JPH0726197A - Water-borne resin composition for coating of high storability - Google Patents

Abstract

PURPOSE:To obtain a water-borne resin composition which is used in coating substrates such as plastic film, metal, paper or glass, namely as a printing ink or a coating with high storage stability by using a specific resin emulsion and a hydrazine derivative at a specific ratio. CONSTITUTION:In the presence of a water-soluble resin (i) prepared by neutralizing a resin containing aldo or keto groups and carboxyl groups with ammonia or an organic amine, a mixture of an ethylenically unsaturated compound bearing a glycidyl group and other ethylenically unsaturated compound (ii) is subjected to emulsion polymerization to prepare (A) a resin emulsion containing aldo or keto groups and carboxyl groups. The resin emulsion (A) is combined with (B) a hydrazine derivative having 2 or more hydrazine residues so that the hydrazine residues becomes 0.1 to 5 equivalents per equivalent of the aldo or keto groups to give the objective water-borne resin composition for coating.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has excellent storage stability when used as a coating for substrates such as plastic film, metal, paper and glass, that is, as a printing ink, paint, sealant, adhesive, surface treatment agent and the like. The present invention relates to 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. These aqueous dispersions have attracted attention because they form a film at a relatively low temperature and have good adhesion to the adherend. For example, Japanese Patent Application Laid-Open No. 54-110248 discloses an aqueous dispersion of a carbonyl group-containing copolymer containing a hydrazine derivative, a composition using a carbonyl group-containing copolymer, an organic hydrazine derivative, and a heavy metal ion. Is described.

An aqueous dispersion composition of carbonyl group-containing copolymer particles is disclosed in Japanese Patent Laid-Open No. 57-3850. The core portion is emulsion-polymerized, and then the shell portion is emulsion-polymerized. A resin having a multi-layer structure is used. JPA
In the aqueous dispersion composition of a carbonyl group-containing copolymer disclosed in JP 57-3857 A, emulsion-polymerized resins having different glass transition temperatures (Tg) are mixed and used. Kohei
JP-A-4-249587 and JP-A-4-372674 disclose, as a resin composition for an aqueous dry-crosslinkable coating composition, a crosslinkable carbonyl group-containing emulsion particle synthesized using a nonionic or anionic activator and a dihydrazide compound. A system consisting of is disclosed.

However, the aqueous dispersions of these resins are all emulsions obtained in the presence of a surfactant. Resins of this type are easy to handle because a resin dispersion with a relatively low viscosity can be obtained even if the molecular weight is increased.
High film formability. However, on the other hand, there are problems that the dispersion stability is poor, the physical properties of the coating film are adversely affected due to the large amount of surfactant, and the coating and printability are insufficient.

[0005]

As a result of intensive studies to solve the above problems, the present inventors have found that an aqueous solution obtained by neutralizing a resin containing an aldo group or keto group and a carboxyl group with ammonia or an organic amine. Resin emulsion containing an aldo group or keto group, a glycidyl group and a carboxyl group obtained by emulsion polymerization of a glycidyl group-containing ethylenically unsaturated compound and another ethylenically unsaturated compound in the presence of an organic resin is a hydrazine derivative. The present invention was found to have excellent storage stability after coating in a specific ratio, suitability for coating, and excellent coating physical properties after drying.

[0006]

Means for Solving the Problems That is, the present invention is a water-soluble resin obtained by neutralizing a resin containing an aldo group or keto group and a carboxyl group with ammonia or an organic amine.
Containing an aldo group or keto group, carboxyl group and glycidyl group obtained by emulsion polymerization of a mixture (b) of a glycidyl group-containing ethylenically unsaturated compound with another ethylenically unsaturated compound in the presence of (a) Resin emulsion (A)
And a hydrazine derivative having two or more hydrazine residues
An aqueous resin composition for coating containing (B) in a ratio such that the hydrazine residue is 0.1 to 5 equivalents relative to 1 equivalent of an aldo group or keto group.

