JP2002309162A - Resin composition for water-based coating and water- based coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for a water-based coating excellent in water resistance, corrosion resistance and chemical resistance and exhibiting excellent stability without causing separation or aggregation of a resin or a pigment contained therein, and a water-based coating obtained using the resin composition for a water-based coating. SOLUTION: The resin composition for a water-based coating comprises a vinyl-modified epoxy ester resin having an acid value of 10-50, which is obtained by reacting 3-20 pts.wt. of a polymerizable monomer (c) containing a nonionic reactive emulsifier with 100 pts.wt. of a fatty acid-modified epoxy ester resin obtained by a reaction of reactive components comprising 20-75 wt.% of a bisphenol type epoxy resin (a) and 20-60 wt.% of a fatty acid (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for a water-based paint and a water-based paint.

[0002]

2. Description of the Related Art Generally, a coating material uses a large amount of an organic solvent, so that the organic solvent is discharged into the atmosphere during coating. These organic solvents cause air pollution,
There is a high risk that these organic solvents may cause a fire. In recent years, various efforts have been made to reduce the amount of organic solvents, and high solid paints, powder paints, electron beam / ultraviolet curable paints, aqueous paints, and the like have been developed for the purpose. In particular, water-based paints have attracted attention because they use water that is free from danger, is highly economical, and is easily diverted from conventional coating equipment. However, the conventional water-based paint has a problem in that the paint dries slowly, has poor water resistance and corrosion resistance, and has poor paint stability.

[0003] In order to solve these problems, for example, in a water-based alkyd resin coating method, a resin component contains a phenol resin, a petroleum resin, an epoxy resin, or the like, or a polymerizable monomer in the presence of a radical polymerization initiator. Attempts have been made to polymerize monomers. As the resin thus improved, there is a water-dilutable vinyl-modified epoxy ester resin obtained by polymerizing a vinyl monomer in the presence of a bisphenol-type epoxy resin and an ester of a fatty acid. JP-B-51-11128, JP-B-4-672
The resin described in Japanese Patent No. 6 has good water resistance, but has disadvantages such as poor corrosion resistance and paint stability. Further, in the resin described in JP-B-54-30249, an attempt has been made to improve paint stability and water dilutability by using an anionic or nonionic emulsifier, but the emulsifier tends to be localized on the surface. Therefore, there is a disadvantage that the water resistance is reduced. The resin described in Japanese Patent No. 30000487 is excellent in corrosion resistance due to acrylic modification after reacting an epoxy ester with a polybasic acid or an acid anhydride thereof, but has a drawback that paint stability is poor. Was. Therefore, in the resin described in JP-A-8-81512, an anionic reactive emulsifier is introduced in order to improve paint stability. There was selectivity and the paint stability was not sufficiently improved. In addition, recently, when used in various paint formulations or spray-painted in a paint booth, paint dust that does not adhere to the object to be coated is often generated, so it is dissolved or dispersed in booth water in the paint booth. Attempts have been made to supplement. In view of the above, stability against various ions contained in water and various ions contained in acidic and basic pigments is important. Usually, since the carboxyl group is neutralized with an amine or the like, the stability to ions, especially cations, is extremely poor. As the cause,
It is conceivable that the cation such as Ca ²⁺ contained in the pigment or the water has a strong interaction due to the electric interaction between the carboxyl group and the amine and does not dissociate the ions.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems, and by using a specific vinyl-modified epoxy ester resin, it is possible to obtain a water-based paint having excellent water resistance, corrosion resistance, and chemical resistance. An object of the present invention is to provide a water-based paint resin composition having excellent stability without causing separation and aggregation of a resin and a pigment in the composition, and a water-based paint using the water-based paint resin composition.

