JP5504062B2 - Aqueous resin composition, method for producing aqueous resin composition and metal paint - Google Patents

Description

  The present invention relates to an aqueous resin composition and a method for producing the same, and further to a metal paint containing the aqueous resin composition.

Among aqueous resin compositions, aqueous polyurethane resin dispersions containing cationic groups have been widely used as aqueous coating compositions for architectural interiors, leather, metals, wood, and the like (Patent Document 1).
Such a cationic group-containing polyurethane resin aqueous dispersion generally tends to yellow and has an influence on the appearance. In particular, dusting and yellowing are conspicuous when placed under high-temperature conditions after coating, so that high-temperature drying cannot be performed after coating, and it is difficult to shorten the coating film formation time.

  In applications where weather resistance and toughness are required, a cationic group-containing polyurethane resin aqueous dispersion and an unsaturated polymerizable monomer polymer aqueous dispersion may be used in combination. Since the stability is poor, gelation and sedimentation are likely to occur, and it is necessary to add an emulsifier such as a surfactant.

International Publication No. WO2005 / 092998

  In view of the above-mentioned conventional problems, the present invention provides an aqueous resin composition having a good appearance of a coating film and excellent blending stability with an unsaturated polymerizable monomer polymer, a method for producing the same, and a metal paint. Is an issue.

  The unsaturated polymerizable monomer polymer (A) is emulsified with a cationic group-containing polyurethane resin (B).

Further, the aqueous resin composition of the present invention is obtained by dispersing a solution containing an unsaturated polymerizable monomer (a) and a cationic group-containing isocyanate group-terminated urethane prepolymer (b) in water, and using water and / or polyamine. The cationic group-containing isocyanate group-terminated urethane prepolymer (
b) chain-elongating to emulsify the cationic group-containing polyurethane resin (B), simultaneously with the emulsification,
Or after emulsification, the Ru obtained by unsaturated polymerizable monomers wherein the unsaturated polymerizable monomer polymer by polymerizing (a) (A).

The method for producing an aqueous resin composition of the present invention comprises a step of dispersing a solution containing an unsaturated polymerizable monomer (a) and a cationic group-containing isocyanate group-terminated urethane prepolymer (b) in water;
Emulsifying the cationic group-containing polyurethane resin (B) by chain-extending the cationic group-containing isocyanate group-terminated urethane prepolymer (b) with water and / or polyamine, and the unsaturated polymerizable monomer (a). And a step of producing an unsaturated polymerizable monomer polymer (A).

The metal paint of the present invention is characterized by containing the above aqueous resin composition.

In the aqueous resin composition of the present invention, since the unsaturated polymerizable monomer polymer (A) is emulsified with the cationic group-containing polyurethane resin (B), yellowing and turbidity do not easily occur in the coated film.
In addition, because it is highly compatible with the unsaturated polymerizable monomer polymer, it can be stably dispersed without using an emulsifier or a dispersant when mixed with the unsaturated polymerizable monomer polymer aqueous dispersion. Can do.
In addition, the aqueous resin composition of the present invention is particularly suitable for use as a metal paint such as a metal surface treatment agent because yellowing and turbidity do not easily occur in the coated film as described above.

  The present invention relates to an aqueous resin composition in which an unsaturated polymerizable monomer polymer (A) is emulsified with a cationic group-containing polyurethane resin (B).

<Unsaturated polymerizable monomer polymer (A)>
The unsaturated polymerizable monomer polymer (A) of the present invention is composed of an unsaturated polymerizable monomer (a).
As the unsaturated polymerizable monomer (a) constituting the unsaturated polymerizable monomer polymer (A) of the present invention, a carboxylic acid group-containing unsaturated polymerizable monomer, an alkyl ester of a carboxylic acid group-containing unsaturated polymerizable monomer, A vinyl compound etc. are mentioned.

  Examples of the carboxylic acid group-containing unsaturated polymerizable monomer include (meth) acrylic acid containing methacrylic acid, crotonic acid, maleic acid, itaconic acid and the like.

