JPH11189698A - Aqueous resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aq. resin compsn. which is excellent in reactivity with a curing agent and is used e.g. for a coating material capable of forming a coating film having good hardness and processibility on the surface of iron, a nonferrous metal, or the like. SOLUTION: This compsn. contains an acryl-modified polyester resin and a solvent. The resin is obtd. by the graft polymn. of an acrylic monomer onto a polyester resin which has ethylenic double bounds and contains units derived from a trihydric or higher alcohol, units derived from a tribasic or higher acid, and units derived from a tribasic or higher hydroxyacid in an amt. of the sum of these units of not higher than 5 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous resin composition which is excellent in reactivity with a curing agent and is preferably used for a paint capable of forming a coating film having good hardness and workability on the surface of iron, non-ferrous metal or the like. About things.

[0002]

2. Description of the Related Art In the fields of home appliances, pre-coated metal, automobiles, etc., for reasons of work environment, resource saving, low pollution, etc.
Aqueous paints such as an acrylic paint containing an acrylic resin as a main component and a polyester paint containing a polyester resin as a main component have been widely used.

[0003] Acrylic resin-based ones have excellent coating film hardness, weather resistance, stain resistance, and chemical resistance.
Widely used in home electric appliances etc.
665). However, since acrylic resin has low flexibility, paint based on this resin has a brittle coating film and poor impact resistance, and in order to satisfy the flexibility, it is necessary to soften the composition of acrylic resin. It was difficult to show the hardness of the coating film and the stain resistance so as to endure practical use.

On the other hand, those based on polyester resins are excellent in pigment dispersibility and flexibility, and are therefore used as coatings for automobile middle coats and top coats for home electric appliances (Japanese Patent Application Laid-Open No. 64-67070). However, a normal polyester resin which is a linear polyester resin generally has a drawback of being inferior in hardness and water resistance. Further, the branched type saturated polyester resin has been used for coil coating such as color tin, but has a drawback that the workability, hardness and stain resistance of the coating film cannot be balanced. On the other hand, a straight-chain high-molecular-weight polyester resin or a low-branching high-molecular-weight polyester resin has an excellent balance of the processability, hardness and stain resistance of a coating film as compared with a normal polyester resin. It has also been put to practical use in the painting of home appliances.

Therefore, various attempts have been made to combine the properties of both an acrylic resin and a linear or low-branched high molecular weight polyester resin. For example, a method of blending a polyester resin and an acrylic resin (JP-B-07-39555, JP-B-63-23077)
No. 9, JP-A-07-011188). However, just blending
Phase separation occurs, a uniform solution cannot be obtained, and it cannot be practically used as a paint.

[0006] A resin in which a hydrophilic acrylic resin and a hydrophobic polyester resin are reacted with each other by transesterification has been proposed (Japanese Patent Application Laid-Open No. 1-129072). There is a problem.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an aqueous resin composition containing a resin component having excellent reactivity with a curing agent as a main component. It is an object of the present invention to provide an aqueous resin composition for a paint suitable for a steel sheet which can form a coating film excellent in hardness and water resistance.

[0008]

That is, the present invention relates to a unit derived from a trivalent or higher polyhydric alcohol, a unit derived from a trivalent or higher polybasic acid and a unit derived from a trivalent or higher hydroxy acid. An acrylic modified polyester resin (C) and a solvent (D) obtained by graft polymerizing an acrylic monomer (B) to a polyester resin (A) containing an ethylenic double bond having a total content of 0 to 5% by weight. The present invention provides an aqueous resin composition containing the same.

That is, the aqueous resin composition of the present invention comprises, as a base resin, an acrylic-modified polyester resin obtained by graft-polymerizing an acrylic monomer to a polyester resin having an ethylenic double bond; A straight-chain polyester resin or a low-branched polyester resin is used as the polyester resin as the trunk polymer of the above.
Linear polyester resins or low-branched polyester resins have few functional groups in the molecular chain, and most of the functional groups are located at the ends of the polymer chain. Therefore, when these polyester resins are cured together with a curing agent such as an etherified amino resin, the crosslinked density of the coating film is low and the crosslinked structure becomes non-uniform. Compared with resin,
The processability of the coating film is improved.