[0005]

The present invention relates to a fatty acid-modified epoxy ester obtained by reacting a reaction component containing 20 to 75% by weight of a bisphenol type epoxy resin (a) with 20 to 60% by weight of a fatty acid (b). An acid value of 10 obtained by reacting 3 to 20 parts by weight of a polymerizable monomer (c) containing a nonionic reactive emulsifier with 100 parts by weight of a resin.
The present invention relates to a resin composition for water-based paints, comprising from 50 to 50 vinyl-modified epoxy ester resins. The present invention also relates to an aqueous paint containing the above resin composition for aqueous paint.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The fatty acid-modified epoxy ester resin used in the present invention can be obtained, for example, by adding and condensing a reaction component containing a bisphenol type epoxy resin and a fatty acid. As the fatty acid, for example,
Fatty acids derived from drying oils, semi-drying oils or non-drying oils,
Specific examples of synthetic fatty acids include dry oils, semi-dry oils and non-drying oils, such as tung oil, soybean oil, linseed oil, castor oil, dehydrated castor oil, safflower oil, cottonseed oil, and the like. Examples thereof include versatic acid (trade name of Shell Chemical Company) and the like. Among these fatty acids and synthetic fatty acids, fatty acids derived from a drying oil or a semi-drying oil are preferable, since they can impart room-temperature curability to the obtained aqueous paint resin composition. The fatty acids are used alone or in combination of two or more.

Examples of the bisphenol type epoxy resin include an epoxy resin obtained by a reaction between bisphenol and epichlorohydrin. Examples of the bisphenol include bisphenol A and bisphenol F. Specific examples of the bisphenol type epoxy resin include Epicoat 828, Epicoat 1001, Epicoat 1004, Epicoat 10
07 and Epicoat 1009 (both are trade names of Shell Chemical Company). Among these bisphenol-type epoxy resins, Epicoat 10 is preferred because the resulting water-based paint resin composition has excellent water dispersibility and drying properties.
01 and Epicoat 1004 (both are trade names of Shell Chemical Company) are preferred. The bisphenol type epoxy resins are used alone or in combination of two or more, and the epoxy equivalent of these epoxy resins is not particularly limited.

[0008] The fatty acid-modified epoxy ester resin comprises:
Since the obtained coating film has excellent corrosion resistance and excellent hardness, in addition to the fatty acid and the bisphenol-type epoxy resin, one molecule per molecule other than the bisphenol-type epoxy resin is used.
It is preferably obtained by adding and condensing a reaction component containing an epoxy compound having two or more glycidyl groups. Examples of the epoxy compound having one or more glycidyl groups in one molecule include an aliphatic epoxy compound having one or more glycidyl groups in one molecule, and an epoxy compound having one or more glycidyl groups in one molecule. Cyclic epoxy compounds, aromatic epoxy compounds having one or more glycidyl groups in one molecule and the like, and the like, from the viewpoint that the resulting water-based paint resin composition has excellent corrosion resistance, one to one in one molecule.
Aliphatic epoxy compounds having four glycidyl groups are preferred. Examples of the aliphatic epoxy compound having 1 to 4 glycidyl groups in one molecule include glycidyl ether of a monohydric aliphatic alcohol, diglycidyl ether of a dihydric aliphatic alcohol, and diglycidyl ether of a trihydric aliphatic alcohol. Triglycidyl ethers of trihydric aliphatic alcohols, diglycidyl ethers of tetrahydric or higher aliphatic alcohols, triglycidyl ethers of tetrahydric or higher aliphatic alcohols, tetraglycidyl ethers of tetrahydric or higher aliphatic alcohols, aliphatic dicarboxylic acids And diglycidyl esters of acids.

As the monohydric aliphatic alcohol, for example,
Lauryl alcohol, allyl alcohol and the like,
Examples of the dihydric aliphatic alcohol include alkylene glycol, diethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, tetramethylene glycol, poly (tetramethylene glycol), 1,6-hexanediol, neopentyl glycol, and the like. Examples of the alkylene glycol include, for example, ethylene glycol, propylene glycol, butylene glycol, and the like.Examples of the trihydric aliphatic alcohol include, for example, trimethylolpropane, glycerin, and the like. For example, pentaerythritol, sorbitol, glycerin dimer, glycerin multimer and the like, and examples of the aliphatic dicarboxylic acid include adipic acid, tetramethylene A carboxylic acid. Among these components, diglycidyl ether of 1,6-hexanediol is preferred because the resulting coating film has excellent hardness. The epoxy compound may be used alone or
More than one kind is used in combination, and the epoxy equivalent of these epoxy compounds is not particularly limited.

