JPH10324841A - Aqueously dispersed resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous resin composition which can give a coating film capable of being baked within a short time into a cured film having good appearance and excellent boiling-water resistance, adhesion, processability and corrosion resistance. SOLUTION: There is provided an aqueously dispersed resin composition prepared by dispersing a resin in an aqueous medium, wherein the resin comprises an epoxy resin or a phenoxy resin (A), a resin (B) obtained by grafting an ethylenically unsaturated monomer containing an ethylenically unsaturated carboxylic acid onto an epoxy resin or a phenoxy resin and a resin (C) being compatible with component A and being a polyester resin, an ethylene/ acrylic acid copolymer, a vinyl acetate/vinyl alcohol resin or a polyvinyl acetal resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a water-dispersed resin composition useful for coating metal materials and the like.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for energy saving and energy saving for coating materials, adhesives, and the like for coatings for automobile industrial machines, steel furniture, electric appliances and the like. Furthermore, the use of organic solvents is being restricted for reasons such as preventing air pollution from organic solvents radiating from paints and improving the working environment, and the development of solvent-free paints such as powder paints and radiation-curable paints and water-based paints has been increasing. Is promoted.

[0003] Among them, aqueous processing of epoxy resin has been performed in many cases because of excellent processability and chemical resistance even in a solvent system, and a carboxyl group-functional polymer is converted to an epoxy resin in the presence of an amine esterification catalyst. Esterification,
Water-dispersed with an amine (JP-A-55-3482)
Reference), methacrylic acid reacts with the epoxy group,
Further, those obtained by polymerizing an acrylic monomer, neutralizing with an amine, and dispersing in water (see JP-B-59-37287).
A quaternary ammonium hydroxide is produced by reacting an amine-neutralized acrylic resin with a high molecular weight epoxy resin, and further reacts with a carboxyl functional polymer to form a polymeric quaternary ammonium compound of a carboxyl functional polymer. Water-dispersed resin composition (see Japanese Patent Publication No. 4-5072) in which an amine mixed salt is formed and dispersed in water, and an acrylic resin containing a carboxyl group-containing monomer in the side chain of an epoxy resin using a catalyst such as benzoyl peroxide. The monomer is graft polymerized, and the obtained resin is ammonia,
A complex resin having an excess of carboxyl groups obtained by mixing an amine-based neutralized and stably dispersed in water (see JP-A-53-1228), a mixture of an acrylic resin, a partially combined epoxy resin and a phenol resin. A composition obtained by neutralizing the composition with ammonia and dispersing in water (see Japanese Patent Publication No. 25489/1993); an aqueous dispersion of an acrylic resin-modified epoxy resin obtained by precondensing a phenol resin (see JP-A-60-215015); Using a phenoxy resin instead of an epoxy resin to maintain processability (Japanese Patent Publication No. 6-212)
No. 79), composed of an epoxy resin having no oxirane ring and an acrylic resin, has excellent storage stability, and does not react with the remaining epoxy group and the amine. Aqueous resin composition that does not decrease heat resistance, retort resistance, workability, etc.
A method of dispersing in water using an epoxy resin (self-emulsifiable resin) obtained by modifying an aromatic high molecular weight epoxy resin with a carboxyl group-containing acrylic polymer for high processability and high corrosion resistance (a special feature), and a phenol resin. Kaihei 7
138523).

However, when an acrylic resin is reacted with an epoxy resin in the presence of an esterification catalyst such as an amine or in the absence of a catalyst, the particles tend to be large, causing a problem in coating workability. Further, when a carboxyl group-containing monomer is grafted onto an epoxy resin, a low-molecular-weight non-grafted acrylic resin is formed, whereby the processability tends to be reduced, and a crack tends to occur. Further, when the epoxy group remains as described above, the storage stability decreases. In addition, when a phenoxy resin is used in order to improve processability, the graft efficiency of an acrylic monomer decreases. Adhesion and corrosion resistance are improved by dispersing in water using an epoxy resin (self-emulsifying resin) obtained by modifying an aromatic high molecular weight epoxy resin with a carboxyl group-containing acrylic polymer and a phenol resin, but a phenol resin is blended. Therefore, workability is reduced. Then, after the epoxy and phenol are reacted, the acrylic monomer is dropped and grafting is performed, so that the grafting efficiency is reduced, and the water dispersibility is reduced. Furthermore, when the epoxy phenol is reacted with an epoxy acryl grafted product as a dispersant and then dispersed in water, the processability is less reduced, but the processability cannot be improved as compared with the epoxy acryl grafted product as the base resin.