In addition, by modifying the linear or low-branched polyester resin with an acrylic resin component by graft polymerization, the drawbacks of low hardness and low water resistance of the linear and low-branched polyester resin can be solved. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester resin (A) used in the production of the acrylic-modified polyester resin (C) in the aqueous resin composition of the present invention is prepared by mixing an acid component and an alcohol component with a known production method, for example, It can be produced by performing an esterification reaction or a transesterification reaction by a melting method, a solvent method or the like.

As the acid component used for producing the polyester resin (A), a saturated polybasic acid and an unsaturated polybasic acid having an ethylenic double bond are usually used. Examples of the saturated polybasic acid include terephthalic acid, isophthalic acid, phthalic acid, aromatic dicarboxylic acids such as naphthalene dicarboxylic acid, adipic acid, sebacic acid, azelaic acid, succinic acid, hymic acid, and 1,6-cyclohexanedicarboxylic acid. Tribasic or higher polybasic acids such as saturated aliphatic dicarboxylic acids, trimellitic acid, and pyromellitic acid; lower alkyl esters thereof (eg, C _1-4 alkyl esters);
These acid anhydrides are exemplified. Dibasic acids such as aromatic dicarboxylic acids and saturated aliphatic dicarboxylic acids are each 1
The species may be used alone, or two or more species may be used in combination.
In addition, tribasic or higher polybasic acids may be used alone or in combination of two or more.

Examples of unsaturated polybasic acids having an ethylenic double bond include fumaric acid, maleic acid, itaconic acid, citraconic acid, lower alkyl esters thereof (eg, C _1-4 alkyl esters), and Acid anhydride and the like. The unsaturated polybasic acids having an ethylenic double bond may be used alone or in combination of two or more.

The alcohol component used for producing the polyester resin (A) includes ethylene glycol, propylene glycol, 1,3-propanediol, 1,3
-Butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-
Hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-
1,3-propanediol, 2-butyl-2-ethyl-
Dihydric alcohols such as 1,3-propanediol, ethylene oxide adduct of hydrogenated bisphenol A, propylene oxide adduct of hydrogenated bisphenol A, ethylene oxide adduct of bisphenol A, and propylene oxide adduct of bisphenol A; trimethylol Examples thereof include trihydric or higher polyhydric alcohols such as ethane, trimethylolpropane, glycerin, and pentaerythritol. Each of the dihydric alcohols may be used alone,
Two or more kinds may be used in combination. In addition, trihydric or higher polyhydric alcohols may be used alone or in combination of two or more.

It is also possible to use a hydroxy acid such as dimethylolpropionic acid together with the above-mentioned carboxylic acid and alcohol.

The polyester resin (A) used in the present invention is preferably a straight-chain polyester resin or a low-branched polyester resin. It is necessary that the total content of units derived from polybasic acids having a valency of 3 or more and units derived from hydroxy acids having a valency of 3 or more is 0 to 5% by weight, and preferably 0 to 2% by weight. When the total content of these units exceeds 5% by weight, the processability of a coating liquid of a coating material using the aqueous resin composition of the present invention is significantly reduced. Accordingly, the total amount of the trihydric or higher polyhydric alcohol used in the synthesis of the polyester resin (A), the trivalent or higher polybasic acid, and the trivalent or higher hydroxyl acid is 0% of the total monomer materials used in the synthesis. To 5% by weight,
More preferably, it is 0 to 2% by weight.

The content of the unit derived from the unsaturated polybasic acid having an ethylenic double bond in the polyester resin (A) is 0.5 to 0.5% of the total amount of the polyester resin (A).
It is preferably 10% by weight, more preferably 0.1% by weight.
The content is 5 to 7% by weight, more preferably 1 to 5% by weight, and particularly preferably 1 to 3% by weight. When the content of the unit derived from the unsaturated polybasic acid having an ethylenic double bond is less than 0.5% by weight, the acrylic unreacted portion increases, and the water resistance and the effect of improving the hardness tend to be insufficient. If it exceeds 10% by weight, a large number of acrylic components are grafted on the polyester resin (A), so that the coating properties such as processability tend to decrease. Therefore, the amount of the polybasic acid having an ethylenic double bond used in the synthesis of the polyester resin (A) is preferably 0.5 to 10% by weight of the total monomer raw material used in the synthesis, more preferably. Is 0.5 to 7% by weight, more preferably 1 to 5% by weight, particularly preferably 1 to 3% by weight.

