaction product of an epoxy resin containing two or more epoxy groups in one molecule and a fatty acid can be used. The reaction product of the epoxy resin and fatty acid has a secondary hydroxyl group, and the aqueous resin composition of the present invention is applied to an undercoat paint applied to a building exterior top coat, a metal building material, or other metal surfaces. When used in applications that require weather resistance, corrosion resistance, water resistance, quick-drying, finish, etc., such as a one-coat finish paint, it can be suitably selected as the fatty acid ester (f). In particular, when a bisphenol A glycidyl ether type epoxy resin is used as an epoxy resin, it is suitable for use as an undercoat paint requiring high corrosion resistance.

  Examples of the epoxy resin include glycidyl ether type epoxy resins such as bisphenol A and bisphenol F, hydrogenated bisphenol A type epoxy resins, glycidyl ester type epoxy resins, alicyclic epoxy resins, and polyglycol type epoxy resins; Modified epoxy resin obtained by modifying a resin with at least one modifier selected from alkylphenol and fatty acid; epoxy group-introduced alkylphenol or alkylphenol novolak resin obtained by reacting alkylphenol or alkylphenol novolac resin with epichlorohydrin; dibasic acid Examples thereof include a modified epoxy resin, an epoxy resin modified with a dibasic acid and a carboxyl group-containing phenol.

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

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

  As the fatty acid ester (f), a reaction product of a compound containing two or more carboxyl groups in one molecule and a monoepoxy compound containing a long-chain hydrocarbon group can be used. The reaction product has a secondary hydroxyl group, and when the aqueous resin composition of the present invention is used in applications where water resistance, finish, etc. are required, such as a one-coat finish paint applied to a metal surface, It can be suitably selected as the fatty acid ester (f).

  Examples of the compound containing two or more carboxyl groups in one molecule include 1,4-butanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, and naphthalene. Dicarboxylic acid, 4,4-diphenyldicarboxylic acid, diphenylmethane-4,4′-dicarboxylic acid, het acid, maleic acid, fumaric acid, itaconic acid, trimellitic acid, pyromellitic acid, cyclohexane-1,3-dicarboxylic acid, Polyvalent carboxylic acids such as cyclohexane-1,4-dicarboxylic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, tetrahydrophthalic acid, hexahydrotrimellitic acid, methylhexahydrophthalic acid, malic acid and citric acid Acids and their acid anhydrides, which are German, or two or more in combination can be used.

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

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

  As the fatty acid ester (f), a reaction product of a cyclic carbonate compound and a fatty acid amine can be used. Since the reaction product has a urethane bond, it has excellent hydrolyzability during storage and can be suitably selected as the fatty acid ester (f).

  The cyclic carbonate compound contains at least one cyclic carbonate group per molecule and is usually a compound containing a 5- or 6-membered cyclic carbonate group. Examples of the 5-membered cyclic carbonate include glycerin carbonate (1,3-dioxolan-2-one-4-methanol), 1,3-dioxolan-2-one-4-propanol, 1,3-dioxolan-2-one- Reaction product of polyhydric alcohol such as butanol and 1,3-dioxolan-2-one-pentanol and carbonate; ethylene carbonate, propylene carbonate; diglycidyl ether and bisphenol type epoxy of phenols such as bisphenol A and bisphenol F Examples include a reaction product of a resin and carbon dioxide gas. 6-membered cyclic carbonates are (1,3-dioxolan-2-one) -2methyl, 2-ethylpropanol, (1,3-dioxolan-2-one) -2,2 diethylpropanol, (1,3 dioxolane) -2-one) -2,2 dimethylpropanol and the like. Of these, glycerin carbonate can be suitably used from the viewpoint of ease of synthesis. As the cyclic carbonate compound, those having a bisphenol skeleton can be suitably used from the viewpoint of improving the corrosion resistance of the formed coating film.

  Fatty acid amines contain an amino group and a fatty acid residue in one molecule. For example, oleic acid, linoleic acid, stearic acid, palmitic acid, myristic acid, beef tallow, fish oil, coconut oil, soybean oil, olive oil, linseed Examples are obtained by amine-modifying at least one selected from oil, cottonseed oil, rapeseed oil, and hardened oil obtained by hydrogenating these oils and fats using alkylene diamine such as ethylene diamine, polyoxyalkylene diamine, etc. it can. Among these, those derived from unsaturated fatty acids can be preferably used from the viewpoint of the drying property and curability of the formed coating film.

