JP7081522B2 - Vinyl-modified epoxy resin composition, water-based coating agent - Google Patents

Description

The present invention relates to a vinyl-modified epoxy resin composition and an aqueous coating agent.

Conventionally, the coating film obtained by the aqueous coating agent has a property of being inferior in rust resistance as compared with the solvent-based coating agent. A vinyl-modified epoxy ester obtained by polymerizing a body has been publicized (Patent Document 1). Since the vinyl-modified epoxy ester uses an epoxy resin as a raw material, it has relatively good rust resistance, can be expected to cure at room temperature due to the fatty acid component, and can be made water-based by selecting the vinyl monomer component. It has the characteristic that it is possible.

However, as the field of application of the water-based coating material expands, the required performance for the water-based coating agent also increases, and the level of rust prevention and water resistance is required to be improved, and the initial hardness of the coating film is required to be high. Esters and the like cannot satisfy the requirement. For example, the hardness of the coating film increases with the oxidative polymerization of the fatty acid component in the resin, but since it takes several days for the hardness to reach the target value, damage at the initial stage of coating film formation becomes a problem, and the subject concerned. The phenomenon that the coating film prepared from the resin whitens when flooded (hereinafter referred to as water-resistant whitening) has also been an issue. Such water-resistant whitening is improved by increasing the ratio of the fatty acid component in the vinyl-modified epoxy ester, but there is a problem that the hardness of the coating film is further lowered.

Therefore, the applicant proposes a vinyl-modified epoxy resin aqueous product obtained by using an aromatic epoxy resin and an aliphatic epoxy resin in combination as a vinyl-modified epoxy resin composition having a high coating hardness and less water whitening resistance. (See Patent Document 2). However, although the vinyl-modified epoxy resin aqueous product has a high hardness of the coating film and is excellent in water whitening resistance, it is poor in alkali resistance, acid resistance and the like.

Japanese Unexamined Patent Publication No. 11-269249 Japanese Unexamined Patent Publication No. 2005-120340

An object of the present invention is to provide a vinyl-modified epoxy resin composition having high hardness of a coating film, excellent water whitening resistance, and alkali resistance and acid resistance without deteriorating rust resistance.

As a result of diligent studies, the present inventors have found that a vinyl-modified epoxy resin composition obtained by copolymerizing a modified epoxy resin having a relatively low amine value with a vinyl monomer having a specific functional group solves the above-mentioned problems. We have found and completed the present invention. That is, the present invention relates to the following vinyl-modified epoxy resin compositions and aqueous coating agents.

1. 1. A vinyl-modified epoxy resin composition containing a polymer containing the following (A) and (B) as constituents.
(A) A modified epoxy resin comprising an epoxy resin (a1) containing a bisphenol type epoxy resin, amines (a2) and a glycidyl group-containing vinyl monomer (a3), and having an amine value of 15 to 85 mgKOH / g. (B) Monomer component containing a carboxyl group-containing vinyl monomer (b1) and / or a sulfone group-containing vinyl monomer (b2)

2. 2. The usage ratio of the component (a1), the component (a2) and the component (a3) is {(the number of epoxy groups of the component (a1)) + (the number of epoxy groups of the component (a3))} / (the amino group of the component (a2)). The vinyl-modified epoxy resin composition according to item 1 above, wherein the number of active hydrogens) = 100/120 to 100/80.

3. 3. (A1) The vinyl-modified epoxy resin composition according to item 1 or 2 above, wherein the epoxy group concentration of the component is 0.4 × 10 ^-3 to 3.5 × 10 ^-3 eq / g.

4. The vinyl-modified epoxy resin composition according to any one of the above items 1 to 3, wherein the component (a2) contains an alkanolamine.

5. The vinyl-modified epoxy resin composition according to any one of the above items 1 to 4, wherein the component (B) further contains styrenes (b3) and / or (meth) acrylic acid ester (b4).

6. The vinyl-modified epoxy resin according to any one of the above items 1 to 5, wherein the ratio of the component (A) and the component (B) used [(A) / (B)] is 60/40 to 99/1 in terms of solid content weight. Composition.

7. An aqueous coating agent containing the vinyl-modified epoxy resin composition according to any one of the above items 1 to 6.

