JPH11343377A - Aqueous resin composition - Google Patents

Abstract

(57) [Problem] To provide an aqueous resin composition capable of forming a film having excellent film forming properties, transparency, water whitening resistance and water adhesion by drying. SOLUTION: A monomer (a) having at least one aldehyde group or ketone group and a radical polymerizable unsaturated bond in a molecule, and a radical polymerizable polymerizable with the monomer (a) Copolymer (A) with monomer (b) having an unsaturated bond; the following formula (1): (In the above formula, R ¹ , R ² , R ³ and R ⁴ are each independently hydrogen or a hydroxyl group, p is an integer of 0 to 3, q is an integer of 2 to 8, p + q ≦ 8 and hydrazine compound (B) represented by the following formula: (p <q is satisfied); and an aqueous resin composition containing an aqueous medium.

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 useful as a coating material for various substrates such as wood, metal, and resin molded products, a binder such as a paint or printing ink, a coating material, an adhesive and the like. Further, the present invention relates to an aqueous resin composition capable of forming a tough film having excellent water resistance by drying.

[0002]

2. Description of the Related Art In the field of coating film formation, it is strongly desired to switch from an organic solvent system to an aqueous emulsion from the viewpoint of environmental hygiene and resource saving. Insufficient properties and adhesive strength. For the purpose of improving these physical properties, a functional group is often introduced into an aqueous emulsion to form a crosslinked coating film. As the aqueous emulsion for 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. In response to such a demand, US Pat. No. 3,345,336 (JP-B-46)
No. -20053) discloses a method of crosslinking a carbonyl group-containing polymer emulsion with a polyhydrazide compound. The aqueous emulsion used in this method is a one-part type, and the hydrazide group and the carbonyl group are crosslinked by a dehydration condensation reaction when the water of the emulsion is dried after coating 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, preferably an aliphatic saturated compound having 2 to 10 carbon atoms. Dihydrazide of dicarboxylic acid, specifically oxalic acid, sebacic acid,
Particularly preferably, dihydrazide of adipic acid is mentioned.

[0003] Various improvements have been made to the one-part crosslinked aqueous emulsion using polyhydrazide. Such an improvement is described, for example, in German Offenlegungsschrift 28
No. 19092 (JP-A-54-144432), German Patent Publication No. 2803258 (JP-A-54-110248), JP-A-57-3850, JP-A-57-3857, JP-A-58-96
No. 643, JP-A-58-104902, JP-A-60-38468, JP-A-62-25163, JP-A-62-62853, and German Patent Publication No. JP-A-1-2256), JP-A-1-234416, JP-A-3-68
669, JP-A-4-227947 (German Patent Publication No. 4016056) and JP-A-4-249.
No. 587, WO96 / 01252 and the like. In these one-part crosslinked aqueous emulsions,
In most cases, dihydrazide of an aliphatic dicarboxylic acid is used as the polyhydrazide compound, and in many cases, adipic dihydrazide is preferably used. However, although adipic dihydrazide functions as an effective cross-linking agent, the solubility in water is not sufficient, and the cross-linking is not sufficiently performed, and the water resistance of the formed coating film is not necessarily sufficient.

[0004] One-part cross-linkable aqueous emulsions using trihydric or higher polyhydrazide compounds are also exemplified in the above prior art. JP-B-61-6861 describes tri- or tetrahydrazide of pyromellitic acid, tri- or tetrahydrazide of nitrilotriacetic acid, and is described in JP-A-60-38468, German Patent Publication No. 372860 and German Patent. No. 401605
No. 6 discloses pentane-1,3,5-tricarboxylic trihydrazide, hexene-4-1,2,6-tricarboxylic trihydrazide and 3-cyanopentane-1,3,5.
-Tricarboxylic trihydrazides are described.

