JPH06248235A - Aqueous resin composition and coating - Google Patents

Abstract

PURPOSE:To obtain an aqueous resin composition containing a specific alkyd modified acrylic emulsion and excellent in coating stability, and dryability hardness, luster, adhesiveness, impact resistance, waterproofness, corrosion resistance of the coating film. CONSTITUTION:The composition consists of an alkyd modified acrylic emulsion having 10-50 acid value, obtained by emulsion polymerizing 90-40(wt.)% mixture of polymerizable monomers containing an ethylenic unsaturated carboxylic acid in the presence of 10-60% alkyd resin using a reactive emulsion which contains ethylenic unsaturated groups. The above-mentioned alkyd modified acrylic emulsion can be obtained by forcibly dispersing an alkyd resin containing an emulsifier in water by a homogenizer, etc., then, emulsion polymerizing the monomer mixture at 30-100 deg.C by using a radical polymerization catalyst and further neutralizing the polymerized emulsion at pH7-10 with ammonia, etc. Here, a fatty acid used for an alkyd resin production is preferably derived from a (semi) drying oil.

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 paint is required to have gloss, quick-drying property, water resistance, corrosion resistance and the like. JP-A-4-170410 discloses an acrylic-modified alkyd resin having excellent water resistance and corrosion resistance, which is obtained by graft-copolymerizing an alkyd resin and an ethylenically unsaturated monomer in an organic solvent. However, in the above solution polymerization method, since there is a water dispersion step in the subsequent step, the molecular weight cannot be increased, and the coating film is liable to be whitened or swollen in the water resistance test. Emulsion polymerization generally gives high molecular weight products, but conventional acrylic emulsions are inferior in gloss, room temperature curability and corrosion resistance.
Japanese Patent No. 637 discloses an acrylic emulsion in which a high acid value alkyd 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]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and a reactive emulsifying agent was used as an emulsifier, and an alkyd resin and an ethylenically unsaturated copolymerization monomer were graft-emulsified and copolymerized. It was found that by using a specific alkyd-modified acrylic emulsion, it is possible to obtain an aqueous resin composition and a coating having excellent gloss, drying properties, water resistance, corrosion resistance, etc., and it has been completed.

[0004]

Means for Solving the Problems That is, according to the present invention, 90 to 40% by weight of a polymerizable monomer mixture containing an ethylenically unsaturated carboxylic acid is mixed in the presence of 10 to 60% by weight of an alkyd resin, and ethylene is used as an emulsifier. The acid value obtained by emulsion polymerization using a reactive emulsifier having a water-saturated group is 1
The present invention relates to an aqueous resin composition containing 0 to 50 alkyd-modified acrylic emulsion and a coating material containing the resin composition.

The alkyd resin in the present invention is a product obtained by adding and condensing oil or fatty acid, polyhydric alcohol, monobasic acid, polybasic acid or its anhydride. The oil or fatty acid used in the present invention includes a drying oil, a semi-drying oil, a non-drying oil and its fatty acid, for example, tung oil, linseed oil, soybean oil, castor oil, dehydrated castor oil, safflower oil, coconut oil and their oils. Examples include fatty acids and versatic acids 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.

The polyhydric alcohol, the monobasic acid, the polybasic acid or the anhydride thereof is not particularly limited.
170410 can be used, for example,
If necessary, a phenol resin, an epoxy resin or the like can be used together. The oil or fatty acid used in the alkyd resin is preferably contained in the alkyd resin in an amount of 30 to 70% by weight from the viewpoint of drying property and water resistance. The acid value of the alkyd resin is preferably 20 or less from the viewpoint of water resistance and corrosion resistance.