  The cyclic carbonate compound and the fatty acid amine have a molar ratio of the cyclic carbonate group in the cyclic carbonate compound to the amino group in the fatty acid amine of 1: 0.8 to 1: 1.2, preferably 1: 0. It is desirable to make it react so that it may become the range of 95-1: 1.05. This reaction is usually performed at a temperature of 25 to 250 ° C, preferably 50 to 160 ° C.

  Production of the urethane prepolymer (II) is not particularly limited, and a conventionally known method can be employed. For example, the components (c), (d), and (e) described above (component (f) as necessary) May be reacted at once, or may be reacted in multiple stages. The proportions of the components (c), (d) and (e) (component (f) if necessary) can be varied, but the equivalent ratio of isocyanate groups to active hydrogen groups in all components is generally It is desirable that the ratio is 1: 0.9 to 1: 0.5, preferably 1: 0.9 to 1: 0.7. 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, amine catalysts such as triethylamine, N-ethylmorpholine, and triethylenediamine used in ordinary urethanization reactions and tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate are used as necessary. It may be used.

  In the aqueous resin composition of the present invention, the polyurethane resin (III) obtained by the reaction between the epoxy prepolymer (I) and the urethane prepolymer (II) is dispersed in water in an aqueous medium.

  The reaction between the epoxy prepolymer (I) and the urethane prepolymer (II) is not particularly limited, and a conventionally known method can be adopted. Usually, the reaction is performed by heating at 20 to 80 ° C. for 0.1 to 10 hours. Is called. The ratio of both can be varied, but the equivalent ratio of the amino group in the epoxy prepolymer (I) to the isocyanate group in the urethane prepolymer (II) is 0.01: 1 to 0.9: 1, It is desirable to select it so that it is preferably 0.2: 1 to 0.8: 1. Here, the amino group subjected to the reaction with the isocyanate group is naturally a primary and secondary amino group having active hydrogen.

  The polyurethane resin (III) obtained as described above is dispersed in an aqueous medium. Examples of the aqueous medium include water or a water-organic solvent mixed solution obtained by dissolving water or an organic solvent such as a water-soluble organic solvent. Water dispersion can be carried out by a conventionally known method without any particular limitation. In particular, a part or all of the tertiary amino group in the polyurethane resin (III) is neutralized with an acid or quaternized with a quaternizing agent. Can be done.

  Examples of the acid used for the neutralization include formic acid, acetic acid, lactic acid, and phosphoric acid. These acids may be neutralized with tertiary amino groups in addition to polyurethane resin (III), or may be neutralized simultaneously with dispersion by adding to water as a dispersion medium.

  Examples of the quaternizing agent include epoxy compounds such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide and epichlorohydrin, sulfates such as dimethyl sulfate, diethyl sulfate and methyl paratoluenesulfonate, methyl chloride, and ethyl. Examples thereof include alkyl halides such as chloride, benzyl chloride, methyl bromide, and ethyl bromide.

  In the present invention, as described above, part or all of the tertiary amino group in the polyurethane resin (III) is neutralized with an acid or quaternized with a quaternizing agent, and then emulsified and dispersed in water. The chain extension reaction with an aqueous medium may be partially allowed to proceed simultaneously with the dispersion, and then the chain extension reaction may be further performed with a chain extender to increase the molecular weight. Examples of the chain extender include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, and 3,3′-. Diamines such as dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, polyoxyethylenediamine, polyoxypropylenediamine, amine-terminated polyoxyethylene-polyoxypropylene copolymer; diethylenetriamine, dipropylenetriamine, tri Polyamines such as ethylenetetramine and tetraethylenepentamine; hydroxyethylhydrazine, hydroxyethyldiethylenetriamine, 2-[(2-aminoethyl) amino] ethanol, 3-aminopropanedio Compounds having an amino group and a hydroxyl group, such as Le; hydrazines, acid hydrazides, and the like. These may be used singly or in combination.