According to the vinyl-modified epoxy resin composition of the present invention, the rust resistance is not deteriorated, the hardness of the coating film is high, the water whitening resistance is excellent, and the film has alkali resistance and acid resistance. In addition, the coating film also maintains high primary adhesion and water resistance to various metals.

The vinyl-modified epoxy resin composition of the present invention comprises (A) a specific modified epoxy resin (hereinafter referred to as (A) component) and (B) a specific monomer component (hereinafter referred to as (B) component) as constituent components. It contains a polymer. Hereinafter, each component will be described in detail.

[About (A) component]
The component (A) is an epoxy resin (a1) containing a bisphenol type epoxy resin (hereinafter referred to as (a1) component), amines (a2) (hereinafter referred to as (a2) component), and a glycidyl group-containing vinyl monomer (a3). It is a reaction product (hereinafter referred to as component (a3)).

The bisphenol type epoxy resin is not particularly limited, and examples thereof include bisphenols and reaction products of haloepoxides such as epichlorohydrin and 2-methylepichlorohydrin.

The bisphenols are not particularly limited, and are reaction products of phenol or 2,6-dihalophenol (hereinafter referred to as phenols) and aldehydes (eg, formaldehyde, acetaldehyde, etc.); phenols and ketones (eg, acetone). , Acetphenone, Cyclohexanone, Benzophenone, etc.); Oxidation reaction product of dihydroxyphenylsulfide due to peracid; Etherealization reaction product of hydroquinones, etc., and details thereof include 2,2-bis (4-). Examples thereof include hydroxyphenyl) propane (bisphenol A) and bis (4-hydroxyphenyl) methane (bisphenol F). These may be used alone or in combination of two or more. Of these, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) is preferable because of its excellent hardness and rust resistance of the coating film.

The component (a1) may include an epoxy resin other than the bisphenol type epoxy resin (hereinafter, also referred to as another epoxy resin). By using another epoxy resin, the glass transition temperature and the weight average molecular weight of the vinyl-modified epoxy resin composition can be adjusted, and the coating film tends to have excellent rust resistance and water adhesion. Specific examples of other epoxy resins are not particularly limited, and examples thereof include aliphatic epoxy resins and aromatic epoxy resins. These may be used alone or in combination of two or more.

The aliphatic epoxy resin is not particularly limited, and examples thereof include resins containing a glycidyl ester of an aliphatic dibasic acid, a glycidyl ether of an aliphatic polyol, and a glycidyl ether of a polyether polyol.

The aliphatic dibasic acid is not particularly limited, and is, for example, sebacic acid, azelaic acid, dodecanoic acid, malonic acid, succinic acid, glutaric acid, adipic acid, 8,11-dimethyl-7,11-octadecadien-. Examples thereof include 1,18-dicarboxylic acid, 7-ethyloctadecanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid.

The aliphatic polyol is not particularly limited, and for example, 1,4-butanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1, Examples thereof include 10-decanediol.

The polyether polyol is not particularly limited, and for example, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, heptaethylene glycol, octaethylene glycol, dipropylene glycol, tripropylene glycol, and tetrapropylene glycol are used. , Pentapropylene glycol, hexapropylene glycol, polyethylene glycol, polypropylene glycol, polyoxyethylene polyoxypropylene glycol, polybutylene glycol and the like.

The aromatic epoxy resin is not particularly limited, and is not particularly limited, and is cresol novolac type epoxy resin, phenol novolac type epoxy resin, triphenol methane type epoxy resin, triphenol ethane type epoxy resin, trisphenol type epoxy resin, diphenyl ether type epoxy resin, biphenyl. Examples include type epoxy resins.

The ratio of the bisphenol type epoxy resin and the other epoxy resin to be used is not particularly limited, but is preferably about (bisphenol type epoxy resin) / (other epoxy resin) = 30/70 to 100/0 in terms of solid content weight.

The physical properties of the component (a1) are not particularly limited, but the epoxy group concentration is about 1.47 × 10 ^-3 to 2.5 × 10 ^-3 eq / g . When an epoxy group having a concentration in the above range is used, the component (A) having a desired amine value can be obtained by reacting with the component (a2). In addition, the hardness of the coating film, rust resistance, acid resistance and alkali resistance are also excellent.

The epoxy group concentration of the component (a1) is represented by the number of epoxy groups contained in 1 g of the component (a1).