  Examples of alkyl esters of carboxylic acid group-containing unsaturated polymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, N-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, (meth) acrylic Decyl acid, stearyl (meth) acrylate, isostearyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, ( (Meth) acrylic acid adamantyl, (meth) acrylic acid bicyclo [3, 3, 1] nonyl, 2-methoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, allyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (Meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid 4-hydroxybutyl, methoxyethylene glycol (meth) acrylate, methoxypolyethylene Glycol (meth) acrylate, ethoxyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, propoxyethylene glycol (meth) acrylate, propoxypolyethylene glycol (meth) acrylate, Mono, such as methoxypropylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, ethoxypropylene glycol (meth) acrylate, ethoxy polypropylene glycol (meth) acrylate, propoxypropylene glycol (meth) acrylate, propoxy polypropylene glycol (meth) acrylate (Meth) acrylic acid ester, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, etc. Di (meth) acrylate compound, trimethylolpropane tri (meth) acrylate, Examples include tri (meth) acrylate compounds such as lysine tri (meth) acrylate, tetra (meth) acrylate compounds such as pentaerythritol tetra (meth) acrylate, and hexa (meth) acrylate compounds such as sorbitol hexa (meth) acrylate. .

  Examples of the vinyl compound of the carboxylic acid group-containing unsaturated polymerizable monomer include vinyl acetate, vinyl propionate, styrene, α-methylstyrene, vinyl toluene, acrylonitrile, methacrylonitrile, butadiene, and isoprene.

  Each unsaturated polymerizable monomer (a) can be used alone or in combination of two or more.

When the unsaturated polymerizable monomer (a) is polymerized, a known polymerization initiator (c) can be added to cause a polymerization reaction in addition to thermal polymerization.
Examples of the polymerization initiator (c) include 2,2′-azobisisobutyronitrile,
2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazoline- 2-yl) propane] dihydrochloride, azo initiators such as 2,2′-azobis (N, N′-dimethyleneisobutylamidine); substituted ethane initiators such as phenyl substituted ethane, and the like can be used.
Or persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate;
Peroxide initiators such as peroxides such as hydrogen peroxide, t-butyl hydroperoxide, cumene hydroperoxide, and sulfites such as sodium sulfite; bisulfites such as sodium hydrogen sulfate; Metal salts such as copper and ferrous sulfate; redox initiators in combination with a reducing agent such as an organic reducing agent such as L-ascorbic acid can also be used.
As the polymerization method, a known method such as emulsion polymerization is used.
Although superposition | polymerization temperature is adjusted with the kind of said polymerization initiator, 20 to 100 degreeC is preferable, for example.
The amount of the polymerization initiator (c) used is usually suitably 0.005 to 1% with respect to 100 parts by weight of the unsaturated polymerizable monomer (a).

  The following are used as the cationic group-containing polyurethane resin (B) contained in the aqueous resin composition of the present invention.

<Cationic group-containing polyurethane resin (B)>
The cationic group-containing polyurethane resin (B) used in the present invention can be produced by a conventionally known method, for example, a polyol compound (b-1), an isocyanate compound (b-2) and a cationic group-containing The cationic group contained in the isocyanate group-terminated urethane prepolymer (b) obtained by reacting the compound (b-3) is neutralized with an acid or quaternized with a quaternizing agent, and then with water or / and a polyamine. Obtained by chain extension reaction.

(Polyol compound (b-1))
Examples of the polyol compound include low molecular weight polyols having a molecular weight of 400 or less, polyester polyols, polyether polyols, castor oil-based polyols, polycarbonate polyols, and hydrocarbon-based polyols.
These polyol compounds may be used alone or in combination of two or more.

  The low molecular weight polyol has a molecular weight of 400 or less, and examples of the low molecular weight polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 3-methylpentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,3-propanediol, bisphenol A, hydrogenated Bisphenol A, cyclohexanedimethanol, glycerin, or trimethylolpropane can be used.

Examples of the polyester polyol include a hydroxyl group-terminated esterified condensate obtained by reacting the low molecular weight polyol with a polyvalent carboxylic acid.
Examples of the polyvalent carboxylic acid include succinic acid, glutaric acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, tetrahydrofuran acid, endomethine tetrahydrofuran acid, and hexahydrophthalic acid. Can be mentioned.

Examples of the polyether polyol include those obtained by addition polymerization of alkylene oxide to the low molecular weight polyol such as bisphenol A, pentaerythritol, sorbitol, or sucrose.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and the like.

