JP2001335670A - Aqueous resin composition and crosslinking agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous resin composition capable of forming a film having excellent transparency, water whitening resistance and adhesion after drying, and a good dispersion in water, and also to obtain an aqueous emulsion. Providing a hydrazide cross-linking agent with excellent storage stability and film forming properties. SOLUTION: A polymer having an aldehyde group or a ketone group, a hydrazide compound represented by any of the following formulas,
And a hydrazide-based cross-linking agent for these polymers. Embedded image (Wherein, R ₁ and R ₂ are each independently hydrogen or a methyl group, and R ₃ is an aliphatic hydrocarbon group having 2 to 18 carbon atoms or a xylylene group)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for forming a tough and water-resistant film after drying, which is useful for wood, metal,
The present invention relates to an aqueous resin composition useful as a coating material for various substrates such as resin molded products, a binder such as an aqueous paint or printing ink, a coating material, an adhesive, and the like. The invention also relates to a crosslinking agent that can be used in such a composition.

[0002]

2. Description of the Related Art In the field of paints, conversion from organic solvent-based paints to water-based emulsion paints is strongly desired from the viewpoint of environmental hygiene and resource saving. It is not sufficient in terms of toughness and adhesive strength. In order to improve these physical properties, a crosslinked coating film is often formed by introducing a functional group into a base polymer contained in an aqueous emulsion.

As a water-based emulsion capable of forming a crosslinked coating film, a one-pack type emulsion obtained by mixing a curing agent and a polymer is desired from the viewpoint of workability and workability. As such a one-part type emulsion, U.S. Pat. No. 3,345,336 (JP-B-46-20053) discloses a crosslinkable emulsion containing a polymer having a carbonyl group and a polyhydrazide compound. I have. This aqueous emulsion is a one-part type, and the water in the emulsion evaporates after application.
By drying, a hydrazide group and a carbonyl group undergo a dehydration condensation reaction and crosslink to form a film. The polyhydrazide compound used herein is a compound having at least two or more hydrazide groups, for example, dihydrazide of an aromatic dicarboxylic acid such as phthalic acid, isophthalic acid or terephthalic acid, and preferably an aliphatic having 2 to 10 carbon atoms. Dihydrazide of a saturated dicarboxylic acid, specifically, oxalic acid, sebacic acid, and particularly preferably dihydrazide of adipic acid are exemplified.

[0004] One-part cross-linkable aqueous emulsions using polyhydrazide compounds have also been described, for example, in German Offenlegungsschrift No. 2819092 (JP-A-54-144).
432), German Offenlegungsschrift 2803258 (Japanese Patent Laid-Open No. 54-110248), Japanese Patent Laid-open No.
3850, JP-A-57-3857, JP-A-58-96643, JP-A-58-104902, JP-A-60-38468, JP-A-62-2
No. 5163, Japanese Patent Application Laid-Open No. 62-62853, and German Patent Publication No. 3720860 (Japanese Patent Application Laid-Open No. 1-202).
No. 56), JP-A-1-234416, JP-A-3-68669, JP-A-4-227947 (German Patent No. 4016056) and JP-A-4
Various improvements have been proposed in JP-A-249587, WO96 / 01252 and the like.

Most of these one-part aqueous emulsions use an aliphatic dicarboxylic acid dihydrazide as a polyhydrazide compound, and most use adipic dihydrazide. However, although adipic dihydrazide functions effectively as a cross-linking agent, cross-linking does not proceed sufficiently due to insufficient solubility in water, and thus the formed film does not necessarily have sufficient water resistance.

A water-dispersible resin composition containing a polyhydrazide compound having high water solubility is disclosed in JP-A-7-6218.
No. 8 discloses 1,3-bis (hydrazinocarboethyl)-
An aqueous dispersion resin composition containing a hydrazide such as 5-isopropylhydantoin and N, N'-dihydrazidecarboethylpiperazine is disclosed, but these are all bifunctional hydrazides and have a sufficient coating after crosslinking. The strength has not been obtained.

