JP2774234B2 - Resin composition for water-based paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for a water-based paint capable of forming a coating film having excellent weather resistance, water resistance, and durability. The present invention relates to a cold-crosslinkable water-based paint resin composition suitable for painting vehicles and the like.

[0002]

2. Description of the Related Art In general, an aqueous dispersion of an acrylic copolymer has been used for an aqueous paint for normal drying. The aqueous dispersion of an acrylic copolymer requires fusion of emulsion particles during the film formation process after coating. Therefore, it is difficult to increase the resin Tg of the acrylic copolymer used for the water-based paint for normal drying because of its film forming property, so that the stain resistance is reduced, and the water resistance and the like are weak. I can't deny it. On the other hand, the market is becoming more and more expensive year by year, and the demand for water-based paints is also increasing in terms of film elasticity, toughness, stain resistance, and acid rain resistance comparable to organic solvent type urethane paints. On the other hand, general organic solvent-type urethane paints are often difficult to apply under the influence of the solvent used and to select a base coat, especially for repainting applications. Also,
In recent years, in view of environmental hygiene, the Fire Service Law, etc., there has been a demand for water-based coating, and there is a strong expectation for an aqueous urethane coating for normal drying having the function of an organic solvent type urethane coating.

[0003] For the purpose of imparting a urethane function to an aqueous emulsion, attempts have been made to mix an aqueous dispersion of a urethane polymer having a hydrazide residue with an aqueous dispersion of a carbonyl group-containing copolymer (particularly). Kaihei 1-30
1761, JP-A-1-301762). However, this composition does not solve the brittleness at the time of film formation as a paint for normal drying, and does not provide satisfactory quality in dryness, water resistance, outdoor pollution, and acid rain resistance. The present inventors have sought to solve the problems in the above-mentioned water-based paint by reinforcing the brittleness of the water-based emulsion paint at the time of film formation with a crosslinking agent having a relatively small molecular weight, and further comprising a urethane resin water having a crosslinking property. A water-based paint for normal drying using a dispersion in combination has been previously proposed (Japanese Patent Application No. 4-171683).
issue).

[0004]

The above-mentioned water-based paint solves the problem of the coating film. However, since hydrazine or an aqueous solution of hydrazine is used when producing an aqueous urethane resin aqueous dispersion, there are some problems in terms of safety and health. The problem remained.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by adding a carbonyl group to the aqueous urethane resin instead of leaving a hydrazide group, Finding that they can solve the problem,
The present invention has been completed. Thus, according to the present invention, "1. Aqueous dispersion of carbonyl group-containing copolymer (A)
The carbonyl group-containing aqueous polyurethane resin (B) is converted to (A)
A hydrazide compound (C) having at least two hydrazide groups per molecule as a cross-linking agent is blended in an amount of 5 to 150 parts by weight with respect to 100 parts by weight of the solid content of the components (A) and (B). One of the carbonyl groups contained in
A resin composition for an aqueous paint obtained by adding 0.01 to 2 mol per mol. 2. The carbonyl group-containing copolymer dispersion (A) is
(A) 0.1 to 30% by weight of a polymerizable carbonyl group-containing monomer having at least one carbonyl group in one molecule, (b) monoolefinically unsaturated carboxylic acid, the same unsaturated carboxylic acid amide, N of the unsaturated carboxylic acid amide
0 to 10% by weight of a monomer selected from the group consisting of -alkyl or N-alkylol derivative, and (c) vinyl aromatic compound, n-alkyl having 1 to 8 carbon atoms of (meth) acrylic acid 60 to 99.9% by weight of a monomer selected from the group consisting of esters, vinyl esters of saturated carboxylic acids, 1,3-diene, tertiary butyl acrylate, vinyl halide, ethylene, and (meth) acrylonitrile. 2. The resin composition for an aqueous coating composition according to item 1, which is a copolymer dispersion obtained by emulsion-copolymerizing a contained monomer mixture in the presence of a dispersant. 3. Aqueous carbonyl group-containing polyurethane resin (B)
Neutralizes a carboxyl group of a polyurethane resin obtained by reacting a diisocyanate compound (d) with a glycol (e), an alcohol having a carboxyl group and / or a glycol (f) and an alcohol having a carbonyl group (g) with an alkali. 2. The resin composition for an aqueous paint according to item 1, which is obtained by the following method. 4. The carbonyl group-containing aqueous polyurethane resin (B) is a resin having an acid value of 10 to 200 per 1 g of resin solid content.
Item 4. The resin composition for water-based paint according to any one of Items 1 to 3. 5. The resin for an aqueous coating material according to any one of Items 1 to 4, wherein the carbonyl group-containing aqueous polyurethane resin (B) is a resin having a carbonyl group content of 0.005 to 0.3 mol per 100 g of solid content. Composition. 6. The crosslinking agent (C) is H ₂ N—NH—CO—NH—NH
₂ ,

