JPH06248161A - Aqueous resin composition and coating material - Google Patents

Abstract

PURPOSE:To obtain a coating material excellent in stability and capable of giving a coating film improved in driability, water resistance, corrosion resistance, hardness, adhesion and impact resistance. CONSTITUTION:The 4' composition contairns an epoxy-ester-modified acrylic emulsion of an acid value of 10 to 50 btained by emulsion-polymerizing 80-40wt.% polymerizable monomer mixture containing an ethylenically unsaturated carboxylic acid in the presence of 20-60wt.% epoxy ester resin with the aid of a reactive emulsifier having an ethylenic unsaturation.

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 which is useful for paints, adhesives, etc. and a paint using the same.

[0002]

2. Description of the Related Art In recent years, effective use of petroleum resources in metal coatings for automobiles, industrial machinery, steel furniture, home appliances, etc.
From the viewpoint of environmental protection and safety measures, the transition from conventional solvent-based paints to water-based paints is progressing. Such water-based paints are required to have fast drying properties, corrosion resistance, water resistance and the like.
There is known an aqueous paint using an acrylic emulsion obtained by emulsion polymerization (for example, JP-A-4-272903). Emulsion polymerization generally gives high molecular weight products, but conventional acrylic emulsions have poor corrosion resistance. Further, Japanese Patent Publication No. 10637 / 51-1036 discloses an acrylic emulsion in which a high acid value epoxy ester resin having an acid value of 30 to 300 is neutralized with an amine to be water-solubilized and used as an emulsifier. However, this is not stable in emulsion polymerization and is not industrially applicable.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves these problems. A reactive emulsifier is used as an emulsifier, and an epoxy ester resin and an ethylenically unsaturated copolymerization monomer are graft-copolymerized. By using the specific epoxy ester-modified acrylic emulsion thus prepared, it was found that a resin composition for water-based coating and a coating having excellent drying properties, water resistance, corrosion resistance, chemical resistance, etc. can be obtained, and it has been completed. .

[0004]

That is, the present invention provides a polymerizable monomer mixture 80 containing an ethylenically unsaturated carboxylic acid in the presence of 20 to 60% by weight of an epoxy ester resin.
-40% by weight, and an epoxy resin-modified acrylic emulsion having an acid value of 10 to 50 obtained by emulsion polymerization using a reactive emulsifier having an ethylenically unsaturated group as an emulsifier. And a coating material containing the resin composition.

The epoxy ester resin in the present invention is a product obtained by adding and condensing a fatty acid and an epoxy resin. This addition and condensation reaction can be performed according to a known method. Fatty acids used in the present invention include dry oils, semi-dry oils, and fatty acids that can be derived from non-drying oils, such as tung oil, linseed oil, soybean oil, castor oil, dehydrated castor oil, safflower oil, and palm oil Fatty acids,
Examples thereof include versatic acid obtained by synthesis. In order to impart room temperature curability, it is preferable to use a fatty acid derived from a drying oil or a semi-drying oil.

Examples of the epoxy resin used in the present invention include bisphenol A or F type epoxy resins and the like, such as Epicoat 828, 1001, 1004 (trade name of Shell Chemical Co.). Aliphatic epoxy compounds having a glycidyl group can also be used, for example, alkylene glycols such as ethylene glycol and propylene glycol, diglycidyl ethers such as polyethylene glycol, polypropylene glycol, tetramethylene glycol, 1,6-hexanediol and neopentyl glycol. , Di- or triglycidyl ethers such as trimethylolpropane, glycerin, pentaerythritol, sorbitol, glycerin dimer, polyglycidyl ethers of multimers, adipic acid, diglycidyl esters such as tetramethylenedicarboxylic acid, etc., one of these Or two or more kinds are used. From the viewpoints of dryness and corrosion resistance, the compounding ratio of the fatty acid and the epoxy resin used in the epoxy ester resin is preferably 30 to 70% by weight of the fatty acid and 70 to 30% by weight of the epoxy resin. The acid value of the obtained epoxy ester resin is preferably 30 or less from the viewpoint of water resistance.