The polymerizable monomer mixture is blended in the presence of the alkyd 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 Co., Ltd., ADEKA RIASOAP SE10N, manufactured by Sanyo Chemical Co., Ltd .; Eleminol R.
Anionic reactive emulsifiers having an ethylenically unsaturated group such as S30 and Eleminol JS2, manufactured by Asahi Denka Kogyo Co., Ltd .; nonionic reactive emulsifiers such as Adecaria Soap NE10, 20, 30, 40. 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 these reactive emulsifiers used, the better the water resistance,
It is preferable from the viewpoint of corrosion resistance, and 0.5 to 5% by weight is appropriate with respect to the resin solid content of the alkyd-modified acrylic emulsion, and if it is less than 0.5% by weight, the stability during emulsion polymerization tends to decrease.

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 are blended so that the alkyd-modified acrylic emulsion has an acid value of 10 to 50. If the acid value is less than 10, the stability of the coating is insufficient, and if 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, an ester of methacrylic acid or acrylic acid and an alkanol having 1 to 12 carbon atoms, α, β-monoethylenically unsaturated Examples include hydroxyalkyl esters of carboxylic acids. 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. Also acrylonitrile,
Methacrylonitrile, acrylic amide, methacrylic amide, styrene, vinyltoluene, vinylpyrrolidone, N, N-dimethylaminoethyl acrylate or methacrylate, vinyl pyridine, polyethylene glycol monoacrylate or methacrylate, acid phosphooxyethyl acrylate or methacrylate, polyethylene glycol mono Acrylic or methacrylate phosphoric acid esters can also be used, and these are appropriately selected according to the required properties and one or more kinds are used.

In the production of the alkyd-modified acrylic emulsion, the content of the alkyd resin is 10 to 60% by weight.
(That is, the polymerizable monomer mixture is 90 to 40% by weight)
If it is less than 10% by weight, room temperature curability is poor, and if it exceeds 60% by weight, stability during emulsion polymerization is poor and water resistance is also reduced.

The alkyd-modified acrylic emulsion can be produced by a known method by emulsion polymerization. Further, it is useful to forcibly disperse the alkyd resin containing the emulsifier in water using a homogenizer or the like, and then emulsion-polymerize. The emulsion polymerization is carried out by using an ordinary aqueous radical polymerization catalyst in an amount of 30 to 10
It can be synthesized at 0 ° C. Chain transfer agents such as carbon tetrachloride and mercaptans can be used to control the molecular weight.

The emulsion after emulsion polymerization is neutralized with amines such as ammonia, triethylamine and dimethylaminoethanol (adjusted to pH 7 to 10) to obtain a stable emulsion resin. The amount of amine used is 1 for the amount of carboxyl groups in the emulsion before neutralization.
Then, it is preferable to set it to 0.5 to 1.

The alkyd-modified acrylic emulsion thus obtained is used as the aqueous resin composition of the present invention. As hydrophilic organic solvents, butyl cellosolve, ethyl cellosolve, 3-methyl-3-methoxybutanol, isopropanol, Butanol and the like can also be used in combination. These are spray coatability, smoothness of coating film, drying property,
From the viewpoint of gloss and the like, 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 Alkyd Resin (A-1)] Dehydrated castor oil fatty acid; 63 g, linseed oil fatty acid; 322 g, ethylene in a flask equipped with a stirrer, a reflux condenser, an inert gas inlet and a thermometer. Glycol; 120 g, glycerin; 116 g, pentaerythritol; 31 g,
Phthalic anhydride; charged with 422 g, 230 over 2 hours
The temperature was raised to 0 ° C., the reaction was further continued for 2 hours, and the mixture was cooled to obtain an alkyd resin (A-1) having an acid value of 5.

Example 1 In a beaker, the above alkyd resin (A-1); 200 g, Antox MS60; 40 g, water; 1465 g
Was added to the homogenizer for 5 minutes to emulsify, and the mixture was 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; 100 g, 2-ethylhexyl acrylate; 190 g, β-hydroxyethyl methacrylate; 20 g, methacrylic acid; 40 g
The mixture liquid consisting of is charged into a dropping funnel and added dropwise over 1 hour, then kept warm for 2 hours and cooled to 25% ammonia;
7 g and butyl cellosolve; 100 g, water; 20 g were added to obtain an alkyd-modified acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 28.