The epoxy group concentration when one kind of the component (a1) is used is calculated by the reciprocal of the epoxy equivalent (= the epoxy equivalent of the component (a1)).

When two types of the component (a1) are used, the epoxy group concentration of the component (a1) is calculated from (Equation 1) using the respective charged weights and epoxy equivalents. The two types of (a1) components are referred to as (a1-1) component and (a1-2) component, respectively.

(Equation 1)

Similarly, when n kinds of the component (a1) are used, the epoxy group concentration of the component (a1) is calculated from (Equation 2).

(Equation 2)

The component (a2) is not particularly limited, and various known components can be used. For example, alkanolamines, aliphatic amines, alicyclic amines, aromatic amines and the like can be mentioned. These may be used alone or in combination of two or more. By using the component (a2), the component (A) having a high molecular weight can be obtained, and rust prevention and water resistance are imparted when the coating film is formed.

The alkanolamine is not particularly limited, and is, for example, a primary alkanolamine such as monoethanolamine or monoisopropanolamine; diethanolamine, diisopropanolamine, di-2-hydroxybutylamine, N-methylethanolamine, N-ethylethanol. Secondary alkanolamines such as amines and N-benzylethanolamine; tertiary alkanolamines such as triethanolamine and tripropanolamine can be mentioned. These may be used alone or in combination of two or more.

The aliphatic amine is not particularly limited, and for example, ethylamine, n-propylamine, n-butylamine, n-hexylamine, n-octylamine, n-laurylamine, n-stearylamine, n-palmitylamine, and the like. Primary aliphatic monoamines such as n-oleylamine, 2-ethylhexylamine; secondary aliphatic monoamines such as diethylamine, din-propylamine, din-butylamine; ethylenediamine, propylenediamine, hexamethylenediamine, 2,2 , 4-trimethylhexanediamine, 2,4,4-trimethylhexanediamine, aliphatic diamines such as isophoronediamine and the like. These may be used alone or in combination of two or more.

The alicyclic amine is not particularly limited, and examples thereof include cyclopentylamine, cyclohexylamine, and norbonylamine. These may be used alone or in combination of two or more.

The aromatic amine is not particularly limited, and examples thereof include toluidine, xylidine, kumidine (isopropylaniline), hexylaniline, nonylaniline, dodecylaniline, benzylamine, and phenethylamine. These may be used alone or in combination of two or more.

Among these components (a2), it is preferable to contain alkanolamine, and more preferably monoethanolamine, from the viewpoint that the coating film has excellent hardness. When an alkanolamine is used, the amount used is not particularly limited, and the total amount of the components (a2) is 100% by weight, and is usually 1 to 90% by weight, preferably 1 to 60% by weight. Within this range, the coating film has excellent primary adhesion and water resistance.

The component (a3) is not particularly limited, and various known components can be used. Examples of the component (a3) include glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl (meth) acrylate, 1,2. -Epoxy-4-vinylcyclohexane and the like can be mentioned, and these may be used alone or in combination of two or more. Of these, glycidyl acrylate and glycidyl methacrylate are preferable.

As the usage ratio of the component (a1), the component (a2) and the component (a3), {(the number of epoxy groups of the component (a1)) + (the number of epoxy groups of the component (a3))} / (the amino group of the component (a2)) The number of active hydrogens) is about 100/120 to 100/80, preferably about 100/110 to 100/90, and more preferably about 100/105 to 100/95. Within this range, the component (A) can be obtained in a high yield, and excellent coating film performance can be easily exhibited.

The number of epoxy groups of the component (a1) is a value obtained by dividing the charged weight of the component (a1) by the epoxy equivalent of the component (a1). When n kinds of (a1-1) component, (a1-2) component, ..., (A1-n) are used as the component (a1), the number of epoxy groups is calculated from (Equation 3). ..

(Equation 3)

The number of epoxy groups of the component (a3) can also be calculated by the same method as the above-mentioned calculation of the number of epoxy groups of the component (a1).

The number of active hydrogens of the amino group of the component (a2) is a value obtained by dividing the charged weight of the component (a2) by the amine equivalent of the component (a2). (A2) When there are a plurality of components, the number of active hydrogens is calculated from (Equation 4).

(Equation 4)

Further, polyisocyanate may be used as a constituent component of the component (A), if necessary.

The polyisocyanate is not particularly limited, and examples thereof include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and blocked isocyanates. These may be used alone or in combination of two or more.