[0007] One-part crosslinking aqueous emulsions using trihydric or higher polyhydrazide compounds are also exemplified in some of the above documents. For example, Japanese Patent Publication No. 61-6861
JP-A-60-38468 discloses tri- or tetrahydrazide of pyromellitic acid, trihydrazide nitrilotriacetic acid, and tetrahydrazide of ethylenediaminetetraacetic acid.
No. 3,720,860 and German Patent No. 4016056, pentane-1,
3,5-tricarboxylic trihydrazide, hexene-4
-1,2,6-Tricarboxylic trihydrazide and 3-cyanopentane-1,3,5-tricarboxylic trihydrazide are described, respectively.

When a hydrazide compound having three or more functional groups is used, the crosslinking density can be increased, so that the water resistance of the coating film is expected to be improved. However, if the number of hydrazide groups is excessively large, the number of hydrazide groups that cannot participate in crosslinking due to steric hindrance or the like increases, and the water resistance of the coating may rather decrease. Also, Japanese Patent Application Laid-Open No. Hei 1-234416
Polymer hydrazide described in JP-A-6-80619 and 1,2,3,4 described in JP-A-6-80619.
In the case of -butanetetracarboxylic acid hydrazide, since the hydrazide compound itself is hardly soluble in water, crosslinking does not proceed sufficiently as in the case of adipic acid dihydrazide, so that the water resistance of the coating film is often insufficient.

Further, nitrilotriacetic acid trihydrazide and ethylenediamine tetraacetic acid tetrahydrazide described in JP-B-6-92574 are apt to cause a hydrazine ring-closing reaction because of their structures and are not suitable for use as a crosslinking agent. Until now, it has been difficult to obtain a crosslinked film having excellent properties such as water resistance and adhesion to a substrate with an aqueous resin composition containing a crosslinking agent and a carbonyl compound.

As other hydrazide compounds having three or more functional groups, trifunctional or tetrafunctional hydrazide compounds used in the present invention are disclosed in JP-A-59-67256 and JP-A-60-178851. It has been proposed to use as a curing agent for resins.

[0011]

The present inventor has previously proposed an aqueous resin composition using a specific polyvalent hydrazide compound as a crosslinking agent in Japanese Patent Application Laid-Open No. H11-343377. An object of the present invention is to provide an aqueous resin composition obtained by further improving the above technology and a carbonyl compound crosslinking agent used for the same.

That is, the present invention relates to an aqueous resin composition capable of forming a film having excellent transparency, water-whitening resistance and adhesion after drying, a good dispersion in water, and a method of preparing an aqueous emulsion. An object of the present invention is to provide a crosslinking agent based on a hydrazide compound having excellent storage stability and film forming properties.

[0013]

Means for Solving the Problems The present inventor has conducted various studies including the steric structure of a hydrazide compound in order to solve these problems. As a result, a trifunctional or tetrafunctional hydrazide compound having a specific structure has been found. But its water solubility is high,
It has been found that an aqueous resin composition having good storage stability by being uniformly dispersed in water can be prepared. Moreover, by drying the aqueous resin composition in which the hydrazide compound and the carbonyl group-containing polymer are combined, a film forming property,
The inventors have also found that a film having excellent transparency and water-whitening resistance can be formed, and have completed the present invention.

That is, the gist of the present invention is to provide an aqueous resin composition containing a polymer having an aldehyde group or a ketone group, a hydrazide compound represented by the formula (1) or (2) and an aqueous medium, wherein the hydrazide compound is Tri (hydrazinocarboethyl) amine (formula (3)), N, N, N'N'-
Tetra (hydrazinocarboethyl) ethylenediamine (Formula (4)) and N, N, N'N'-tetra (hydrazinocarboethyl) hexamethylenediamine (Formula (5))
At least one compound selected from the group consisting of:

[0015]

Embedded image

(Wherein R ₁ and R ₂ are each independently hydrogen or a methyl group, and R ₃ is an aliphatic hydrocarbon group having 2 to 18 carbon atoms or a xylylene group)

[0017]