  The polyurethane resin (III) has an amine value of 10 to 100 mgKOH / g, preferably 10 to 90 mgKOH / g, and a hydroxyl value of 20 to 200 mgKOH / g, preferably 30 to 150 mgKOH / g. From the viewpoints of properties and corrosion resistance.

  The aqueous resin composition of the present invention contains the polyurethane resin (III), and may further contain other water-soluble or water-dispersible resins and curing agents as necessary. Examples of other water-soluble or water-dispersible resins include acrylic resins, alkyd resins, silicon resins, fluorine resins, epoxy resins, urethane resins, and polyester resins. The curing agent can be used without particular limitation as long as it reacts with the crosslinkable functional group in the polyurethane resin (III). For example, (block) polyisocyanate, melamine resin, polyepoxy compound, phenol resin, urea resin, Guanamin resin and the like can be suitably used.

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

  The present invention also provides an aqueous coating composition comprising the above aqueous resin composition. The aqueous paint composition can be used as a clear paint or as an enamel paint. When used as an enamel paint, a color pigment, a luster pigment, an extender pigment, a rust preventive pigment and the like known in the paint field can be blended as a pigment component.

  The aqueous coating composition may further contain additives such as a pigment dispersant, a surfactant, and a flash last inhibitor, if necessary, alone or in combination of two or more.

The aqueous coating composition of the present invention can be applied to a surface to be coated by a method such as air spray coating, airless spray coating, electrostatic coating, brush coating, roller coating, lysing gun, or universal gun.
The coated surface to which the water-based coating composition can be applied is not particularly limited, and examples thereof include metals such as iron and aluminum; inorganic base materials such as concrete, mortar, slate plate, wood and stone; plastics and the like Examples thereof include a substrate surface such as an organic substrate and a surface-treated surface thereof, and a metal surface and a surface-treated surface thereof are particularly suitable. The water-based coating composition of the present invention can be applied to these coated surfaces as an undercoat, and a known topcoat can be further applied as necessary.

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

Example 1
Preparation of epoxy prepolymer (I-1) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, in which a bisphenol A type epoxy resin (180 g) having an epoxy equivalent of 450 g / eq, It melt | dissolves in propylene glycol monopropyl ether (49.6g), 2-aminoethanol (18.3g) is added to this, and it hold | maintains at 85 degreeC for 3 hours, and epoxy group and amino group content (Note 1) is 1. The reaction was continued until it reached about 5 to 1.55 mmol / g. Thereafter, methyl ethyl ketone (148.7 g) was added to obtain an epoxy prepolymer (I-1) solution. The resulting epoxy prepolymer (I-1) solution had a solid concentration of 50%.

(Note 1) Epoxy group and amino group content: Followed by the following measurement method.
The sample (g) is weighed in an Erlenmeyer flask, and 40 ml of methyl ethyl ketone is added to dissolve it. If difficult to dissolve, heat to 50 ° C to dissolve. Next, 10 ml of CTAB (cetyltrimethylammonium bromide) solution is added with a total pipette to make it uniform. Subsequently, 0.2 ml of screen indicator is accurately added, titrated with an N / 10 perchloric acid-acetic acid solution, and the end point is reached when pink lasts for about 30 seconds with the last drop. Calculated from the following calculated values. The CTAB solution was dissolved by adding 200 ml of acetic acid to 20 g of CTAB, and further adjusted to a uniform solution by adding 200 ml of methyl ethyl ketone. Was prepared by mixing a solution prepared by dissolving the solution in 500 ml of methanol.
Calculation formula: E = (AB) × 0.1 × F / ( S × 0.01 × W )
Where E: epoxy group and amino group content (mmol / g)
A: Amount of N / 10 perchloric acid-acetic acid solution used in this test (ml)
B: Amount of N / 10 perchloric acid-acetic acid solution used in the blank test (ml)
Factor of F: N / 10 perchloric acid-acetic acid solution
S: Sample heating residue (%)
W: Sample amount

Preparation of urethane prepolymer (II-1) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which “Bisol 3PN” (Note 2) (203.2 g), “Bisol 6PN "(Note 3) (292.8 g) and methyldiethanolamine (59.8 g) were dissolved in N-methylpyrrolidone (149.5 g), and hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes. The reaction was carried out at ° C for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 32-36. Thereafter, methyl ethyl ketone (461.3 g) was added to obtain a urethane prepolymer (II-1) solution. The solid content concentration of the obtained urethane prepolymer (II-1) solution was 60.0%, and the amine value of the prepolymer was 30.7 mgKOH / g.

