JP2920577B2 - Aqueous crosslinkable resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention easily crosslinks at room temperature and gives a film excellent in water resistance and solvent resistance after crosslinking, and is applied to metals, inorganic materials, plastics, old paint films and the like. The present invention relates to an aqueous crosslinkable resin composition which gives a cured coating film having excellent adhesiveness and hardness when crosslinked.

[0002]

2. Description of the Related Art Aqueous emulsion containing a carbonyl group-containing resin obtained by emulsion-copolymerizing a carbonyl group-containing monomer containing a carbonyl group based on an ald group or a keto group has at least two hydrazino groups in the molecule. That is, an aqueous crosslinkable resin composition comprising a compound having a hydrazine residue, —NHNH ₂ ) (that is, a hydrazine derivative) is known (for example, JP-A-54-1443).
No. 2). This resin composition has excellent properties such as a cross-linking reaction at room temperature and is easy to use as a one-pack type, but it does not always have sufficient adhesiveness to a substrate and water resistance.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to improve the above-mentioned drawbacks of a conventional aqueous emulsion of a carbonyl group-containing copolymer resin containing a hydrazine derivative. It is intended to provide an aqueous crosslinkable resin composition comprising a carbonyl group-containing copolymer blended with a hydrazine derivative capable of giving a crosslinked cured coating film having excellent balance between water resistance and body solvent properties. Is what you do.

[0004]

The aqueous crosslinkable resin composition of the present invention comprises at least 0.5% by weight of an unsaturated carboxylic acid monomer,
Unsaturated carbonyl group-containing monomer containing at least one carbonyl group based on an aldo group or a keto group.
The aqueous resin dispersion (I) obtained by emulsion copolymerization of a monomer mixture containing 5% by weight or more and 99% by weight or less of another unsaturated monomer copolymerizable with these monomers (I) )
And at least two hydrazino groups (—NHN
A hydrazine derivative (II) having H ₂ )
And a composition characterized by being solubilized by adding an alkali and / or a polar organic solvent such that the solubilization ratio of the resin component constituting the aqueous resin dispersion (I) becomes 5% by weight or more. Things.

[0005] The aqueous resin dispersion (I) of the present invention comprises:
As described above, this is a resin dispersion obtained by emulsion polymerization of a specific monomer mixture.

The unsaturated carboxylic acid monomer, which is one component of the monomer mixture, includes unsaturated monocarboxylic acids having 3 to 5 carbon atoms and unsaturated polycarboxylic acids. can give. Specific examples thereof include acrylic acid, methacrylic acid, itaconic acid, and maleic acid. One type of unsaturated carboxylic acid monomer may be used, or two or more types may be used in combination.

The amount of the unsaturated carboxylic acid monomer used is 0.5% by weight or more, preferably 2 to 30% by weight of the monomer mixture.
% By weight. If the proportion of the unsaturated carboxylic acid monomer used is too small, the solubilization of the dispersed resin becomes insufficient when the aqueous resin dispersion is solubilized by adding an alkali and / or a polar organic solvent. On the other hand, if the proportion of the unsaturated carboxylic acid monomer is too large, the solvent resistance of the crosslinked coating film is improved, but the water resistance tends to decrease.

The carbonyl group-containing unsaturated monomer as another component constituting the monomer mixture is a polymerizable unsaturated compound having at least one carbonyl group based on an ald group or a keto group. Therefore, even in the case of a polymerizable unsaturated compound containing a carbonyl group, a polymerizable unsaturated monomer containing a carbonyl group based on, for example, a carboxyl group, a carboxylic acid ester group, or a carboxylic acid amide group is added to this. Not included.