In the present invention, a water-soluble resin obtained by neutralizing a resin containing an aldo group or keto group and a carboxyl group instead of a surfactant with ammonia or an organic amine is used as a protective colloid, and a glycidyl group-containing ethylene is used. Alde groups or keto groups in resin emulsions obtained by emulsion polymerization of water-soluble unsaturated compounds with other ethylenically unsaturated compounds react with hydrazine residues after water removal to form excellent coating films. To form.

A resin containing an aldo group or keto group and a carboxyl group is a resin such as styrene or methylstyrene, together with a carboxyl group-containing ethylenically unsaturated monomer and an aldo group or keto group-containing ethylenically unsaturated monomer. Styrenes, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, propyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, (meth) acrylic Carbon number of methoxyethyl acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, butoxyethoxyethyl (meth) acrylate 1-18 aliphatic monohydric alcohol, 3-30 carbon atoms ethylene glycol Copolymerization of one or more monomers such as ester of chol monoalkyl ether or diethylene glycol monoalkyl ether having 3 to 30 carbon atoms with (meth) acrylic acid, vinyl acetate, maleic acid ester, acrylonitrile, etc. can get.

Examples of the unsaturated monomer containing a carboxyl group include polymerizable unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid and their anhydrides, which are aldo groups or keto groups. Group-containing unsaturated monomers 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.

The composition of the monomer is such that the amount of the unsaturated monomer containing an aldo group or keto group is 1 to 50% by weight, more preferably 1 to 30% by weight, based on the total amount of the monomer. The acid value of is preferably selected in the range of 70 to 350. When the amount of the unsaturated monomer containing an aldo group or keto group is less than 1% by weight, the cross-linking density of the obtained aqueous resin composition for coating tends to be small and the solvent resistance and water resistance of the coating after drying tend to be slightly inferior. %, The storage stability of the obtained coating aqueous resin composition tends to be slightly low. When the acid value is less than 70, the resin obtained by the following neutralization operation has poor water solubility and the performance as a protective colloid is poor. Further, when the acid value exceeds 350, the water-soluble resin obtained by neutralizing the resin has good performance as a protective colloid, but in the presence of this, a resin emulsion obtained by emulsion polymerization of an ethylenically unsaturated compound The physical properties of the coating film deteriorate. The molecular weight of the water-soluble resin is preferably 3000 to 60,000.

The above-mentioned resin containing an aldo group or keto group and a carboxyl group can be produced by a polymerization method such as bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization which are well known in the art. 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 resin containing an aldo group or keto group and a carboxyl group obtained as described above has ammonia or triethylamine, trimethylamine, dimethylaminoethanol, monoethanolamine or the like in the reaction system after completion of the polymerization reaction. The desired water-soluble resin (a) can be obtained by adding amines and neutralizing. The addition amount of ammonia or the like is preferably in a range such that the carboxyl group neutralization ratio in the resin is about 70 to 120%. If the neutralization rate is too low, the ability of the resulting water-soluble resin as a protective colloid decreases, which is not preferable.

A resin emulsion (A) containing an aldo group or keto group, a carboxyl group and a glycidyl group is
Mixture of a glycidyl group-containing ethylenically unsaturated compound and another ethylenically unsaturated compound in the presence of 100 parts by weight of the water-soluble resin (a) obtained as described above (b) 20 to 1000 parts by weight, preferably Obtained by emulsion polymerization of 50 to 600 parts by weight. Add a mixture of ethylenically unsaturated compounds (b) to 20
When it is used in an amount less than the weight part, the content of the water-soluble resin component becomes large, resulting in poor film forming property and physical properties of the coated product. 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 mixture (b) of ethylenically unsaturated compounds is
It is selected in consideration of hardness, heat resistance, adhesiveness, film-forming property and the like of the obtained coating aqueous composition. Examples of the glycidyl group-containing ethylenically unsaturated compound include glycidyl (meth) acrylate. Other ethylenically unsaturated compounds include (meth) acrylic acid esters having an alkyl group having 1 to 22 carbon atoms, (meth) acrylic acid ester having a hydroxyl group and an amino group, (meth) acrylic acid amide, (meth) acrylonitrile. , Styrene, (meth) acrylic acid, maleated monoester, etc., acrolein, diacetone (meth) acrylamide, formyl styrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, (meth) acryloxymethyl propanal, diacetone ( Aldo group- or keto group-containing ethylenic compounds such as N-substituted (meth) acrylic monomers such as (meth) acrylate, acetonyl (meth) acrylate, N-methylol (meth) acrylamide, and N-butoxymethyl (meth) acrylamide Saturated compounds are mentioned. The above compounds can be used in combination with a glycidyl group-containing ethylenically unsaturated compound and other one kind or two or more kinds.