Embedded image

Another gist of the present invention is that a polymer having an aldehyde group or a ketone group is a monomer having at least one aldehyde group or a ketone group and a radical polymerizable double bond in a molecule (hereinafter referred to as “a monomer having an aldehyde group or a ketone group”). Monomer (a) ”) and a monomer copolymerizable with the monomer (a) (hereinafter referred to as“ monomer (b) ”).
And the monomer (a) is a copolymer of diacetone acrylamide and diacetone methacrylamide (hereinafter, “acryl” and “methacryl” together with “(meth) Acrylic)), acrolein, methacrolein (hereinafter referred to as “(meth)
Acrolein "), acetoacetoxyethyl acrylate, and acetoacetoxyethyl methacrylate (hereinafter," acrylate "and" methacrylate "are abbreviated as" (meth) acrylate "). The above aqueous resin composition which is a monomer, and wherein the monomer (b) has 1 to 1 carbon atoms.
The above-mentioned aqueous resin composition which is an alkyl (meth) acrylate having an alkyl group of 18 also exists.

Another gist of the present invention is that a polymer having an aldehyde group or a ketone group is prepared by converting a monomer mixture containing a monomer (a) and a monomer (b) in the presence of a surfactant. The present invention resides in the above-mentioned aqueous resin composition obtained by emulsion polymerization in an aqueous medium, and an aqueous paint containing any of the above-mentioned aqueous resin compositions. Another aspect of the present invention resides in a crosslinking agent for a polymer having an aldehyde group or a ketone group, comprising a hydrazide compound represented by the formula (1) or (2). Another gist of the present invention is that
When the hydrazide compound is tri (hydrazinocarboethyl)
Amine (the following formula (3)), N, N, N'N'-tetra (hydrazinocarboethyl) ethylenediamine (the following formula (4)) and N, N, N'N'-tetra (hydrazinocarboethyl) As the crosslinking agent and the polymer having an aldehyde group or a ketone group, which are at least one compound selected from the group consisting of hexamethylenediamine (formula (5)), those dispersed or dissolved in an aqueous medium are used. The crosslinking agent also exists.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component of the aqueous resin composition of the present invention and a crosslinking agent will be described in detail. (1) Aqueous resin composition The aqueous resin composition of the present invention contains a specific polymer and a specific hydrazide compound. Among them, the hydrazide compound will be described in another section. <Polymer> As the polymer having an aldehyde group or a ketone group used in the aqueous resin composition of the present invention, 1
A monomer having at least one aldehyde group or ketone group and a radical polymerizable double bond (monomer (a)), and a monomer copolymerizable with the monomer (a) (monomer A copolymer with (b)) is preferably exemplified.

The monomer (a) having one or more aldehyde groups or ketone groups and a radically polymerizable double bond in the molecule includes (meth) acrolein, diacetone (meth) acrylamide, formylstyrene , Vinyl methyl ketone, vinyl ethyl ketone, diacetone (meth) acrylate, acetoacetoxyethyl (meth) acrylate and the like.

Among these, diacetone (meth)
Acrylamide, (meth) acrolein, and acetoacetoxyethyl (meth) acrylate are preferred. The content of the monomer (a) in the copolymer is preferably from 1 to 40% by weight, and more preferably from 2 to 20% by weight. When the content is less than 1% by weight, the content of the carbonyl group in the polymer decreases, so that the crosslinking density at the time of crosslinking between the polymer and the hydrazide compound decreases, and the effect of improving the film properties such as water resistance is improved. May not be obtained sufficiently.
Conversely, when the content of the monomer (a) is more than 40% by weight, the content of the monomer (b) becomes relatively small, so that various properties required for the intended use can be obtained. Tends to be difficult to be performed.

The structure of the monomer (b) having a radical polymerizable double bond copolymerizable with the monomer (a) is not particularly limited as long as it can be copolymerized with the monomer (a). Not done.
Examples of such a monomer (b) include styrene, α
-Aromatic vinyl compounds such as methylstyrene and vinylnaphthalene; methyl (meth) acrylate, ethyl (meth)
C1-C18 cycloalkyl or alkyl (meth) acrylates such as acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and stearyl (meth) acrylate; Α) β-unsaturated carboxylic acids such as acrylic acid; α, β-unsaturated dicarboxylic acids such as itaconic acid, maleic acid and 2-methyleneglutaric acid; 2-hydroxyethyl (meth) acrylate;
(Meth) acrylic acid esters having a hydroxy group at the terminal such as 4-hydroxybutyl (meth) acrylate; vinyl esters such as vinyl acetate and vinyl propionate;
Examples thereof include (meth) acrylamide, N-alkylolacrylamide, (meth) acrylonitrile, and vinyl halide.