Examples of the unsaturated monomer containing at least one carbonyl group based on the ald group or keto group (hereinafter simply referred to as "carbonyl group") include, for example, acrolein, diacetone acrylamide, formylstyrene, Vinyl alkyl ketones having up to 7 carbon atoms (e.g. vinyl methyl ketone,
Vinyl ethyl ketone, vinyl butyl ketone, etc.), diacetone acrylate, acetonitrile acrylate, diacetone methacrylate, 2-hydroxypropyl acrylate acetyl acetate, butanediol-1,4
Acrylate acetyl acetate, and acryl (or methacryl) oxyalkyl propenal represented by the following general formula.

[0010]

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In the formula, R ¹ is H or CH ₃ , R ² is H or an alkyl group having 1 to 3 carbon atoms, and R ³ is 1 to 3
An alkyl group having ⁴ carbon atoms, and R ⁴ is 1-4
Represents an alkyl group having 5 carbon atoms.

Particularly preferred unsaturated monomers containing a carbonyl group are diacetone acrylamide, acrolein and vinyl methyl ketone. Two or more carbonyl group-containing unsaturated monomers can be used in combination. The use ratio of the carbonyl group-containing unsaturated monomer is 0.5% by weight or more, preferably 5 to 50% by weight in the monomer mixture.
If the proportion of the carbonyl group-containing unsaturated monomer is too small,
Since the crosslink density with the hydrazine derivative is low, the physical properties of the crosslinked cured coating film, for example, water resistance and solvent resistance become insufficient. Further, even if the ratio is too large, the effect cannot be improved beyond a certain effect.

Other unsaturated monomers copolymerizable with the above monomers constituting the monomer mixture include, for example, alkyl esters of acrylic acid or methacrylic acid having 1 to 8 carbon atoms (for example, acrylic Acid or methacrylic acid methyl, ethyl, isopropyl, n-propyl,
esters such as n-butyl, isobutyl and t-butyl),
Glycidyl methacrylate, glycol mono- or diacrylates, glycol mono- or dimethacrylates, vinyl aromatic compounds (eg, styrene), vinyl halides (eg, vinyl chloride,
Vinyl bromide), vinylidene chloride, acrylonitrile, methacrylonitrile, saturated vinyl carboxylate (eg, vinyl acetate, vinyl propionate, etc.).

In addition, when the aqueous dispersion of the resulting resin is added with an alkali and / or a polar organic solvent to solubilize the dispersion resin, unsaturated monomers having an effect of enhancing the solubilization include, for example, unsaturated monomers. Carboxylic acid amides (eg, acrylamide, methacrylamide, itaconic amide, etc.), N-alkyl and / or unsaturated carboxylic amides;
Or N-alkylol derivatives (eg, N-methylacrylamide, N-isobutylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethoxymethylacrylamide), unsaturated sulfonic acids (eg, vinylsulfonic acid, methylacrylamidepropanesulfone) Acids, etc.) and hydroxyl group-containing unsaturated monomers (eg, hydroxyethyl methacrylate, hydroxypropyl acrylate, etc.). When these specific other unsaturated monomers are copolymerized to produce an aqueous resin dispersion, the solubilization rate of the resulting aqueous resin dispersion can be increased.

Two or more of these other unsaturated monomers can be used in combination, and the proportion of these other unsaturated monomers used is appropriately 99% by weight or less based on the monomer mixture. These are appropriately selected and combined according to the desired solubilization ratio of the aqueous resin dispersion and the use of the aqueous crosslinkable resin composition as a final product.

The emulsion copolymerization method of the monomer mixture for preparing the aqueous resin dispersion of the present invention includes the following:
There are a method of performing emulsion copolymerization using a usual emulsifier, and a method of performing copolymerization using a copolymer dispersant, particularly a water-soluble or alkali-soluble carbonyl group-containing copolymer dispersant.

Examples of the emulsifier used in the above method include sulfates of higher alcohols, alkylbenzene sulfonates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl phenol ether sulfates, vinyl sulfonates, and vinyl sulfosuccinates. And anionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, ethylene oxide propylene oxide block polymer, and sorbitan derivatives.