The glycidyl group-containing ethylenically unsaturated compound is a resin emulsion (A) containing an aldo group, a keto group, a carboxyl group and a glycidyl group.
It is preferably used in an amount of 0.1 to 30% by weight, more preferably 1 to 15% by weight. If it is less than 0.1% by weight, the effect of improving the physical properties of the coating film such as heat resistance, alcohol resistance and alkali resistance cannot be fully exerted, and if it is more than 40% by weight, the storage stability of the obtained aqueous resin composition for coating Tends to be low. As an initiator for emulsion-polymerizing the mixture (b) of the ethylenically unsaturated compound, ammonium persulfate,
Examples thereof include persulfate catalysts such as potassium persulfate and redox catalysts obtained by combining these with acidic sulfites. Further, a molecular weight modifier or a surfactant may be added to the emulsion polymerization reaction system of the present invention, if necessary.

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

[Chemical 1]

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, when it exceeds 5 equivalents, the storage stability of the obtained coating aqueous resin composition becomes low.

The aqueous resin composition for coating of the present invention has 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 is heated or dried at room temperature. To be done.

[0021]

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 the 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, 600 parts of ammonia water containing an equivalent amount of ammonia to the carboxyl group in the reaction product was added, and an aqueous resin solution containing an aldo group or keto group (solid content 25%) ( a) to (d) were obtained. Table 1
The acid value shown in is the value before neutralizing the resin containing aldo group or keto group with ammonia.

[0022]

[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 20 parts of methyl methacrylate and 2 ethylhexyl acrylate were added.
Solution, 15 parts of glycidyl methacrylate and 0.1 part of ammonium persulfate in 1.9 parts of purified water 2.0
The mixture 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%. A resin emulsion (e) containing a keto group and a glycidyl group having a viscosity of 2100 cps. At 25 ° C was obtained.

[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
Heated to ℃, 90 parts of methyl methacrylate, methacrylic acid
0.5 part, n-butyl acrylate 89.5 parts, glycidyl methacrylate 20 parts and ammonium persulfate 1.0 part were added to purified water 9.0
10 parts of an aqueous solution obtained by dissolving in 10 parts of the solution was added dropwise over 120 minutes,
Then react at 90 ℃ for 1 hour, add purified water to remove solid content
Adjusted to 42%. A resin emulsion (f) containing an aldo group and a glycidyl group having a viscosity of 260 cps. At 25 ° C was obtained.

[Production Example 7] 400 parts of the resin aqueous solution (c) and 400 parts of purified water were charged in the same reactor as in Production Examples 1 to 4.
Heated to 80 ℃, n-butyl methacrylate 390 parts, 2-ethylhexyl acrylate 200 parts, glycidyl methacrylate 10
Parts, 3 parts of 2-ethylhexyl thioglycolate and 1.0 part of ammonium persulfate as a molecular weight regulator were dissolved in 9.0 parts of purified water, 10 parts of an aqueous solution was added dropwise over 150 minutes, and then the mixture was allowed to react at 90 ° C for 1 hour, and purified water was added. And add the solid content to 46
Adjusted to%. A keto group- and glycidyl group-containing resin emulsion (g) having a viscosity of 170 cps. At 25 ° C was obtained.