The mixing ratio of the fatty acid is 20 to 60% by weight based on the total amount of the reaction components used for obtaining the fatty acid-modified epoxy ester resin in view of the balance between the hardness of the obtained coating film and the corrosion resistance. Yes, 20 to 50% by weight
And more preferably 20 to 30% by weight. If the blending ratio is less than 20% by weight, the resulting coating film is inferior in drying properties, and if it exceeds 60% by weight, unreacted fatty acids remain, and the resulting coating film has poor corrosion resistance. The mixing ratio of the bisphenol-type epoxy resin, from the viewpoint of the balance of hardness and corrosion resistance of the obtained coating film,
20 to 75% by weight, preferably 30 to 70% by weight, and more preferably 40 to 7% by weight based on the total amount of the reaction components used to obtain the fatty acid-modified epoxy ester resin.
More preferably, it is 0% by weight. This compounding ratio is 2
When the amount is less than 0% by weight, the obtained coating film is inferior in corrosion resistance and hardness, and when it exceeds 75% by weight, the obtained water-based paint resin composition is inferior in drying property.

When an epoxy compound having one or more glycidyl groups in one molecule is used in addition to the fatty acid and the bisphenol type epoxy resin in order to obtain the fatty acid-modified epoxy ester resin, the compounding ratio is as follows: In terms of the balance between the corrosion resistance and hardness of the resulting coating,
It is preferably 2 to 50% by weight, more preferably 2 to 40% by weight, and more preferably 2 to 30% by weight, based on the total amount of the reaction components used for obtaining the fatty acid-modified epoxy ester resin. Is more preferable. If the blending ratio is less than 2% by weight, the corrosion resistance and hardness of the coating film obtained by adding the epoxy compound tend to be hardly expected. If the mixing ratio exceeds 50% by weight, the obtained coating film tends to become brittle. It is in.

As a method of adding and condensing the fatty acid, the bisphenol type epoxy resin and the epoxy compound having one or more glycidyl groups in one molecule,
For example, normal addition and operation for condensation reaction can be used, and the method is not particularly limited,
For example, these components are mixed, and 130-250 degreeC, 4
A method of heating for 10 to 10 hours can be used. At that time, an organic solvent that does not react with these reaction components may be added to the reaction system. These components may be mixed at the same time, or the fatty acid and the bisphenol-type epoxy resin may be mixed and heated and reacted, and then the epoxy compound having one or more glycidyl groups in one molecule may be mixed. And then react by heating, or the fatty acid and the 1
An epoxy compound having one or more glycidyl groups in the molecule may be mixed and heated to react, and then the bisphenol-type epoxy resin may be mixed and heated to react.

The vinyl-modified epoxy ester resin used in the present invention is obtained by reacting the fatty acid-modified epoxy ester resin obtained as described above with a polymerizable monomer (c) containing a nonionic reactive emulsifier. As the nonionic reactive emulsifier, it is preferable to use a nonionic reactive emulsifier having an ethylenically unsaturated group from the viewpoint of water resistance and corrosion resistance. There is no particular limitation on such a nonionic reactive emulsifier, and examples thereof include the following.

[0014]