The polyester resin (A) is prepared by first mixing an acid component other than the above-mentioned polybasic acid having an ethylenic double bond and an alcohol component, and preparing the ester by a known production method such as a melting method or a solvent method. It is preferable to prepare a saturated polyester resin by performing an oxidation reaction or a transesterification reaction. At that time, if necessary, in the presence of a catalyst such as antimony triacid value, germanium oxide, or N-butyl titanate, under a reduced pressure of 10 mmHg or less, preferably 1 mmHg or less, usually at 200 to 300 ° C., preferably 23 ° C.
By conducting the polycondensation reaction at 0 to 280 ° C, it is also possible to obtain a high molecular weight polyester resin. The polybasic acid having an ethylenic double bond may be charged from the beginning of the reaction, but if it is charged from the beginning, the acrylic monomer is branched during graft polymerization, so that the processability tends to be reduced. When emphasizing processability, after synthesizing a saturated polyester resin containing no unit derived from a polybasic acid having an ethylenic double bond, a polybasic acid having an ethylenic double bond is added, and at 100 to 160 ° C. It is preferable to introduce an ethylenic double bond at the terminal of the saturated polyester resin by the addition reaction.

The weight average molecular weight of the polyester resin (A) is preferably at least 3,000, more preferably at least 5,000. Weight average molecular weight of 3,000
If it is less than 30, the coating properties such as processability and stain resistance tend to be poor. In particular, in the case of a linear polyester resin, the weight average molecular weight is preferably 5,000 or more in order to obtain a coating film which is excellent in processability and simultaneously exhibits hardness and stain resistance.

The polyester resin (A) has a hydroxyl value of 1
00 (mgKOH / g, hereinafter the same) or less, more preferably 80 or less, still more preferably
It is preferably 60 or less. When the hydroxyl value exceeds 100,
There is a tendency that the processability, stain resistance and the like of the coating film decrease.

The solid content acid value of the polyester resin (A) is:
It is preferably 15 (mgKOH / g, the same applies hereinafter), more preferably 12 or less. When the acid value exceeds 15, the acrylic-modified polyester resin is liable to be hydrolyzed, and the properties of the coating film tend to deteriorate.

The acrylic monomer (B) used in the present invention includes, for example, carboxyl group-containing vinyl monomers, acrylic esters, methacrylic esters,
Styrene monomer, vinyl acetate, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, N, N-diethylacrylamide, N, N
-Diethyl methacrylamide, acrylonitrile, methacrylonitrile and the like.

Examples of the carboxyl group-containing vinyl monomer include acrylic acid, methacrylic acid, maleic acid,
Maleic anhydride, fumaric acid, crotonic acid, itaconic acid, and the like, and examples of the acrylate include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, and acryl. C acrylate such as tert-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate
_1-6 alkyl esters, and examples of methacrylates include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-methacrylate
tert-butyl, isobutyl methacrylate, C _1-6 alkyl methacrylate such as 2-ethylhexyl methacrylate, and the styrene-based monomer include, for example, styrene, vinyltoluene, α-methylstyrene, and the like. .

The acrylic monomer (B) may be used alone or
Although it is used in combination of more than one kind, it is preferable to contain the carboxyl group-containing vinyl monomer from the viewpoint of introducing a carboxyl group into the obtained acrylic-modified polyester resin (C) to facilitate aqueous conversion. The compounding amount of the carboxyl group-containing vinyl monomer is such that the obtained acrylic-modified polyester resin (C) has a solid acid value of 20 to 100,
More preferably, it is preferably blended so as to be 30 to 60.

As a method for producing an acrylic-modified polyester resin (C) by polymerizing an acrylic monomer (B) in the presence of the polyester resin (A), for example, a radical polymerization method in an ordinary organic solvent is used. The method is not particularly limited.

As a specific method, for example, the polyester resin (A) is dissolved in an organic solvent, the acrylic monomer (B) and a radical polymerization initiator are added, and the mixture is heated at 80 to 140 ° C. for 2 to 5 hours. A heating method can be used.