The aromatic polyisocyanate is not particularly limited, and is, for example, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-diisocyanate. Examples thereof include benzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylenediocyanate, 1,4-phenylenediocyanate, tolylene diisocyanate, orthotoluidine diisocyanate, and polyphenylpolyisocyanate. These may be used alone or in combination of two or more.

The aliphatic polyisocyanate is not particularly limited, and for example, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate are used. And so on. These may be used alone or in combination of two or more.

The alicyclic polyisocyanate is not particularly limited, and is, for example, cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexanediisocyanate, isophorone diisocyanate. And so on. These may be used alone or in combination of two or more.

The blocked isocyanate is not particularly limited, and examples thereof include compounds obtained by blocking the polyisocyanate with various known blocking agents. The blocking agent is not particularly limited, and for example, a phenol-based blocking agent such as phenol and cresol; an oxime-based blocking agent such as methyl ethyl ketone oxime and acetone oxime; a lactam-based blocking agent such as ε-caprolactam and γ-butyrolactam; acetacetic acid. Active oxime-based blocking agents such as ethyl, acetylacetone, ethyl malonate; alcohol-based blocking agents such as methanol and ethanol; other amine-based blocking agents, imine-based blocking agents, imide-based blocking agents, imidazole-based blocking agents, mercaptan-based Examples include blocking agents. These may be used alone or in combination of two or more.

The amount of the polyisocyanate used is not particularly limited, but the ratio of {number of isocyanate groups of polyisocyanate} / {number of hydroxyl groups of (a1) to (a3) components} is preferably about 0.005 to 2, preferably 0.05. It is more preferably about 0.5.

The number of isocyanate groups of the polyisocyanate is a value obtained by multiplying the charged molar amount of the polyisocyanate by the number of isocyanate groups per molecule of the polyisocyanate. When there are a plurality of polyisocyanates, the number of isocyanate groups is the total number of isocyanate groups of each component.

The number of hydroxyl groups of the component (a1) can be calculated by multiplying the charged molar amount of the component (a1) by the number of hydroxyl groups per molecule including the hydroxyl group generated when the epoxy group of the component (a1) is opened. When the component (a1) contains a plurality of components, the number of hydroxyl groups of the component (a1) is the total number of hydroxyl groups of each component. The same applies to the number of hydroxyl groups of the component (a3).

The number of hydroxyl groups of the component (a2) can be calculated by multiplying the charged molar amount of the component (a2) by the number of hydroxyl groups per molecule of the component (a2). When the component (a2) contains a plurality of components, the number of hydroxyl groups of the component (a2) is the total number of hydroxyl groups of each component.

The component (A) can be obtained by various known production methods using the component (a1), the component (a2) and the component (a3), and if necessary, an epoxy resin other than the component (a1) and a polyisocyanate. .. The production conditions are not particularly limited, and for example, the reaction temperature is usually about 50 to 250 ° C, preferably about 80 to 150 ° C. The reaction time is also not particularly limited, and depends on the reaction temperature, for example, it is usually about 3 to 12 hours, preferably 3 to 8 hours.

In the above-mentioned production method, various known solvents can be used. The solvent is not particularly limited, and for example, aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; propylene glycol monomethyl ether and propylene glycol monoethyl. Ethers such as ether, propylene glycol mono n-butyl ether, propylene glycol mono t-butyl ether; cellosolves such as methyl cellosolve, ethyl cellosolve, n-butyl cellosolve, t-butyl cellosolve; cellosolve acetates such as methyl cellosolve acetate and ethyl cellosolve acetate. These may be used alone or in combination of two or more. After the production of the present invention, alcohols such as isopropyl alcohol and n-butyl alcohol can be used as the diluting solvent without any problem. The amount of the solvent used is not particularly limited, and may be adjusted so that the reaction concentration is about 30 to 80% by weight.

As for the physical properties of the obtained component (A), the amine value is important from the viewpoint that the coating film is excellent in hardness, acid resistance and alkali resistance, and is measured in accordance with JIS K-7237. The amine value of the component (A) is 15 to 85 mgKOH / g. If the amine value is less than 15 mgKOH / g, the resin gels during the production of the component (A), and if it exceeds 85 mgKOH / g, the hardness, alkali resistance and acid resistance of the coating film tend to be inferior. From the same point of view, the amine value is preferably 15 to 75 mgKOH / g, more preferably 15 to 60 mgKOH / g, further preferably 20 to 55 mgKOH / g, and particularly preferably 20 to 50 mgKOH / g.