  Examples of the castor oil-based polyol include castor oil, hydrogenated castor oil hydrogenated to castor oil, castor oil fatty acid, or polyol produced using hydrogenated castor oil fatty acid hydrogenated thereto. Further, a transesterification product of castor oil and other natural fats and oils, a reaction product of castor oil and polyhydric alcohol, an esterification reaction product of castor oil fatty acid and polyhydric alcohol, or a polyol obtained by addition polymerization of the alkylene oxide to these Can be mentioned.

  A conventionally well-known thing is mentioned as said polycarbonate polyol, This polycarbonate polyol is obtained by reaction of the said low molecular weight polyol and diphenyl carbonate, or by reaction of the said low molecular weight polyol and phosgene, for example.

  Examples of the hydrocarbon polyol include polybutadiene polyol, polyisoprene polyol, hydrogenated polybutadiene polyol, and hydrogenated polyisoprene polyol.

(Isocyanate compound (b-2))
Examples of the isocyanate compound include polyisocyanates such as aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and araliphatic polyisocyanates.
The said isocyanate compound can be used individually or in combination of 2 or more types.

  Examples of the aliphatic polyisocyanate include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane- Examples include 1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate.

  Examples of the alicyclic polyisocyanate include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, and the like. Is mentioned.

  Examples of the aromatic polyisocyanate include tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 4,4′-dibenzyl diisocyanate, 1, Examples include 5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, and 1,4-phenylene diisocyanate.

  Examples of the araliphatic polyisocyanate include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and α, α, α, α-tetramethylxylylene diisocyanate.

  In addition, as the isocyanate compound, a dimer or trimer of the polyisocyanate, a modified product such as a buret isocyanate, polymethylene polyphenyl polyisocyanate (polymeric MDI), or the like can be used.

  Among the isocyanate compounds, aliphatic polyisocyanates or alicyclic polyisocyanates are particularly preferable in that yellowing of the aqueous resin composition can be further suppressed.

(Cationic group-containing compound (b-3))
Examples of the cationic group-containing compound include alkyl dialkanolamines such as N-methyldiethanolamine and N-methyldiethanolamine; N-methyldiaminoethylamines; alkyldiaminoalkylamines such as N-ethyldiaminoamine.
Moreover, what quaternized these with an acid or a quaternizing agent can also be used.

Examples of the cationic group in the present invention include a quaternary ammonium group obtained by neutralizing a tertiary amino group with an acid or quaternizing with a quaternizing agent.
Further, the cationic group-containing compound (b-3) may be a tertiary amine group-containing compound capable of forming a quaternary ammonium group.

The polyol compound (b-1), isocyanate compound (b-2) and cationic group-containing compound (b-3) are reacted to obtain an isocyanate group-terminated urethane prepolymer (b). For example, the reaction can be performed at 30 ° C. to 130 ° C. under reaction conditions of about 0.5 hours to 10 hours.

  Acids that neutralize the cationic groups contained in the isocyanate group-terminated urethane prepolymer (b) include inorganic acids such as hydrochloric acid and sulfuric acid, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, malic acid, and malonic acid. And organic acids such as adipic acid.

  Examples of the quaternizing agent for quaternizing the cationic group contained in the isocyanate group-terminated urethane prepolymer (b) include alkyl halides such as methyl chloride and methyl bromide, and dialkyl sulfates such as dimethyl sulfate and diethyl sulfate. Can be mentioned.

As described above, the cationic group-containing polyurethane resin (B) is obtained by chain-extending the isocyanate group-terminated urethane prepolymer (b) neutralized or quaternized with a cationic group with water or a mixture of water and a polyamine. It is formed.
Examples of the polyamine mixed with water as the chain extender include aliphatic polyamines such as ethylenediamine, trimethylenediamine, propylenediamine, diethylenetriamine, and triethylenetetramine, and aromatic polyamines such as metaxylenediamine, tolylenediamine, and diaminodiphenylmethane. An alicyclic polyamine such as piperazine and isophoronediamine, a polyhydrazide such as hydrazine and adipic acid dihydrazide, and the like can be used.
The said polyamine compound may be used independently and may use 2 or more types together.
Moreover, you may use reaction terminators, such as monoamines, such as a dibutylamine, and methyl ethyl ketoxime, as a reaction terminator to such an extent that polymerization is not inhibited greatly.
Also, a mixture of the polyamine and water can be used as a chain extender.