[0005] As described above, those which can be baked for a short time, have a good appearance of a cured coating film, have excellent storage stability, and have a balance of boiling water resistance, adhesion, processability and corrosion resistance have not yet been obtained. The situation has not been found.

[0006]

The first and second aspects of the present invention solve the above-mentioned problems, and can be baked for a short time, have a good appearance of a cured coating film, and have a boiling water resistance. The present invention provides an aqueous resin composition having excellent adhesion, processability, and corrosion resistance.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, introduced a processability improving component (hydrophobic component) into water-dispersed resin particles to improve processability. The present inventors have completed the present invention, considering that it can be improved.
That is, the present invention relates to a water-dispersible resin composition comprising a resin dispersed in an aqueous medium, wherein the resin is an epoxy resin or a phenoxy resin (A), and the epoxy resin or the phenoxy resin is an ethylenically unsaturated aliphatic carboxylic acid. The present invention relates to a water-dispersible resin composition containing a resin (B) obtained by a graft reaction of an ethylenically unsaturated monomer containing a resin (B) and a resin (C) compatible with the component (A). The present invention also relates to the water-dispersed resin composition, wherein the resin (C) is a polyester resin, an ethylene-acrylic acid copolymer, a vinyl acetate-vinyl alcohol resin, or a polyvinyl acetal resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the water-dispersible resin composition of the present invention, the resin dispersed in water generally takes the form of resin particles. The component (A) forms a nucleus in the resin particles. The component (B) forms an outer shell as a dispersant, and the component (C) is considered to be compatible with the component (A) or both the components (A) and (B). Regardless of the state, it is necessary for the present invention to include the components (A), (B) and (C).

The component (A) is an epoxy resin or a phenoxy resin.

The epoxy resin which can be used as the component (A) has two or more epoxy groups in one molecule, and is preferably a bisphenol type epoxy resin. Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol AD type epoxy resin, which are, for example, bisphenol A, F or AD and epichlorohydrin, respectively, in the presence of an alkali catalyst. Are obtained by polycondensation. Commercially available products include Epicoat 1010, Epicoat 1004, Epicoat 10
07, Epikote 1009, Epikote 1010 (both trade names, manufactured by Yuka Shell Epoxy Co., Ltd.), R30
1, R304, R307, and R309 (trade names, manufactured by Mitsui Petrochemical Industries, Ltd.). In addition,
Bisphenol A is 2,2-bis (4-hydroxyphenyl) propane, and bisphenol F is bis (4-hydroxyphenyl) propane.
Hydroxyphenyl) methane and bisphenol AD refer to 1,1-bis (4-hydroxyphenyl) ethane.

The phenoxy resin which can be used as (A) is obtained, for example, by polycondensing a bisphenol such as bisphenol A and epichlorohydrin in the presence of an alkali catalyst, similarly to the epoxy resin. It has a higher molecular weight and has thermoplasticity. The number of epoxy groups in the molecule is 0 to 2 on average. Commercially available products include Phenotote YP50, YP5
0S (Tokyo Kasei Co., Ltd., trade name), PKH
C, PKHH, and PKHJ (all, manufactured by Union Carbide Co., Ltd., trade names).

As the component (A), the epoxy resin and the phenoxy resin may be used alone or in combination. However, the epoxy resin and the phenoxy resin should be used in combination from the viewpoints of workability, warm water resistance, corrosion resistance and the like. Is preferred. Use of a phenoxy resin alone improves processability, but tends to be inferior in warm water resistance and corrosion resistance because the number of functional groups is smaller than the molecular weight. When used in combination, the epoxy resin and the phenoxy resin are used in a weight ratio of 80/20 to 10/90 in terms of the former / the latter in terms of balance between workability, warm water resistance, corrosion resistance and the like.
Is preferable, 70/30 to 20/80 is more preferable,
60/40 to 30/70 is more preferred. When workability is particularly required, the epoxy resin and / or the phenoxy resin preferably have a number average molecular weight of 5,000 or more, more preferably 5,000 to 30,000. The number average molecular weight can be determined by measuring by gel permeation chromatography and converting to standard polystyrene.