Since the crosslinking density can be increased by using a hydrazide compound having three or more functional groups, it is expected that the water resistance of the crosslinked coating film is improved. However, it is not sufficient to simply make the polymer multifunctional. Excessive polyfunctionality increases the number of hydrazide groups that cannot participate in cross-linking due to steric hindrance and the like, and rather reduces the water resistance of the coating film. When a polymer polyhydrazide obtained by polymerizing two or more hydrazine compounds is used as described in JP-A-1-234416, the polymer hydrazide is poorly water-soluble, and therefore, is not sufficiently contained in an aqueous emulsion. And it is difficult to perform sufficient crosslinking. Further, JP-A-6-80619 describes 1,2,3,4-butanetetracarboxylic acid hydrazide as an adsorbent for formaldehyde. However, this hydrazide is also poorly water-soluble, and the emulsion used as a curing agent Is poor in water resistance. As described above, it has been difficult to form a crosslinked film having excellent properties such as water resistance and adhesion to a substrate even when a conventional aqueous resin composition containing a curing agent and a carbonyl compound is used.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new aqueous resin composition which has solved the above-mentioned problems of the prior art. That is, an object of the present invention is to provide an aqueous resin composition in which each component is sufficiently dispersed and storage stability is good. Another object of the present invention is to provide an aqueous resin composition capable of forming a film having excellent film-forming properties, transparency, water whitening resistance and water adhesion by drying.

[0007]

Means for Solving the Problems In order to solve these problems, the inventors of the present invention have made intensive studies including the steric structure of the hydrazide compound. As a result, the present inventors have found that a trifunctional hydrazide compound having a specific structure can be used. It was found that an aqueous resin composition having sufficient storage stability could be prepared. Moreover, it was also found that by drying this aqueous resin composition, a film having excellent film-forming properties, transparency, water whitening resistance and water adhesion can be formed. The present invention has been provided based on these findings.

That is, the present invention relates to a monomer (a) having at least one aldehyde group or ketone group and a radically polymerizable unsaturated bond in a molecule, and a monomer (a) copolymerizable with the monomer (a). (B) having a radically polymerizable unsaturated bond
(A) with the following formula (1):

Embedded image (In the above formula, R ¹ , R ² , R ³ and R ⁴ are each independently hydrogen or a hydroxyl group, p is an integer of 0 to 3, q is an integer of 2 to 8, p + q ≦ 8 and hydrazine compound (B) represented by the following formula: (p <q is satisfied); and an aqueous resin composition containing an aqueous medium.

The present invention also relates to a monomer (a) having at least one aldehyde group or ketone group and a radically polymerizable unsaturated bond in a molecule, and a monomer (a) copolymerizable with the monomer (a). A polymer crosslinking agent used for a crosslinking reaction of the copolymer (A) with the monomer (b) having a radically polymerizable unsaturated bond, wherein the hydrazine compound (B) represented by the above formula (1) And a polymer cross-linking agent characterized by containing Furthermore, the present invention provides the following formula (2):

Embedded image (In the above formula, R ¹ , R ² , R ³ and R ⁴ are each independently hydrogen or a hydroxyl group, p is an integer of 0 to 3, q is an integer of 2 to 8, p + q ≦ 8 and a monomer having one or more aldehyde groups or ketone groups and a radically polymerizable unsaturated bond in the molecule, having a structure crosslinked by a structural unit represented by the following formula:
And a coating film containing a copolymer (A) of a monomer (b) having a radical polymerizable unsaturated bond copolymerizable with the monomer (a).

In a preferred embodiment of the present invention, the copolymer (A) is an aqueous dispersion resin obtained by emulsion polymerization of the monomer (a) and the monomer (b) in an aqueous medium. Use Further, it is preferable to use a monomer selected from the group consisting of diacetone (meth) acrylamide, (meth) acrolein and acetoacetoxyethyl (meth) acrylate as the monomer (a). Further, it is preferable to use butanetricarbohydrazide as the hydrazine compound (B) represented by the formula (1). In another preferred embodiment of the present invention, the aqueous resin composition is a one-part type.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component and action of the aqueous resin composition of the present invention will be described in detail. Copolymer (A) The copolymer (A) comprises a monomer (a) having at least one aldehyde group or ketone group and a radically polymerizable unsaturated bond in a molecule, and the monomer (A) It is obtained by copolymerizing a) and a monomer (b) having a copolymerizable radically polymerizable unsaturated bond. Monomers (a) having at least one aldehyde group or ketone group and a radically polymerizable unsaturated bond in the molecule include (meth) acrolein, diacetone (meth) acrylamide, formylstyrene, vinyl methyl ketone, vinyl Ethyl ketone, diacetone (meth) acrylate, acetoacetoxyethyl (meth) acrylate and the like are used. Among these, it is particularly preferable to use diacetone (meth) acrylamide, (meth) acrolein, and acetoacetoxyethyl (meth) acrylate. In this specification, “(meta)
The notation "acrylic acid" means acrylic acid or methacrylic acid, and the notation of a (meth) acrylic acid derivative similar thereto also means an acrylic acid derivative or a methacrylic acid derivative.