The aqueous resin composition of the present invention can be produced by the following method.
The polyol compound (b-1), the isocyanate compound (b-2) and the cationic group-containing compound (b-3) are reacted to form an isocyanate group-terminated urethane prepolymer, which is cooled to 5 ° C to 45 ° C. Then, an acid or a quaternizing agent is added to produce a cationic base-containing isocyanate group powder urethane prepolymer (b).
As the solvent, any organic solvent such as acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, ethyl acetate, butyl acetate can be used.
In this case, the mixing ratio of the polyol compound (b-1), the isocyanate compound (b-2) and the cationic group-containing compound (b-3) is such that the free isocyanate group content of the isocyanate group-terminated urethane prepolymer is the same. The cationic base-containing isocyanate group urethane prepolymer (b) is preferably mixed in an amount of 0.1 to 10% by weight, preferably 0.5 to 5% by weight.
The mixing ratio of the cationic group-containing compound (b-3) is such that the amine value of the isocyanate group-terminated urethane prepolymer is 20 to 60 mgKOH / g .
Subsequently, 1 to 900 parts by weight of the unsaturated polymerizable monomer (a) is added to 100 parts by weight of the cationic group-containing isocyanate group-terminated urethane polymer (b) to obtain a uniform solution, and then the unsaturated polymerizable monomer ( a) and a cationic group-containing isocyanate group-terminated urethane polymer (b) are emulsified by adding 100 to 900 parts by weight of water with respect to 100 parts by weight of the total amount, and if necessary, a polyamine is added to carry out a chain extension reaction. By doing so, a polyurethane resin (B) is obtained.
Further, at the same time as chain extension or after reaction, the unsaturated polymerizable monomer (a) is polymerized to produce an unsaturated polymerizable monomer polymer (A). An aqueous resin composition is produced in which the polymerizable monomer polymer (A) is emulsified with the cationic group-containing isocyanate group-terminated urethane prepolymer (b).

In the aqueous resin composition of the present invention, the unsaturated polymerizable monomer polymer (A) and the cationic group-containing polyurethane resin (B) component have a weight ratio of A / B = 40/60 to 50/50 . Oh Ru. By setting it within the above range, the dispersion stability of the aqueous resin composition can be further improved, and yellowing of the obtained film can be further suppressed.

Furthermore, in the aqueous resin composition of the present invention, various commonly used additives can be used as necessary. Examples of such additives include weathering agents, antibacterial agents, antifungal agents, pigments, fillers, rust inhibitors, pigments, dyes, film-forming aids, inorganic crosslinking agents, organic crosslinking agents (for example, blocked isocyanates). -Based crosslinking agents, epoxy-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, melamine-based crosslinking agents), silane coupling agents, antiblocking agents, viscosity modifiers, leveling agents, antifoaming agents, dispersion stabilizers, light Stabilizers, antioxidants, ultraviolet absorbers, inorganic and organic fillers, plasticizers, lubricants, antistatic agents and the like can be mentioned.
The aqueous resin composition of the present invention can be widely used as a general paint, but is particularly suitable for use as a metal paint such as a metal surface treatment agent.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
First, each aqueous resin composition of the following Examples and Comparative Examples is prepared.

Example 1
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube is adducted with 2 moles of bisphenol A ethylene oxide as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) 120 parts by weight, 6 parts by weight of trimethylolpropane, 33 parts by weight of N-methyldiethanolamine as b-3 component, 231 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 260 parts by weight of methyl ethyl ketone as b-2 component were added, and 75 ° C. For 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (b) having an amine value of 40 mgKOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C., and quaternized by adding 34.9 parts by weight of dimethyl sulfuric acid, and then 260 parts by weight of methyl methacrylate was added as a component. Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 2)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen blowing tube is adducted with 4 moles of bisphenol A ethylene oxide as a b-1 component (New Pole BPE-40, manufactured by Sanyo Chemical Industries, Ltd.) 75.6 parts by weight, 7.30 parts by weight of trimethylolpropane, N-methyldiethanolamine 2 8 as b-3 component. 0 part by weight, polyethylene glycol (PEG-600S, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as 53.2 parts by weight b-2 component, 190.8 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 266 parts by weight of methyl ethyl ketone In addition, the mixture was reacted at 75 ° C. for 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) having an amine value of 37 mgKOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.2%.
Next, this solution was cooled to 45 ° C., added with 17.8 parts by weight of dimethylsulfuric acid, and then quaternized. Then, 372.7 parts by weight of methyl methacrylate was added as a component.
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) and the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 50/50.