Particularly preferred as the copolymer dispersant used in the above method are (i) a carbonyl group-containing monomer having one ald or keto group and one polymerizable double bond in the molecule. 0.5 to 99.5% by weight of a monomer unit, (ii)
A monoolefinic unsaturated carboxylic acid unit having 3 to 5 carbon atoms, an unsaturated carboxylic acid amide unit, an N-alkyl and / or N-alkylol derivative unit of the unsaturated carboxylic acid amide unit, an amino group-containing unit Monomer unit (for example, N, N-dimethylaminoethyl methacrylate unit,
N, N-diethylamino methacrylate unit), 99.5 to 0.5% by weight of a monomer unit selected from the group consisting of a monoolefinic unsaturated carboxylic acid unit, and (iii) the carbon number of acrylic acid or methacrylic acid. 1 to 8 alkyl ester units, vinyl aromatic monomer units, vinyl halide units, ethylene units, acrylonitrile units, methacrylonitrile units, saturated carboxylic acid vinyl ester units,
There is a copolymer containing 0 to 70% by weight of a monomer unit selected from the group consisting of a hydroxyl group-containing monomer unit (for example, a hydroxyethyl acrylate unit and a hydroxyethyl methacrylate unit) and a 1,3-diene unit. This copolymer-based dispersant is prepared by emulsifying a mixture of these monomers containing the monomer units (i) to (iii) at a substantially same ratio as the above-mentioned monomer units in water or an organic solvent. It can be easily produced by polymerizing and, if necessary, adding an alkali such as NaOH or aqueous ammonia.

In both the emulsion copolymerization method and the emulsion copolymerization method, emulsion polymerization is carried out in an aqueous medium using a polymerization initiator. In this case, for example, potassium persulfate, Examples include persulfates such as ammonium persulfate, hydrogen peroxide, peroxides such as benzoyl peroxide, cumene hydroperoxide and tertiary butyl hydroperoxide, and azobisisobutyronitrile. In particular, these water-soluble initiators and redox type initiators are preferred.

The aqueous crosslinkable resin composition of the present invention prepared by using the aqueous resin dispersion obtained by the above emulsion copolymerization method, and the aqueous crosslinkable resin composition of the present invention prepared by the above emulsion copolymerization method When compared with the product, the coating film of the composition obtained by the above method has better physical properties of the crosslinked cured coating film because the dispersant itself participates in the crosslinking reaction.

In the above-mentioned emulsion copolymerization method for preparing the resin aqueous dispersion (I) used in the present invention, when a chain transfer agent is present in the emulsion copolymerization system, the obtained copolymer dispersion is obtained. The properties of the coating film of the aqueous crosslinkable resin composition of the present invention used, particularly its adhesion to the substrate, are remarkably improved. This is because the presence of a chain transfer agent in the copolymer system lowers the molecular weight of the resulting dispersion resin, and when the solubilization treatment is performed by adding an alkali and / or polar organic solvent, the dispersion resin is more solubilized. It is presumed to be easier.

As the chain transfer agent to be used, any chain transfer agent can be used as long as it is generally used for polymerization and copolymerization of vinyl monomers and the like. As a specific example,
For example, mercaptans such as methyl mercaptan, t-butyl mercaptan, decyl mercaptan, benzyl mercaptan, lauryl mercaptan, stearyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, mercaptoacetic acid, mercaptopropionic acid; methanol, n-propanol, isopropanol, alcohols such as t-butanol, benzyl alcohol and allyl alcohol; hydrocarbons such as ethylbenzene and cumene; halogenated hydrocarbons such as chloroethane, chloroform, carbon tetrachloride and carbon tetrabromide.

[0023] The amount of the chain transfer agent greatly affects the solubilization of the dispersion resin. That is, if the amount of use increases, even if the resin composition is the same, it becomes easier to be solubilized, and the adhesion of the crosslinked coating film of the aqueous crosslinkable resin composition to the substrate is improved. However, if the amount is too large, the water resistance and the solvent resistance of the coating film deteriorate, which is not preferable. Therefore, the amount of the chain transfer agent is 0.01 to 100 parts by weight of the resin solid content.
3 parts by weight are preferred.