The polymerizable monomer mixture is blended in the presence of the epoxy ester resin and emulsion-polymerized. The emulsifier used for emulsion polymerization in the present invention is a reactive emulsifier having an ethylenically unsaturated group from the viewpoint of water resistance and corrosion resistance. Examples of such reactive emulsifiers include those manufactured by Nippon Emulsifier Co., Ltd .;
Antox MS60, manufactured by Asahi Denka Kogyo; ADEKA RIASOAP SE10N, manufactured by Sanyo Kasei; anionic reactive emulsifiers having ethylenically unsaturated groups such as eleminol RS30, eleminol JS2, manufactured by Asahi Denka Kogyo; ADEKA Rear soap NE10, 20, 30, 40
There are nonionic reactive emulsifiers such as. These reactive emulsifiers can be used alone or in combination of two or more. If necessary, they can be used in combination with a usual emulsifier. The smaller the amount of the reactive emulsifier used, the more preferable it is from the viewpoint of water resistance and corrosion resistance, and is 0.5 with respect to the resin solid content of the epoxy ester-modified acrylic emulsion.
-5% by weight is suitable.

Examples of the ethylenically unsaturated carboxylic acid used in the present invention include α, β-monoethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid. These have an epoxy ester-modified acrylic emulsion with an acid value of 10 to 5
Blend so that it becomes 0. When the acid value is less than 10, the stability of the coating is insufficient, and when it exceeds 50, the water resistance and corrosion resistance of the coating film are poor. Further, as the copolymerizable monomer other than the ethylenically unsaturated carboxylic acid used in the present invention,
There are esters of methacrylic acid or acrylic acid with alkanols having 1 to 12 carbon atoms, hydroxyalkyl esters of α, β-monoethylenically unsaturated carboxylic acids, and the like. Examples thereof include methyl acrylate or methacrylate, ethyl acrylate or methacrylate, propyl acrylate or methacrylate, butyl acrylate or methacrylate, 2-ethylhexyl acrylate or methacrylate, 2-hydroxyethyl acrylate or methacrylate, 2-hydroxypropyl acrylate or methacrylate and the like. Also, acrylonitrile, methacrylonitrile, acrylate, methacrylamide, styrene, vinyltoluene,
Phosphoric acid esters of vinylpyrrolidone, N, N-dimethylaminoethyl acrylate or methacrylate, vinylpyridine, polyethylene glycol monoacrylate or methacrylate, acid phosphooxyethyl acrylate or methacrylate, polyethylene glycol monoacrylate or methacrylate can also be used. These are appropriately selected according to the required characteristics, and one kind or two or more kinds are used.

It is also useful to make the emulsion particles into a three-dimensionally crosslinked microgel, and for this purpose polyfunctional monomers such as glycidyl methacrylate, divinylbenzene, ethylene glycol diacrylate or methacrylate are fully polymerized. 0 for reactive monomers
It is also possible to use up to 8% by weight. If it exceeds 8% by weight, the film-forming property of the coating film tends to deteriorate.

In the production of the epoxy ester-modified acrylic emulsion, the compounding amount of the epoxy ester resin is 2
0 to 60% by weight (ie 80 to 80 polymerizable monomer mixture)
40% by weight), and if less than 20% by weight, room temperature curability,
Corrosion resistance is poor, and when it exceeds 60% by weight, stability during emulsion polymerization is poor. The epoxy ester-modified acrylic emulsion can be produced by a known method by emulsion polymerization. It is also useful to forcibly disperse the epoxy ester resin containing an emulsifier in water using a homogenizer or the like and then emulsion-polymerize it. Emulsion polymerization can be carried out at 30 to 100 ° C. using an ordinary aqueous radical polymerization catalyst. A fast chain transfer agent such as carbon tetrachloride and mercaptans can be used to control the molecular weight.

The emulsion after emulsion polymerization is neutralized with an amine such as ammonia, triethylamine, dimethylaminoethanol (adjusted to pH 7 to 10) to obtain a stable emulsion resin. The amount of amine used is preferably 0.5 to 1 when the amount of carboxyl groups in the emulsion before neutralization is 1.