(Example 3)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube is adducted with 2 moles of bisphenol A ethylene oxide as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) 43.6 parts by weight, bisphenol A ethylene oxide 4 mol adduct (New Pole BPE-40, Sanyo Chemical Industries, Ltd.) 18.7 parts by weight, 1,4-cyclohexanedimethanol 1.5 parts by weight, tri 5.7 parts by weight of methylolpropane, 23.7 parts by weight of N-methyldiethanolamine as b-3 component, 1.5 parts by weight of methoxypolyethylene glycol (M-PEG CP-2500, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polyethylene 45 parts by weight of glycol (PEG-600S, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 4,4′-disi as b-2 component 190.8 parts by weight of cyclohexylmethane diisocyanate and 266 parts by weight of methyl ethyl ketone were added and reacted at 75 ° C. for 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) having an amine value of 34 mg KOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.0%.
Next, this solution was cooled to 45 ° C., and quaternized by adding 17.8 parts by weight of dimethyl sulfate, and then 325 parts by weight of methyl methacrylate was added as the component a.
Subsequently, the mixture was emulsified and dispersed using a homogenizer while gradually adding 2000 parts by weight of water, 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added, and the mixture was reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) and the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 50/50.

(Example 4)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube is adducted with 2 moles of bisphenol A ethylene oxide as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) 120 parts by weight, 6 parts by weight of trimethylolpropane, 33 parts by weight of N-methyldiethanolamine as b-3 component, 231 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 260 parts by weight of methyl ethyl ketone as b-2 component were added, and 75 ° C. For 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) having an amine value of 40 mgKOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C. and quaternized by adding 34.9 parts by weight of dimethyl sulfate, and then 208 parts by weight of methyl methacrylate and 52 parts by weight of n-butyl acrylate were added as component a. .
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 5)
In a four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen blowing tube, 2-mole addition product of ethylene oxide of bisphenol A as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) 120 parts by weight, 6 parts by weight of trimethylolpropane, 33 parts by weight of N-methyldiethanolamine as component b-3, 4,4′- as component b-2
231 parts by weight of dicyclohexylmethane diisocyanate and 260 parts by weight of methyl ethyl ketone were added and reacted at 75 ° C. for 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) having an amine value of 40 mg KOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C. and quaternized by adding 34.9 parts by weight of dimethyl sulfuric acid, and then 208 parts by weight of methyl methacrylate and 52 parts by weight of 2-ethylhexyl acrylate were added as component a. .
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 6)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube is adducted with 2 moles of bisphenol A ethylene oxide as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) 120 parts by weight, 6 parts by weight of trimethylolpropane, 33 parts by weight of N-methyldiethanolamine as b-3 component, 231 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 260 parts by weight of methyl ethyl ketone as b-2 component were added at 75 ° C. For 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (b) having an amine value of 40 mgKOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C. and quaternized by adding 34.9 parts by weight of dimethyl sulfuric acid, and then 247 parts by weight of methyl methacrylate and 13 parts by weight of triethylene glycol dimethacrylate were added as component a.
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 7)
In a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing tube, 120 parts by weight of polyester polyol (Kuraray polyol P-520, manufactured by Kuraray Co., Ltd.) as b-1 component, 6 weight of trimethylolpropane Part, N-3 methyldiethanolamine 33 parts by weight as b-3 component, 231 parts by weight 4,4'-dicyclohexylmethane diisocyanate and 260 parts by weight methyl ethyl ketone as b-2 component, and reacted at 75 ° C. for 4 hours to give an amine value of 40 mgKOH / G of a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) was obtained.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C. and quaternized by adding 34.9 parts by weight of dimethyl sulfuric acid, and then 247 parts by weight of methyl methacrylate and 13 parts by weight of triethylene glycol dimethacrylate were added as component a.
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 8)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube was added to ethylene oxide 2-mol adduct of bisphenol A as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) ) 120 parts by weight, 6 parts by weight of trimethylolpropane, 33 parts by weight of N-methyldiethanolamine as the b-3 component, 100 parts by weight of 4,4′-diphenylmethane diisocyanate (MDI) as the b-2 component, 4,4′-dicyclohexyl 130 parts by weight of methane diisocyanate and 260 parts by weight of methyl ethyl ketone were added and reacted at 75 ° C. for 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) having an amine value of 40 mg KOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C., and quaternized by adding 34.9 parts by weight of dimethyl sulfuric acid, and then 260 parts by weight of methyl methacrylate was added as a component.
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