In the aqueous crosslinkable resin composition of the present invention, a hydrazine derivative (II) having at least two hydrazino groups in a molecule is added to the aqueous resin dispersion (I) prepared as described above. At the same time, an alkali and / or a polar organic solvent is added to solubilize the resin component constituting the aqueous resin dispersion (I), and the solubilization ratio is 5% by weight.
It is prepared as described above.

The solubilization treatment of the aqueous resin dispersion (I) by adding an alkali and / or a polar organic solvent may be performed before the emulsion polymerization of the monomers constituting the dispersion (I) starts, Hydrazine derivative (II) for aqueous resin dispersion (I)
May be added before, at the same time as the addition, or after the addition. And
In any case, the “solubilization rate” described in the present specification refers to the solubilization rate measured by the following method.

That is, in any of the above cases, the hydrazine derivative (11) is not used at all, but otherwise the solubilization treatment is performed under exactly the same conditions as those actually performed to prepare an aqueous resin dispersion. After diluting the obtained resin dispersion with water so that the non-volatile content becomes 15% by weight, the diluted solution was centrifuged at 1.8 × 10 ⁵ g to 60%.
When the amount of nonvolatile components in the obtained supernatant liquid is measured and set to w parts by weight, and the total amount of nonvolatile components in the aqueous resin solution used for centrifugation is measured and set to W parts by weight. Means the solubilization rate represented by the following formula: Solubilization rate = w / W × 100 (% by weight)

Examples of the alkali used for preparing the aqueous crosslinkable resin composition of the present invention include inorganic water-soluble alkalis (eg, sodium hydroxide, potassium hydroxide, etc.) and inorganic salts dissolved in water and exhibiting alkalinity (eg, Aqueous ammonia, organic amines and the like can be used as well as sodium hydrogen carbonate and sodium pyrophosphate.

As the polar organic solvent, an organic solvent which is compatible with water or is insoluble in water but is soluble to a considerable extent in water, for example, methanol, ethanol, n
-Propanol, isopropanol, n-butanol,
alcohols such as sec-butanol and ethylene glycol; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve and esters thereof; carbitols such as methyl carbitol, ethyl carbitol and butyl carbitol and esters thereof; tetrahydrofuran; Dioxane, dimethylformamide, ethyl acetate and the like are used.

The solubilization treatment in the present invention may be solubilization by the addition of the above-mentioned alkali, may be solubilization by the addition of the above-mentioned polar organic solvent, or may be the above-mentioned alkali and the above-mentioned polarity. Solubilization by adding both of them with an organic solvent may be used. The solubilization is performed so that the above-mentioned solubilization ratio is 5% by weight or more, preferably 10% by weight or more.

Next, the hydrazine derivative (II) used for preparing the aqueous crosslinkable resin composition of the present invention has at least two hydrazino groups (ie, -NHNH ₂ groups as hydrazine residues) in the molecule. Compound. Specific examples thereof include dicarboxylic acid dihydrazide which is a dehydration condensate of a dicarboxylic acid having 2 to 10, preferably 4 to 6 carbon atoms with hydrazine (eg, oxalic acid dihydrazide, malonic acid dihydrazide, succinic dihydrazide, glutar Acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide,
Etc.); aliphatic water-soluble dihydrazines having 2 to 4 carbon atoms (for example, ethylene-1,2-dihydrazine,
Propylene-1,3-dihydrazine, butylene-1,4
-Dihydrazine, etc.).

Further, a polymer having a hydrazino group represented by the following general formula can also be used as the hydrazine derivative. Such a polymer having a hydrazino group is described in detail, for example, in JP-A-55-6535.

