JPH0873812A - Aqueous resin composition for coating having excellent storage stability - Google Patents

Abstract

PURPOSE: To obtain an aqueous resin composition for coating, having excellent storage stability, useful as printing ink, a coating compound, a sealant, an adhesive, a surface treating agent, etc. CONSTITUTION: This aqueous resin composition for coating comprises (A) a resin emulsion containing an aldo group or a keto group obtained by subjecting (b) an ethylenic unsaturated compound containing at least an aldo group or a keto group to emulsion polymerization in the presence of (a) a water-soluble resin prepared by neutralizing an amino group-containing resin with an inorganic or organic acid and (B) a hydrazine derivative containing two or more hydrazine residues in a ratio to give 0.1-5 equivalents of the hydrazine residue based on 1 equivalent of the aldo group or the keto group in the component (A). The aqueous resin composition for coating has excellent physical properties as a cured coating film and excellent storage viscose stability is obtained.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is used as a coating for substrates such as plastic film, metal, paper and glass, that is, it is used as printing ink, paint, sealant, adhesive, surface treatment agent, etc. and has excellent storage stability. And an aqueous resin composition for coating.

[0002]

2. Description of the Related Art As a curable aqueous resin composition for coating, an aqueous dispersion containing a hydrazine derivative and a carbonyl group-containing copolymer such as an aldo group or a keto group is known. As these aqueous dispersions, those obtained by using a resin emulsion obtained by polymerization in the presence of a surfactant are disclosed, for example, in JP-A-54-110248 and JP-A-57-3850.
JP-A-57-3857, JP-A-2-155956, JP-A-4-249587, and JP-A-5-179102. Resin emulsions obtained in the presence of these surfactants are easy to handle because they give a resin dispersion with a relatively low viscosity even when the molecular weight of the resin is increased. There are problems such as poor stability, adverse effects on coating film properties and other properties due to the large amount of surfactant contained, and insufficient coating and printability.

As a solution to these drawbacks, there is a resin emulsion obtained in the presence of a water-soluble resin. For example, JP-A-62-25163 and JP-A-64-48801 disclose an aldo group or a keto group. A composition comprising an aqueous dispersion of a copolymer containing an aldo group or a keto group obtained by polymerizing a polymerizable monomer using a water-soluble copolymer having a group and a hydrazine derivative is disclosed. There is. However, the composition has a problem that its stability is insufficient.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous resin composition for coating, which has excellent storage stability, coating suitability, and coating properties after drying.

[0005]

[Means for Solving the Problems] That is, the present invention is directed to the presence of a water-soluble resin (a) obtained by neutralizing a resin containing an amino group with an inorganic or organic acid, in the presence of an aldo group- or keto group-containing ethylenic monomer. A resin emulsion (A) containing an aldo group or a keto group obtained by emulsion polymerization of an ethylenically unsaturated compound (b) containing at least a saturated compound, and a hydrazine derivative (B) having two or more hydrazine residues. , The hydrazine residue is 0.1 to 5 per equivalent of the aldo group or keto group.
Provided is an aqueous resin composition for coating, which is contained in a ratio so as to be equivalent.

In the present invention, the aldo group or keto group in the resin emulsion (A) produced by using a water-soluble resin obtained by neutralizing a resin containing an amino group with an inorganic or organic acid as a protective colloid is In water, the protective colloid does not come into contact with the hydrazine residue, but the water is removed and after film formation, it reacts with the hydrazine residue to form an excellent coating film.

Resins containing amino groups include amino group-containing ethylenically unsaturated monomers, styrenes such as styrene and methylstyrene, methyl (meth) acrylate, and (meth) acrylate.
Ethyl acrylate, Butyl (meth) acrylate, Propyl (meth) acrylate, 2-Ethylhexyl (meth) acrylate, Stearyl (meth) acrylate, Methoxyethyl (meth) acrylate, Ethoxyethyl (meth) acrylate, Propoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, butoxyethoxyethyl (meth) acrylate, etc. Aliphatic monohydric alcohol having 1 to 18 carbon atoms One or more monomers of 3 to 30 ethylene glycol monoalkyl ether or C3 to C30 diethylene glycol monoalkyl ether ester of (meth) acrylic acid, vinyl acetate, maleic acid ester, acrylonitrile, etc. It is obtained by copolymerizing.

Examples of the amino group-containing ethylenically unsaturated monomer include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate, Vinyl pyridine, 2-methyl 5-vinyl pyridine, 2-ethyl 5-vinyl pyridine, N- (2-dimethylaminoethyl) (meth) acrylamide, N- (2-dimethylaminopropyl) (meth) acrylamide, N- ( 2-
Diethylaminoethyl) (meth) acrylamide, N-
(2-diethylaminopropyl) (meth) acrylamide, N, N-dimethylaminostyrene, N, N-dimethylaminomethylstyrene, 2-dimethylaminoethyl vinyl ether and the like can be mentioned.