The content of the monomer (a) in the copolymer is from 4 to
It is preferably 40% by weight, more preferably 5 to 20% by weight. When the content is less than 4% by weight, the content of carbonyl groups in the copolymer decreases, so that the crosslink density of the copolymer and the hydrazine derivative decreases, and the effect of sufficiently improving the coating properties such as water resistance is reduced. It tends to be difficult to obtain. Conversely, when the content of the monomer (a) is more than 40% by weight, the content of the monomer (b) becomes relatively small, and various properties required for the intended use are obtained. Tends to be difficult to be performed.

The monomer (b) having a radical polymerizable unsaturated bond copolymerizable with the monomer (a) has a structure as long as it can be copolymerized with the monomer (a). There is no particular limitation. As the monomer (b), for example, styrene, α-
Aromatic vinyl compounds such as methylstyrene and vinylnaphthalene; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate Α, β-unsaturated carboxylic acids such as (meth) acrylic acid; itaconic acid, maleic acid, 2-methylene glutaric acid, etc. α, β-unsaturated dicarboxylic acid; (meth) acrylate having a hydroxy group at a terminal such as 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate;
Vinyl esters such as vinyl acetate vinyl propionate; (meth) acrylamide, N-alkylolacrylamide, (meth) acrylonitrile, vinyl halide and the like can be used. If necessary, allyl (meth) acrylate, ethylene glycol di (meth)
A crosslinkable monomer having two or more radically polymerizable double bonds in one molecule such as acrylate and trimethylolpropane triacrylate can also be used. The content of the monomer (b) in the copolymer is preferably from 96 to 60% by weight, and more preferably from 95 to 80% by weight.

As the monomer (a) and the monomer (b), one kind of monomer may be used alone, or two or more kinds of monomers may be used in combination. . When two or more monomers are used in combination as the monomer (b), one or more hard polymerizable monomers having a homopolymer glass transition temperature of 40 ° C. or more and a homopolymer glass It is preferable to use a copolymer with one or more soft polymerizable monomers having a transition temperature of 25 ° C. or lower. Examples of the hard polymerizable monomer include methyl methacrylate, ethyl methacrylate, and styrene. Examples of the soft polymerizable monomer include butyl acrylate and 2-ethylhexyl acrylate.

The glass transition temperature of the copolymer (A) can be appropriately adjusted depending on the use of the aqueous resin composition.
Among them, the copolymer (A) calculated by the following formula
Is preferably in the range of -60 ° C to 60 ° C.

[Number 1] _{1 / Tg = W a / Tg} a + W b / Tg b ( wherein, Tg is the glass transition temperature calculated value of the copolymer (K), Tg _a and Tg _b are each monomer (a ) and the monomer (glass transition temperature of the homopolymer of b) (K), W _a and W _b represents a weight fraction of each monomer (a) and the monomer (b).)

The aqueous medium used in the aqueous resin composition of the present invention may be either an aqueous solution or an aqueous dispersion. Therefore, it is preferable that the copolymer (A), which is the main component of the aqueous resin composition, is also prepared as an aqueous solution or an aqueous dispersion, and the remaining components are added and mixed. When preparing an aqueous solution of the copolymer (A), not only water but also a mixed solvent of water and a water-soluble organic solvent can be used as the solvent. Examples of 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; ethers such as tetrahydrofuran and 1,4-dioxane. No.

On the other hand, when preparing an aqueous dispersion of the copolymer (A), any of emulsion polymerization, suspension polymerization, or a method of performing a solution polymerization in an organic solvent and then adding an aqueous medium to invert the phase is used. A method may be used. In particular, it is preferably prepared by emulsion polymerization in an aqueous medium in the presence of a polymerization initiator and a surfactant according to a conventional method. Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; peroxides such as hydrogen peroxide, benzoyl peroxide, and t-butyl hydroperoxide;
Azo-based polymerization initiators such as azobisisobutyronitrile; redox-type polymerization initiators obtained by combining these polymerization initiators with a reducing agent such as ascorbic acid can be used. In addition, these polymerization initiators may be used not only alone but also in plural combinations as needed. The amount of the polymerization initiator to be used is preferably 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer.
More preferably, it is 2 parts by weight.