(Note 2) Bisol 3PN: manufactured by Toho Chemical Co., Ltd., propylene oxide modified bisphenol A (propylene oxide modified amount = 3 mol)
(Note 3) Bisol 6PN: manufactured by Toho Chemical Co., Ltd., propylene oxide modified bisphenol A (propylene oxide modified amount = 6 mol)
(Note 4) NCO value: The amount of isocyanate group contained in 1 g of urethane prepolymer was converted to the weight of isocyanate (mg), and was tracked by the following measuring method. In addition, when a tertiary amino group containing compound is included in a manufacturing raw material, the quantity of the tertiary amino group is also converted and contained in the weight of isocyanate.
Sample (g) is correctly weighed into an Erlenmeyer flask, 10 ml of dioxane is added, the dissolved sample is heated to 50 ° C., 10 ml of N / 5 dibutylamine-dioxane solution that has been correctly weighed is added, and the mixture is stirred for 2 minutes. React butylamine. Next, add 2 to 3 drops of bromophenol blue-ethyl alcohol solution and titrate with N / 10 hydrochloric acid solution, and the end point is when the color changes from blue to yellowish green.
Formula N = {0.1 × 42 × (AB) × f} / { 0.01 × S × W} + C
Here, N: NCO value (mg of NCO contained in 1 g of sample)
A: Used to neutralize blank N / 5 dibutylamine-dioxane solution
Amount of N / 10 hydrochloric acid solution (ml)
B: Amount of N / 10 hydrochloric acid solution used for titration of sample (ml)
f: Factor of N / 10 hydrochloric acid solution
S: Sample heating residue (%)
W: Amount of sample (g)
42: Molecular weight of NCO
C: The amount (mol) of the tertiary amino group contained in the sample is the weight of the isocyanate.
Calculated with the following formula using the converted value (mg)
Formula C = {D / M × 42 × 1000} / E
Where D: blended during urethane prepolymer synthesis
Weight of tertiary amino group-containing monomer
M: Blended during urethane prepolymer synthesis
Molecular weight of tertiary amino group-containing monomer
E: Weight of all blended monomers

Preparation of aqueous polyurethane resin dispersion (III-1) Using a device similar to the above, a 60.0% urethane prepolymer (II-1) solution (1526 g) was kept at 50 ° C. in a stirred state. A 50% epoxy prepolymer (I-1) solution (753.6 g) was added and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% phosphoric acid aqueous solution (25.4 g), deionized water (2401.3 g) was added and dispersed, and then the temperature was raised to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-1) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 83.1 mgKOH / g.

Example 2
Preparation of epoxy prepolymer (I-2) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, in which a bisphenol A type epoxy resin (660 g) having an epoxy equivalent of 825 g / eq, Dissolved in propylene glycol monopropyl ether (174.2 g), 2-aminoethanol (36.6 g) was added thereto, and the mixture was kept at 85 ° C. for 3 hours. The epoxy group and amino group contents (Note 1) were 0. The reaction was continued until it reached about 86 to 0.865 mmol / g. Thereafter, methyl ethyl ketone (522.5 g) was added to obtain an epoxy prepolymer (I-2) solution. The solid content concentration of the obtained epoxy prepolymer (I-2) solution was 50%.

Preparation of urethane prepolymer (II-2) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which “Bisol 3PN” (Note 2) (177.8 g), “Bisol 6PN "(Note 3) (256.2 g) and methyldiethanolamine (74.9 g) were dissolved in N-methylpyrrolidone (140.1 g), and hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes. The reaction was carried out at ° C for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 33-40. Thereafter, methyl ethyl ketone (439.4 g) was added to obtain a urethane prepolymer (II-2) solution. The resulting urethane prepolymer (II-2) solution had a solid content concentration of 60.0%, and the amine value of the prepolymer was 40.6 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-2) Using a device similar to the above, a 60.0% urethane prepolymer (II-2) solution (1449.0 g) was kept at 50 ° C. with stirring, A 50% epoxy prepolymer (I-2) solution (1323.5 g) was added thereto and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% aqueous phosphoric acid (30.1 g), dispersed with deionized water (2843 g), then heated to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-2) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 88.1 mgKOH / g.