The amino group-containing ethylenically unsaturated monomer is
It is preferable to copolymerize so as to account for 10 to 50% by weight of the obtained resin. If it is less than 10% by weight, the resin obtained by the following neutralization operation is poor in water solubility and the performance as a protective colloid is poor. On the other hand, if it exceeds 50% by weight, the water-soluble resin obtained by neutralizing the resin has good performance as a protective colloid, but the resin emulsion obtained by emulsion polymerization of the ethylenically unsaturated compound in the presence of this resin is applied. The physical properties of the film deteriorate. The molecular weight of the resin containing amino groups is 3000-
60,000 is preferred.

The resin containing an amino group can be produced by a conventionally known polymerization method such as bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization. For example, in the case of the solution polymerization method, it can be easily produced by polymerizing a predetermined amount of the constituent monomers in the presence of an appropriate organic solvent. As the polymerization initiator, a catalyst such as benzoyl peroxide or azobisisobutyronitrile can be used. If necessary, mercaptans and the like can be added to the reaction system, and the degree of polymerization can be adjusted accordingly.

The amino group-containing resin obtained as described above is neutralized by adding an inorganic acid such as hydrochloric acid or an organic acid such as formic acid or acetic acid into the reaction system after completion of the polymerization reaction. It can be a desired water-soluble resin (a). The amount of acid added is such that the neutralization ratio of amino groups in the resin is approximately 70-120%.
The range is preferably. If the neutralization rate is too low, the ability of the resulting water-soluble resin as a protective colloid decreases, which is not preferable.

The resin emulsion (A) containing an aldo group or keto group is a water-soluble resin obtained as described above.
(a) In the presence of 100 parts by weight, an ethylenically unsaturated compound containing at least an ethylenically unsaturated compound containing an aldo group or a keto group (b) 20 to 1000 parts by weight, preferably 50 to 600 parts by weight, is emulsion polymerized. can get. Ethylenically unsaturated compound (b)
When using less than 20 parts by weight of water-soluble resin (a)
The content of the components becomes large, and the film-forming properties and physical properties of the coated product deteriorate. On the other hand, when it is used in an amount exceeding 1000 parts by weight, the obtained resin emulsion causes aggregation and thickening, resulting in poor storage stability. In addition, thixotropy becomes large, and the smoothness of the coating is poor.

The proportion of the ethylenically unsaturated compound containing an aldo group or keto group in the resin containing an aldo group or keto group is preferably 0.1 to 30% by weight. If it is less than 0.1% by weight, the cross-linking density of the obtained coating aqueous resin composition will be low, and the solvent resistance and water resistance of the coating after drying will be poor. On the other hand, if it exceeds 30% by weight, the water resistance tends to deteriorate due to an increase in hydrophilic functional groups.

Examples of the ethylenically unsaturated compound containing an aldo group or a keto group include acrolein and diacetone (meth).
Acrylamide, formyl styrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone,
(Meth) acryloxymethylpropanal, diacetone (meth) acrylate, acetonyl (meth) acrylate, and N-methylol (meth) acrylamide, N-
Examples include N-substituted (meth) acrylic monomers such as butoxymethyl (meth) acrylamide. These compounds can be used alone or in combination of two or more.

The components of the ethylenically unsaturated compound (b) other than the aldo group- or keto group-containing ethylenically unsaturated compound are
It is selected in consideration of hardness, heat resistance, adhesiveness, film-forming property, etc. of the obtained aqueous coating composition. For example, (meth) acrylic acid ester having 1 to 22 carbon atoms of alkyl group, (meth) acrylic acid ester having hydroxyl group, amino group, (meth) acrylic acid amide, (meth) acrylonitrile, styrene and the like are used. Further, the carboxyl group-containing ethylenically unsaturated compound is added to the ethylenically unsaturated compound (b) in an amount of 0.1 to
The coating strength is improved by using 3% by weight. Examples of the carboxyl group-containing ethylenically unsaturated monomer include polymerizable unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, fumaric acid and crotonic acid, and anhydrides thereof.

Examples of the initiator for emulsion-polymerizing the ethylenically unsaturated compound (b) include radical-forming initiators such as azo compounds and persulfates. If necessary, a surfactant may be added to the emulsion polymerization reaction system of the present invention within a range that does not adversely affect the molecular weight modifier and coating film physical properties.

The hydrazine derivative (B) having two or more hydrazine residues is a compound having a plurality of functional groups represented by the following general formula.