Examples of the surfactant include anionic surfactants such as alkyl benzene sulfonate, higher alcohol sulfate, and polyoxyethylene alkyl sulfonate; and polyoxyethylene alkyl ether and polyoxyethylene alkyl phenol ether. Nonionic surfactants; 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. Examples of the reactive surfactant include sodium alkylallyl sulfosuccinate (manufactured by Sanyo Chemical; Eleminol JS-2) and sodium methacryloyloxy polyoxyalkylene sulfate (manufactured by Sanyo Chemical; Eleminor RS)
-30), polyoxyethylene alkyl allyl phenol ether (Daiichi Kogyo Seiyaku; Aqualon RN series), polyoxyethylene alkyl allyl phenol ether sulfate (Daiichi Kogyo Seiyaku; Aqualon H)
S series). These surfactants may be used not only alone but also in plural combinations. These surfactants are generally used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the radically polymerizable unsaturated compound.

At the time of polymerization, a water-soluble polymer compound such as polyvinyl alcohol and hydroxyethyl cellulose can be added as a protective colloid in addition to the polymerization initiator and the surfactant. Further, depending on the type of the emulsifier, when an unsaturated carboxylic acid monomer such as acrylic acid is copolymerized, the emulsifying power may be reduced in an acidic region. In such a case, it is preferable to carry out the polymerization by adding an alkali such as aqueous ammonia to the polymerization reaction system.
The temperature conditions for performing the emulsion polymerization are not particularly limited, but are usually 40 to 95 ° C, preferably 60 to 90 ° C.

Hydrazine Compound (B) The hydrazine compound (B), which is an essential component of the aqueous resin composition of the present invention, is a compound having three hydrazide groups in the molecule as shown in the general formula (1). Since it is trifunctional, three-dimensional crosslinking is possible, and the crosslinking density can be increased as compared with a conventional bifunctional hydrazide such as adipic dihydrazide. Therefore, the hydrazide compound (B) represented by the general formula (1) is converted to the copolymer (A)
When used as a crosslinking agent, the water resistance of the resulting coating film can be drastically increased. In addition, the hydrazine compound (B) represented by the general formula (1) has low steric hindrance because no three hydrazide groups are bonded to adjacent carbon atoms, and the cross-linking reaction proceeds easily to achieve sufficient cross-linking. The effect is obtained. Furthermore, compared with aromatic hydrazides such as trimellitic acid hydrazide, the structural flexibility is large, so that steric hindrance is low and a sufficient crosslinking effect is obtained, and pyromellitic acid tetrahydrazide and butanetetracarboxylic acid tetrahydrazide are obtained. There is an advantage that the solubility in water is extremely high as compared with a tetrafunctional hydrazine compound such as the above or polyhydrazine obtained by modifying poly (meth) acrylic acid with hydrazine.

The hydrazine compound (B) of the present invention includes 1,2,4-butanetricarbohydrazide,
Aliphatic tricarboxylic acid trihydrazides such as 1,4-butanetricarbohydrazide, 1,2,5-pentanetricarbohydrazide, 1,3,6-hexanetricarbohydrazide and 1,3,7-heptanetricarbohydrazide And a compound having a hydroxyl group as 1-hydroxy-
Examples thereof include 1,2,4-butanetricarbohydrazide and the like, preferably 1,2,4-butanetricarbohydrazide and 1,2,5-pentanetricarbohydrazide, and particularly preferably 1,2,4-pentanetricarbohydrazide. 4-butanetricarbohydrazide. The amount of the hydrazine compound (B) to be used is such that the hydrazino group in the hydrazine compound (B) is usually 0.1 to 5 mol equivalents, preferably 0.5 to 1 mol equivalent of the carbonyl group in the copolymer (A). Desirably, the amount will be に な る 2 molar equivalents.

Other Optional Components In addition to the copolymer (A), the hydrazine compound (B) and the aqueous medium, various components may be added to the aqueous resin composition of the present invention in accordance with the intended use. Can be. For example, to adjust the molecular weight of the copolymer, an alkyl mercaptan can be added as a molecular weight modifier during polymerization. In addition, film forming aids, defoamers, rust inhibitors, thickeners,
Preservatives, ultraviolet absorbers, light stabilizers, pigments, inorganic fillers such as silica and the like can also be blended. These components can be added in amounts that do not impair the desired effects of the present invention, and the order of addition is not particularly limited.