Embedded image And _{H 2 N-NH-CO- (} C n H 2n) -CO-NH
A dihydrazide compound selected from the group consisting of -NH ₂ (n ≦ 8),
Item 14. A resin composition for a water-based paint as described in any one of the above items. 7. A hydrazide compound as a cross-linking agent was added in an amount of 0.01 to 2 mol per 1 mol of carbonyl groups contained in the aqueous copolymer dispersion (A) and the aqueous polyurethane resin (B).
Item 7. The resin composition for a water-based paint according to any one of Items 6 to 6. About.

[0006]

The carbonyl group-containing copolymer aqueous dispersion (A) used in the present invention contains (a) a polymerizable carbonyl group-containing monomer having at least one carbonyl group in one molecule. 1 to 30% by weight, (b) a monomer selected from the group consisting of monoolefinically unsaturated carboxylic acids, the same unsaturated carboxylic acid amides and N-alkyl or N-alkylol derivatives of the same unsaturated carboxylic acid amides 0 to 10
% By weight, and (c) a vinyl aromatic compound, an n-alkyl ester of (meth) acrylic acid having 1 to 8 carbon atoms, a vinyl ester of a saturated carboxylic acid, 1,3-diene, tertiary butyl acrylate, Vinyl halide, ethylene,
It can be easily obtained by emulsion-copolymerizing a monomer mixture containing 60 to 99.9% by weight of a monomer selected from the group consisting of (meth) acrylonitrile in the presence of a dispersant.

As the monomer (a), a monomer having a polymerizable double bond having at least one carbonyl group in one molecule is used. Specific examples of the monomer (a) include acrolein, diacetone (meth) acrylamide, formylstyrene, and a vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone,
Vinyl ethyl ketone, vinyl butyl ketone), acetoacetoxyethyl methacrylate and the like. Particularly preferred is diacetone (meth) acrylamide.

As the monomer (b), monoolefinically unsaturated carboxylic acids such as (meth) acrylic acid and maleic acid; amides of the same unsaturated carboxylic acids; N-methyl (meth) acrylamide, N-methylol N-substituted unsaturated carboxylic amides such as (meth) acrylamide;
And so on.

Examples of the monomer (c) include, in addition to the exemplified monomers, vinyl aromatic compounds such as styrene and vinyl toluene; methyl (meth) acrylate, methyl (meth) acrylate, and butyl (meth) acrylate , 2-
Alkyl esters of (meth) acrylic acid such as ethylhexyl (meth) acrylate; vinyl esters such as vinyl acetate and vinyl propionate; and the like.

The aqueous polyurethane resin (B) used in the present invention can be produced by a preferred method as follows. First, diisocyanate (d)
And a glycol (e) and an alcohol having a carboxyl group and / or a glycol (f) are subjected to a urethanization reaction, and further reacted with an alcohol (g) having a carbonyl group to obtain a urethane polymer.

The diisocyanate (d) includes:
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, m-phenylene diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, lysine diisocyanate, 1,4-cyclohexylene diisocyanate, 4, 4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-
Biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3 '
-Dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalenediisocyanate, 1,5-tetrahydronaphthalenediisocyanate, isophorone diisocyanate and the like.