Embedded image (R ^{1 to} R ⁷ are hydrogen or a hydrocarbon group having 1 to 12 carbon atoms, m, n, o, p, q and r are integers of 1 or more;
It is preferably an integer of 1 to 50. AQUALON RN-10, AQUALON RN-20, AQUALON RN-2025 (all of the compounds of the above general formula (I)) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Adekaria Soap NE manufactured by Asahi Denka Kogyo KK -1
0, 20, 30, 40 (all compounds of the above general formula (II)) Blemmer PE-90, 200, manufactured by NOF Corporation
350 (polyethylene glycol monomethacrylate;
All are compounds of the above general formula (III)), Blemmer AE-90, 200, 400 (polyethylene glycol monoacrylate; all compounds of the above general formula (III)), Blemmer PP-1000, 500, 800
(Polypropylene glycol monomethacrylate; both compounds of the above general formula (IV)), Blemmer AP-
150, 400, 800 (polypropylene glycol monoacrylate; all compounds of the above general formula (IV)), Blemmer 50 PEP-300 (poly (ethylene glycol-propylene glycol) monomethacrylate; all compounds of the above general formula (V)) MA-30, 50, 100, 150 manufactured by Japan Emulsifier
(Polyethylene glycol monomethacrylate; all compounds of the above general formula (III)) and other nonionic emulsifiers having an ethylenically unsaturated group. Further, the above-mentioned polyethylene glycol monoacrylate or methacrylate obtained by alkoxylating the terminal, FA2000M
(Mixture of methoxypolyethylene glycol methacrylate and methyl methacrylate, manufactured by Hitachi Chemical Co., Ltd.), acid phosphoxyethyl acrylate or methacrylate, polyethylene glycol monoacrylate or methacrylate phosphate, polypropylene glycol monoacrylate or methacrylate phosphate ( Adecaria soap PP70), phosphate of poly (ethylene glycol-propylene glycol) monoacrylate or methacrylate (Adecaria soap P
P710) can also be used.

One or more of these reactive emulsifiers can be used. If necessary, ordinary emulsifiers can be used in combination with these. The use amount of these reactive emulsifiers is preferably the minimum necessary, but from the viewpoint of water resistance and corrosion resistance, component (a) and component (b)
0.2 to 10% by weight, preferably 0.2 to 5% by weight, more preferably 0.2 to 3% by weight, based on the total amount of the component and the component (c).

In the present invention, as the polymerizable monomer, the following ethylenically unsaturated carboxylic acids, acrylates, styrene monomers and others can be used. Examples of the ethylenically unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid. As the acrylate, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, te acrylate
rt-butyl, isobutyl acrylate, 2-acrylate
Ethylhexyl and the like, and as the methacrylate, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, ter methacrylate
t-butyl, isobutyl methacrylate, methacrylic acid 2
-Ethylhexyl and the like, and styrene-based monomers include, for example, styrene, vinyltoluene, α-methylstyrene and the like. In addition, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, N, N-diethylacrylamide, N, N
-Diethyl methacrylamide, acrylonitrile, methacrylonitrile can also be used.

These polymerizable monomers are used singly or in combination of two or more. However, from the viewpoint of facilitating aqueous conversion by introducing a carboxyl group into the obtained water-based paint resin composition, the above-mentioned ethylenically unsaturated monomer is used. It preferably contains a saturated carboxylic acid. This ethylenically unsaturated carboxylic acid can be blended so as to adjust to an intended resin acid value. That is, it is adjusted and blended so that the obtained resin acid value is 10 to 50, preferably 20 to 40.

The polymerizable monomer (c) containing a nonionic reactive emulsifier is allowed to react with the fatty acid-modified epoxy ester resin. The compounding ratio is 100 parts by weight of the fatty acid-modified epoxy ester resin. (C)
3 to 20 parts by weight. Preferably, it is 5 to 10 parts by weight. When the compounding ratio of the polymerizable monomer (c) exceeds 20 parts by weight, the obtained coating film has poor corrosion resistance, and when it is less than 3 parts by weight, the obtained water-based paint resin composition has poor water dispersibility.

A method for producing a vinyl-modified epoxy ester resin solution by reacting a polymerizable monomer (c) containing a nonionic reactive emulsifier in the presence of the fatty acid-modified epoxy ester resin and an organic solvent includes, for example, An ordinary radical polymerization method can be used, and the method is not particularly limited. As a specific method, for example, the fatty acid-modified epoxy ester resin is dissolved in an organic solvent, and the polymerizable monomer (c) containing a nonionic reactive emulsifier and a radical polymerization initiator are added. C., a method of heating for 2 to 5 hours can be used.