If necessary, two or more radicals in one molecule such as allyl (meth) acrylate, ethylene glycol di (meth) acrylate, and trimethylolpropane triacrylate may be added to the above monofunctional monomer. A crosslinkable monomer having a polymerizable double bond can also be used. The content of the monomer (b) in the copolymer is 99 to 60.
%, More preferably from 98 to 80% by weight.

Particularly preferred monomers (b) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and stearyl (meth) acrylate. (Meth) having a (cyclo) alkyl group having 1 to 18 carbon atoms such as acrylate
Acrylic acid esters, and these monomers account for 50 to 99% by weight, preferably 60 to 95% by weight, of all monomers.
Preferably, it is included.

The monomers (a) and (b) each have 1
Each type of monomer may be used, or two or more types of monomers may be used in combination. When two or more monomers are used in combination as the monomer (b), one or more monomers having a glass transition temperature of the homopolymer of 40 ° C. or more and a glass transition temperature of the homopolymer of 25 or more are used.
It is preferable to use a combination of at least one kind of monomer having a temperature of not more than ° C.

The above homopolymer has a glass transition temperature of 4
Examples of the monomer having a temperature of 0 ° C. or higher include, for example, methyl methacrylate, ethyl methacrylate, and styrene, and examples of the monomer having a glass transition temperature of the homopolymer of 25 ° C. or lower include, for example, butyl acrylate and 2-ethylhexyl acrylate. Each can be mentioned. The glass transition temperature of the copolymer can be appropriately adjusted depending on the use of the aqueous resin composition. Among them, those having a calculated glass transition temperature of a copolymer in the range of -60 ° C to 80 ° C, which is calculated by the following formula, are preferable. A more preferred glass transition temperature is from -20C to 60C.

[0028]

1 / Tg = Wa / Tga + Wb / Tgb (where Tg is the calculated glass transition temperature (K) of the copolymer, and Tga and Tgb are the monomer (a) and the monomer ( glass transition temperature (K) of the homopolymer of b), W
a and Wb indicate the weight fraction of the monomer (a) and the monomer (b), respectively. In preparing the aqueous resin composition of the present invention, a polymer having an aldehyde group or a ketone group to be used is prepared as an aqueous solution or an aqueous dispersion, and other components are added and mixed with the aqueous solution. It is preferable in the preparation of a product.

When preparing an aqueous solution of the polymer, not only water but also a mixed solvent of water and an organic solvent soluble in water can be used as the solvent. Examples of such water-soluble organic solvents include alcohols such as methanol, ethanol, and isopropyl alcohol; ketones such as acetone and methyl ethyl ketone; glycol ethers such as methyl cellosolve and butyl cellosolve; tetrahydrofuran;
Ethers such as 1,4-dioxane;

On the other hand, when preparing an aqueous dispersion of a polymer, a method capable of obtaining a dispersion at the same time as the production of a polymer, that is, emulsion polymerization, suspension polymerization, or solution polymerization in an organic solvent followed by aqueous polymerization It is preferable to use a method of adding a medium and inverting the phase. Among them, it is particularly preferable to prepare a dispersion by emulsion polymerization in the presence of a polymerization initiator and a surfactant in an aqueous medium.

Examples of the polymerization initiator used in the emulsion polymerization include persulfates such as potassium persulfate and ammonium persulfate; peroxides such as hydrogen peroxide, benzoyl peroxide and t-butyl hydroperoxide; azobisisobutyrate Azo-based polymerization initiators such as lonitrile; redox-type polymerization initiators obtained by combining these polymerization initiators with a reducing agent such as ascorbic acid can be used. These polymerization initiators may be used alone or in combination of two or more as needed. The amount of the polymerization initiator used is 0.01 to 1 with respect to 100 parts by weight of the total amount of the monomers.
It is preferably 0 parts by weight, more preferably 0.1 to 2 parts by weight.