As the glycols (e) for preparing the urethane polymer, low molecular weight glycols, high molecular weight glycols, polyester polyols, polycarbonate polyols and the like may be used alone.
Further, a low molecular weight glycol may 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, tricyclodiol. There are decanemethylol, hydrogenated bisphenol A, cyclohexanedimethanol, and the like, and these may be used alone or as a mixture of two or more.

Examples of the high molecular weight glycols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like. Polyester polyols are obtained by reacting a glycol component and a dicarboxylic acid component, and are easily produced by a known method. Therefore, it can be produced not only by the esterification reaction but also by a transesterification reaction. Also included are polyester diols obtained by a ring opening reaction of a cyclic ester compound such as ε-caprolactone, and co-condensed polyesters thereof.

Examples of the alcohol having a carboxyl group (f) include hydroxycarboxylic acids such as 12-hydroxystearic acid, paraoxybenzoic acid and salicylic acid. Examples of the glycols having a carboxyl group (f) include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, and a polyester polyol or polyether polyol obtained by condensing the same. Examples of the alcohol having a carbonyl group (g) include diacetone alcohol and 4-hydroxy-2-butanonehydroxyacetone.

The synthesis reaction of the urethane polymer can be carried out in an organic solvent which is inert to isocyanate groups and has a high affinity for water, such as dioxane, acetone, methyl ethyl ketone, methyl isobutyl ketone, N-methylpyrrolidone and tetrahydrofuran. desirable. The urethane polymer produced as described above can be dispersed in water by a conventionally known method, and is not particularly limited. That is, while stirring water (containing a chain extender, a neutralizing agent, a surfactant and the like in some cases), a urethane polymer may be added and mixed or dispersed, or the water may be continuously mixed.

The chain extender is a polyamine compound having at least two active water atoms per molecule, such as ethylenediamine, 1,2-propanediamine,
Diamines such as 1,6-hexamethylenediamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, diethylenetriamine, dipropylenetriamine ,
Examples thereof include polyamines such as triethylenetetramine and hydrazine, which are used alone or in combination. The chain extender may be dissolved in water used as a dispersion medium, or may be added after forming a dispersion, but is usually used after being dissolved in water.

The neutralizing agent is not particularly limited as long as it can neutralize a carboxyl group, and examples thereof include sodium hydroxide, potassium hydroxide, trimethylamine, triethylamine, and ammonia. The neutralizing agent may neutralize the carboxyl group of the dispersant in addition to the polymer, or may neutralize the carboxyl group simultaneously with the dispersion by adding it to water used as a dispersion medium. The amount used is 0.5 to 2.0, preferably 0.7 to 2.0 carboxyl groups.
It is preferable to use in combination with the above-mentioned chain extender in such a ratio as to be 1.3. Further, the aqueous polyurethane resin (B) of the present invention can be desolvated by a known method.

In the present invention, the aqueous polyurethane resin (B)
The acid value therein is preferably from 10 to 200 per 19 resin solids. When the acid value is less than 10, the urethane polymer is neutralized,
When making water-based using water, water-solubilization or dispersion is not sufficient, and storage stability is poor. On the other hand, when oxidation exceeds 200,
When a coating film is formed, durability, water resistance, and the like may be reduced.

In the present invention, the carbonyl group content in the aqueous polyurethane resin (B) is 0.005 to 0.3 mol, preferably 0.01 to 0.2 mol, per 100 g of the solid content of the polyurethane resin. If the amount is less than 0.005 mol, a sufficient crosslinking effect cannot be obtained. If the amount exceeds 0.2 mol, not only a decrease in the molecular weight of the polyurethane resin is caused,
The storage stability of the paint becomes poor. In the present invention, the mixing ratio of the carbonyl group-containing copolymer aqueous dispersion (A) and the aqueous polyurethane resin (B) is such that (B) is 5 to 150 parts by weight with respect to 100 parts by weight of the solid content of (A). , Preferably 10
100 parts by weight, more preferably 10 to 80 parts by weight. If the amount is less than 5 parts by weight, the effect of improving the physical properties is poor.
If the amount exceeds 0 parts by weight, weather resistance, water resistance, elasticity and the like will be reduced.