Example 3
Preparation of epoxy prepolymer (I-3) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, in which an epoxy equivalent of 1450 g / eq of bisphenol A type epoxy resin (696.0 g) Is dissolved in propylene glycol monopropyl ether (179.5 g), 2-aminoethanol (22.0 g) is added thereto, and the mixture is held at 85 ° C. for 3 hours. The epoxy group and amino group contents (Note 1) are It was made to react until it was set to about 0.50-0.505 mmol / g. Thereafter, methyl ethyl ketone (538.5 g) was added to obtain an epoxy prepolymer (I-3) solution. The resulting epoxy prepolymer (I-3) solution had a solid concentration of 50%.

Preparation of urethane prepolymer (II-3) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which "Bisol 3PN" (Note 2) (135.4g), "Bisol 6PN "(Note 3) (195.1 g), methyldiethanolamine (100.3 g) was dissolved in N-methylpyrrolidone (124.5 g), and hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes. The reaction was carried out at ° C for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 37-45. Thereafter, methyl ethyl ketone (403.0 g) was added to obtain a urethane prepolymer (II-3) solution. The solid content concentration of the obtained urethane prepolymer (II-3) solution was 60.0%, and the amine value of the prepolymer was 59.7 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-3) Using a device similar to the above, a 60.0% urethane prepolymer (II-3) solution (1318.7 g) was kept at 50 ° C. with stirring, A 50% epoxy prepolymer (I-3) solution (2273.5 g) was added thereto and stirred for 1 hour. The mixture was then cooled to 40 ° C., neutralized with 89% aqueous phosphoric acid (37.9 g), deionized water (3580 g) was added and dispersed, and then the temperature was raised to 70 ° C. and held for 1 hour. Then, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-3) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 93.7 mgKOH / g.

Example 4
Preparation of epoxy prepolymer (I-4) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, and an epoxy equivalent of 450 g / eq of bisphenol A type epoxy resin (180.0 g) Is dissolved in propylene glycol monopropyl ether (82.1 g), and 3-aminopropyltriethoxysilane (66.4 g) is added thereto, and the mixture is held at 85 ° C. for 3 hours to obtain an epoxy group and amino group content (Note The reaction was continued until 1) was about 1.21 to 1.22 mmol / g. Thereafter, methyl ethyl ketone (164.3 g) was added to obtain an epoxy prepolymer (I-4) solution. The resulting epoxy prepolymer (I-4) solution had a solid content of 50%.

Preparation of urethane prepolymer (II-4) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which "Bisol 3PN" (Note 2) (195.0 g), "Bisol 6PN "(Note 3) (281.0 g) and methyldiethanolamine (64.7 g) were dissolved in N-methylpyrrolidone (146.5 g), and hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes. The reaction was carried out at ° C for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 33-40. Thereafter, methyl ethyl ketone (454.3 g) was added to obtain a urethane prepolymer (II-4) solution. The solid content concentration of the obtained urethane prepolymer (II-4) solution was 60.0%, and the amine value of the prepolymer was 33.8 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-4) Using a device similar to the above, a 60.0% urethane prepolymer (II-4) solution (1501.8 g) was kept at 50 ° C. in a stirred state. A 50% epoxy prepolymer (I-4) solution (936.3 g) was added thereto, and the mixture was stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% aqueous phosphoric acid (26.9 g), deionized water (2542.9 g) was added and dispersed, and then the temperature was raised to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-4) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 55.1 mgKOH / g.