[0032]

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In the formula, X is a hydrogen atom or a carboxyl group, Y is a hydrogen atom or a methyl group, A is each unit of acrylamide, methacrylamide, acrylate, methacrylate or maleic anhydride;
B is a unit of a monomer copolymerizable with acrylamide, methacrylamide, acrylate, methacrylate or maleic anhydride. Further, k, m and n are numbers satisfying the following formulas: 2 mol% ≦ k ≦ 100 mol% 0 mol% ≦ (m + n) ≦ 98 mol% (k + m + n) = 100 mol%

The proportion of the hydrazine derivative in the present invention is preferably from 0.05 to 5 mol, more preferably from 0.4 to 1. mol, per mol of the carbonyl group contained in the resin of the aqueous resin solution. It is a ratio of 2 mol.

Further, other aqueous resin dispersions can be added to the aqueous crosslinkable resin composition of the present invention as long as the physical properties of the coating film are not impaired. For example, an aqueous resin dispersion obtained by general emulsion polymerization or a urethane resin emulsion can be added.

The aqueous crosslinkable resin composition of the present invention may further contain a dispersant, a lubricant, an antifoaming agent, a solvent, a film-forming aid, a plasticizer, an antifreeze, depending on the purpose of use and the field of use. Various additives such as an agent, a thickener, an air entraining agent, a water reducing agent, a quick-setting agent, a hardening accelerator, a setting retarder, and a tack fire can be added. In addition, it can be used as an adhesive for plywood and woodwork, an adhesive for paper and tape, a coating agent for fibers, and the like, not only for paints, utilizing its crosslinking property.

[0037]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples of aqueous resin dispersions. “Parts” and “%” in these examples are based on weight unless otherwise specified.

Production Example 1 of Resin Aqueous Dispersion Temperature controller, squirrel type stirrer, reflux condenser, supply vessel,
In a reaction vessel equipped with a thermometer and a nitrogen inlet tube, 200
After the reactor was charged, the inside of the reaction vessel was replaced with nitrogen gas. Separately, the following mixture was prepared as Feed I.

Feed I Water 200 parts 35% aqueous solution of sulfuric acid half ester sodium salt of p-nonylphenol (hereinafter referred to as “anionic emulsifier A”) to which 20 mol of ethylene oxide has been added 30 parts Addition of 25 mol of ethylene oxide 20% aqueous solution of p-nonylphenol (hereinafter referred to as “nonionic emulsifier B”) 20 parts Methyl methacrylate 200 parts Butyl acrylate 140 parts Diacetone acrylamide 40 parts Acrylic acid 20 parts

The inside of the reaction vessel replaced with nitrogen gas is 90
While maintaining the mixture at a temperature of 0 ° C., the mixture of the above-mentioned feed I and an initiator solution obtained by dissolving 2.5 parts of potassium persulfate in 85 parts of water were used.
The polymerization reaction was carried out by continuously supplying the mixture little by little over 3.5 hours. After the completion of the supply, the polymerization was completed by keeping the temperature at 90 ° C. for 2 hours to obtain an aqueous resin dispersion (solid content: 50%).
Table 1 summarizes the types and amounts of the monomers and dispersants used in the polymerization system, and the solid content of the resulting resin dispersion.

Resin aqueous dispersion preparation examples 2 to 7 The types and amounts of unsaturated monomers and dispersants were changed as shown in Tables 1 and 2, and the others were as described in Resin aqueous dispersion preparation example 1. A resin aqueous dispersion was produced according to the method.
The solid contents of the obtained aqueous resin dispersion were as shown in Tables 1 and 2.

Preparation Examples 8 to 10 of Resin Aqueous Dispersions The types and amounts of unsaturated monomers and dispersants were changed as shown in Table 2, and the amounts of Aqueous resin dispersion was prepared in the same manner as in Production Example 1 except that the chain transfer agent shown in No. 2 was added. The solid content of the obtained aqueous resin dispersion was as shown in Table 2.