Example 2 400 g of alkyd resin (A-1) in a beaker, 40 g of ADEKA REASOAP SE10N, styrene; 340
g, butyl acrylate; 80 g, 2-ethylhexyl acrylate; 140 g, β-hydroxyethyl methacrylate; 10 g, methacrylic acid; 30 g, and water; 1000 g, ammonium persulfate; 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. After charging the remaining emulsion A into a dropping funnel and dropping the mixture over 1 hour,
After keeping the temperature for 2 hours and cooling, 25% ammonia; 17 g, butyl cellosolve; 100 g, and water: 20 g were added to obtain an alkyd-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 emulsifying agent ADEKA REASOAP SE10N was used as a general emulsifying agent (Newco).
l) Substituted for 560SN (sodium polyoxyethylene nonylphenyl ether sulfate) and prepared in the same manner. An alkyd-modified acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 23.5 was obtained.

Comparative Example 2 ADEKA REASOAP SE10N in beaker; 40 g, styrene; 570 g, butyl acrylate; 125 g, 2-ethylhexyl acrylate; 250 g, β-hydroxyethyl methacrylate; 25 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; 465
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, dropped for 1 hour, kept warm for 2 hours and then cooled to 25% ammonia; 17
g and butyl cellosolve; 100 g, water; 20 g were added to obtain an acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 19.5.

Comparative Example 3 In a beaker, the above alkyd resin (A-1); 800 g, ADEKA REASOAP SE10N; 40 g, styrene; 150
g, 2-ethylhexyl acrylate; 10 g, β-hydroxyethyl methacrylate; 10 g, methacrylic acid; 30 g, and water; 1000 g, ammonium persulfate; 2.5 g are added, and the mixture is emulsified in a homogenizer for 5 minutes. did. This emulsion A: 100 g
And 465 g of water were placed in the same flask as in the production example of (A-1) and heated to 80 ° C., and 1 g of ammonium persulfate was added. The rest of the emulsion A was charged into a dropping funnel, dropped for 1 hour, then kept warm for 2 hours and cooled, 25% ammonia; 17 g, butyl cellosolve; 100 g, water; 2
0 g was added to obtain an alkyd-modified acrylic emulsion, but there were many aggregates.

Comparative Example 4 In a beaker, the above alkyd resin (A-1); 400 g, ADEKA REASOAP SE10N; 40 g, styrene; 370
g, butyl acrylate; 80 g, 2-ethylhexyl acrylate; 140 g, β-hydroxyethyl methacrylate; 10 g to a mixed solution, water; 1000 g, ammonium persulfate;
It was emulsified over a period of time to obtain an emulsion A. This emulsion A; 1
00 g and water; 465 g was placed in the same flask as in the production example of the above (A-1) and heated to 80 ° C., ammonium persulfate;
1 g was added. The remaining emulsion A was charged into a dropping funnel, dropped over 1 hour, then kept warm for 2 hours and cooled to 2
5% ammonia; 7 g, butyl cellosolve; 100 g,
Water; 30 g was added, heating residue 40%, acid value (solid content) 4
An alkyd-modified acrylic emulsion of was obtained.

COMPARATIVE EXAMPLE 5 The above alkyd resin (A-1); 400 g, ADEKA REASOAP SE10N; 40 g, styrene; 270 were added to a beaker.
g, butyl acrylate; 80 g, 2-ethylhexyl acrylate; 140 g, β-hydroxyethyl methacrylate; 10 g, methacrylic acid; 100 g in a mixed solution of water; 1000 g, ammonium persulfate; 2.5 g
Is added to a homogenizer for 5 minutes to emulsify the emulsion A.
And 100 g of this emulsion A and 445 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. After charging the remaining emulsion A into a dropping funnel and dropping the mixture over 1 hour,
After keeping the temperature for 2 hours and cooling, 25 g of ammonia; 37 g, butyl cellosolve; 100 g, and water: 20 g were added to obtain an alkyd-modified acrylic emulsion having a heating residue of 40% and an acid value (solid content) of 69.