Embedded image

Examples of the hydrazine derivative (B) include fatty acid dihydrazides such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, carbonic acid polyhydrazide, aliphatic and alicyclic. Group, aromatic bissemicarbazide, aromatic dicarboxylic acid dihydrazide,
Examples thereof include polyhydrazide of polyacrylic acid, trihydrazide, dihydrazide of aromatic hydrocarbon, hydrazine-pyridine derivative and dihydrazide of unsaturated dicarboxylic acid such as maleic acid dihydrazide and fumaric acid dihydrazide.

The hydrazine derivative (B) having two or more hydrazine residues is based on 1 equivalent of the aldo group or keto group.
It is used at a ratio of 0.1 to 5 equivalents, preferably 0.2 to 3 equivalents. If the hydrazine residue is less than 0.1 equivalent, the cross-linking density of the resulting coating aqueous resin composition will be low, and the solvent resistance and water resistance of the coating after drying will be poor. On the other hand, if it exceeds 5 equivalents, the water resistance of the resulting coating aqueous resin composition tends to be poor.

The aqueous resin composition for coating of the present invention includes the above
In addition to (A) and (B), organic or inorganic pigments such as phthalocyanine blue, phthalocyanine green, titanium oxide and carbon black, dyes, calcium carbonate, precipitating barium sulfate, clay and other extender pigments, fine Thixotropic agents such as powdered silica, colloidal silica, sols such as alumina sol, polyvinylpyrrolidone, polyvinylalicol, shellac, water-soluble polyester resin, water-soluble or water-dispersible polyurethane resin or polyamide resin, etc. Resin, emulsifier, defoamer,
A leveling agent, a tackifying resin, a water-soluble or hydrophilic solvent such as ethanol or carbitol, an antiseptic agent, an antifungal agent, etc. are mixed and dispersed, mixed or kneaded by a known disperser, mixer or kneader. To be done.

The aqueous resin composition for coating of the present invention is a gravure printing machine, a flexographic printing machine, a roll coater, a spray coater, a spin coater, a brush, a roller coater, a roll coater, a reverse coater, a knife coater, depending on the purpose. By means such as plastic, paper, metal,
It is printed or applied as a printing ink, paint, sealant, adhesive, surface treatment agent, etc. on a substrate such as wood, glass, concrete, slate, non-woven fabric, leather, synthetic leather, etc., and cured and dried at room temperature or by heating. It

[0022]

EXAMPLES The present invention will now be described in more detail by way of examples. In the examples, "part" means "part by weight" and "%" means "% by weight". [Production Examples 1 to 4] Isopropyl alcohol 300 in a reaction vessel equipped with a stirrer, a thermometer, a dropping device and a reflux condenser.
Then, 200 parts of a monomer mixture having the composition shown in Table 1 and 6 parts of azobisisobutyronitrile were added dropwise over 2 hours, and the mixture was reacted at 83 ° C. for 4 hours. Next, the entire amount of isopropyl alcohol was distilled off under reduced pressure, and Production Examples 1 to 3 were performed.
For the production example 4, 600 parts of an aqueous solution in which the amino group in the reaction product and the equivalent amount of formic acid are mixed, and for the production example 4, the carboxyl group in the reaction product and the equivalent amount of ammonia are added, the resin aqueous solution (solid content 25%) ( a) to (d) were obtained.

[0023]

[Table 1]

[Production Example 5] 400 parts of the resin aqueous solution (a) was charged in the same reactor as in Production Examples 1 to 4 and heated to 80 ° C., and 10 parts of methyl methacrylate, 10 parts of styrene and 30 parts of diacetone acrylamide were added. Parts and 0.1 parts of ammonium persulfate in purified water
2.0 parts of an aqueous solution obtained by dissolving in 1.9 parts was added dropwise over 30 minutes, then reacted at 90 ° C for 1 hour, and purified water was added to adjust the solid content to 28%, and the keto group-containing resin emulsion (e) Got

[Production Example 6] 400 parts of the resin aqueous solution (b) and 80 parts of purified water were charged in the same reactor as in Production Examples 1 to 4 and
Heat to ℃, 100 parts methyl methacrylate, 70 styrene
Solution, 30 parts of diacetone acrylamide and 1.0 part of ammonium persulfate in 9.0 parts of purified water.
Parts over 120 minutes, then react at 90 ° C for 1 hour,
Purified water was added to adjust the solid content to 42% to obtain a keto group-containing resin emulsion (f).

[Production Example 7] 400 parts of an aqueous resin solution (c) and 400 parts of purified water were charged in the same reactor as in Production Examples 1 to 4.
Heat to 80 ℃, n-butyl methacrylate 349 parts, styrene
221 parts, diacetone acrylamide 30 parts, 2-ethylhexyl thioglycolate as a molecular weight modifier 3 parts and ammonium persulfate 1.0 part were dissolved in 9.0 parts of purified water, 10 parts of an aqueous solution was added dropwise over 150 minutes, and then 90 ° C. The mixture was reacted for 1 hour, and purified water was added to adjust the solid content to 46% to obtain a keto group-containing resin emulsion (g).