The component (B) in the present invention is obtained by a graft reaction of an ethylenically unsaturated monomer containing an ethylenically unsaturated aliphatic carboxylic acid onto an epoxy resin or a phenoxy resin. As the epoxy resin and the phenoxy resin in the component (B), those described in the description of the component (A) can be used.

Examples of the ethylenically unsaturated aliphatic carboxylic acids include α, β-monoethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid. Examples of the ethylenically unsaturated monomer other than the ethylenically unsaturated aliphatic carboxylic acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
2-hydroxyethyl methacrylate, 2-methacrylic acid 2-
Α having a hydroxyl group such as hydroxypropyl,
β-ethylenically unsaturated carboxylic acid hydroxyl ester, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-methacrylic acid Α, β- such as ethylhexyl
Alkyl esters of monoethylenically unsaturated carboxylic acids,
Acrylamide derivatives such as acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, and diacetone acrylamide; glycidyl esters of α, β-monoethylenically unsaturated carboxylic acids such as glycidyl acrylate and glycidyl methacrylate; vinyl acetate And vinyl esters of saturated carboxylic acids such as vinyl propionate, and aromatic unsaturated monomers such as styrene, α-methylstyrene and vinyl toluene.

These ethylenically unsaturated monomers are preferably compounded so as to have an acid value of 200 to 600, more preferably 200 to 550, and more preferably 250 to 500. Is more preferably blended, and particularly preferably blended to be 300 to 490. If the acid value is less than 200, the dispersibility tends to be poor, and the graft component must be increased in the component (B) in order to compensate for the poor dispersibility, whereby the processability tends to decrease. On the other hand, when the acid value exceeds 600,
The properties of the coating film, especially the boiling water resistance, tend to decrease, and they tend to gel during the graft reaction.

The graft reaction between an ethylenically unsaturated aliphatic carboxylic acid and other ethylenically unsaturated monomers and either or both of an epoxy resin and a phenoxy resin is carried out by a radical reaction such as azobisisobutylnitrile and benzoyl peroxide. It can be carried out by reacting an ethylenically unsaturated monomer in the presence of an epoxy resin and / or a phenoxy resin using a polymerization initiator. This reaction is preferably performed in an organic solvent at a temperature of 80 to 150 ° C. The radical polymerization initiator is preferably used in an amount of 4% by weight or more based on the total amount of the ethylenically unsaturated monomers,
More preferably, it is used in the range of 6 to 15% by weight.
If it is less than 4% by weight, the grafting efficiency is poor, and the water dispersibility and the stability of the resin tend to be lacking. On the other hand, if it exceeds 15% by weight, workability and corrosion resistance tend to decrease.

In the production of the component (B), the epoxy resin and the phenoxy resin serving as the skeleton and the ethylenically unsaturated monomer to be grafted to the skeleton are used in a weight ratio of 99/1 to 1/1. / 99, more preferably 90/10 to 10/90, and even more preferably 80/20 to 40/60. This ratio is 9
If the ratio exceeds 9/1, the dispersibility tends to decrease.
If it is less than 9, workability and corrosion resistance tend to decrease. The component (B) can be obtained by the above method.

The mixing ratio of the above components (A) and (B) is preferably from 95/5 to 1/99, more preferably from 85/15 to 1/99 by weight ratio of the (A) component / (B) component (the former / the latter). 1/99
Is more preferable, and 85/15 to 30/70 is particularly preferable. If it exceeds 95/5, water dispersibility tends to decrease, and if it is 1/99% by weight, processability and corrosion resistance tend to decrease.

The component (C) in the present invention is a resin that is compatible with the component (A). However, from the viewpoint that the resulting water-dispersed resin composition has an excellent balance of properties and improves processability, It is preferable to use a polyester resin, an ethylene-acrylic acid copolymer, a vinyl acetate-vinyl alcohol resin or a polyvinyl acetal resin which is compatible with the component (A). Coalescence is more preferred. The amount of the component (C) varies depending on the type thereof, but is generally preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, based on the total amount of the components (A) and (B). Is more preferable.