The mixing ratio of the organic solvent is not particularly limited, but is usually 0.4 to 3 times by weight based on the total amount of the fatty acid-modified epoxy ester resin and the polymerizable monomer (c). Quantity. Examples of the radical polymerization initiator include, for example, azobisnitrile type catalysts, peroxides, and the like, and examples of the azobisnitrile type catalyst include, for example, azobisisobutyronitrile, azobisvaleronitrile, and the like. Examples of the peroxide include benzoyl peroxide, butyl perbenzoate, and the like. These radical polymerization initiators can be used alone or
Used in combination of more than one type. The mixing ratio of these radical polymerization initiators is not particularly limited,
Usually, the amount of the polymerizable monomer (c) is set at 0.
It is 3 to 10% by weight.

Examples of the organic solvent include a hydrophilic solvent, and specific examples thereof include methyl cellosolve,
Ethyl cellosolve, butyl cellosolve, tert-butyl cellosolve, isopropyl cellosolve, isopropyl alcohol, butyl alcohol, tert-butyl alcohol, isobutyl alcohol and the like. These organic solvents are used alone or in combination of two or more.

The weight-average molecular weight of the vinyl-modified epoxy ester resin (hereinafter referred to as "component (A)") obtained by the polymerization reaction is preferably 8,000 to 60, from the viewpoint of dispersion stability of the obtained water-based coating resin composition. , Preferably from 9,000 to 40,000, and more preferably from 10,000 to 30,000. If the weight average molecular weight is less than 8,000 or exceeds 60,000, the resulting aqueous coating resin composition tends to have poor dispersion stability. The weight average molecular weight in the present invention is a value measured by a gel permeation chromatography method and determined using a standard polystyrene calibration curve. The resin acid value (solid content acid value) of the component (A) is 10 to 50, preferably 20 to 40.
It is adjusted so as to be blended. If the acid value is less than 10, the paint stability will be poor, and if the acid value exceeds 50, the water resistance and the stability to ions will be poor. The acid value can be adjusted by adjusting the amount of the carboxyl group-containing polymerizable monomer used.

The vinyl-modified epoxy ester resin thus obtained is neutralized, if necessary, and dissolved or dispersed in the above-mentioned mixed solvent of hydrophilic solvent and water or only water (diluted with water). Can be used for use. Neutralization and water dilution, when the polymerization is carried out in a hydrophilic solvent, after the completion of the polymerization, can be subsequently neutralized, can be performed by further adding water, after the polymerization, after removing the solvent , Neutralization and water dilution. The above-mentioned neutralization is performed by neutralizing a part or all of the carboxyl groups in the resin with a neutralizing agent, and preferably has a pH of 7 to 10, more preferably 8.5 to 9.5. preferable. Examples of the neutralizing agent include amines, alkali metal hydroxides, alkali metal carbonates, and bicarbonates. Examples of the amine include ammonia, triethylamine, and dimethylethanolamine.Examples of the alkali metal hydroxide include sodium hydroxide and potassium hydroxide.Examples of the alkali metal carbonate include, for example, , Sodium carbonate and the like, and as the bicarbonate, for example, sodium bicarbonate and the like.

The obtained resin composition for water-based paint can be used as it is as a water-based paint, but if necessary, a pigment, an antifoaming agent, a plasticizer, an organic solvent, a water-soluble or water-dispersible resin, a metal A water-based paint or another paint may be prepared by blending a desiccant, a surface treatment agent and the like. Examples of the pigment include titanium white, carbon black, zinc oxide (a rust-preventive pigment), talc (an extender pigment), and zinc phosphate (a rust-preventive pigment). As an antifoaming agent, for example, BYK-02
2 (trade name of Big Chemie Co., Ltd.). Examples of the plasticizer include dimethyl phthalate and dioctyl phthalate. Examples of the organic solvent include those described above. Examples of the water-soluble or water-dispersible resin include a modified amino resin, an epoxy resin, a polyester resin, and an acrylic resin. Examples of the metal desiccant include cobalt naphthenate and lead naphthenate. As the surface treatment agent, for example, BYK
And silicone-based slip leveling agents such as -301 (trade name of Big Chemie Co., Ltd.). In addition, the modified amino resin or epoxy resin is blended with the obtained water-based paint resin composition, and can be used as a baking paint. Further, the fatty acid of the drying oil or semi-dry oil is used as the fatty acid used in the fatty acid-modified epoxy ester, and further, a metal drying agent is added to the water-based coating resin composition to be used as a room temperature-curable coating. Can be.