Function of the Aqueous Resin Composition The aqueous resin composition of the present invention prepared by mixing the above-mentioned components is dried at room temperature to form the carbonyl group of the copolymer (A) and the hydrazino compound of the hydrazine compound (B). The group causes a crosslinking reaction (room temperature crosslinking). By this reaction, a cross-link is formed between the two, and a tough film having excellent water resistance is obtained. Since the hydrazine compound (B) having three hydrazino groups in the molecule is used in the present invention, the copolymer (A) is crosslinked by the structural unit represented by the formula (2). For this reason, compared with a typical conventional product using a hydrazine compound having two hydrazino groups in a molecule, it is possible to form a film having a higher density and a firmly crosslinked film.

Since the crosslinking reaction between the carbonyl group and the hydrazino group is a dehydration reaction, while the aqueous resin composition contains water, the water acts as a crosslinking inhibitor and the reaction does not proceed. Therefore, the aqueous resin composition of the present invention has sufficient storage stability for a long period of time while being one liquid.

[0025]

EXAMPLES The present invention will be described more specifically with reference to production examples and examples. Materials, ratios, operating conditions, and the like shown in the following Production Examples and Examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. Production Examples 1 to 3 and 5 to 8 show a method for producing an aqueous dispersion of the copolymer (A), and Production Example 4 shows a method for producing an aqueous solution of a hydrazine compound (B) and a hydrazine compound for comparison. Further, in Examples, the production method of the aqueous resin composition of the present invention using these components and the results of physical properties tests are shown together with Comparative Examples. “Parts” and “%” described in Production Examples and Examples represent “parts by weight” and “% by weight” unless otherwise specified.

(Production Example 1) In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, ammonium persulfate (1 part), sodium dodecylbenzenesulfonate (10 parts) and water (90 parts) were placed. 85 ℃ under nitrogen atmosphere
And heated. 2-ethylhexyl acrylate (120
Part), styrene (60 parts), diacetone acrylamide (20 parts), sodium dodecylbenzenesulfonate (10 parts), and water (90 parts) were added dropwise over 2 hours. Simultaneously with the start of emulsified droplet drop,
After 30 minutes, 1 hour, and 1 hour and 30 minutes, an aqueous solution in which ammonium persulfate (1 part) was dissolved in water (20 parts) was added dropwise in four times. After the completion of the emulsification, the reaction was further performed at 85 ° C. for 3 hours. Thereafter, the reaction mixture was cooled and 28
% Aqueous ammonia was added dropwise to adjust the pH to 8, whereby a milky white aqueous dispersion having a solid content of 50.6% was obtained.

(Production Example 2) In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, potassium persulfate (0.36 parts), an anionic emulsifier (Newcol 707SN, manufactured by Nippon Emulsifier) ( 6.9 parts) and water (94 parts) and heated at 85 ° C. under a nitrogen atmosphere. Methyl methacrylate (78 parts), butyl acrylate (45 parts), 2-ethylhexyl acrylate (30 parts), styrene (29 parts)
Part), acrylic acid (1 part), diacetone acrylamide (9.6 parts), the above anionic emulsifier (9.3 parts), and a mixture of water (100 parts) emulsified with a homomixer over 3 hours. And dropped. After the completion of the emulsified droplet, an aqueous solution in which potassium persulfate (0.21 part) was dissolved in water (2 parts) was added as a catalyst, and the mixture was further reacted at 85 ° C. for 3 hours. The resulting reaction mixture was cooled, and the pH was adjusted to 8 by dropwise addition of 28% aqueous ammonia to obtain a milky white aqueous dispersion having a solid content of 45.7%.

(Production Example 3) In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, ammonium persulfate (1.8 parts), an anionic reactive emulsifier (Aqualon HS manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 25% aqueous solution of -1025) (1
2.0 parts) and water (210.0 parts) and heated at 75 ° C. in a nitrogen atmosphere. Ethyl acrylate (85.0 parts),
2-hydroxyethyl acrylate (10.0 parts), styrene (77.0 parts), methacrylic acid (8.0 parts), diacetone acrylamide (20.0 parts), anionic reactive emulsifier (24.0 parts) ), Lauryl mercaptan (2.0 parts), and a mixture of water (72 parts) with a homomixer were added dropwise over 3 hours. Thirty minutes after the completion of the emulsified droplet, 28% aqueous ammonia (6.4 parts) was added, and ammonium persulfate (0.2%) was added as a catalyst.
Was dissolved in water (2 parts) and added at 80 ° C.
For 3 hours. The milky white aqueous dispersion having a solid content of 39.8% was obtained by cooling the obtained reaction mixture.