Examples of the surfactant used in the emulsion polymerization include anionic surfactants such as alkylbenzene sulfonates, higher alcohol sulfates and polyoxyethylene alkyl sulfonates; polyoxyethylene alkyl ethers and polyoxyethylenes. Nonionic surfactants such as alkyl phenyl ethers; cationic surfactants can be used. In addition, a reactive surfactant having a radical polymerizable unsaturated bond in the molecule can also be used as the surfactant, and such a reactive surfactant is preferable because the water resistance of a formed film is improved. .

Examples of the reactive surfactant include sodium alkyl allyl sulfosuccinate (manufactured by Sanyo Chemical; Eleminor JS-2, manufactured by Kao; Latemul S-180) and sodium methacryloyloxy polyoxyalkylene sulfate (manufactured by Sanyo Chemical; Eleminor RS-). 30), polyoxyethylene alkyl allyl phenyl ether (Daiichi Kogyo Seiyaku; Aqualon RN series), polyoxyethylene alkyl allyl phenyl ether sulfate (Daiichi Kogyo Seiyaku; Aqualon HS series) and the like.
These surfactants may be used alone or in combination of two or more. These surfactants are usually added in an amount of 0.1 to 100 parts by weight of the total amount of the monomers.
10 to 10 parts by weight, preferably 1 to 5 parts by weight is used.

At the time of polymerization, a water-soluble polymer compound such as polyvinyl alcohol and hydroxyethyl cellulose may be added as a protective colloid in addition to the polymerization initiator and the surfactant, and the molecular weight of the copolymer is adjusted. For this purpose, an alkyl mercaptan may be added as a molecular weight regulator. In addition, when an unsaturated carboxylic acid monomer such as acrylic acid is copolymerized, the emulsifying power may be reduced in an acidic region depending on the type of emulsifier. It is preferable to carry out the polymerization by adjusting the pH inside.

The temperature during the emulsion polymerization is not particularly limited.
Usually, it is 40 to 95 ° C, preferably 60 to 90 ° C. <Blending ratio> The blending ratio of the aqueous resin composition of the present invention is not particularly limited. For example, the polymer is used in an amount of 5 to 200 parts by weight per 100 parts by weight of the aqueous medium, and the hydrazide compound is added to the polymer. And may be used at the ratio described later. If the amount of the polymer used is less than 5 parts by weight, it takes a long time to dry after coating, while if it is added in a large amount exceeding 200 parts by weight, the viscosity of the composition becomes high and the handleability becomes poor. There is.

The other components can be used in amounts that do not impair the effects of the present invention, depending on the purpose of their addition. <Optional Components> The aqueous resin composition of the present invention contains an aldehyde group or a ketone group. In addition to the polymer having, a hydrazide compound and an aqueous medium, depending on the use thereof, within a range that does not impair the effects of the present invention, a film forming aid, an antifoaming agent, a rust inhibitor, a thickener, a preservative, An ultraviolet absorber, a light stabilizer, a pigment, an inorganic filler such as silica, and the like can be blended. (2) Crosslinking Agent (Hydrazide Compound) The hydrazide compound, which is an essential component of the aqueous resin composition containing a polymer having an aldehyde group or a ketone group according to the present invention, is represented by the above formula (1) or (2). Is a compound having 3 or 4 hydrazide groups in the molecule. Because of the multifunctionality, three-dimensional cross-linking is easily possible, and the cross-linking density can be increased as compared with a conventionally used bifunctional hydrazide such as adipic dihydrazide, and thus the obtained product can be obtained. The water resistance of the coating can be dramatically improved.

In particular, the hydrazide compound represented by the formula (1) has a low steric hindrance because the hydrazide group is not bonded to a secondary carbon atom unlike cyclohexanetricarboxylic acid trihydrazide, and the crosslinking reaction is easy. Progress and an excellent crosslinking effect is obtained. Furthermore, compared with aromatic hydrazides such as trimellitic acid hydrazide, etc., they exhibit good crosslinking reactivity because of the high degree of molecular freedom in structure, and have the same properties as tetrahydrazide such as pyromellitic tetrahydrazide and butanetetracarboxylic acid tetrahydrazide. There is an advantage that the solubility in water is extremely high as compared with a functional hydrazide compound or polyhydric hydrazide obtained by modifying poly (meth) acrylic acid with hydrazine.