As a method of forming a coating, known methods such as a paint shaker method, a roll mill method, a sand mill method, a disperser method, a kneader method, and a high-speed impeller mill method can be used. The obtained water-based paint can be subjected to painting according to a usual painting method,
For the coating, a known coating method such as a dipping method, a brush coating method, a spray coating method, a roll coating method, a flow coater coating method, a shibori (or shigoki) coating method, and a knife coater coating method can be used. After coating, the coating film can be dried and cured by natural drying or forced drying by a dryer. Aqueous coating resin composition obtained by the production method of the present invention, the resulting coating film has excellent corrosion resistance,
It can be used as a coating paint for wood, paper, fiber, plastic, ceramic, iron, non-ferrous metal, etc., and is particularly suitable for coating paint for iron or non-ferrous metal.

[0026]

Next, the present invention will be described in detail with reference to examples. “Parts” and “%” indicate “parts by weight” and “% by weight”, respectively. Example 1 (A) In a 3 liter glass flask equipped with an inert gas introduction tube, 250 g of bisphenol-type epoxy resin epicoat 1001 and 250 g of bisphenol-type epoxy resin (manufactured by Shell Chemical Co., Ltd., bisphenol-type epoxy resin) were added.
-100 g of hexanediol diglycidyl ether, 300 g of soybean oil fatty acid and 100 g of dehydrated castor oil fatty acid are added, and the addition and condensation reaction is advanced at 230 ° C. until the acid value becomes 5 or less, and the fatty acid-modified epoxy having a weight average molecular weight of 9,800 An ester resin was obtained. (B) In a 3 liter flask similar to the flask used in (A), 950 g of the fatty acid-modified epoxy ester resin obtained in (A) and 300 g of isopropyl cellosolve were charged, and 40 g of acrylic acid and Aqualon RN were added.
-20 (Nonionic reactive emulsifier, Daiichi Kogyo Pharmaceutical Co., Ltd.)
10 g) and heated to 135 ° C. Thereafter, a mixed solution of 90 g of isopropyl cellosolve and 20 g of azobisisobutyronitrile was added dropwise over 10 minutes, and 3
The temperature was maintained for a time to obtain a vinyl-modified epoxy ester resin solution. The weight average molecular weight of the resin was 18,000. After cooling, 56 g of triethylamine was added, and 1,110 g of water was further added. The heating residue was 40%, and the pH was 8.
9. A vinyl-modified epoxy ester resin having a resin solid content acid value of 32 and a viscosity of 2.0 Pa · S was obtained.

Example 2 Adekaria Soap NE-20 (manufactured by Asahi Denka Kogyo KK) in place of Aqualon RN-20 in Example 1 (B)
A water-based paint resin composition was obtained according to Example 1 except that the composition was used. This resin composition for water-based paint was of a water-dispersible type, and the heating residue was 40.1%, the pH was 8.5, the acid value of the resin solid was 32, and the viscosity was 3.0 Pa · S.

Example 3 A resin composition for water-based paint was obtained according to Example 1 except that Blemmer AE-400 (manufactured by NOF CORPORATION) was used in place of AQUALON RN-20 in Example 1 (B). Was. This resin composition for water-based paint was of a water-dispersed type, the heating residue was 40.2%, the pH was 8.5, the acid value of the resin solid was 32, and the viscosity was 2.5 Pa · S.