(Production Example 4) 1,2,4-butanetricarbohydrazide (BTC) which is a hydrazine compound (B)
H) (10 parts) was mixed with water (90 parts) at room temperature, and 1,2,4-butanetricarbohydrazide was easily dissolved in water to form an aqueous solution. On the other hand, as a hydrazine compound for comparison, adipic dihydrazide (ADH) (1
0 part) was mixed with water (90 parts) at room temperature, and adipic dihydrazide did not dissolve easily, so that an aqueous solution was prepared by heating. Similarly, as a hydrazine compound for comparison, a polymer polyhydrazide (Otsuka Chemical: A
When PA-H) (10 parts) was mixed with water (90 parts), it was not dissolved even by heating and stirring.

(Production Example 5) In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, ammonium persulfate (2 parts), an anionic reactive emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .:
Aqualon HS-1025 25% aqueous solution) (8.0
Parts), 28% ammonia water (2.0 parts), water (200.
0 parts) and heated to 75 ° C. under a nitrogen atmosphere. Butyl acrylate (180.0 parts), 2-hydroxyethyl methacrylate (16.0 parts), styrene (150.0 parts)
Parts), acrylic acid (16.0 parts), diacetone acrylamide (30.0 parts), the anionic reactive emulsifier (32.0 parts), lauryl mercaptan (8.0 parts),
A mixture of water (170 parts) was mechanically emulsified in advance with a homomixer, and the emulsion was added dropwise over 3 hours. Thirty minutes after the completion of the dropping of the pre-emulsion, 28% aqueous ammonia (2.0 parts) and ammonium persulfate (0.3 parts) were added. After the addition of the catalyst, the reaction was further performed at 80 ° C. for 3 hours. After the reaction, 28% aqueous ammonia (6.0%) was added.
Parts). The obtained emulsion is cooled and the solid content is 5
A milky white aqueous dispersion of 1.1% by weight was obtained.

(Production Example 6) 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 (manufactured by Daiichi Kogyo Seiyaku; Aqualon HS- 1025 25% aqueous solution) (8.
0 parts), 28% aqueous ammonia (2.0 parts), water (29 parts)
0.0 part) and heated to 75 ° C under a nitrogen atmosphere. Butyl acrylate (120.0 parts), 2-ethylhexyl acrylate (60 parts), styrene (60.0 parts), methyl methacrylate (130.0 parts), acrylic acid (8.
0 parts), diacetone acrylamide (30.0 parts), the anionic reactive emulsifier (32.0 parts), water (170 parts)
Part) was mechanically emulsified in advance with a homomixer, and this emulsion was added dropwise over 3 hours. 30 minutes after the completion of the dropping of the pre-emulsion, 28% ammonia water (2.0%
Parts) and ammonium persulfate (0.3 parts). After the addition of the catalyst, the reaction was further performed at 80 ° C. for 3 hours.
After completion of the reaction, 28% aqueous ammonia (2.0 parts) was further added. The obtained emulsion was cooled and the solid content was 45.5.
A wt.% Aqueous milky dispersion was obtained.

(Production Example 7) An aqueous dispersion resin was obtained in the same manner as in Production Example 6, except that lauryl mercaptan (1.0 part) was added as a chain transfer agent. The solid content of the obtained aqueous dispersion resin was 45.9%.

(Production Example 8) An aqueous dispersion resin was obtained in the same manner as in Production Example 6, except that lauryl mercaptan (8.0 parts) was added as a chain transfer agent. The solid content of the obtained aqueous dispersion resin was 45.6%.

Example 1 The aqueous dispersions of Production Examples 1 to 3 and Production Example 4 were prepared so that the number of moles of the amino group of the hydrazine compound was a predetermined amount with respect to the carbonyl group of the copolymer (A).
Was stirred and mixed to obtain an aqueous resin composition. At this time, 15 kinds of aqueous resin compositions were prepared by changing the combination of the copolymer (A) and the hydrazine compound and the use ratio thereof as shown in Table 1 below. In addition, about the aqueous resin composition 5, 10, and 15, an appropriate amount of water was added instead of the hydrazine compound.