Examples of the polyester resin include a saturated polyester resin and an unsaturated polyester resin. The polyester resin can be produced by subjecting a polybasic acid and a polyhydric alcohol to a condensation reaction. Examples of the polybasic acids include saturated polybasic acids, unsaturated polybasic acids, and the like,
Saturated polybasic acids include phthalic anhydride, terephthalic acid,
Succinic acid and the like can be mentioned, and as the unsaturated polybasic acid, maleic acid, maleic anhydride, fumaric acid and the like can be mentioned. Examples of the polyhydric alcohol include dihydric alcohols and trihydric alcohols. Examples of the dihydric alcohol include ethylene glycol and diethylene glycol. Examples of the trihydric alcohol include glycerin and trimethylolpropane. Commercially available polyester resins that can be used in the present invention include Espel 161
2, 1710B, 1615-20L (trade names of Hitachi Chemical Co., Ltd.) and the like.

When a polyester resin is used as the component (C), its amount is preferably 1 to 40% by weight, and more preferably 5 to 30% by weight based on the total amount of the components (A) and (B). %, More preferably 5 to 1% by weight.
More preferably, the content is 5% by weight. If the compounding ratio is less than 1% by weight, the processability tends to decrease, and
If the content exceeds 0% by weight, the hydrophobic component increases, so that the water dispersibility tends to decrease, and the processability, adhesion, boiling water resistance and the like also tend to decrease.

The ethylene-acrylic acid copolymer is
A copolymer containing ethylene and acrylic acid as copolymer components. Particularly preferred is a copolymer comprising both components. As commercial products, Premacol 5990 (weight ratio of ethylene / acrylic acid is 80/20), Prepolymer Call 5980
(Weight ratio of ethylene / acrylic acid is 80/20), Premacol 3440 (weight ratio of ethylene / acrylic acid is 9/20).
0.5 / 9.5), Premacol 1410 (ethylene /
The weight ratio of acrylic acid is 91/9) (both manufactured by Dow Chemical Co., Ltd.). Among these commercial products, the resulting water-dispersible resin composition has a weight ratio of ethylene / acrylic acid of 70/30 to 90/10 from the viewpoint of excellent processability, water dispersibility, and the like. Premacol 5980 is particularly preferred.

When an ethylene-acrylic acid copolymer is used as the component (C), the amount of the copolymer is preferably 1 to 30% by weight based on the total amount of the components (A) and (B). Preferably, it is 2 to 20% by weight, more preferably 2 to 15% by weight. If the compounding ratio is less than 1% by weight, the processability tends to decrease, and if it exceeds 30% by weight, the hydrophobic component increases, so that the water dispersibility tends to decrease, and the processability, adhesion, boiling water resistance and the like. The properties also tend to decrease.

The vinyl acetate-vinyl alcohol resin is a polymer having a constitutional unit of vinyl acetate and a constitutional unit of vinyl alcohol. For example, polyvinyl acetate or a copolymer of vinyl acetate and another monomer is used. Alkalis, acids,
It can be produced by partially saponifying with ammonia or the like to convert a part of the acetate group to a hydroxyl group. Commercially available vinyl acetate-vinyl alcohol resins include Technolink R100 (90% saponified of vinyl acetate), Technolink R150 (100% saponified of vinyl acetate), and Technolink R400 (50% of vinyl acetate).
Saponification) (both are trade names of Taoka Chemical Industry Co., Ltd.).

When a vinyl acetate-vinyl alcohol resin is used as the component (C), the amount of the vinyl acetate-vinyl alcohol resin depends on the amount of the component (A).
The total amount of the component and the component (B) is preferably 1 to 20% by weight, more preferably 2 to 15% by weight, and even more preferably 2 to 8% by weight. If the compounding ratio is less than 1% by weight, the processability tends to decrease, and if it exceeds 20% by weight, the hydrophobic component increases, so that the water dispersibility tends to decrease and also the processability, adhesion, boiling water resistance. The properties also tend to decrease.

The polyvinyl acetal resin is obtained, for example, by partially saponifying polyvinyl acetate with an alkali, an acid, ammonia, or the like to partially or entirely convert the alcohol into polyvinyl alcohol. In addition, it can be obtained by acetalizing a part or all thereof. Examples of the polyvinyl acetal resin include a polyvinyl butyral resin and a polyvinyl formal resin, and the polyvinyl butyral resin is preferable because of its excellent workability and the like.