The amount of the polyester resin (A) used for the graft polymerization is from 50 to 90% by weight based on the total amount of the polyester resin (A) and the acrylic monomer (B) from the viewpoint of the processability of the obtained coating film. And preferably 6
0 to 85% by weight, more preferably 70 to 80% by weight.
More preferably, it is% by weight. If this amount is less than 50% by weight, the resulting coating film tends to be inferior in workability, and if it exceeds 90% by weight, the coating film tends to be inferior in hardness and water resistance.

The organic solvent used in the reaction for grafting the acrylic monomer (B) to the polyester resin (A) includes, for example, a hydrophilic solvent, and specific examples thereof include methyl cellosolve, ethyl cellosolve, and butyl cellosolve. Tert-butyl cellosolve, isopropyl cellosolve, isopropyl alcohol, butyl alcohol, tert-butyl alcohol, isobutyl alcohol and the like. These organic solvents are used alone or in combination of two or more.

The proportion of the organic solvent to be used is not particularly limited, but is usually from 0.4 to 0.4 by weight based on the total amount of the polyester resin (A) and the acrylic monomer (B).
The amount is tripled.

Examples of the radical polymerization initiator include azobisnitrile type catalysts and peroxides.
Examples of the azobisnitrile type catalyst include azobisisobutyronitrile and azobisvaleronitrile, and examples of the peroxide include benzoyl peroxide and butyl perbenzoate.

These radical polymerization initiators are used alone or in combination of two or more.

The proportion of the radical polymerization initiator used is not particularly limited, but is usually from 0.3 to 10% by weight based on the total amount of the acrylic monomer (B).

The weight-average molecular weight of the acrylic-modified polyester resin (C) obtained by the above polymerization reaction is determined from the viewpoint of processability, viscosity and dispersion stability of the obtained aqueous resin composition.
It is preferably from 8,000 to 100,000,
More preferably, it is from 9,000 to 60,000,
More preferably, it is 10,000 to 30,000. If the weight average molecular weight is less than 8,000, the processability of the coating film tends to be inferior, and if it exceeds 100,000,
The resulting aqueous resin composition tends to be inferior in viscosity and dispersion stability.

The weight average molecular weight in the present invention is:
It is a value measured by gel permeation chromatography and determined using a standard polystyrene calibration curve.

The resin acid value of the acrylic-modified polyester resin (C) depends on the type of the acrylic monomer (B) used and the amount used, and is not particularly limited, but is preferably from 20 to 100, preferably from 25 to 80. Is more preferable, and 30-60 are still more preferable.

The resin hydroxyl value of the acrylic-modified polyester resin (C) is not particularly limited, but is preferably 20 to
150 is preferable, and 30 to 80 is more preferable.

The aqueous resin composition of the present invention contains the acrylic-modified polyester resin (C) thus obtained and the solvent (D) as essential components.

As the solvent (D), a mixed solvent of an organic solvent and water is usually used. Examples of the organic solvent include those exemplified as the organic solvent used in the synthesis of the acrylic-modified polyester resin (C), and the organic solvent used in the synthesis may be used without being separated after the synthesis. The mixing ratio of the organic solvent and water is the weight ratio of the organic solvent /
Water = 50/50 to 10/90 is preferred, and 30/70 to
10/90 is more preferred.

The ratio of the solvent (D) used is usually 10 to 40 with respect to 100 parts by weight of the acrylic-modified polyester resin.
0 parts by weight, more preferably 50 to 50 parts by weight.
200 parts by weight.

The aqueous resin composition of the present invention has a pH value of 7
, Preferably from 7.5 to 9.0, more preferably from 7.5 to 9.0. Adjustment of the pH of the aqueous resin composition is performed by a neutralization operation of adding a neutralizing agent to a mixture of the acrylic-modified polyester resin (C) and a solvent. Usually, the neutralization operation can be performed by adding a neutralizing agent and reacting a part or all of the carboxyl groups of the acrylic-modified polyester resin (C) with a base. Examples of the neutralizing agent include amines, alkali metal hydroxides, alkali metal carbonates, and bicarbonates. Examples of the amine include ammonia, triethylamine, and dimethylaminoethanol.Examples of the alkali metal hydroxide include, for example, sodium hydroxide and potassium hydroxide.Examples of the alkali metal carbonate include, for example, , Sodium carbonate and the like, and as the bicarbonate, for example, sodium bicarbonate and the like.