Example 9
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube was added to ethylene oxide 2-mol adduct of bisphenol A as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) ) 120 parts by weight, 6 parts by weight of trimethylolpropane, 33 parts by weight of N-methyldiethanolamine as the b-3 component, 231 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 260 parts by weight of methyl ethyl ketone as the b-2 component, The reaction was carried out at 4 ° C. for 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) having an amine value of 40 mgKOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, after cooling this solution to 45 degreeC and adding 12.8 weight part of formic acid and making it quaternized, 260 weight part of methyl methacrylate was added as a component.
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 10)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube was added to ethylene oxide 2-mol adduct of bisphenol A as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) ) 120 parts by weight, 6 parts by weight of trimethylolpropane, 33 parts by weight of N-methyldiethanolamine as the b-3 component, 231 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 260 parts by weight of methyl ethyl ketone as the b-2 component, The reaction was carried out at 4 ° C. for 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) having an amine value of 40 mgKOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C., and quaternized by adding 34.9 parts by weight of dimethyl sulfuric acid, and then 260 parts by weight of methyl methacrylate was added as a component.
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. After adding 10 parts by weight of diethylenetriamine, 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added. After reacting at 3 ° C. for 3 hours to polymerize the unsaturated polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 11)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube was added to ethylene oxide 2-mol adduct of bisphenol A as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) ) 120 parts by weight, 6 parts by weight of trimethylolpropane, 33 parts by weight of N-methyldiethanolamine as the b-3 component, 231 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 260 parts by weight of methyl ethyl ketone as the b-2 component, The reaction was carried out at 4 ° C. for 4 hours to obtain a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (B) having an amine value of 40 mgKOH / g.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C., and quaternized by adding 34.9 parts by weight of dimethyl sulfuric acid, and then 260 parts by weight of methyl methacrylate was added as a component.
Subsequently, 2300 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. After adding 1 part by weight of ammonium persulfate and reacting at 70 ° C. for 3 hours, the unsaturated polymerizable monomer was polymerized. The emulsified dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 12)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube was added to ethylene oxide 4 mol adduct of bisphenol A as a b-1 component (New Pole BPE-40NK, manufactured by Sanyo Chemical Industries, Ltd.) ) 75.6 parts by weight, 7.30 parts by weight of trimethylolpropane, 13.0 parts by weight of N-methyldiethanolamine as the b-3 component, polyethylene glycol (PEG-600S, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as the b-1 component ) 53.2 parts by weight, 153.0 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 266 parts by weight of methyl ethyl ketone as b-2 components were added and reacted at 75 ° C. for 4 hours to terminate the isocyanate group having an amine value of 20 mgKOH / g. A methyl ethyl ketone solution of urethane prepolymer (B) was obtained.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.2%.
Next, this solution was cooled to 45 ° C., and quaternized by adding 13.8 parts by weight of dimethyl sulfuric acid, and then 303.1 parts by weight of methyl methacrylate was added as a component.
Subsequently, emulsifying and dispersing using a homogenizer while gradually adding 2300 parts by weight of water,
After adding 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite and reacting at 25 ° C. for 3 hours to polymerize the unsaturated polymerizable monomer, the emulsion dispersion is depressurized at 50 ° C. to remove it. Solvent was used to obtain an aqueous resin composition having a nonvolatile content of 25%.
The weight ratio of the polyurethane resin (B) and the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 50/50.