[About (B) component]
The component (B) is a monomer component containing a carboxyl group-containing vinyl monomer (b1) (hereinafter referred to as (b1) component) and / or a sulfone group-containing vinyl monomer (b2) (hereinafter referred to as (b2) component). When these monomer components are used, the vinyl-modified epoxy resin composition is easily dispersed in water. In the present invention, the component (b1) and the component (b2) may be used in combination.

The component (b1) is not particularly limited, and for example, α, β-unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; maleic acid, fumaric acid, itaconic acid, muconic acid, citraconic acid and the like. Examples thereof include α, β-unsaturated dicarboxylic acid; an anhydride of the carboxylic acid; an alkali metal salt such as a sodium salt and a potassium salt of the carboxylic acid. These may be used alone or in combination of two or more. Of these, (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid are preferable, and methacrylic acid and acrylic acid are more preferable, from the viewpoint that the vinyl-modified epoxy resin composition disperses well in water.

The amount of the component (b1) used is not particularly limited, but is 0.1 to 40 parts by weight with respect to 100 parts by weight of the component (A) from the viewpoint that the vinyl-modified epoxy resin composition is well dispersed in water. The degree is preferable, and about 1 to 20 parts by weight is more preferable.

When the component (b1) is used, carbodiimide may be used if necessary.

The carbodiimide is not particularly limited, and is, for example, poly (4,4'-diphenylmethanecarbodiimide), poly (tolylcarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (3,3'. -Dimethyl-4,4'-diphenylmethanecarbodiimide), poly (naphthylenecarbodiimide), poly (1,6-hexamethylenecarbodiimide), poly (1,4-tetramethylenecarbodiimide), poly (1,3-cyclohexylenecarbodiimide) ), Poly (1,4-cyclohexylenecarbodiimide), Poly (1,3,5-triethylphenylenecarbodiimide), Poly (4,4'-methylenebiscyclohexylcarbodiimide), Poly (1,3-diisopropylphenylenecarbodiimide), Poly (1-methyl-3,5-diisopropylphenylene carbodiimide), poly (isopropylphenylene carbodiimide), N, N'-dicyclohexylcarbodiimide, N, N'-diisopropylcarbodiimide, N, N'-diisopropylphenylcarbodiimide, N-ethyl -N'-(3-dimethylaminopropyl) -carbodiimide, hydrochloride and the like can be mentioned. Examples of commercially available products include "Carbodilite E-02", "Carbodilite V-02", and "Carbodilite V-04" (all manufactured by Nisshinbo Chemical Co., Ltd.). These may be used alone or in combination of two or more.

The amount of carbodiimide used is not particularly limited, but is preferably about 0.005 to 2 and preferably about 0.05 to 0.5 in terms of the ratio of {number of imide groups of carbodiimide} / {number of carboxylic acid groups of (b1) component}. Is more preferable.

The number of imide groups of carbodiimide is a value obtained by multiplying the charged molar amount of carbodiimide by the number of imide groups per molecule of carbodiimide. When there are a plurality of carbodiimides, the number of imide groups is the total number of imide groups of each component.

The number of carboxylic acid groups of the component (b1) is a value obtained by multiplying the charged molar amount of the component (b1) by the number of carboxylic acid groups per molecule of the component (b1). When there are a plurality of components (b1), the number of carboxylic acid groups is the total number of carboxylic acid groups of each component.

The component (b2) is not particularly limited, and is, for example, styrene sulfonic acid, metharyl sulfonic acid, metharyl oxybenzene sulfonic acid, allyl oxybenzene sulfonic acid, acrylamide-2-methyl propane sulfonic acid, acrylamide-t-butyl. Sulfonic acids such as sulfonic acids; examples thereof include sodium salts and alkali metal salts such as potassium salts of these sulfonic acids. These may be used alone or in combination of two or more. Of these, acrylamide-2-methylpropanesulfonic acid and acrylamide-t-butylsulfonic acid are preferable, and acrylamide-t-butylsulfonic acid is more preferable, from the viewpoint that the vinyl-modified epoxy resin composition is well dispersed in water.