Commercially available polyvinyl butyral resins include denka butyral # 2000-L (polyvinyl acetate / polyvinyl alcohol / polyvinyl butyral = 2
/ 21/77 (molar ratio); number average degree of polymerization 300), denkabutyral # 3000-2 (polyvinyl acetate / polyvinyl alcohol / polyvinyl butyral = 2/19/7)
9 (molar ratio); number average degree of polymerization 700), denkabutyral # 6000-C (polyvinyl acetate / polyvinyl alcohol / polyvinyl butyral = 2/17/81 (molar ratio); number average degree of polymerization 2400), # 6000- EP (polyvinyl acetate / polyvinyl alcohol / polyvinyl butyral = 13/16/71 (molar ratio); number average degree of polymerization 2
400) (all manufactured by Denki Kagaku Kogyo Co., Ltd., trade names)
And the like. Among these butyral resins, the number-average degree of polymerization is 1,000 to 3,000, and the proportion (mol) of polyvinyl butyral units is 60 per 100 parts of the total amount.
~ 80 parts, # 6000-EP as a commercial product,
The water-dispersed resin composition is preferable because of excellent workability and adhesion.

When a polyvinyl acetal resin is used as the component (C), the amount added is preferably 1 to 40% by weight based on the total amount of the components (A) and (B). , 5 to 30% by weight, more preferably 5 to 15% by weight. If the compounding ratio is less than 1% by weight, the processability tends to decrease, and if it exceeds 40% by weight, the hydrophobic component increases, so that the water dispersibility tends to decrease and also the processability, adhesion, boiling water resistance. The properties also tend to decrease.

The component (A), the component (B) and the component (C) are mixed by mixing the component (A) with the component (C) and then mixing the component (B)
A method of mixing the components and then neutralizing the carboxyl group in the component (B) with a base to obtain a water-dispersible resin composition, (B)
First, neutralize the carboxyl group in the component with a base,
The method can be carried out by a method of mixing the components (A) and (C) or separately mixing the components to obtain a water-dispersible resin composition. At this time, part or all of the component (C) may be reacted with the component (A) or the components (A) and (B). As the base, a volatile base such as ammonia and amine is preferable. If the amine remains in the coating film, the corrosion resistance and the like tend to decrease.

Suitable amines include primary, secondary and tertiary aliphatic and aromatic amines. Specific compounds include monopropylamine, monobutylamine, diethylamine, dibutylamine, triethylamine, tributylamine, monoethanolamine, ethyl monoethanolamine, monocyclohexylamine, dimethylaminoethanol, 2-amino-2-methyl-1 -Propanol, morpholine, piperidine and the like are preferred.

The base is preferably used in the range of 0.6 to 1.0 mol per 1 mol of carboxyl groups in the resin. When the amount of the amine is less than 0.6 mol, the dispersibility in water tends to be poor. When the amount exceeds 1.0 mol, the viscosity of the final product tends to increase, and the amine tends to remain in the coating film. The water-dispersed resin composition of the present invention, as a dispersion medium,
Contains water or a mixed solvent of water and a water-soluble organic solvent. The amount of the dispersion medium is not particularly limited, but is usually 100 to 300 parts by weight, assuming that the weight of the other components is 100 parts by weight. The water-soluble organic solvent is a dispersion medium 100
It is preferred that the content be not more than 20 parts by weight in the weight part.

As the water-soluble organic solvent, methanol,
Ethanol, n-propanol, isopropanol, n
-Butanol, sec-butanol, tert-butanol,
Alkyl alcohols such as isobutanol, methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, 2-ethylhexyl cellosolve, hexyl cellosolve, ether alcohols such as methyl carbitol, ethyl carbitol, butyl carbitol, methyl cellosolve acetate, ethyl cellosolve Ether esters such as acetate, other dioxane, diacetone alcohol, 3-methoxy-3-methylbutane-1
-All.

The water-dispersed resin composition of the present invention comprises
An inorganic acid or an organic acid may be added as a catalyst. Examples of the inorganic acid include hydrochloric acid and phosphoric acid, and examples of the organic acid include p-toluenesulfonic acid. The amount added is preferably 1% by weight or less based on the total amount of the components (A) and (B). If it exceeds 1% by weight, workability tends to decrease.