The crosslinking agent (C) used in the present invention is H
₂ N-NH-CO-NH-NH ₂ (dihydrazine ketone),

Embedded image (Phthalic acid dihydrazide) and _H 2 N-NH-CO-
Is a _(C n _H 2n) dihydrazide compound represented by _{-CO-NH-NH 2 (n} ≦ 8). Among them, preferred are those in which n in the general formula is 1 to 6, and particularly preferred is adipic dihydrazide wherein n = 4.
In the present invention, the mixing ratio of the dihydrazide compound (C) as the crosslinking agent is such that the hydrazide compound is 0 with respect to 1 mol of the carbonyl group contained in the copolymer aqueous dispersion (A) and the aqueous urethane resin (B). 0.01 to 2 mol, preferably 0.05 to 1 mol. If the amount is less than 0.01 mol, a sufficient crosslinking effect cannot be obtained, so that a problem of vulnerability at the time of film formation occurs. On the other hand, even if it is added in an amount of 2 mol or more, it is not possible to obtain an effect higher than the desired crosslinking effect.

[0022] In the present invention, by mixing the dihydrazide compound is a carbonyl group-containing copolymer aqueous dispersion and a carbonyl group-containing aqueous polyurethane down trees <br/> butter and crosslinking agents, film forming time of acrylic copolymer The carbonyl group of the aqueous polymer dispersion and the hydrazide group of the crosslinking agent react with and crosslink with the carbonyl group of the aqueous urethane resin,
In addition to solving the brittleness of the aqueous emulsion paint at the time of film formation, the toughness, durability, stain resistance, elasticity of the urethane resin, the weather resistance of the acrylic resin, and the like are effectively exhibited. Further, when producing the aqueous urethane resin, it is not necessary to use the hydrazine can achieve safe increase of total hygiene.

Further, in the present invention, when producing a paint, a pigment, a filler, an aggregate, a pigment dispersant,
Wetting agents, thickeners, defoamers, plasticizers, film-forming aids, organic solvents, preservatives, fungicides, pH adjusters, rust inhibitors, etc. are selected and combined according to their respective purposes, and are usually Can be performed in the following manner. The composition of the present invention has weather resistance, drying properties,
Because of its excellent water resistance, elasticity, toughness, stain resistance, and acid rain resistance, it is suitable for painting of building exteriors, bridges, vehicles, etc. Because of its many advantages in terms of safety, odor, etc.
Suitable for indoor use.

[0024]

The present invention will be described in more detail with reference to the following examples.

1. Production Example of Aqueous Emulsion Production Example 1 To a 2 liter four-necked flask, 312 parts by weight of deionized water and 2.3 parts by weight of Newcol 707SF (manufactured by Nippon Emulsifier, solid content 30% by weight) were added, and after replacing with nitrogen, 80 ° C.
To keep. Immediately before dropping the pre-emulsion having the following composition, 0.7 parts by weight of ammonium persulfate was added, and the pre-emulsion was dropped over 3 hours. Deionized water 338 parts by weight Diacetone acrylamide 32 parts by weight Acrylic acid 3.2 parts by weight Styrene 97 parts by weight Methyl methacrylate 260 parts by weight 2-ethylhexyl acrylate 100 parts by weight n-butyl acrylate 150 parts by weight Newcol 707SF 62 parts by weight Ammonium persulfate 1 .2 parts by weight From 30 minutes after the completion of the dropping, a solution prepared by dissolving 0.7 parts by weight of ammonium persulfate in 7 parts by weight of deionized water was added dropwise for 30 minutes, and kept at 80 ° C. for another 2 hours.
After the temperature was lowered to 60 ° C., the pH was adjusted to 8 to 9 with aqueous ammonia to obtain Emulsion A-1.