Example 5
Preparation of urethane prepolymer (II-5) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, in which polycarbonate diol (261.4 g) having a number average molecular weight of 500, fatty acid monoglyceride ( Riken Vitamin, Emergy MU) (185.1 g) and methyldiethanolamine (56.5 g) were dissolved in N-methylpyrrolidone (139.0 g), and hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes. The reaction was carried out at 60 ° C. for 1.5 hours. Thereafter, the temperature was raised to 80 ° C., and the reaction was carried out for 2 hours. Isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 33-41. Thereafter, methyl ethyl ketone (436.7 g) was added to obtain a urethane prepolymer (II-5) solution. The solid content concentration of the obtained urethane prepolymer (II-5) solution was 60.0%, and the amine value of the prepolymer was 30.8 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-5) Using a device similar to the above, a 60.0% urethane prepolymer (II-5) solution (1439 g) was kept at 50 ° C. with stirring, A 50% epoxy prepolymer (I-1) solution (753.6 g) was added and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% aqueous phosphoric acid solution (24.4 g), deionized water (2303.4 g) was added and dispersed, and then the temperature was raised to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-5) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 86.6 mgKOH / g.

Example 6
Preparation of urethane prepolymer (II-6) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, and "Amine SB" (soy alkylamine, manufactured by NOF Corporation) (264 g) ), Glycerin carbonate (118 g) was added, and the mixture was stirred at 100 ° C. for 1 hour. After confirming that the amine value was 1 or less, fatty acid amine-modified glycerin carbonate was obtained.

  Another apparatus similar to the above was used, in which the fatty acid amine-modified glycerol carbonate (198.5 g), polycarbonate diol (259.8 g) having a molecular weight of 500, and methyldiethanolamine (57.3 g) were mixed with N-methylpyrrolidone (141 0.5 g), hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes, and the reaction was carried out at 60 ° C. for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 32-40. Thereafter, methyl ethyl ketone (442.6 g) was added to obtain a urethane prepolymer (II-6) solution. The solid content concentration of the obtained urethane prepolymer (II-6) solution was 60.0%, and the amine value of the prepolymer was 30.8 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-6) Using a device similar to the above, a 60.0% urethane prepolymer (II-6) solution (1460 g) was kept at 50 ° C. with stirring, A 50% epoxy prepolymer (I-1) solution (753.6 g) was added and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% aqueous phosphoric acid solution (24.6 g), dispersed by adding deionized water (2326.8 g), then heated to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-6) of a polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 85.8 mgKOH / g.

Example 7
Preparation of urethane prepolymer (II-7) A four-necked flask equipped with a thermometer, a stirrer and a reflux condenser was replaced with nitrogen, and bisphenol A type epoxy resin (375 g) having an epoxy equivalent of 187 g / eq, Soybean oil fatty acid (560 g) and tetrabutylammonium bromide (0.075 g) were added and stirred at 140 ° C. for 5 hours. After confirming that the acid value was 1 or less, soybean oil fatty acid-modified epoxy resin was obtained.

  Using another apparatus similar to the above, soybean oil fatty acid modified epoxy resin (431.7 g), polycarbonate diol (230.9 g) having a molecular weight of 500, and methyldiethanolamine (71.1 g) were mixed with N-methylpyrrolidone ( 185.1 g), hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes, and the reaction was performed at 60 ° C. for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 25 to 33. Thereafter, methyl ethyl ketone (544.3 g) was added to obtain a urethane prepolymer (II-7) solution. The solid content concentration of the obtained urethane prepolymer (II-7) solution was 60.0%, and the amine value of the prepolymer was 30.6 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-7) Using a device similar to the above, a 60.0% urethane prepolymer (II-7) solution (1823.5 g) was kept at 50 ° C. with stirring. A 50% epoxy prepolymer (I-1) solution (753.6 g) was added to the solution and stirred for 1 hour. Subsequently, the mixture was cooled to 40 ° C., neutralized with 89% aqueous phosphoric acid (28.9 g), dispersed by adding deionized water (2731.7 g), then heated to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-7) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 73.0 mgKOH / g.

Example 8
Preparation of urethane prepolymer (II-8) A four-necked flask equipped with a thermometer, stirrer, and reflux condenser was replaced with nitrogen, and neodecanoic acid glycidyl ester (456 g) and adipic acid (146 g) were added to tetrabutyl. Ammonium bromide (0.09 g) was added and stirred at 140 ° C. for 5 hours. It was confirmed that the acid value was 1 or less, and adipic acid-modified neodecanoic acid glycidyl ester was obtained.