The amount of the component (b2) used is not particularly limited, but is 0.1 to 40 parts by weight with respect to 100 parts by weight of the component (A) from the viewpoint that the vinyl-modified epoxy resin composition is well dispersed in water. The degree is preferable, and about 1 to 20 parts by weight is more preferable.

Further, the component (B) is further excellent in hardness, water whitening resistance, alkali resistance, acid resistance, and water adhesion resistance when formed into a coating film, and thus styrenes (b3) (hereinafter referred to as (b3) component). And / or (meth) acrylic acid ester (b4) (hereinafter referred to as (b4) component) is preferably contained.

The component (b3) is not particularly limited, and examples thereof include styrene, α-methylstyrene, t-butylstyrene, dimethylstyrene, acetoxystyrene, hydroxystyrene, vinyltoluene, chlorvinyltoluene, and the like, and these may be used alone. Two or more types may be combined. Of these, styrene is preferable from the viewpoints of hardness, water whitening resistance, alkali resistance, acid resistance, and water adhesion resistance when formed into a coating film.

The amount of the component (b3) used is not particularly limited, but is 0.1 to 40 parts by weight with respect to 100 parts by weight of the component (A) from the viewpoint that the vinyl-modified epoxy resin composition is well dispersed in water. The degree is preferable, and about 1 to 20 parts by weight is more preferable.

The component (b4) is not particularly limited, and is, for example, methyl (meth) acrylate, ethyl (meth) acrylate, -n-propyl (meth) acrylate, -n-butyl (meth) acrylate, (meth). ) Isobutyl acrylate, -t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate and the like, and these may be used alone or in combination of two or more. Among them, (meth) acrylate-n-butyl, (meth) acrylate isobutyl, (meth) acrylate-t-butyl, (meth) acrylate 2-ethylhexyl, from the viewpoint of excellent water resistance of the coating film. Lauryl acrylate (meth) is preferred.

The amount of the component (b4) used is not particularly limited, but 100 parts by weight of the component (A) is excellent in that the vinyl-modified epoxy resin composition is well dispersed in water and the coating film has excellent water resistance. On the other hand, about 0.1 to 40 parts by weight is preferable, and about 1 to 20 parts by weight is more preferable.
The degree is more preferable.

Further, as the component (B), a monomer component (b5) (hereinafter referred to as a component (b5)) other than the components (b1) to (b4) may be used, if necessary. The component (b5) is not particularly limited, and is, for example, vinyl acetate, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N. , N-diethyl (meth) acrylamide, (meth) acrylonitrile and the like, and these may be used alone or in combination of two or more.

The amount of the component (b5) used is not particularly limited, but the vinyl-modified epoxy resin composition is well dispersed in water, and the coating film is also excellent in water resistance. Therefore, with respect to 100 parts by weight of the component (A). Therefore, it is preferably about 0.1 to 40 parts by weight.

The polymerization method of the component (A) and the component (B) is not limited, but a solution polymerization method is preferable. The conditions are not particularly limited, and for example, the temperature is about 60 to 150 ° C., preferably about 70 to 140 ° C., and the time is about 1 to 8 hours, preferably 2 to 6 in the presence of the polymerization initiator. It's about time. Further, a solvent may be used in the system.

The ratio of the component (A) and the component (B) to be used is not particularly limited, and the vinyl-modified epoxy resin composition is well dispersed in water and the coating film is excellent in rust prevention. Usually, (A) / (B) = about 60/40 to 99/1, preferably about 70/30 to 95/5.

The polymerization initiator is not particularly limited, and is, for example, an azo compound such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, or benzoyl peroxide. Examples thereof include organic peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, t-butylperoxy-2-ethylhexanoate, dicumyl peroxide, and lauroyl peroxide, and these are two or more kinds alone. May be combined.

The amount of the polymerization initiator used is not particularly limited, but is preferably about 1 to 30 parts by weight with respect to 100 parts by weight of the total of the components (A) and (B).

The solvent is not particularly limited, and examples thereof include those listed in the section of the method for producing the component (A). The amount of the solvent used is not particularly limited, and may be adjusted so that the reaction concentration is about 30 to 90% by weight. Although the polymer obtained by the above-mentioned production method may contain a solvent, it is preferable that the content thereof is less than 20% by weight except by distilling off under reduced pressure as appropriate.