[Production Example 8] 400 parts of the resin aqueous solution (b), 80 parts of purified water and 2 parts of methacrylic acid were charged in the same reactor as in Production Examples 1 to 4 and heated to 80 ° C. to give 98% of methyl methacrylate.
Part, styrene 70 parts, diacetone acrylamide 30 parts and ammonium persulfate 1.0 part dissolved in 9.0 parts of purified water, 10 parts of an aqueous solution is added dropwise over 120 minutes, and then at 90 ° C. for 1 minute.
React for hours, add purified water to adjust the solid content to 42%,
A keto group-containing resin emulsion (h) was obtained.

[Production Example 9] 400 parts of the resin aqueous solution (c) and 80 parts of purified water were charged in the same reactor as in Production Examples 1 to 4,
Heated to ℃, 100 parts methyl methacrylate, 50 styrene
Parts, n-butyl methacrylate 50 parts and ammonium persulfate
10 parts of an aqueous solution obtained by dissolving 1.0 part in 9.0 parts of purified water
Drop for 120 minutes, then react at 90 ° C for 1 hour, add purified water to adjust the solid content to 42%, and resin emulsion.
got (i).

[Production Example 10] 400 parts of the resin aqueous solution (d) and 80 parts of purified water were charged in the same reactor as in Production Examples 1 to 4.
Heated to 80 ℃, methyl methacrylate 100 parts, styrene 70
Solution, 30 parts of diacetone acrylamide and 1.0 part of ammonium persulfate in 9.0 parts of purified water.
Parts over 120 minutes, then react at 90 ° C for 1 hour,
Purified water was added to adjust the solid content to 42% to obtain a keto group-containing resin emulsion (j).

[Examples 1 to 4 and Comparative Examples 1 and 2] Table 2
The composition shown in 1 was mixed to prepare an aqueous resin composition for coating. The obtained coating aqueous resin composition was applied onto an aluminum foil with a wire bar. Table 2 shows the results of evaluation of cellophane adhesiveness, alcohol resistance, alkali resistance and heat resistance of the obtained dry coating film. Table 2 shows the results of evaluation of the viscosity stability of the coating aqueous resin composition when stored at 40 ° C for 7 days. The evaluation method and the display of the results are as follows.

[0031]

[Table 2] In the table, RIONOL BLUE FG-7330 is phthalocyanine blue manufactured by Toyo Ink Mfg. Co., Ltd., and Surfynol PC is an antifoaming agent manufactured by Air Products.

Cellophane adhesiveness: The degree of peeling with cellophane tape manufactured by Nichiban was visually evaluated. Alcohol resistance: The surface of the coating film was rubbed with absorbent cotton containing 60% ethyl alcohol, and the state of the coating film was visually evaluated. Alkali resistance: A 12.5 aqueous solution of sodium hydroxide was spotted on the coating for 5 minutes, and the degree of peeling of the coating was evaluated visually. Heat resistance: The coating film and aluminum foil were layered and pressed at 130 ° C for 2 seconds (2 kg / cm ² ), the aluminum foil was peeled off, and the degree of peeling of the coating film was visually evaluated. ⊚: No peeling is observed. ◯: Peeling is slightly observed. Δ: A part of the coating film is peeled off. X: Most of the coating film is peeled off. Storage viscosity stability: ○: viscosity increase of 10% or less, △: viscosity increase of 50% or less, ×: viscosity increase of 50% or more.

[0033]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain an aqueous resin composition for coating which has excellent physical properties of a cured coating and good storage viscosity stability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C09D 151/08 PGX C09J 201/06 JAU

Claims (4)

[Claims] 1. An ethylenic unsaturated containing at least an ethylenically unsaturated compound containing an aldo group or keto group in the presence of a water-soluble resin (a) obtained by neutralizing a resin containing an amino group with an inorganic or organic acid. Alde group- or keto group-containing resin emulsion (A) obtained by emulsion polymerization of compound (b)
And a hydrazine derivative having two or more hydrazine residues
A coating aqueous resin composition containing (B) and a hydrazine residue in a ratio of 0.1 to 5 equivalents per equivalent of an aldo group or keto group. 2. A resin containing an aldo group or a keto group,
The ethylenically unsaturated compound containing an aldo group or keto group
The aqueous resin composition for coating according to claim 1, which is 0.1 to 30% by weight. 3. The aqueous resin composition for coating according to claim 1, wherein the ethylenically unsaturated compound (b) is 20 to 1000 parts by weight with respect to 100 parts by weight of the water-soluble resin (a). Stuff. 4. The aqueous resin composition for coating according to claim 1, wherein the ethylenically unsaturated compound (b) contains 0.1 to 3% by weight of a carboxyl group-containing ethylenically unsaturated compound.