Production Example 2 Emulsion A-2 was obtained in the same manner as in Production Example 1, except that the pre-emulsion to be dropped had the following composition. Deionized water 315 parts by weight Diacetone acrylamide 74 parts by weight Acrylic acid 3.9 parts by weight Styrene 105 parts by weight Methyl methacrylate 269 parts by weight 2-ethylhexyl acrylate 105 parts by weight n-butyl acrylate 176 parts by weight Hydroxyethyl acrylate 15 parts by weight Newcol 707SF 49 parts by weight Ammonium persulfate 1.5 parts by weight The ammonium persulfate added after the completion of the reaction was a solution in which 0.8 parts by weight was dissolved in 8 parts by weight of deionized water. Table 1 shows the property values of the emulsions A-1 and A-2 obtained in Production Examples 1 and 2 above.

[0027]

[Table 1]

Note 1 The solid content was calculated by heating a sample at 150 ° C. for 30 minutes and measuring the remaining amount. Note 2 Emulsion particle size is measured using a spectrophotometer.
D. (Optical Density: absorbance) is 0.
O.I. at 430 nm and 700 nm of the emulsion diluent diluted to about 1 to 1.0. D. (Absorbance). D. ratio (absorbance ratio) was calculated using the following formula, and the literature [Bull. Indus
trial Chemical Research V
ol. 42, 142 (1964)], and the average particle diameter was determined. O. D. ratio = O. D. (430 nm) / O.
D. (700nm)

2. Production Example of Aqueous Polyurethane Resin Production Example 1 Methyl ethyl ketone 39 was placed in a two-liter four-necked flask.
6 parts by weight, polypropylene glycol (molecular weight about 1,0
00) 333.3 parts by weight, 2,2'-dimethylolpropionic acid 67 parts by weight, 1,6-hexanediol
7 parts by weight and 296 parts by weight of isophorone diisocyanate were added, dry nitrogen was sealed in with stirring, the temperature was raised to 70 ° C., the temperature was maintained for 1 hour, and the reaction was further performed at 80 ° C. for 2 hours. 0.3 parts by weight to about 3
The solution is added dropwise over 0 minutes, and the reaction is further carried out at 80 ° C. for 4 hours. Then, it cooled to 30 degreeC and obtained the urethane prepolymer solution. This polyurethane solution was previously stirred in an aqueous amine solution in which 11.8 parts by weight of triethylamine and 10.0 parts by weight of piperazine were dissolved in 868 parts by weight of deionized water. 565.6 parts by weight were gradually poured to obtain a product. This was heated to 50 ° C., and the solvent was removed under reduced pressure.
The concentration was adjusted by adding deionized water to obtain a translucent aqueous polyurethane resin B-1 having a solid content of 30.2% by weight, a pH of 8.5 and an acid value of 36.

Production Example 2 Methyl ethyl ketone 38 was placed in a two-liter four-necked flask.
5 parts by weight, polypropylene glycol (molecular weight about 1,0
00) 333.3 parts by weight, 2,2'-dimethylolpropionic acid 67 parts by weight, 1,6-hexanediol
7 parts by weight and 296 parts by weight of isophorone diisocyanate were charged, dry nitrogen was sealed with stirring, the temperature was raised to 70 ° C., the temperature was maintained for 1 hour, and the reaction was continued at 80 ° C. for 5 hours. Then, it cooled to 30 degreeC and obtained the urethane prepolymer solution. This polyurethane solution was previously
In a 4 liter four-necked flask, 3.4 parts by weight of triethylamine and 17.2 parts by weight of piperazine were added to deionized water 8
550.5 parts by weight was gradually poured into an aqueous amine solution dissolved in 83 parts by weight while stirring to obtain a product. The temperature was raised to 50 ° C., the solvent was removed under reduced pressure, the concentration was adjusted by adding deionized water, the solid content was 29.5% by weight,
8.2, translucent aqueous polyurethane resin B- having an acid value of 37
2 was obtained.