When the vinyl-modified epoxy resin composition obtained by the above-mentioned production method is used as an aqueous coating agent, it is dissolved or dispersed by adding water, but in order to facilitate dissolution or dispersion in water, the vinyl-modified epoxy resin composition is made to be dissolved or dispersed. It is preferable that the resin composition is neutralized with a base (that is, a base-neutralized product of a vinyl-modified epoxy resin composition). The pH after neutralization is preferably about 7 to 10. The base used as the neutralizing agent is not particularly limited, and examples thereof include ammonia; amines such as triethylamine and N, N-dimethylethanolamine; and hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide. These may be used alone or in combination of two or more. Of these, ammonia and amines are preferable because they easily volatilize during drying.

The physical properties of the vinyl-modified epoxy resin composition of the present invention are not particularly limited, but for example, the weight average molecular weight (polystyrene equivalent value by gel permeation chromatography) is determined from the viewpoint of excellent hardness and rust resistance of the coating film. It is preferably about 10,000 to 250,000, more preferably about 40,000 to 200,000. The solid content concentration is not particularly limited and may be appropriately determined in consideration of the viscosity, but is usually about 30 to 45% by weight.

The viscosity at a concentration of 33% by weight and a temperature of 23 ° C. is usually about 800 to 4000 mPa · s, preferably about 1000 to 3000 mPa · s.

The aqueous coating agent of the present invention contains the vinyl-modified epoxy resin composition. The water-based coating agent of the present invention can be applied to paints, surface treatment agents and the like of various raw materials such as wood, paper, fibers, plastics, ceramics, iron and non-ferrous metals.

In the preparation of the aqueous coating agent of the present invention, coloring pigments such as carbon black and titanium oxide; extender pigments such as talc, calcium carbonate and barium sulfate; rust preventive pigments such as aluminum phosphate, zinc phosphate and zinc oxide; cobalt. A metal compound such as a compound, a nickel compound or a zinc compound; a silane coupling agent, colloidal silica or the like can be appropriately blended. Further, if necessary, a curing agent such as melamine resin, urea resin, isocyanate, blocked isocyanate, or carbodiimide, or additives such as various known solvents, colorants, plasticizers, and rust preventives may be appropriately added. good. The solid content concentration of the aqueous coating agent is not particularly limited, but is preferably about 5 to 80% by weight, more preferably about 10 to 60% by weight.

The physical properties of the aqueous coating agent of the present invention are not particularly limited, and for example, the viscosity at a concentration of 20 to 60% by weight and a temperature of 23 ° C. is usually about 10 to 500 mPa · s, preferably about 50 to 300 mPa · s. be.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these examples. Further, in each Example and Comparative Example, parts or% are shown by weight.

Example 1
A reactor equipped with a stirrer, a cooler, a thermometer and a nitrogen gas introduction tube, 80 parts of t-butyl cellosolve, as a component (a1), YD-128 (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name: " Epototo YD-128 ”, epoxy equivalent: 189 g / eq) 20 parts, YD-014 (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name:“ Epototo YD-014 ”, epoxy equivalent: 950 g / eq) 180 parts and After adding 1 part of glycidyl methacrylate and dissolving at 120 ° C. under a nitrogen stream, 2.1 parts of 2-ethylhexylamine, 2.0 parts of din-butylamine, 26.3 parts of stearylamine and 4.3 parts of monoethanolamine. Was reacted for 7 hours to obtain a modified epoxy resin (A-1). Next, a mixture consisting of 8 parts of methacrylic acid, 8 parts of styrene, 3 parts of methyl methacrylate, 4 parts of glycidyl methacrylate and 15 parts of t-butylperoxy-2-ethylhexanoate was charged into the dropping funnel and into the reaction system. It was dropped over 1 hour and kept warm for 3 hours. After cooling to 80 ° C., 20 parts of triethylamine and 300 parts of water were added and mixed in this order to obtain a vinyl-modified epoxy resin composition (C-1) having a non-volatile content of 33% and a pH of 9.5. The physical characteristics of the component (C-1) are shown in Table 1 (the same applies hereinafter).