The obtained aqueous resin composition can be used as it is as an aqueous paint, but if necessary, a pigment, an antifoaming agent, a plasticizer, an organic solvent, a curing agent, a surface treating agent and the like are blended. It may be used as a water-based paint or another paint.

Examples of the pigment include titanium white, carbon black, zinc oxide (anti-corrosion pigment), talc (extended pigment), zinc phosphate (anti-corrosion pigment), barium metaborate (corrosion-resistant pigment) and the like. . The amount of the pigment is 2 parts per 100 parts by weight of the acrylic-modified polyester resin (C).
The amount is preferably 0 to 70 parts by weight, more preferably 40 to 60 parts by weight.

As the antifoaming agent, for example, BYK-022
(Trade name, manufactured by Big Chemie Co., Ltd.). The amount of the defoamer is acrylic-modified polyester resin (C)
The amount is preferably 0.001 to 0.5 part by weight, more preferably 0.01 to 0.1 part by weight, per 100 parts by weight.

Examples of the plasticizer include dimethyl phthalate and dioctyl phthalate. The mixing amount of the plasticizer is preferably 1 to 10 parts by weight based on 100 parts by weight of the acrylic-modified polyester resin (C).
More preferably, it is 5 parts by weight.

Examples of the organic solvent include those described above.

As the curing agent, for example, amino resin,
Compounds having an isocyanato group are exemplified. Specific examples of the amino resin include, for example, methylated melamine resin (for example, methyl etherified melamine resin), methylated benzoguanamine resin, methylbutylated melamine resin, methylbutylated benzoguanamine resin, and the like. Specific examples of the compound having an isocyanato group include:
For example, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethyl xylylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated And diisocyanurate-type trimers, biuret-type trimers, and blocked products thereof. When making a one-pack type paint, a block body is usually used.

The compounding amount of the curing agent is preferably 10 to 100 parts by weight, more preferably 25 to 45 parts by weight, based on 100 parts by weight of the acrylic-modified polyester resin (C).

As the surface treatment agent, for example, BYK-3
01 (manufactured by BYK-Chemie KK, trade name) and the like. The amount of the surface treatment agent is preferably 0.005 to 0.5 part by weight, more preferably 0.01 to 0.1 part by weight, based on 100 parts by weight of the acrylic-modified polyester resin (C). preferable.

Examples of the method of forming the aqueous resin composition of the present invention into a paint by mixing the above components include a paint shaker method, a roll mill method, a sand mill method, a disperser method, a kneader method and a high-speed impeller mill method. Known methods can be used.

The obtained water-based paint can be used for coating according to a usual coating method. In the coating, for example, a dipping method, a brush coating method, a spray coating method, a roll coating method, a flow coater coating method, and a shibori ( Alternatively, a known coating method such as a coating method or a knife coater coating method can be used.

After coating, the coating film can be dried and cured by natural drying or forced drying with a dryer.

The aqueous resin composition of the present invention has a coating film having excellent corrosion resistance and can be used as a paint for coating wood, paper, fiber, plastic, ceramic, iron, non-ferrous metal, etc. It is suitable as a paint for coating.

[0053]

Next, the present invention will be described in detail with reference to examples. “Parts” and “%” indicate “parts by weight” and “% by weight”, respectively.