[Production Example 8] 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, and
After heating to ℃, dissolve 10 parts of diacetone acrylamide, 80 parts of methyl methacrylate, 65 parts of n-butyl acrylate, 40 parts of 2-ethylhexyl acrylate, 5 parts of glycidyl methacrylate and 1.0 part of ammonium persulfate in 9.0 parts of purified water. 10 parts of the resulting aqueous solution was added dropwise over 120 minutes and then reacted at 90 ° C for 1 hour, and purified water was added to adjust the solid content to 44%. A resin emulsion (h) containing a keto group and a glycidyl group having a viscosity of 250 cps at 25 ° C. was obtained.

[Production Example 9] A reactor similar to that of Production Examples 1 to 4 was charged with 400 parts of the resin aqueous solution (d) and 80 parts of purified water,
Heated to ℃, 100 parts of methyl methacrylate, methacrylic acid
0.5 part, butyl acrylate 99.5 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 120 minutes, and then the mixture was reacted at 90 ° C for 1 hour. The minute was adjusted to 42%. A resin emulsion (i) having a viscosity of 1200 cps. At 25 ° C was obtained.

[Production Example 10] The same reactor as in Production Examples 1 to 4 was charged with 400 parts of the resin aqueous solution (d) and 80 parts of purified water.
Heat to ℃ 65, methyl methacrylate 65 parts, methacrylate n-
70 parts of butyl, 15 parts of glycidyl methacrylate and 1.0 part of ammonium persulfate were dissolved in 9.0 parts of purified water, 10 parts of an aqueous solution was added dropwise over 120 minutes, and then the mixture was reacted at 90 ° C for 1 hour. The mold component was adjusted to 38%. A glycidyl group-containing resin emulsion (j) having a viscosity of 180 cps. At 25 ° C was obtained.

[Production Example 11] A reactor similar to that of Production Examples 1 to 4 was charged with 400 parts of the resin aqueous solution (b) and 80 parts of purified water.
Heat to ℃, methyl methacrylate 75 parts, methacrylic acid
An aqueous solution obtained by dissolving 0.5 part, 74.5 parts of n-butyl acrylate 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 38%. An aldo group-containing resin emulsion (k) having a viscosity of 250 cps. At 25 ° C was obtained.

[Examples 1 to 4 and Comparative Examples 1 to 5] 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 the appearance state, cellophane adhesiveness, solvent resistance, alkali resistance and heat resistance of the obtained dried 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.

Appearance: Visual evaluation. ○: Good, ×: Poor Cellophane adhesiveness ... The degree of peeling with cellophane tape manufactured by Nichiban was visually evaluated. Solvent resistance: The surface of the coating film was rubbed with absorbent cotton containing methyl ethyl ketone, and the state of the coating film was visually evaluated. Alkali resistance: An aqueous sodium hydroxide solution having a pH of 13 was spotted on the coating film for 10 minutes, and the degree of peeling of the coating film was visually evaluated.

Heat resistance: 180 layers of coating and aluminum foil
After pressurizing (2kg / cm ² ) at ℃ for 2 seconds, peel off the aluminum foil,
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 100% or less, XX: gelation.

[0034]

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.

Claims (4)

[Claims] 1. A glycidyl group-containing ethylenically unsaturated compound and another resin in the presence of a water-soluble resin (a) obtained by neutralizing a resin containing an aldo group or keto group and a carboxyl group with ammonia or an organic amine. A resin emulsion (A) containing an aldo group or keto group, a carboxyl group and a glycidyl group, obtained by emulsion polymerization of a mixture (b) with an ethylenically unsaturated compound, and a hydrazine derivative having two or more hydrazine residues ( A coating aqueous resin composition containing B) and B in a ratio such that the hydrazine residue is 0.1 to 5 equivalents relative to 1 equivalent of an aldo group or keto group. 2. The glycidyl group-containing ethylenically unsaturated compound is contained in the solid content of the resin emulsion (A) containing an aldo group, keto group, carboxyl group and glycidyl 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 resin containing an aldo group or keto group and a carboxyl group has an acid value of 70 to 350. 4. The coating aqueous solution according to claim 1, wherein the mixture (b) of the ethylenically unsaturated compound is 20 to 1000 parts by weight with respect to 100 parts by weight of the water-soluble resin (a). Resin composition.