The epoxy ester-modified acrylic emulsion thus obtained is used as the aqueous resin composition of the present invention, and butyl cellosolve, ethyl cellosolve, 3-methyl-3-methoxybutanol and isopropanol are used as hydrophilic organic solvents. , Butanol and the like can also be used together. These are spray coatability, smoothness of coating film,
From the viewpoint of drying property, gloss, etc., it is preferable to selectively use.

The aqueous resin composition of the present invention is mixed with other aqueous resins, pigments, other additives, etc. to form a coating material depending on the purpose. For example, it can be used as a baking paint by combining with a modified amino resin. Further, in particular, when a fatty acid of a drying oil or a semi-drying oil is used in the aqueous resin composition of the present invention, it is useful as a room temperature dry type coating material to which a metal desiccant is added. In addition to spray coating, roll coater coating, dipping coating,
Electrodeposition coating etc. can be adopted, and in addition to metal such as iron and aluminum, it can be coated on the surface of plastic, ceramic, wood, paper, fiber and the like.

[0014]

The present invention will be described with reference to the following examples. % Means% by weight.

[Production Example of Epoxy Ester Resin (A-1)] In a flask equipped with a stirrer, a reflux condenser, an inert gas inlet and a thermometer, Epicoat 828; 417 g,
Dehydrated castor oil fatty acid; 63 g, linseed oil fatty acid; 501
g, dimethyl ethanolamine; 1 g was charged, 220
After reacting at 0 ° C for 5 hours, the temperature was lowered to 120 ° C, 20 g of maleic acid was charged and reacted for 1 hour to obtain an epoxy ester resin (A-1) having an acid value of 10.

Example 1 The above epoxy ester resin (A-1); 200 was added to a beaker.
g, Antox MS60; 40 g,
Water (1465 g) was added and the mixture was emulsified in a homogenizer for 5 minutes, transferred to the same flask as in the above Production Example, heated to 80 ° C., and ammonium persulfate (2.5 g) was added. Separately from this, styrene; 450 g, butyl acrylate; 8
0 g, 2-ethylhexyl acrylate; 190 g, β
-Hydroxyethylmethacrylate; 40g, methacrylic acid;
After dropping over a period of time, the mixture was kept warm for 2 hours and cooled, 25% ammonia; 17 g, butyl cellosolve; 100 g, water;
20 g was added to obtain an epoxy ester-modified acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 28.

Example 2 The above epoxy ester resin (A-1); 400 was added to a beaker.
g, ADEKA rear soap SE10N; 40 g, styrene;
1. 340 g, butyl acrylate; 60 g, 2-ethylhexyl acrylate; 140 g, β-hydroxyethyl methacrylate; 30 g, methacrylic acid; 30 g in a mixed solution of water; 1000 g, ammonium persulfate;
5 g was added and the mixture was emulsified in a homogenizer for 5 minutes to obtain an emulsion A. 100 g of this emulsion A and 465 g of water were placed in the same flask as in the production example of (A-1) above, and the temperature was 80 ° C.
The temperature was raised to 1, and ammonium persulfate (1 g) was added. The remaining emulsion A was placed in a dropping funnel, dropped over 1 hour, then kept warm for 2 hours and cooled to 25% ammonia; 17 g,
Butyl cellosolve (100 g) and water (20 g) were added to obtain an epoxy ester-modified acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 23.5.

Comparative Example 1 In Example 2, the reactive emulsifier ADEKA REASOAP SE10N was used as a general emulsifier Newc (Newc).
ol) 560SN (sodium polyoxyethylene nonyl phenyl ether sulphate). An epoxy ester-modified acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 23.5 was obtained.