Further, a phenol resin can be added as a curing agent. In this case, the amount of the phenol resin added is 40% based on the total amount of the components (A) and (B).
%, Preferably 2 to 20% by weight, more preferably 2 to 10% by weight, particularly preferably 2 to 5% by weight. If it exceeds 40% by weight, the crosslinking density tends to be too high and the processability tends to be significantly reduced. Further, various pigments and other additives may be used according to the purpose. When the resulting water-dispersed resin composition is used as a coating, the coating method includes spray coating, coating with a roll coater,
Dipping or the like can be adopted. Usually 200-300 ° C
By baking at a temperature of 10 seconds to 3 minutes, a coating film having excellent coating film characteristics can be obtained.

[0035]

The present invention will be described more specifically with reference to the following examples. Parts mean parts by weight. Example 1 Preparation of (A) Component Solution 118.3 parts of bisphenol A type epoxy resin (Epicoat 1010, manufactured by Yuka Shell Epoxy Co., Ltd.) and bisphenol A type phenoxy resin (Phenotote YP50, manufactured by Toto Kasei Co., Ltd.) 3 parts were charged together with a solvent into a flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet, gradually heated to 118 ° C., and completely dissolved (heating residue: 71.5%). weight%).
As the solvent, a mixed solvent of 67.4 parts of butanol and 27.1 parts of 3-methyl-3-methoxybutanol (trade name: Solfit, manufactured by Kuraray Co., Ltd.) was used.

(B) Preparation of Component Solution 65.7 parts of bisphenol A type epoxy resin (Epicoat 1010, manufactured by Yuka Shell Epoxy Chemical Co., Ltd.) and bisphenol A type phenoxy resin (Phenotote YP50, manufactured by Toto Kasei Co., Ltd.) 65 In a flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet, 0.7 part was charged together with a solvent, gradually heated to 118 ° C., and completely dissolved. The solvent is butanol 16
A mixed solvent of 7.9 parts and 45.1 parts of the Solfit was used. Then, when the temperature was lowered to 95 ° C. and reached 95 ° C., 49.4 parts of methacrylic acid, 15.2 parts of styrene and 1.1 parts of ethyl acrylate were mixed with 9.1 parts of benzoyl peroxide. A solution dissolved in 10 parts of butanol was added dropwise over 2 hours. The acid value of the monomer component was 490. Further, 10 parts of butanol was poured, and the mixture was stirred at the same temperature for 3 hours to be reacted to obtain a component (B) (residue of heating was 47% by weight, viscosity Z6).

Example 1 A flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas inlet was charged with 331.1 parts of the component (A) solution, and then an ethylene-acrylic acid copolymer (Premacol 59) was added.
80: Dow Chemical Co., Ltd.) 40.7 parts (12 parts per 100 parts of the aqueous dispersion component ((A) + (B))) was dissolved. After cooling to 100 ° C., 230.8 parts of the component (B) solution was charged and sufficiently mixed at 100 ° C. Next, the temperature was lowered to 80 ° C., 24.4 parts of dimethylaminoethanol was added, and 1
The mixture was stirred for 0 minutes and neutralized (solid content: 61.5% by weight). After the neutralization, 780 parts of ion-exchanged water was added dropwise over 1 hour (solid content: 27.4% by weight). Further, the mixture was desolvated to remove butanol, diluted with water, and the components of the solvent were mixed in a weight ratio of ion-exchanged water / butanol / solfit = 78.
0 / 8.5 / 13.5, and a white water-dispersed resin composition having a solid content of 23.0% by weight was obtained. The obtained water-dispersed resin composition was in a good dispersed state and had a viscosity of 4.2 Ps (25
° C) and the pH was 7.0.

Example 2 In Example 1, 18.5 parts of Premacol 5980 was added to a vinyl acetate-vinyl alcohol resin (Technolink R400 (50% saponification of vinyl acetate added 46%)) (water dispersion component ((A) + (B) was replaced with 5 parts per 100 parts) to produce a water-dispersed resin composition, which was in a good dispersed state and had a solid content of 18. 4% by weight, viscosity 2.2P · s (25 ° C), pH 7.3
Met.

Example 3 In Example 1, Premacol 5980 was replaced with a polyvinyl acetal resin (denkabutyral # 2000L (polyvinyl acetate / polyvinyl alcohol / polyvinyl butyral = 2/21/77; number average degree of polymerization 300)) 40.7
A water-dispersed resin composition was produced in the same manner except that the water-dispersed resin composition was replaced with 12 parts of water-dispersed component (12 parts per 100 parts of (A) + (B)). The dispersion state was good, the solid content was 26.8% by weight, and the viscosity was 4.0 Ps (25
° C), pH 7.4.