(Example 13)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube was added to ethylene oxide 4 mol adduct of bisphenol A as a b-1 component (New Pole BPE-40NK, manufactured by Sanyo Chemical Industries, Ltd.) ) 75.6 parts by weight, 7.30 parts by weight of trimethylolpropane, 44.0 parts by weight of N-methyldiethanolamine as the b-3 component, polyethylene glycol (PEG-600S, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as the b-1 component ) 53.2 parts by weight, 233 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 266 parts by weight of methyl ethyl ketone as b-2 components were reacted at 75 ° C. for 4 hours to react with an isocyanate group-terminated urethane prepolymer having an amine value of 60 mg KOH / g. A methyl ethyl ketone solution of polymer (B) was obtained.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.2%.
Next, this solution was cooled to 45 ° C., and quaternized by adding 43.4 parts by weight of dimethyl sulfuric acid, and then 413.1 parts by weight of methyl methacrylate was added as the component a.
Subsequently, emulsifying and dispersing using a homogenizer while gradually adding 2300 parts by weight of water,
After adding 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite and reacting at 25 ° C. for 3 hours to polymerize the unsaturated polymerizable monomer, the emulsion dispersion is depressurized at 50 ° C. to remove it. Solvent was used to obtain an aqueous resin composition having a nonvolatile content of 25%.
The weight ratio of the polyurethane resin (B) and the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 50/50.

(Example 14)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube is adducted with 2 moles of bisphenol A ethylene oxide as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) 120 parts by weight, 6 parts by weight of trimethylolpropane, 30 parts by weight of N-methyldiethanolamine as the b-3 component, 192 parts by weight of isophorone diisocyanate and 260 parts by weight of methyl ethyl ketone as the b-2 component were added and reacted at 75 ° C. for 4 hours. A methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (b) having an amine value of 40 mgKOH / g was obtained.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C., and quaternized by adding 31.8 parts by weight of dimethyl sulfate, and then 232 parts by weight of methyl methacrylate was added as a component. Subsequently, 2200 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Example 15)
A four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube is adducted with 2 moles of bisphenol A ethylene oxide as a b-1 component (New Pole BPE-20NK, manufactured by Sanyo Chemical Industries, Ltd.) 120 parts by weight, 6 parts by weight of trimethylolpropane, 25 parts by weight of N-methyldiethanolamine as the b-3 component, 137 parts by weight of hexamethylene diisocyanate and 260 parts by weight of methyl ethyl ketone as the b-2 component were added and reacted at 75 ° C. for 4 hours. Thus, a methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer (b) having an amine value of 40 mgKOH / g was obtained.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C., 26.5 parts by weight of dimethyl sulfuric acid was added and quaternized, and then 192 parts by weight of methyl methacrylate was added as a component. Subsequently, 2100 parts by weight of water was gradually added and emulsified and dispersed using a homogenizer. 1 part by weight of t-butyl hydroperoxide and 1 part by weight of sodium sulfite were added and reacted at 25 ° C. for 3 hours to be unsaturated. After polymerizing the polymerizable monomer, the emulsion dispersion was depressurized at 50 ° C. to remove the solvent, and an aqueous resin composition having a nonvolatile content of 25% was obtained.
The weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) in the obtained aqueous resin composition was A / B = 40/60.

(Comparative Example 1)
In a four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen blowing tube, 100 parts by weight of bisphenol A ethylene oxide 2-mol adduct (New Pole BPE-20NK, Sanyo Chemical Industries, Ltd.) 5 parts by weight of methylolpropane, 27.5 parts by weight of N-methyldiethanolamine, 192.5 parts by weight of 4,4′-dicyclohexylmethane diisocyanate and 260 parts by weight of methyl ethyl ketone were added and reacted at 75 ° C. for 4 hours to give an amine value of 40 mgKOH / g A methyl ethyl ketone solution of an isocyanate group-terminated urethane prepolymer was obtained.
The content of free isocyanate groups based on the nonvolatile content of this solution was 3.6%.
Next, this solution was cooled to 45 ° C. and quaternized by adding 29.1 parts by weight of dimethyl sulfate. Subsequently, the mixture was emulsified and dispersed using a homogenizer while gradually adding 1380 parts by weight of water, and the solvent was removed under reduced pressure at 50 ° C. to obtain a cationic group-containing polyurethane resin aqueous dispersion having a nonvolatile content of 25%.

(Comparative Example 2)
In a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing tube, 250 parts by weight of methyl methacrylate and a nonionic reactive surfactant (Aqualon RN-30, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) The mixture was emulsified and dispersed using a homogenizer while gradually adding 750 parts by weight of water. Ammonium persulfate was added to the resulting emulsified dispersion and reacted at 80 ° C. for 3 hours to obtain an unsaturated polymerizable monomer polymer aqueous dispersion having a nonvolatile content of 25%.