  Using another apparatus similar to the above, the above-mentioned adipic acid-modified neodecanoic acid glycidyl ester (298.0 g), molecular weight 500 polycarbonate diol (247.5 g) and methyldiethanolamine (63.2 g) were mixed with N-methylpyrrolidone. (160.1 g), hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes, and the reaction was carried out at 60 ° C. for 1.5 hours. Thereafter, the temperature was raised to 80 ° C., and the reaction was carried out for 2 hours. Isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 29 to 37. Thereafter, methyl ethyl ketone (486.0 g) was added to obtain a urethane prepolymer (II-8) solution. The solid content concentration of the obtained urethane prepolymer (II-8) solution was 60.0%, and the amine value of the prepolymer was 30.7 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-8) Using a device similar to the above, a 60.0% urethane prepolymer (II-8) solution (1615 g) was kept at 50 ° C. with stirring, A 50% epoxy prepolymer (I-1) solution (753.6 g) was added and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% aqueous phosphoric acid (26.4 g), deionized water (2499.5 g) was added and dispersed, and then the temperature was raised to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-8) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 79.8 mgKOH / g.

Example 9
Preparation of urethane prepolymer (II-9) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which "Bisol 3PN" (Note 2) (203.0 g), "Bisol 6PN "(Note 3) (292.5 g), methyldiethanolamine (56.1 g) and triethanolamine (4.7) were dissolved in N-methylpyrrolidone (148.7 g), and hexamethylene diisocyanate (191.7 g). Was added dropwise over 30 minutes and reacted at 60 ° C. for 1.5 hours. Thereafter, the temperature was raised to 80 ° C., and the reaction was carried out for 2 hours. Isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 32-39. Thereafter, methyl ethyl ketone (462.5 g) was added to obtain a urethane prepolymer (II-9) solution. The solid content concentration of the obtained urethane prepolymer (II-9) solution was 60.0%, and the amine value of the prepolymer was 30.8 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-9) Using a device similar to the above, a 60.0% urethane prepolymer (II-9) solution (1528 g) was kept at 50 ° C. with stirring, A 50% epoxy prepolymer (I-1) solution (753.6 g) was added and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% phosphoric acid aqueous solution (24.3 g), dispersed by adding deionized water (2402.4 g), then heated to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-9) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 83.1 mgKOH / g.

Example 10
Preparation of urethane prepolymer (II-10) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which "Bisol 3PN" (Note 2) (243.7g), "Bisol 6PN "(Note 3) (351.2 g) and methyldiethanolamine (35.5 g) were dissolved in N-methylpyrrolidone (164.5 g), and hexamethylene diisocyanate (191.7 g) was added dropwise over 30 minutes. The reaction was carried out at ° C for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (168.7 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 28 to 36. Thereafter, methyl ethyl ketone (496.2 g) was added to obtain a urethane prepolymer (II-10) solution. The solid content concentration of the obtained urethane prepolymer (II-10) solution was 60.0%, and the amine value of the prepolymer was 16.9 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (III-10) Using a device similar to the above, a 60.0% urethane prepolymer (II-10) solution (1651.6 g) was kept at 50 ° C. with stirring, A 50% epoxy prepolymer (I-1) solution (753.6 g) was added to the solution and stirred for 1 hour. Subsequently, it cooled to 40 degreeC, dimethyl sulfuric acid (70.6g) was added, and reaction was performed for 1 hour. Thereafter, deionized water (2540.1 g) was added and dispersed, and the temperature was raised to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-10) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, and the hydroxyl value of the polyurethane resin was 78.6 mgKOH / g.

Comparative Example 1
A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which “Bisol 3PN” (Note 2) (269.8 g), “Bisol 6PN” (Note 3) (388.8 g) ) And methyldiethanolamine (77.2 g) were charged and stirred uniformly, and then hexamethylene diisocyanate (252.0 g) was added dropwise over 30 minutes, followed by reaction at 60 ° C. for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours. After adding methyl ethyl ketone (518.5 g) and dissolving, isophorone diisocyanate (222.0 g) was added and the NCO value (Note 4) was further increased at 80 ° C. for 3 hours. It was made to react until it became about 10-15, and the urethane prepolymer solution was obtained. Next, the mixture was cooled to 40 ° C., neutralized with 89% phosphoric acid (23.8 g), dispersed with deionized water (2246.8 g), heated to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (III-11) of polyurethane resin. The solid content concentration of this aqueous dispersion was 35.0%, and the amine value of the polyurethane resin was 30 mgKOH / g.