3. Preparation of Resin Mixture In a 1-liter stainless steel container, 470 parts by weight of emulsion A-1, 232 parts by weight of aqueous urethane resin B-1, and 0.75 parts by weight of adipic dihydrazide were stirred and mixed. D-1 was obtained. Similarly, resin mixtures D-2 to D-10 were obtained according to the formulation shown in Table 2.

[0032]

[Table 2]

4. Production of paint Put the following ingredients in a 5 liter stainless steel container,
The mixture was stirred with a disper for 20 to 40 minutes to obtain a pigment-dispersed paste. Tap water 960 parts by weight Ethylene glycol 240 parts by weight Nopco Spars 44C Note 3) 60 parts by weight SN deformer 364 Note 4) 84 parts by weight Fuji Chemi HEC KF = 100 Note 5) 36 parts by weight Titanium white JR-600A Note 6) 2640 parts by weight 4020 parts by weight Note 3) Pigment dispersant manufactured by San Nopco Co., Ltd. Note 4) Defoamer manufactured by San Nopco Co., Ltd. Note 5) Thickener manufactured by Fuji Chemical Co., Ltd. Note 6) White colored pigment manufactured by Teica Co., Ltd. 1 liter stainless steel container And pigment dispersion paste 20
1 part by weight, 422 parts by weight of the resin mixture, and 18 parts by weight of Texanol were further added with stirring, and the pH was adjusted to 7 to 9 with aqueous ammonia to obtain a paint E-1. Similarly, using the resin mixture D-2 to D-10, the paint E-2 to E-
10 were produced. Table 3 shows the property values of the paints E-1 to E-10.

[0034]

[Table 3]

5. Tests and Test Results Examples 1 to 8 and Comparative Examples 1 to 3 The paints E-1 to E-10 produced were diluted with tap water by 0 to 8%, and test plates were produced by the following method. 70 × 150
Esco (Kansai Paint Co., Ltd., epoxy-amine based rust-preventive undercoat) is applied to both sides of the × 0.8 mm bond plate,
After a lapse of 24 hours, the paints of E-1 to E-11 were applied on one side by air spray at a coating amount of 120 g / m ² .
After drying for 2 hours, 120 g of the same air spray paint
/ M ² . The following tests were performed on the obtained test plates. The results are shown in Table 4.

(1) Water resistance test (A) After coating the above test plate, drying it for 2 hours at a temperature of 20 ° C. and a relative humidity of 75%, the test plate was half-submerged in 20 ° C. water. After one hour, the test plate was pulled up and the coated surface was visually evaluated. A: No change at all. ：: Partial blisters. □: Full blister. X: Paint eluted.

(2) Water resistance test (B) After the test plate was coated, dried for 7 days at a temperature of 20 ° C. and a relative humidity of 75%, the test plate was half-submerged in 20 ° C. water. After 5 days, the test plate was pulled up and the coated surface was visually evaluated. A: No change at all. ：: Partial blisters. Mouth: full bluff. X: Paint eluted.

(3) Accelerated Weather Resistance Test The test plate was subjected to a weather resistance test for 1,500 hours using a sunshine weatherometer, and the gloss retention was calculated using the following formula to evaluate the weather resistance.

[0039]

(Equation 1)

(4) Two-cone hardness test The paints of E-1 to E-11 were applied to a glass plate with a 6-mil blade, dried at room temperature for 10 days, and the two-cone hardness was measured.

(5) JIS A6910 waterproofing standard-related test Elongation test Ares rubber tile rough (manufactured by Kansai Paint Co., Ltd., base material for thickening for exterior) was painted with a 2 mm blade, and after 24 hours, paints E-1 to E- 11 at 100 g / m ²
It was painted with a brush so that it became. Two hours later, the same paint was applied again. Thereafter, the test piece was cured according to JIS A6910 and punched out with a No. 2 damper to obtain a test piece, which was subjected to an elongation test at 20 ° C and -10 ° C. Heating / cooling repetition test Using ALES rubber tile sealer (manufactured by Kansai Paint Co., Ltd., sealer) as a primer, ALES rubber tile rough as a main agent, and using E-1 to E-11 for the overcoat, and using JIS A6910 A test piece was prepared in accordance with the standard, and after 10 cycles of a hot / cold repetition test in accordance with the standard, evaluation was performed according to the following evaluation criteria. ：: Swelling on part of the coating film. □: Swelling on the entire coating film. ×: Cracks are observed in the coating film.