The hydrazide compound of the present invention may be ammonia or NH ₂ —R ₃ —NH ₂ (where R ₃ has 2 to 1 carbon atoms).
And a polycarboxylic acid ester obtained by Michael addition of an alkyl (meth) acrylate at least 3 times or at least 4 times the molar amount of the diamine represented by the formula (8). It can be obtained by reaction with water hydrazine. Examples of the diamine include ethylenediamine, hexamethylenediamine, octamethylenediamine, cyclohexanediamine, 1,3-di (aminomethyl) cyclohexane,
4,4'-diaminodicyclohexylmethane, xylylenediamine and the like can be mentioned.

Specific examples of the hydrazide compound of the present invention include tri (hydrazinocarboethyl) amine, tri (hydrazinocarbomethylethyl) amine, N, N, N ′
N'-tetra (hydrazinocarboethyl) ethylenediamine, N, N, N'N'-tetra (hydrazinocarbomethylethyl) ethylenediamine, N, N, N'N'-tetra (hydrazinocarboethyl) hexamethylenediamine N, N, N'N'-tetra (hydrazinocarboethyl) octadecylmethylenediamine, N, N, N'N '
-Tetra (hydrazinocarboethyl) xylylenediamine, more preferably tri (hydrazinocarboethyl) amine (compound of formula 3), N, N, N'N'-
Tetra (hydrazinocarboethyl) ethylenediamine (compound of formula 4) and N, N, N'N'-tetra (hydrazinocarboethyl) hexamethylenediamine (compound of formula 5).

The amount of the hydrazide compound used is such that the hydrazino group in the hydrazide compound is usually 0.1 to 2 equivalents, preferably 0.3 to 1 equivalent of the carbonyl group in the polymer.
It is desirable that the amount be from 1.5 to 1.5 equivalents, more preferably from 0.5 to 1.0 equivalent. When used as an aqueous resin composition, the amount in the above range may be added according to the amount of the polymer used. (3) Crosslinking In the aqueous resin composition of the present invention containing the specific polymer of the present invention and the hydrazide compound, the crosslinking reaction between the carbonyl group and the hydrazino group, which is a dehydration reaction, hardly occurs because water is present during storage. And it has sufficient storage stability for a long period of time despite being a one-pack type.

On the other hand, when water evaporates, the carbonyl group in the polymer and the hydrazino group of the hydrazide compound undergo a cross-linking reaction even at room temperature to form a tough and water-resistant film. The hydrazide compound of the present invention has 3 or 4
Has two hydrazino groups, so that compared to a composition using a hydrazide compound having two hydrazino groups in a molecule such as adipic acid dihydrazide, a crosslink density is high and a strongly crosslinked film can be formed. .

[0042]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Production Examples and Examples, but the present invention is not limited to these Examples and the like unless departing from the gist thereof. In addition, "part" in the following production examples and examples,
“%” Represents “parts by weight” and “% by weight” unless otherwise specified. (Production Example 1) Production of aqueous dispersion of polymer In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, ammonium persulfate (2.0 parts), an anionic reactive emulsifier (Daiichi Kogyo) Pharmaceutical: Aqualon HS-1
0 (25% aqueous solution) (8.0 parts), 28% aqueous ammonia (2.0 parts), and water (200.0 parts) were charged and heated at 75 ° C. under a nitrogen atmosphere. Here, 2-ethylhexyl acrylate (60.0 parts), styrene (52.0 parts),
N-butyl acrylate (120 parts), methyl methacrylate (130.0 parts), diacetone acrylamide (3 parts)
0.0 parts), acrylic acid (8.0 parts), anionic reactive emulsifier (same as above) (32.0 parts), lauryl mercaptan (1.0 part), and water (170 parts) The emulsion mixed and emulsified by the mixer was dropped over 3 hours.