Production of Aqueous Resin Composition An aqueous resin composition shown in Table 1 below was obtained from the aqueous dispersion of each polyurethane resin obtained above. Each aqueous resin composition was subjected to the following performance test and evaluated. The results are shown in Table 1.
(Note 5) “DICnate 1000W”: manufactured by Dainippon Ink, trade name, metal dryer, Co content 3.6%

Evaluation test method (* 1) Water resistance: Each composition is spray-coated on a steel plate so that the dry film thickness is 25 μm, and dried and heated under the drying conditions described in Table 1 to prepare each test plate. did. The obtained test plate was immersed in a constant temperature water bath at 20 ° C. for 7 days, and the state of the coating film was visually observed.

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

  (* 2) Solvent extraction residue: Each composition was coated on a glass plate with a doctor blade to a dry film thickness of 25 μm, dried and heated under the drying conditions described in Table 1, and then the glass plate The dried film was peeled off and cut into a size of 4 × 4 cm to obtain a test piece. The obtained test piece was immersed in acetone for 6 hours under reflux conditions. The solvent extraction residue was calculated as follows from the coating weight before and after extraction.

  Solvent extraction residue (%) = (weight of membrane after extraction / weight of membrane before extraction) × 100 (%)

  (* 3) Corrosion resistance: Each test plate was prepared in the same manner as the water resistance (* 1), and the obtained test plate was cross-cut with a knife so as to reach the substrate, and this was applied to JIS Z-2371. In accordance with the above, a salt water spray test was conducted for 720 hours, and evaluation was made according to the following criteria based on rust and blister width from knife scratches.

A: Maximum width of rust and blisters is less than 1 mm from the cut part (one side)
○: The maximum width of rust and blisters is 1 mm or more and less than 2 mm from the cut part (one side)
Δ: The maximum width of the rust swelling is 2 mm or more and less than 3 mm (one side) from the cut portion, or blisters are observed on the entire coating surface. ×: The maximum width of rust and swelling is 3 mm or more from the cutting portion on the entire coating surface. Indicates that blistering is observed.

Claims (9)

Epoxy prepolymer (I) having an amino group at the terminal obtained by reaction of polyepoxy compound (a) with amine compound (b) which is an aminosilane having a primary amino group, and two or more hydroxyl groups in one molecule Isocyanate group at the terminal obtained by reaction with compound (c), polyisocyanate compound (d), and compound (e) containing two or more active hydrogen groups in one molecule and containing a tertiary amino group An aqueous resin composition, wherein the polyurethane resin (III) obtained by the reaction with the urethane prepolymer (II) having water is dispersed in water in an aqueous medium. Epoxy prepolymer (I) is a polyepoxy compound (a) an epoxy group and the amine compound in (b) the equivalent ratio of primary amino groups in the 1: 0.5 to 1: is reacted 2 become so The aqueous resin composition according to claim 1 obtained by The aqueous resin composition according to claim 1, wherein the compound (c) comprises a bisphenol skeleton-containing diol compound as at least a part of its components. The aqueous resin composition according to claim 1, wherein the compound (e) is at least one selected from the group consisting of a diol compound having a tertiary amino group, a triol compound, a diamine compound and a triamine compound. The aqueous resin according to claim 1, wherein the urethane prepolymer (II) is obtained by reacting such that the equivalent ratio of isocyanate groups to active hydrogen groups in all components is 1: 0.5 to 1: 0.9. Composition. The polyurethane resin (III) is reacted so that the equivalent ratio of the amino group in the epoxy prepolymer (I) and the isocyanate group in the urethane prepolymer (II) is 0.01: 1 to 0.9: 1. The aqueous resin composition according to claim 1 obtained by An aqueous coating composition comprising the aqueous resin composition according to any one of claims 1 to 6 . A method of forming a coating film, comprising applying the aqueous coating composition according to claim 7 to a surface to be coated. A coated article formed by the method of claim 8 .