Example 4 In Example 1, Premacol 5980 was replaced with a polyvinyl acetal resin (denkabutyral # 6000EP (polyvinyl acetate / polyvinyl alcohol / polyvinyl butyral = 13/16/71; number average degree of polymerization 2400)).
0.7 parts (aqueous dispersion component ((A) + (B)))
A water-dispersed resin composition was produced in the same manner except that 2 parts) was used. The obtained water-dispersed resin composition was in a good dispersed state, and had a solid content of 27.8% by weight and a viscosity of 4.8 P · s.
(25 ° C.) and pH 7.4.

Example 5 In Example 1, Premacol 5980 was replaced with a polyester resin (Espel 1710B (heating residue: 40% by weight)).
A water-dispersed resin composition was produced in the same manner except that 01.8 parts (12 parts per 100 parts of the water-dispersed component ((A) + (B))) was used. The obtained water-dispersed resin composition was in a good dispersed state, and had a solid content of 31.5% by weight and a viscosity of 3.2 P · s.
(25 ° C.) and pH 7.0.

Comparative Example 1 A water-dispersed resin composition was obtained in the same manner as in Example 1 except that only the component solution (A) and the component solution (B) were charged and Premacol 5980 was not added. The obtained water-dispersed resin composition was in a good dispersed state, and had a solid content of 31.0% by weight.
The viscosity was 3.4 P · s (25 ° C.) and the pH was 7.5. The dispersion medium is ion-exchanged water / butanol / Solfit = 78.0.
/8.5/13.5.

(Coating film test) Each of the water-dispersible resin compositions obtained in Examples 1 to 5 and Comparative Example 1 was adjusted to have a solid content of 30% by weight. (Phenol resin, manufactured by Co., Ltd.) was added at 3% by weight based on the solid content, and a physical property test was performed under the following conditions. -Base material: tin plate-Coating: Coated with a bar coater # 18 (film thickness was 5 to 7 µm after baking). Baking: Baking was performed at 270 ° C. for 30 seconds. Then, it was left at room temperature for 24 hours to conduct a coating film test.

Coating film test method: Appearance: The coating film was visually evaluated, and a smooth and glossy film was evaluated as good, and an abnormal film was evaluated as poor. -Pencil hardness: Evaluated according to JIS K5400 using Mitsubishi Uni.・ Bending: The test plate was folded in two at 3 mmφ, and the degree of cracking of the coating film at the bent portion was determined. ◎: No cracking ○: Very slight cracking △: Slight cracking ×: Significant cracking ・ Boiling water resistance: Take out after immersion in boiling water for 1 hour and judge its appearance. ◎: No abnormality at all ○: Very slight whitening △: Slightly whitening ×: Extremely whitening

Adhesion after boiling water resistance: After immersion in boiling water for 1 hour, 100 squares of 1 mm × 1 mm were cut into the coating film, and the percentage of the peeling was judged by using cellophane tape. -Corrosion resistance: It was immersed in a 3% boiling salt solution for 1 hour, and its appearance was determined. ◎: No abnormality at all ○: Very slight whitening Δ: Slightly whitening ×: Extremely whitening The above evaluation results are shown in Table 1.

[0046]

[Table 1]

[0047]

The water-dispersed resin composition according to claims 1 and 2 has excellent stability, can be baked for a short time, has a good appearance of a cured coating film, and has excellent boiling water resistance, adhesion, and the like. It provides a cured coating film having excellent workability and corrosion resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C09D 171/00 C09D 171/00 // C09D 133/02 133/02

Claims (2)

[Claims] 1. A water-dispersible resin composition comprising a resin dispersed in an aqueous medium, wherein the resin is an epoxy resin or a phenoxy resin (A), and the epoxy resin or the phenoxy resin is an ethylenically unsaturated aliphatic carboxylic acid. A water-dispersible resin composition comprising a resin (B) obtained by a graft reaction of an ethylenically unsaturated monomer containing: and a resin (C) compatible with the component (A). 2. The resin (C) is a polyester resin, an ethylene-acrylic acid copolymer, a vinyl acetate-vinyl alcohol resin or a polyvinyl acetal resin.
The water-dispersed resin composition as described in the above.