Production Example 11 of Resin Aqueous Dispersion In the same reaction vessel as in Production Example 1, 300 parts of water and a copolymer dispersant (20 parts of methyl methacrylate / 30 parts of butyl acrylate / 40 parts of diacetone acrylamide / 10 parts of acrylic acid) 40 parts of an aqueous alkali solution (concentration: 20%) having a molecular weight of about 8000). Separately, the following feed I and feed II were prepared.

Feed I Methyl methacrylate 180 parts Butyl acrylate 150 parts Diacetone acrylamide 60 parts Methacrylic acid 10 parts t-Dodecyl mercaptan 0.1 part

Feed II Water 120 parts Sodium persulfate 2.5 parts Sodium hydroxide 4 parts

Next, after the inside of the reaction vessel was replaced with nitrogen gas, 1/10 of the feed I was charged and heated to 90 ° C.
After further charging 1/10 of the feed II, the remaining feed I and the remaining feed II are simultaneously added in small portions 3 to
It was fed into the reaction vessel over 3.5 hours. After the end of the supply, the mixture was further reacted at 90 ° C. for 1.5 hours.
The reaction vessel was cooled to room temperature to produce a resin aqueous dispersion. The summary is shown in Table 3.

Preparation Examples 12 and 13 of Resin Aqueous Dispersion The types and amounts of unsaturated monomers, dispersants and chain transfer agents were changed as shown in Table 3, and the others were the same as those described in Preparation Example 11. To produce an aqueous resin dispersion. The solid content of the obtained resin aqueous dispersion was as shown in Table 3.

Production Example 14 of Resin Aqueous Solution Isopropanol 20 was placed in the same reaction vessel as in Production Example 1.
0 parts were charged. Separately, the following monomer composition was prepared as a supply.

Feed Methyl methacrylate 100 parts Butyl acrylate 70 parts Diacetone acrylamide 20 parts Acrylic acid 10 parts Azobisisobutyronitrile 10 parts

Then, while heating and stirring the inside of the reaction vessel at 80 ° C., the supply was uniformly added continuously over 3 hours to cause a reaction. After the addition was completed, the temperature was further increased to 80 ° C. for 1 hour. The reaction was maintained. Next, the internal temperature was cooled to 30 ° C., and 60 parts of a 10% aqueous solution of sodium hydroxide and water 5
40 parts were added to obtain a resin aqueous solution. Table 3 gives an overview
It was shown to.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

Notes on Tables 1 to 3: * 1... Monomers are described using the following abbreviations. MMA: methyl methacrylate BA: butyl acrylate DAAM: diacetone acrylamide AA: acrylic acid SM: styrene ACR: acrolein EA: ethyl acrylate MAA: methacrylic acid 2EHA .. 2-ethylhexyl acrylate

* 2: sodium sulfate half-ester sodium salt of p-nonylphenol added with 20 mol of ethylene oxide * 3: p-nonylphenol added with 25 mol of ethylene oxide * 4: 20 parts of methyl methacrylate / butyl acrylate 30 Part / diacetone acrylamide 40 parts / acrylic acid 10 parts copolymer in aqueous alkaline solution with a molecular weight of about 8000 (concentration: 20%) * 5 ... Methyl acrylate 20 parts / diacetone acrylamide 20 parts / acrylic acid 60 parts Alkaline aqueous solution of polymer with molecular weight of about 6000 (25% concentration)

Example 1 Aqueous resin dispersion 10 obtained in Production Example 1 of resin dispersion
An aqueous solution of sodium hydroxide was added to 0 parts to adjust the pH to 8.5, then 5 parts of butyl cellosolve was added, 3 parts of adipic dihydrazide were added, and finally, water was added to make the nonvolatile content 20%. Was prepared as follows. Table 4 summarizes the composition of the obtained crosslinkable resin composition and the physical properties of the film.
It was shown to.