(Comparative Example 3)
The cationic group-containing polyurethane resin aqueous dispersion obtained in Comparative Example 1 and the unsaturated polymerizable monomer polymer aqueous dispersion obtained in Comparative Example 2 were converted into a polyurethane resin (B) and an unsaturated polymerizable monomer. The mixture was mixed so that the weight ratio with the polymer (A) was A / B = 60/40 to obtain an unsaturated polymerizable monomer polymer aqueous dispersion.

  Using the aqueous resin compositions obtained in Examples 1 to 15 and the aqueous dispersion obtained in Comparative Examples 1 to 3, test pieces were prepared by the following method, and appearance (turbidity, yellowing), physical properties ( Tensile strength, elongation), corrosion resistance, and blending stability with an unsaturated polymerizable monomer polymer aqueous dispersion were evaluated.

(How to create a test piece)
By placing the aqueous resin composition of each example and comparative example in a fluororesin-coated petri dish to a dry film thickness of 200 μm, heating at 80 ° C. for 6 hours, 120 ° C. for 1 hour, and then drying at 150 ° C. for 30 minutes. A test piece was prepared.

(appearance)
The appearance of the film of each test piece was visually observed to evaluate the presence or absence of turbidity and the presence or absence of yellowing.

(Film physical properties)
According to JIS-K-6301, tensile strength (N / mm ² ) and elongation (%) were measured at a tensile speed of 100 mm / min.

(Corrosion resistance)
Electro-galvanized steel sheet (trade name: non-chromate treatment unijing, Taiho) whose surface was degreased in advance with isopropanol from the aqueous resin compositions obtained in Examples 1 to 15 and Comparative Examples 1 to 3 Co., Ltd.) was applied so as to have a dry film thickness of 3 μm, and baked at 80 ° C. for 30 seconds to prepare a test piece for corrosion resistance evaluation.
Each test piece was sprayed with 5% by weight saline at 35 ° C. for 72 hours, and the presence or absence of white rust was visually confirmed.

(Compounding stability)
50 parts by weight of the aqueous resin composition obtained in Examples 1 to 15 and the aqueous resin composition obtained in Comparative Examples 1 and 3, respectively, and the aqueous dispersion of unsaturated polymerizable monomer polymer obtained in Comparative Example 2 50 parts by weight of the body was mixed.
The state of the liquid mixture when 1 hour passed after mixing was visually observed to confirm the presence or absence of aggregates.

  The results are shown in Table 1.

  From the results, the aqueous resin compositions of the respective examples were less turbid and discolored than Comparative Examples 1 and 3, and were excellent in film physical properties and corrosion resistance, and at the same time, an unsaturated polymerizable monomer polymer aqueous dispersion. It is clear that the compounding stability at the time of mixing with the body is also excellent. In Comparative Example 2, no film could be formed.

Claims (3)

A solution containing an unsaturated polymerizable monomer (a) and a cationic group-containing isocyanate group-terminated urethane prepolymer (b) having an amine value of 20 to 60 mgKOH / g is dispersed in water, and water and / or polyamine is used. The cationic group-containing isocyanate group-terminated urethane prepolymer (b) is chain-extended to emulsify the cationic group-containing polyurethane resin (B), and the unsaturated polymerizable monomer (a) is simultaneously or after emulsification. An aqueous resin composition obtained by emulsifying an unsaturated polymerizable monomer polymer (A) with a cationic group-containing polyurethane resin (B), which is obtained by polymerizing an unsaturated polymerizable monomer polymer (A). Because
An aqueous resin composition , wherein the weight ratio of the polyurethane resin (B) to the unsaturated polymerizable monomer polymer (A) is A / B = 40/60 to 50/50 Dispersing a solution containing an unsaturated polymerizable monomer (a) and a cationic group-containing isocyanate group-terminated urethane prepolymer (b) having an amine value of 20 to 60 mgKOH / g in water;
Emulsifying the cationic group-containing polyurethane resin (B) by chain-extending the cationic group-containing isocyanate group-terminated urethane prepolymer (b) with water and / or a polyamine; and
The unsaturated polymerizable monomer (a) is polymerized to produce an unsaturated polymerizable monomer polymer (A), and the weight of the polyurethane resin (B) and the unsaturated polymerizable monomer polymer (A) method for producing an aqueous resin composition ratio characterized in that it comprises a Cheng Hao to obtain an aqueous resin composition which is a / B = 40 / 60~50 / 50. A metal paint comprising the aqueous resin composition according to claim 1 .