30 minutes after the completion of the dropping of the emulsion,
28% aqueous ammonia (6.4 parts) was added, and ammonium persulfate (0.3 parts) was added as an additional catalyst to water (2 parts).
Was added thereto, followed by a reaction at 80 ° C. for 3 hours. After the reaction for a predetermined time, the reaction mixture was cooled to obtain a milky white aqueous dispersion having a solid content of 50.8%. (Production Example 2) Production of an aqueous dispersion of a copolymer Without using 2-ethylhexyl acrylate as a monomer, the amount of styrene used was 62.0 parts, and acrylic acid-n-
The polymerization was carried out in the same manner as in Production Example 1 except that butyl was changed to 200 parts, methyl methacrylate was changed to 120.0 parts, and the amount of the anionic reactive emulsifier used in the emulsion was changed to 30.0 parts. The reaction was performed and the solid content was 51.0%.
To obtain a milky aqueous dispersion. (Production Example 3) Preparation of 10% aqueous solution of hydrazide compound The hydrazide compound represented by the formula (3) to (5) (10
Part) was mixed with water (90 parts) at room temperature to prepare an aqueous solution of a 10% hydrazide compound. These were easily dissolved in water to obtain an aqueous solution.

Similarly, adipic dihydrazide (ADH) (10 parts) and Amicure VDH (manufactured by Ajinomoto Co.) (10 parts) were used as hydrazide compounds for comparative examples.
Was mixed with water (90 parts) at room temperature to prepare a 10% aqueous solution. However, adipic dihydrazide did not readily dissolve in water at room temperature and was dissolved by heating. In addition, the solubility of various polyfunctional hydrazide compounds in water at 20 ° C. was measured. Table 1 shows the measured values. The numerical value is 20 ° C
Is the amount (g) of the hydrazide compound dissolved in 100 g of distilled water.

[0045]

[Table 1]

Since Comparative Products 3 and 4 had low solubility in water, they were not evaluated when applied to an aqueous dispersion resin. (Examples 1 to 6 and Comparative Examples 1 to 6) Production of aqueous resin compositions The aqueous dispersions of Production Examples 1 and 2 were prepared such that the equivalent of the hydrazino group of the hydrazide compound to the carbonyl group of the polymer became a predetermined amount. The aqueous solution and various 10% aqueous hydrazide compound solutions of Production Example 3 were stirred and mixed to obtain an aqueous resin composition.

At this time, the combination of the polymer and the hydrazide compound was changed as shown in Tables 2 and 3, and
Various types of aqueous resin compositions were prepared. In Comparative Examples 3 and 6, an amount of water corresponding to the aqueous solution was used instead of the hydrazide compound. (Evaluation) <Storage stability> After storing the aqueous resin composition in a 50 ° C constant temperature bath for one month, the storage stability was evaluated by visually determining the state of the composition according to the following criteria.

：: Equivalent to the initial state, and no generation of aggregates or the like was observed. Δ: Aggregates or the like are slightly observed, or the viscosity is increased. ×: The composition is separated or gelled. <Surface Appearance> The aqueous resin composition was treated with a corona-treated polyethylene terephthalate film substrate (thickness 10).
0 μm) using a bar coater (# 20)
The specimen was dried at normal temperature for one week to prepare a test piece having a coating having a thickness of 15 μm.

The appearance of the coating film was evaluated by visually judging the state of the coating film on each test piece according to the following criteria. ：: A uniform coating film is formed. ×: Cracks have occurred in the coating film. <Transparency / water whitening resistance> The haze meter (manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the haze of the test piece, and the transparency was evaluated. Further immerse this test piece in distilled water at room temperature,
The water whitening resistance was evaluated by measuring the change (ΔH) in the haze after 1 day and 7 days using a haze meter. <Water absorption> Each aqueous resin composition was added to a Teflon (registered trademark) container, dried at 40 ° C for 7 days, and dried to a thickness of 1 mm.
Was prepared. 25mm ×
It is cut into 25 mm to make a test piece, and is placed in distilled water at room temperature.
From the weight before and after immersion for a day, the water absorption was calculated using the following equation. Tables 2 and 3 summarize these results.

[0050]

## EQU2 ## Water absorption (%) = {(weight after immersion−weight before immersion) / weight before immersion} × 100

[0051]

[Table 2]

[0052]

[Table 3]

(Evaluation of Results) (1) The aqueous resin dispersion using the hydrazide compound of the present invention shows the same storage stability and surface appearance of the coating as those using the conventionally used hydrazide compound. There is no problem in use. (2) The water whitening resistance and water absorption of Comparative Examples using a hydrazide compound outside the scope of the present invention are almost the same as those of Comparative Examples 1 and 2. Comparative Examples 4 and 5 are inferior in water whitening resistance and water absorption. (3) Comparative Examples 3 and 6, which contain no hydrazide compound at all, are significantly inferior in both water whitening resistance and water absorption.