Example 1 Resin composition for water-based paint (R-
Production of 1) (I): 323.2 parts of isophthalic acid, 256.0 parts of neopentyl glycol, 155.2 parts of adipic acid, 2-butyl-2-ethyl-1,3-propanediol (butylethylpropanediol) 158.4 parts were subjected to an esterification reaction at 250 ° C. in the presence of an inert gas to remove generated water, and the reaction was allowed to proceed to an acid value of 1.0. After cooling to 130 ° C., 16 parts of maleic anhydride was added, and the mixture was kept warm for 1 hour to carry out an addition reaction. After cooling, the solution was diluted with butyl cellosolve to obtain a solution of a polyester resin (A) having a weight average molecular weight of 6,000. (Heating residue 74.4%, resin solids acid value 8.
2. Viscosity T +) (II): The flask containing the solution obtained in the above (I) was heated to 130 ° C., and 159 parts of styrene, 41 parts of methacrylic acid, 20 parts of t-butylperoxybenzoate, A mixture of 1 part of di-t-butyl peroxide was added to 2
The mixture was added dropwise over a period of time, and further kept at 135 ° C. for 2 hours. After cooling, the mixture was diluted with 500 parts of butyl cellosolve to obtain an acrylic-modified polyester resin solution. The heating residue of the obtained resin solution was 70.0%, and the weight average molecular weight of the resin was 1
It was 4,000.

Then, 59 parts of dimethylaminoethanol was added as a neutralizing agent, and 1,000 parts of water were further added.
A resin composition was obtained. Heating residue is 40.0%, pH is 8.
5, resin solid content acid value is 33.9, viscosity is 0.9Pa · s
Met.

Examples 2 to 8 and Comparative Examples 1 and 2 Tables 1 and 2 show the amounts of raw materials used in the production of the resin compositions.
The resin compositions of Examples 2 to 8 and Comparative Examples 1 and 2 were produced in the same manner as in Example 1 except that the amount was changed to the amount shown in Table 1.

Table 3 shows the weight average molecular weight of the polyester resins produced in Examples 1 to 8 and Comparative Examples 1 and 2, the weight average molecular weight of the acryl-modified polyester resin, the viscosity and the pH of the resin composition.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3] Evaluation The resin compositions obtained in each of the examples and comparative examples were each made into a paint at the following ratio, and a test was performed. (1) Formulation of paint 300 parts by weight of resin composition of Example or Comparative Example Melan 523 (trade name of methyl etherified melamine resin manufactured by Hitachi Chemical Co., Ltd.) 50 parts by weight 1 part by weight of p-toluenesulfonic acid Ion-exchanged water 74 Parts by weight (2) Test plate preparation conditions Base material: Bontellite # 144 treated steel sheet (manufactured by Nippon Test Panel, thickness 0.5 mm) Painting: applicator (dry film thickness 5 μm) Baking: 280 ° C. × 90 seconds (3) Test method Coating appearance: The finish of the coating was visually observed. <Evaluation> 5 points: Averagely uniform coating film 3 points: Slightly poor uniformity 1 point: Poor uniformity Pencil hardness: According to JIS K5400.

Workability: The test piece was bent at 180 °, and the crack of the coating film at the bent portion was evaluated by a 20-fold loupe according to the following criteria. <Evaluation> 5 points: No cracks 4 points: Very slightly cracked 3 points: Slightly cracked 2 points: Clearly cracked, partially glossy 1 point: There was a crack on the entire surface. Solvent resistance: The state of the coating film after rubbing 100 times in a rubbing test using xylol on the test piece was evaluated according to the following criteria. <Evaluation> 5 points: No glossiness 3 points: Slight glossiness 1 point: Traces reaching the substrate Water resistance: The test piece was immersed in hot water at 60 ° C. for 10 days. And the occurrence of abnormalities such as prestars. <Evaluation> 5 points: No gloss 4 points: Slight gloss 3 points: Slight gloss 2 points: Some gloss 1 point: Large gloss

[0062]

[Table 4]

[0063]

According to the present invention, there is provided an aqueous resin composition for coatings which is excellent in reactivity with a curing agent and can form a coating film having good hardness, workability and water resistance and is suitable for steel plates and other uses. can do.

Claims (3)

[Claims] A total content of a unit derived from a trivalent or higher polyhydric alcohol, a unit derived from a trivalent or higher polybasic acid and a unit derived from a trivalent or higher hydroxy acid is 0 to 5% by weight. An aqueous resin composition comprising an acrylic modified polyester resin (C) obtained by graft-polymerizing an acrylic monomer (B) to a polyester resin (A) containing a certain ethylenic double bond, and a solvent (D). 2. The polyester resin (A) having a hydroxyl value of 1
The aqueous resin composition according to claim 1, which is not more than 00. 3. The aqueous resin composition according to claim 1, further comprising an amino resin or a compound having an isocyanate group.