[0042]

[Table 4]

[0043]

As can be seen from Table 4, the composition of the present invention does not satisfy the requirements of the present invention (Comparative Examples 1 to 3).
Water resistance, weather resistance, and film elongation (particularly-
(10 ° C.) in a well-balanced and excellent manner in each step. In particular, an aqueous polyurethane having no carbonyl group was branded as a carbonyl group-containing copolymer aqueous dispersion and a dihydrazide compound-containing system (Comparative Example 1). In comparison, it can be seen that the weather resistance, coating film hardness and JIS suitability are significantly improved.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-10948 (JP, A) JP-A-5-51559 (JP, A) JP-A-4-81447 (JP, A) JP-A-2- 238015 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C09D 201/06-201/08 C09D 175/04

Claims (7)

(57) [Claims] 1. A carbonyl group-containing aqueous polyurethane resin (B) is added to a carbonyl group-containing copolymer aqueous dispersion (A) in an amount of 5 to 15 parts by weight based on 100 parts by weight of a solid content of (A).
0 parts by weight, and a hydrazide compound (C) having at least two or more hydrazide groups per molecule as a crosslinking agent is added to 1 mol of the carbonyl group contained in the components (A) and (B). A water-based paint resin composition obtained by adding 0.01 to 2 moles of the resin composition. 2. A carbonyl group-containing copolymer dispersion (A)
(A) 0.1 to 30% by weight of a polymerizable carbonyl group-containing monomer having at least one carbonyl group in one molecule, (b) monoolefinically unsaturated carboxylic acid, unsaturated carboxylic acid 0 to 10% by weight of a monomer selected from the group consisting of an amide and an N-alkyl or N-alkylol derivative of the same unsaturated carboxylic acid amide, and (c) a vinyl aromatic compound, (meth) acrylic acid N-alkyl esters having 1 to 8 carbon atoms, vinyl esters of saturated carboxylic acids, 1,3-diene, tertiary butyl acrylate, vinyl halide, ethylene, (meth) acrylonitrile A copolymer dispersion obtained by emulsion-copolymerizing a monomer mixture containing 60 to 99.9% by weight of a monomer in the presence of a dispersant.
The resin composition for water-based paint described in the above. 3. The aqueous carbonyl group-containing polyurethane resin (B) comprises a diisocyanate compound (d) and a glycol (e), an alcohol having a carboxyl group and / or a glycol (f) and an alcohol (g) having a carbonyl group. The resin composition for an aqueous coating according to claim 1, which is obtained by neutralizing a carboxyl group of a polyurethane resin obtained by the reaction with an alkali. 4. The aqueous paint resin composition according to claim 1, wherein the carbonyl group-containing aqueous polyurethane resin (B) is a resin having an acid value of 10 to 200 per gram of resin solid content. Stuff. 5. The carbonyl group-containing aqueous polyurethane resin (B) is a resin containing 0.005 to 0.3 mol of carbonyl groups per 100 g of solids.
The resin composition for a water-based paint described in any one of the above. 6. The crosslinking agent (C) is H ₂ N—NH—CO—N
H-NH ₂ , And _{H 2 N-NH-CO- (} C n H 2n) -CO-NH
A dihydrazide compound selected from -NH 2 _(n ≦ 8), the resin composition for an aqueous coating material according to any one of claims 1 to 5. 7. The hydrazide compound as a cross-linking agent is added in an amount of 0.01 to 2 mol per 1 mol of carbonyl groups contained in the aqueous copolymer dispersion (A) and the aqueous polyurethane resin (B). 7. The resin composition for a water-based paint described in any one of 6.