[0054]

The aqueous resin composition of the present invention has good storage stability and can form a film having excellent transparency and water resistance by drying.

Such an aqueous resin composition is useful as a coating material for various substrates such as wood, metal, resin molded products, a binder such as a paint or printing ink, a coating material, an adhesive, an adhesive and the like. It is. Further, the polyfunctional hydrazide compound of the present invention has high water solubility, can be easily dissolved and mixed in an aqueous resin, and has excellent crosslinking reactivity with a polymer having a carbonyl group.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 129/12 C09D 129/12 133/00 133/00 201/06 201/06 // (C08F 220/18 (C08F 220/18 220: 58 220: 58 216: 34 216: 34 220: 26) 220: 26) F term (reference) 4J002 BC041 BG031 EQ026 FD146 GH01 GJ01 HA07 4J011 KA04 KA06 KA08 KA09 KA10 KA15 KB14 KB29 4J038 CC011 CC021 CC071 CD001 CE051 CF011 CF021 CG031 CG061 CG141 CG161 CG171 CH031 CH041 CH071 CH121 CH151 DF022 DF042 FA272 GA02 GA03 GA06 GA09 GA12 HA156 JB17 JC09 JC13 KA03 KA09 LA02 MA08 MA09 MA10 NA01 NA04 NA11 A02P08P AM02P AM15P AM21Q BA12Q BA13Q BA14Q BC04P CA04 FA20 JA01 JA03

Claims (10)

[Claims] 1. An aqueous resin composition comprising a polymer having an aldehyde group or a ketone group, a hydrazide compound represented by the formula (1) or (2) and an aqueous medium. Embedded image (Wherein, R ₁ and R ₂ are each independently hydrogen or a methyl group, and R ₃ is an aliphatic hydrocarbon group having 2 to 18 carbon atoms or a xylylene group) 2. A hydrazide compound comprising tri (hydrazinocarboethyl) amine (formula (3)), N, N, N′N ′
-Tetra (hydrazinocarboethyl) ethylenediamine (formula (4)) and N, N, N'N'-tetra (hydrazinocarboethyl) hexamethylenediamine (formula (5))
The aqueous resin composition according to claim 1, which is at least one compound selected from the group consisting of: Embedded image 3. A polymer having at least one aldehyde group or ketone group and a radical polymerizable double bond in a molecule (hereinafter referred to as “monomer (a)”). 3) and a monomer copolymerizable with the monomer (a) (hereinafter referred to as “monomer (b)”). Resin composition. 4. The method according to claim 1, wherein the monomer (a) is diacetone acrylamide, diacetone methacrylamide, acrolein, methacrolein, acetoacetoxyethyl acrylate,
And at least one monomer selected from the group consisting of acetic acid and acetoacetoxyethyl methacrylate.
2. The aqueous resin composition according to item 1. 5. The aqueous resin composition according to claim 3, wherein the monomer (b) is an alkyl acrylate or alkyl methacrylate having an alkyl group having 1 to 18 carbon atoms. 6. A polymer having an aldehyde group or a ketone group is subjected to emulsion polymerization of a monomer mixture containing a monomer (a) and a monomer (b) in an aqueous medium in the presence of a surfactant. The aqueous resin composition according to any one of claims 1 to 5, which is obtained by: 7. An aqueous paint containing the aqueous resin composition according to any one of claims 1 to 6. 8. A crosslinking agent for a polymer having an aldehyde group or a ketone group, comprising a hydrazide compound represented by the formula (1) or (2). 9. A hydrazide compound comprising tri (hydrazinocarboethyl) amine (formula (3)), N, N, N′N ′
-Tetra (hydrazinocarboethyl) ethylenediamine (formula (4)) and N, N, N'N'-tetra (hydrazinocarboethyl) hexamethylenediamine (formula (5))
The crosslinking agent according to claim 8, which is any one compound selected from the group consisting of: 10. The crosslinking agent according to claim 8, wherein the polymer having an aldehyde group or a ketone group is a polymer dispersed or dissolved in an aqueous medium.