Comparative Example 6 In the same flask as in the production example of (A-1) above, 400 g of alkyd resin (A-1) above, butyl cellosolve; 4
00 g was charged and the temperature was raised to 110 ° C. Styrene; 320
g, butyl acrylate; 80 g, 2-ethylhexyl acrylate; 140 g, β-hydroxyethyl methacrylate; 10 g, methacrylic acid; 50 g, azobisisobutyronitrile; 20 g, were charged in a dropping funnel and dropped for 2 hours, and then 2 After keeping the temperature for 2 hours and cooling, 25% ammonia; 27 g was added, and water; 1103 g was added thereto to emulsify to obtain an alkyd-modified acrylic resin having a heating residue of 40% and an acid value (solid content) of 37.

Comparative Example 7 Emulsion polymerization was carried out in the same manner as in Example 2 after removing ADEKA REASOAP SE10N, which is a reactive emulsifier, and adding 7 g of ammonia to neutralize the alkyd resin in Example 2, but agglomerated during the reaction. .

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 made into a paint with the formulation of Table 1.

[Table 1]

The coating material obtained by the above-mentioned coating was applied under the following conditions, and after drying, the coating film characteristics were tested. (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) (Test conditions) Drying: 60 ° C. for 20 minutes, then 22 ° C. for 3 days Gloss: 60 degree gloss JIS K5400 Compliant Dryability: The degree of tackiness of the coating film immediately after drying at 60 ° C. for 20 minutes was observed. Hardness: Based on JIS K5400. Impact test; 500 g, 1/2 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 ion-exchanged water at 20 ° C. for 7 days, swelling and whitening of the coating film were observed. Salt sprayability: The coating film was cut with a cutter, put into a salt spray test, taken out after 48 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. The results are shown in Table 2.

[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, gloss, drying property, hardness, water resistance, corrosion resistance and the like.
Comparative Example 1 is a case where an ordinary emulsifier was used instead of the reactive emulsifier, but the gloss was lowered and the water resistance and the corrosion resistance were poor. Comparative Example 2 is a case of a normal acrylic emulsion resin containing no alkyd resin, but the hardness, water resistance, and corrosion resistance are inferior because the gloss is inferior and room temperature crosslinking is not performed. In Comparative Example 3, the amount of the alkyd resin is too large, but aggregates appear during emulsion polymerization, and the polymerization stability is poor. In Comparative Example 4, the acid value is low, but the paint 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.
Poor dryness, physical properties (impact value), hardness, water resistance and corrosion resistance. Comparative Example 7 is a case where no emulsifier is used. In this case, even if the alkyd resin is neutralized, it does not become a good emulsifier and aggregates during emulsion polymerization.

[0030]

The aqueous resin composition and coating composition of the present invention are excellent in coating stability and coating film drying property, hardness, gloss, adhesion, impact resistance, water resistance, corrosion resistance and the like.

Claims (3)

[Claims] 1. A reactive emulsifier having an ethylenically unsaturated group as an emulsifier, in which 90 to 40% by weight of a polymerizable monomer mixture containing an ethylenically unsaturated carboxylic acid is mixed in the presence of 10 to 60% by weight of an alkyd resin. An aqueous resin composition containing an alkyd-modified acrylic emulsion having an acid value of 10 to 50 obtained by emulsion polymerization using. 2. The alkyd resin is an oil or fatty acid 30 to 30.
The aqueous resin composition according to claim 1, which is an alkyd resin containing 70% by weight and having an acid value of 20 or less. 3. A paint comprising the aqueous resin composition according to claim 1 or 2.