Comparative Example 2 Adeka rear soap SE10N; 40 g, styrene; 570 g, butyl acrylate; 100 g, 2-ethylhexyl acrylate; 250 g, β-hydroxyethyl methacrylate; 50 g, methacrylic acid; 30 g
1000 g of water and 2.5 g of ammonium persulfate were added to the mixed liquid consisting of, and the mixture was emulsified in a homogenizer for 5 minutes to obtain an emulsion A. This emulsion A; 100 g and water; 4
65 g was placed in the same flask as in the production example of (A-1) above, heated to 80 ° C., and ammonium persulfate; 1 g was added. The rest of the emulsion A was placed in a dropping funnel, dropped over 1 hour, kept warm for 2 hours, cooled and added with 17 g of 25% ammonia, 100 g of butyl cellosolve; 100 g of water; 20 g of heating residue, acid value 40%. An acrylic emulsion having a (solid content) of 19.5 was obtained.

COMPARATIVE EXAMPLE 3 The above epoxy ester resin (A-1); 800 was added to a beaker.
g, ADEKA rear soap SE10N; 40 g, styrene;
150 g, 2-ethylhexyl acrylate; 10 g,
To a mixed solution of 10 g of β-hydroxyethyl methacrylate; 30 g of methacrylic acid, 1000 g of water and 2.5 g of ammonium persulfate were added and emulsified in a homogenizer for 5 minutes to obtain an emulsion A. This emulsion A; 10
0 g and water; 465 g were placed in the same flask as in the production example of (A-1) and heated to 80 ° C., and ammonium persulfate; 1
g was added. Charge the remaining emulsion A into a dropping funnel,
After dripping over 1 hour, keep warm for 2 hours and cool to 25%
Ammonia; 17 g, butyl cellosolve; 100 g,
Water; 20 g was added to obtain an epoxy ester-modified acrylic emulsion, but there were many aggregates.

Comparative Example 4 A beaker containing the above epoxy ester resin (A-1); 400
g, ADEKA rear soap SE10N; 40 g, styrene;
370 g, butyl acrylate; 60 g, 2-ethylhexyl acrylate; 140 g, β-hydroxyethyl methacrylate;
g and ammonium persulfate; 2.5 g were added and the mixture was emulsified in a homogenizer for 5 minutes to obtain an emulsion A. 100 g of this emulsified liquid A and 465 g of water were placed in the same flask as in the production example of (A-1) above, heated to 80 ° C., and 1 g of ammonium persulfate was added. The remaining emulsion A was placed in a dropping funnel, dropped over 1 hour, then kept warm for 2 hours and cooled, 25% ammonia; 7 g, butyl cellosolve; 100
g, water; 30 g were added to obtain an epoxy ester-modified acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 4.

COMPARATIVE EXAMPLE 5 The above epoxy ester resin (A-1); 400 was added to a beaker.
g, ADEKA rear soap SE10N; 40 g, styrene;
270 g, butyl acrylate; 60 g, 2-ethylhexyl acrylate; 140 g, β-hydroxyethyl methacrylate; 30 g, methacrylic acid; 100 g in a mixed solution of water; 1000 g, ammonium persulfate;
2.5 g was added and the mixture was emulsified in a homogenizer for 5 minutes to obtain an emulsion A. This emulsion A; 100 g and water; 445
g in a flask similar to the production example of (A-1) above
The temperature was raised to 0 ° C., and ammonium persulfate (1 g) was added. The remaining emulsified liquid A was charged into a dropping funnel and added dropwise over 1 hour, then kept warm for 2 hours and cooled to 25% ammonia; 37
g, butyl cellosolve; 100 g, water; 20 g,
An epoxy ester-modified acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 69 was obtained.

Comparative Example 6 The same flask as in the production example of (A-1) above was charged with 400 g of the above epoxy ester resin (A-1) and 400 g of butyl cellosolve and heated to 110 ° C. Styrene; 320 g, butyl acrylate; 60 g, 2-ethylhexyl acrylate; 140 g, β-hydroxyethyl methacrylate; 30 g, methacrylic acid; 50 g,
Azobisisobutyronitrile; 20 g was charged into a dropping funnel, added dropwise over 2 hours, kept warm for 2 hours, cooled, and 25% ammonia; 27 g was added, and water; 1103
g to emulsify, heating residue 40%, acid value (solid content) 3
Thus, an epoxy ester-modified acrylic resin of 7 was obtained.