Example 4 In Example 1 (B), instead of 950 g of the fatty acid-modified epoxy ester resin, 940 g of the fatty acid-modified epoxy ester resin, FA2000M (a mixture of methoxypolyethylene glycol methacrylate and methyl methacrylate containing 2% of methoxypolyethylene glycol methacrylate)
A water-based paint resin composition was obtained according to Example 1 except that 10 g of 0% by weight (manufactured by Hitachi Chemical Co., Ltd.) was used. This resin composition for water-based paint was of a water-dispersible type, and the residue after heating was 40.1%, the pH was 8.7, the acid value of the resin solid was 32, and the viscosity was 2.8 Pa · S.

Example 5 Instead of 950 g of the fatty acid-modified epoxy ester resin in Example 1 (B), 940 g of the fatty acid-modified epoxy ester resin, Adecaria Soap PP70 (a phosphate ester type reactive surfactant of polypropylene glycol monoacrylate, A resin composition for water-based paint was obtained according to Example 1 except that 10 g of Asahi Denka Kogyo KK was used. This resin composition for water-based paint was of a water-dispersed type, and the residue after heating was 40.0%, the pH was 8.6, the acid value of the resin solid was 32, and the viscosity was 1.0 Pa · S.

Example 6 In place of 950 g of the fatty acid-modified epoxy ester resin in Example 1 (B), 900 g of the fatty acid-modified epoxy ester resin, 40 g of styrene, FA2000M (a mixture of methoxypolyethylene glycol methacrylate and methyl methacrylate, Hitachi Chemical Co., Ltd. A resin composition for water-based paint was obtained in the same manner as in Example 1 except that 10 g was used. This resin composition for water-based paint was of a water-dispersed type, and the residue after heating was 40.1%, the pH was 8.6, the acid value of the resin solid was 32, and the viscosity was 2.5 Pa · S.

Comparative Example 1 A resin composition for an aqueous paint was obtained in the same manner as in Example 1 (B), except that 960 g of the fatty acid-modified epoxy ester resin was used and Aqualon RN-20 was not blended. This resin composition for water-based paint was of a water-dispersible type, and the heating residue was 40.1%, the pH was 8.5, the acid value of the resin solid was 32, and the viscosity was 3.0 Pa · S.

Comparative Example 2 A resin for water-based paint was prepared in the same manner as in Example 1 (B) except that 900 g of the fatty acid-modified epoxy ester resin, 70 g of acrylic acid and 20 g of styrene were used instead of 950 g of the fatty acid-modified epoxy ester resin. A composition was obtained. This resin composition for water-based paint was of a water-dispersed type, the heating residue was 40.1%, the pH was 8.5, the acid value of the resin solid was 55, and the viscosity was 4.4 Pa · S.

Comparative Example 3 A resin composition for water-based paint was obtained in the same manner as in Example 1 (B) except that 750 g of the fatty acid-modified epoxy ester resin and 200 g of styrene were used instead of 950 g of the fatty acid-modified epoxy ester resin. Was. This resin composition for water-based paint is of a water-dispersed type, and the heating residue is 4%.
0.1%, the pH was 8.5, the acid value of the resin solid was 32, and the viscosity was 2.5 Pa · S.

Comparative Example 4 In Example 1 (B), 980 g of the fatty acid-modified epoxy ester resin and 300 g of isopropyl cellosolve obtained in (A) were placed in a 3 liter flask similar to the flask used in (A). Charge, acrylic acid 20
g was heated to 135 ° C. Thereafter, 90 g of isopropyl cellosolve and azobisisobutyronitrile 2
0 g of the mixture was added dropwise over 10 minutes, and the temperature was further maintained for 3 hours to obtain a vinyl-modified epoxy ester resin solution. The weight average molecular weight of the resin was 18,000. After cooling, 28 g of triethylamine was added, and water was further added to 1110
g was added to obtain a vinyl-modified epoxy ester resin having a heating residue of 40%, a pH of 8.5, an acid value of resin solids of 15, and a viscosity of 0.9 Pa · S.