After storing each prepared aqueous resin composition in a thermostat at 50 ° C. for one month, the storage stability was evaluated by visually judging the state of the composition according to the following criteria. ：: Equivalent to the initial state, no generation of aggregates and the like was observed. Δ: Aggregates or the like are slightly observed, or the viscosity is increased. ×: The composition is separated or gelled.

Each of the prepared aqueous resin compositions is applied to a polyethylene terephthalate film substrate (thickness: 100 μm) on which easy adhesion processing has been performed using a bar coater (# 16), and dried at room temperature for one week. By thickness 1
A test piece having a coating of 0 μm was prepared. The appearance of the coating film was evaluated by visually determining the coating of each test piece according to the following criteria. ：: A uniform coating film is formed. ×: Cracks have occurred in the coating film.

Further, the transparency was evaluated by measuring the haze of the test piece with a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd.). Further, the test piece was immersed in distilled water at room temperature, and the change in haze (ΔH) after 7 days was measured using a haze meter to evaluate the water whitening resistance.

The test piece was immersed in distilled water at room temperature, and the state of the coating film after 7 days was visually judged according to the following criteria to evaluate the water-resistant adhesion. ：: The coating adheres to the substrate without peeling. D: Part or all of the coating was peeled off from the substrate. Table 1 summarizes the test results.

[0039]

[Table 1]

The results in Table 1 show that the aqueous resin composition of the present invention containing a copolymer (A) having an aldehyde group or a ketone group and a hydrazine compound (B) having three hydrazino groups in the molecule is as follows: It shows that the storage stability is high, and that the formed film has excellent coating appearance, transparency, water whitening resistance and water adhesion resistance (compositions 1, 2, and 2).
6, 7, 11, 12). On the other hand, an aqueous resin composition containing a hydrazine compound having two hydrazino groups in a molecule has low storage stability and poor water whitening resistance and water adhesion resistance of a formed film (compositions 3 and 4). , 8,9,1
3, 14). Further, the aqueous resin composition containing no hydrazine compound had low transparency, water whitening resistance and water adhesion resistance of the coating (compositions 5, 10, 15). The above results show that the aqueous resin composition of the present invention is an excellent composition having good physical properties of the composition and the properties of the coating.

Example 2 The aqueous dispersion of Production Example 5 and an aqueous solution of a predetermined hydrazine compound were prepared such that the number of moles of the amino group of the hydrazine compound was a predetermined amount with respect to the carbonyl group of the copolymer (A). Were mixed under stirring to obtain six types of aqueous resin compositions shown in Table 2. In addition, about the water-soluble resin composition of the composition 21, instead of a hydrazine compound,
An appropriate amount of water was added. With respect to each of the prepared water-soluble compositions, the appearance of the coating film, transparency, resistance to water whitening and resistance to water adhesion were evaluated in the same manner as in Example 1. The water whitening resistance was also measured after immersion in distilled water at room temperature for one day. Table 2 summarizes the results.

[0042]

[Table 2]

The results in Table 2 show that 1,2,4-butanetricarbohydrazide, which is a hydrazine compound (B) having a specific structure of the present invention, has higher solubility in water than other hydrazine compounds. It is shown that. Furthermore, a coating film formed from the aqueous resin composition of the present invention containing the copolymer (A) having an aldehyde group or a ketone group and the hydrazine compound (B) having a specific structure of the present invention has a coating film appearance. ,
It also shows that transparency, water whitening resistance and water adhesion are excellent (composition 23). On the other hand, the coating film formed from the aqueous resin composition containing the hydrazine compound having two hydrazino groups in the molecule had low water whitening resistance and low water adhesion (composition 22). A coating film formed from a hydrazine compound having three hydrazino groups in the molecule but not satisfying the specific structure of the present invention or an aqueous resin composition containing a hydrazine compound having four hydrazino groups in the molecule is used for coating. Film appearance and water whitening resistance were low (Composition 2
4, 25, 26). In addition, the aqueous resin composition containing no hydrazine compound had low water whitening resistance and low water adhesion (composition 21). The above results show that the physical properties of the coating film formed from the aqueous resin composition of the present invention are good.