Examples 2 to 12 Comparative Examples 1 to 4 Tables 4 to 7 show the types of the aqueous resin dispersion, the type and the pH of the alkali, the type and the amount of the polar organic solvent used, and the type and the amount of the hydrazine derivative used. Except as shown, a crosslinkable resin composition was prepared according to the method of Example 1, except that Comparative Example 2 was a non-crosslinkable resin composition. The film properties of each resin composition were as shown in Tables 4 to 7.

[0058]

[Table 4]

[0059]

[Table 5]

[0060]

[Table 6]

[0061]

[Table 7]

Note to Tables 4 to 7: Non-volatile content of composition (* 1) Dry residue (% by weight) when the resin composition was dried at 120 ° C. for 30 minutes.

Water resistance of coating (* 2) The aqueous resin composition has a thickness of 500 μm after drying on a glass plate.
and dried at 20 ° C. for one week to form a film. This film was punched out into a 5 cm × 5 cm square to prepare a test piece. After this test piece was immersed in water at 20 ° C. for one day, it was taken out and the water absorption (% by weight) of the film was measured.

Solvent Resistance of Film (* 3) A test piece prepared under the same conditions as in the case of water resistance of the film was immersed in toluene for one day, taken out, and the side expansion coefficient (%) of the film was measured. .

Adhesion of PP plate (* 4) An aqueous resin composition was applied onto a polypropylene plate (abbreviated as PP plate) so that a dry coating film having a thickness of 20 μm was obtained.
The specimen was dried at 0 ° C. for one week to prepare a test piece. The test piece was subjected to a peeling test using an adhesive tape (Nichiban Co., Ltd., Cellotape) and evaluated according to the following criteria. A: No peeling at all B: Partial peeling C: Peeling all

PET Board Adhesion (* 5) Except for using a polyester board (abbreviated as PET board),
The test was conducted in the same manner as the PP plate adhesion, and evaluated according to the same criteria.

Coating film hardness (* 6) The aqueous resin composition was applied on a steel plate test piece so as to obtain a dry coating film of 20 μm, and dried at 20 ° C. for one week. It was tested and evaluated according to the pencil scratch test method specified in 5400.

PAH (* 7) A 30% by weight solution of a polyhydrazine compound obtained by reacting hydrazine hydrate with polymethyl acrylate (molecular weight: about 8,000) and having a hydrazine conversion ratio of about 30 mol%, in isopropanol.

[0069]

According to the aqueous crosslinkable resin composition of the present invention, a carbonyl group and a hydrazino group react with each other at room temperature to easily form a crosslinked and cured coating film, and the coating film has an adhesion to a substrate. Because of its excellent balance of water resistance and solvent resistance, and high hardness, it is extremely excellent as a base reinforcing material for plastics and metals, and a paint for repairing coating films.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yoshinori Kato 1000, Kawajiri-cho, Yokkaichi, Mie Prefecture Inside Mitsubishi Yuka Birdsie Co., Ltd. (56) References JP-A-2-18466 (JP, A) JP-A-62-62853 (JP, A) JP-A-62-25163 (JP, A) JP-A-57-3857 (JP, A) JP-A-60-38468 (JP, A) JP-A-3-68669 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 23/00-101/14 C08K 5/16 -5/357 C09D 123/00-201/10

Claims (1)

(57) [Claims] 1. An unsaturated carboxylic acid monomer, 0.5% by weight or more, a carbonyl group-containing unsaturated monomer containing at least one carbonyl group based on an ald group or a keto group, 0.5% by weight or more, and An aqueous resin dispersion (I) obtained by emulsion copolymerization of a monomer mixture containing not more than 99% by weight of another unsaturated monomer copolymerizable with these monomers; At least two hydrazino groups (-
(NHNH ₂ ) -containing hydrazine derivative (II), and the solubilization ratio of the resin component constituting the resin aqueous dispersion (I) becomes 5% by weight or more by adding an alkali and / or a polar organic solvent. Aqueous crosslinkable resin composition characterized by being solubilized.