Evaluation (mixing of paint) Carbon (trade name: MA-100, manufactured by Mitsubishi Kasei Co., Ltd.) 7.5 parts LF Bosei P-W-2 (anti-rust pigment, manufactured by Kikuchi Pigment Co., Ltd.) 10.0 Zinc Hana No. 1 (Anti-rust pigment, manufactured by Sakai Chemical Co., Ltd.) 10.0 LMS200 (Extended pigment, manufactured by Fuji Talc Co., Ltd.) 123.0 3-Methyl-3-methoxybutanol 16.0 Surfynol 104 (pigment dispersion 3.5 BYK022 (antifoaming agent, manufactured by BYK Chemie) 0.3 Vinyl-modified epoxy ester resin (solid content) 100.0 DICNATE3111 (metal dryer, Dai Nippon Ink Co., Ltd.) 4.5 The above amount was dispersed together with glass beads by a sand grinder to obtain a black enamel. This was diluted with water, the viscosity was adjusted with Ford cup # 4 so as to be 30 seconds, and the coating and coating film tests were performed under the following conditions.

(Coating method) Coating: spray coating, Iwata Weider 61, dry film thickness 20
μm Substrate: Untreated steel plate (manufactured by Japan Test Panel Co., Ltd., trade name: SPCC-SD plate, thickness: 0.8 mm) Drying: After performing at 60 ° C. for 20 minutes, performing at 22 ° C. for 3 days.

(Evaluation method) (1) Pencil hardness According to the pencil scratching test method of JIS K 5400, the results were indicated by a pencil hardness symbol in which no breakage of the coating film was observed. (2) Adhesion (Crosscut) 100 squares of 1 mm square were cut with a cutter, and after peeling off with Cellotape (registered trademark), the squares of the remaining coating film were indicated. (2) Water resistance The test plate was immersed in ion exchanged water at 40 ° C. for 240 hours,
The presence or absence of whitening on the surface of the coating film was visually determined. (3) Corrosion resistance According to the salt water spray test of JIS K 5400, a cut portion was formed on the test plate, and the rust width (one side) from the cut portion after salt water spraying for 480 hours was measured. In addition, the blister of the coating film was visually observed. (4) Paint stability The state of the paint after storage at 40 ° C. for 10 days was observed. (5) Resin chemical stability One 10% calcium chloride solution was added to 100 g of resin.
After adding 0 g and stirring, the state of the resin was observed.

[0039]

[Table 1]

As can be seen from Examples 1 to 6, the resin compositions for water-based paints of the present invention are excellent in paint stability, water resistance, corrosion resistance, chemical stability and the like. Comparative Example 1 is a case where the reactive emulsifier was not used in Example 1, but the paint stability and the chemical stability were inferior. Comparative Example 2 has a high acid value, but is inferior in paint stability, chemical stability, water resistance, and corrosion resistance. Comparative Example 3 is a case where the ratio of the epoxy ester resin is small, but the corrosion resistance is inferior. Comparative Example 3 is a case where the acid value is low, but causes agglomeration during coating.

[0041]

The water-based resin composition and the water-based paint of the present invention are excellent in the water resistance of the coating film and extremely excellent in corrosion resistance, paint stability, chemical stability and the like.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J038 CP091 DB032 DB061 DB351 DB361 GA06 KA03 KA06 KA08 MA12 MA14 NA03 NA04 NA26 NA27 PA18 PA19 PC02 PC03 PC06 PC08 PC10

Claims (4)

[Claims] 1. Bisphenol type epoxy resin (a) 2
A polymerizable monomer (c) containing a nonionic reactive emulsifier in 100 parts by weight of a fatty acid-modified epoxy ester resin obtained by reacting a reaction component containing 0 to 75% by weight and a fatty acid (b) with 20 to 60% by weight. An aqueous coating resin composition containing a vinyl-modified epoxy ester resin having an acid value of 10 to 50 and obtained by reacting 3 to 20 parts by weight. 2. The resin composition according to claim 1, wherein the polymerizable monomer (c) contains an ethylenically unsaturated carboxylic acid. 3. The composition according to claim 1, wherein the content of the nonionic reactive emulsifier is 0.2 to 10% by weight based on the total amount of the components (a), (b) and (c). A resin composition for aqueous paints. 4. A water-based paint comprising the resin composition for water-based paint according to claim 1, 2 or 3.