Example 3 The aqueous dispersions of Production Examples 6 to 8 and Production Example 4 were prepared so that the number of moles of the amino group of the hydrazine compound was a predetermined amount with respect to the carbonyl group of the copolymer (A).
Were mixed under stirring to obtain six types of aqueous resin compositions shown in Table 3. For each of the prepared water-soluble compositions, the coating film appearance, transparency, water whitening resistance (1 day and 7 days) and water adhesion were evaluated in the same manner as in Example 1. In addition, the water absorption was evaluated as follows. That is,
Each aqueous dispersion resin was placed in a Teflon container and dried at 35 ° C. for 5 days to form a resin film having a thickness of 1 mm. This film was cut into 25 mm x 25 mm to form a test piece, immersed in distilled water at room temperature, and the water absorption calculated by the following equation was measured. Table 3 summarizes the results.

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

[0045]

[Table 3]

The results in Table 3 show that the water absorption of a coating film formed using 1,2,4-butanetricarbohydrazide, which is a hydrazine compound (B) having a specific structure of the present invention, is adipic dihydrazide. This is lower than that of a coating film formed by using No. 1, and is shown to be excellent in water resistance.

[0047]

As described above, the aqueous resin composition of the present invention has high storage stability and can form a film having excellent film forming properties, transparency, water whitening resistance and water adhesion by drying. Further, by using the hydrazine compound (B) having high water solubility, there is also an advantage in production that it can be easily dissolved and mixed in an aqueous resin. The aqueous resin composition of the present invention having these features is useful as an aqueous resin used for coating materials of various substrates such as wood, metal, and resin molded products, binders such as paints and printing inks, coating materials, and adhesives. It is.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI C09D 133/14 C09D 133/14 133/24 133/24 (72) Inventor Kazunari Kinugasa 1-8-8 Shinkawa, Chuo-ku, Tokyo Nippon Kasei Co., Ltd.

Claims (8)

[Claims] 1. A monomer (a) having at least one aldehyde group or ketone group and a radical polymerizable unsaturated bond in a molecule, and a radical polymerization copolymerizable with the monomer (a) Copolymer (A) with monomer (b) having an unsaturated unsaturated bond; the following formula (1): (In the above formula, R ¹ , R ² , R ³ and R ⁴ are each independently hydrogen or a hydroxyl group, p is an integer of 0 to 3, q is an integer of 2 to 8, p + q ≦ 8 and hydrazine compound (B) represented by the following formula: (p <q is satisfied); and an aqueous resin composition containing an aqueous medium. 2. The aqueous dispersion resin according to claim 1, wherein the copolymer (A) is obtained by emulsion-polymerizing the monomer (a) and the monomer (b) in an aqueous medium. The aqueous resin composition as described in the above. 3. The aqueous resin composition according to claim 1, wherein the monomer (a) is selected from the group consisting of diacetone (meth) acrylamide, (meth) acrolein, and acetoacetoxyethyl (meth) acrylate. Stuff. 4. The aqueous resin composition according to claim 1, wherein the hydrazine compound (B) is butanetricarbohydrazide. 5. The aqueous resin composition according to claim 1, which is a one-pack type. 6. A monomer (a) having at least one aldehyde group or ketone group and a radical polymerizable unsaturated bond in a molecule, and radical polymerization copolymerizable with the monomer (a). A polymer crosslinking agent used for a crosslinking reaction of a copolymer (A) with a monomer (b) having a carboxylic acid unsaturated bond, comprising the following formula (1): (In the above formula, R ¹ , R ² , R ³ and R ⁴ are each independently hydrogen or a hydroxyl group, p is an integer of 0 to 3, q is an integer of 2 to 8, p + q ≦ 8 and p <q is satisfied), and a hydrazine compound (B) represented by the formula: 7. The method of claim 1, wherein the hydrazine compound (B) is 1,2,2
The polymer crosslinking agent according to claim 6, which is 4-butanetricarbohydrazide. 8. The following formula (2): (In the above formula, R ¹ , R ² , R ³ and R ⁴ are each independently hydrogen or a hydroxyl group, p is an integer of 0 to 3, q is an integer of 2 to 8, p + q ≦ 8 and a monomer having one or more aldehyde groups or ketone groups and a radically polymerizable unsaturated bond in the molecule, having a structure crosslinked by a structural unit represented by the following formula:
And a monomer (b) having a radical polymerizable unsaturated bond copolymerizable with the monomer (a).