COMPARATIVE EXAMPLE 7 The procedure of Example 2 was repeated except that the reactive emulsifier ADEKA REASOAP SE10N was removed and 25% of ammonia 17 g was added, but the emulsion polymerization reaction was agglomerated.

The reactive emulsifiers used in the examples, Antox MS60 and ADEKA REASOAP SE10N.
The structural formula of is shown below.・ Antox MS60

[Chemical 1] (However, A is an alkylene group, R and R'are monovalent organic groups, and m and n are positive numbers indicating the repetition of AO.) ADEKA REASOAP SE10N

[Chemical 2]

Examples 1, 2 and Comparative Examples 1, 2, 4, 5,
The resin of No. 6 was used to prepare a coating composition shown in Table 1.

[Table 1]

The coating material obtained by the above-described coating was applied under the following conditions, and after drying, the coating film characteristics were tested. The results are shown in Table 2. (Painting conditions) Painting: Spray painting, Iwata Wider 61, dry film thickness 30
μm Base material: untreated steel; SPCC-SD plate thickness 0.8 mm (manufactured by Japan Test Panel Co.) Drying: 60 ° C. × 20 minutes + 22 ° C. × 3 days (test condition) Dryability: Drying at 60 ° C. for 20 minutes The degree of stickiness of the coating film immediately after was observed. Hardness: Based on JIS K5400. Impact test: 500 g, ½ inch. Goban: Cut 100 mm squares with a cutter.
After peeling with cellophane tape, the number of squares of the remaining coating film is shown. Water resistance: After immersing in 40 ° C. ion-exchanged water for 10 days, swelling and whitening of the coating film were observed. Salt sprayability: The coating film was cut with a cutter, put in a salt spray test, taken out after 240 hours, peeled off with cellophane tape, and the peeling width on one side was expressed in mm. Paint stability: The condition of the paint after storage at 40 ° C for 10 days was visually observed.

[0028]

[Table 2]

As can be seen from Examples 1 and 2, the coating material using the aqueous resin composition of the present invention is excellent in all of coating stability, drying property, water resistance, corrosion resistance and the like. Comparative Example 1 is a case where a normal emulsifier is used instead of the reactive emulsifier, but the water resistance and the corrosion resistance are poor. Comparative Example 2 is a case of a normal acrylic emulsion resin containing no epoxy ester resin, but the hardness, water resistance and corrosion resistance are poor. This is a case where the amount of the epoxy ester resin of Comparative Example 3 is too large, but aggregates appear during emulsion polymerization, and the polymerization stability is poor. Comparative Example 4 is a case where the unsaturated carboxylic acid is not used and the acid value is low, but the coating stability is poor. Comparative Example 5 has a high acid value, but is inferior in water resistance and corrosion resistance. Comparative Example 6 is a modified acrylic resin synthesized in an organic solvent, but the drying property, hardness, water resistance, and corrosion resistance are poor. Comparative Example 7 is a case where no emulsifier is used, but neutralizing the epoxy ester does not provide an effective emulsifier and aggregates during emulsion polymerization.

[0030]

EFFECT OF THE INVENTION The aqueous resin composition and coating composition of the present invention have coating stability, coating drying property, water resistance, corrosion resistance, hardness,
Excellent adhesion and impact resistance.

Claims (3)

[Claims] 1. Epoxy ester resin 20 to 60% by weight
Of the polymerizable monomer mixture containing an ethylenically unsaturated carboxylic acid in the presence of, and an acid value obtained by emulsion polymerization using a reactive emulsifier having an ethylenically unsaturated group as an emulsifier An aqueous resin composition comprising 10 to 50 epoxy ester-modified acrylic emulsion. 2. The epoxy ester resin comprises 30 to 30 fatty acids.
70% by weight and 70 to 30% by weight of epoxy resin are added,
The aqueous resin composition according to claim 1, which is an epoxy ester resin having an acid value of 30 or less obtained by condensation. 3. A paint comprising the aqueous resin composition according to claim 1 or 2.