[Weight average molecular weight of vinyl-modified epoxy resin composition]
Equipment: HLC-8220 (manufactured by Tosoh Corporation)
Column: TSKgel α-2500 × 1, α-3000 × 1
Separation solvent: DMF (containing 5 mmol / kg of LiBr),
Flow rate: 1 ml / min Temperature: 40 ° C
Standard: Polystyrene

Examples 2 to 10, Comparative Examples 1 to 4
The compositions shown in Table 1 were synthesized according to the same method as in Example 1 to obtain vinyl-modified epoxy resin compositions (C-2) to (C-14), respectively.

(Preparation of aqueous coating agent)
Mixtures having the compositions shown below were kneaded with a paint shaker to prepare an aqueous coating agent. The obtained aqueous coating agent is placed on a defatted dull steel sheet (SPCC-SD, 0.8 × 70 × 150 mm) (hereinafter referred to as SPCC-SD) with a bar so that the film thickness after drying is 25 to 30 μm. The coating film was prepared by coating with a coater, forced drying (80 ° C. × 20 minutes), and then left to stand in an environment of a temperature of 20 ° C. and a humidity of 60% for 6 days. The obtained coating film was used for the following tests.

(composition)
(C) component of each example and comparative example 200 parts talc 38 parts carbon black 4 parts zinc oxide 2.7 parts zinc phosphate-based rust preventive pigment 8 parts calcium carbonate 18 parts ion-exchanged water 5 parts

(Evaluation test of coating film)
(1) Pencil hardness Complies with JIS K5600-5-4. The evaluation results are shown in Table 1. (Same below)

(2) Primary adhesion The adhesiveness to the grid when the coating film cured for 6 days in an environment of temperature 23 ° C. and humidity 50% after coating is peeled off is set to 100. evaluated.

(3) Water Adhesion Resistance According to JIS K5600-6-2, the adhesiveness to the grid when the coating film immersed in warm water at a temperature of 40 ° C. for 10 days was peeled off was evaluated as 100.

(4) Water-resistant whitening Apply each water-based coating film on SPCC-SD with a bar coater so that the film thickness after drying is 25 to 30 μm, and force it with a circulation dryer at a temperature of 100 ° C. for 20 minutes. After drying, the film was left to stand for 6 days in an environment of a temperature of 20 ° C. and a humidity of 60% to prepare a coating film. According to JIS K5600-6-2, the appearance of the coating film immersed in warm water at a temperature of 40 ° C. for 10 days was visually observed. The evaluation criteria are shown below.
(Evaluation criteria)
◯: Not bleached △: Partially bleached ×: Completely bleached

(5) Alkali resistance Immediately after applying each aqueous coating agent on SPCC-SD with a bar coater so that the film thickness after drying is 2 to 3 μm, it is dried in a circulation dryer at 180 ° C. for 1 minute. Obtained a test plate. The test plate was cured at a temperature of 20 ° C. for one day, and the appearance of the coating film after being immersed in a 1% aqueous sodium hydroxide solution (normal temperature) was visually observed. The evaluation criteria are shown below.
(Evaluation criteria)
◎: No abnormality in appearance ○: Almost no abnormality in appearance (slight peeling and swelling)
Δ: The coating film peeled off a little and some swelling was seen. ×: The coating film peeled off and a lot of swelling was seen.

(6) Acid resistance The appearance of the coating film after the test plate having a film thickness of 2 to 3 μm obtained by the above method is cured at a temperature of 20 ° C. for 1 day and immersed in a 1% hydrochloric acid aqueous solution (normal temperature) is visually observed. Observed at. The evaluation criteria are shown below.
(Evaluation criteria)
◎: No abnormality in appearance ○: Almost no abnormality in appearance (slight peeling and swelling)
Δ: The coating film peeled off a little and some swelling was seen. ×: The coating film peeled off and a lot of swelling was seen.

(7) Rust resistance Performed according to JIS K5600-7-9, and shown by the cellophane tape peeling width (mm) after 10 days and 20 days of the salt spray test.

[(A) component]
(A1) Ingredients-YD-128: Bisphenol A type epoxy resin ((manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name: "Epototo YD-128", epoxy equivalent: 189 g / eq))
YD-011: Bisphenol A type epoxy resin (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name: "Epototo YD-011", epoxy equivalent: 475 g / eq)
-YD-014: Bisphenol A type epoxy resin (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name: "Epototo YD-014", epoxy equivalent: 950 g / eq)
-YD-017: Bisphenol A type epoxy resin (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name: "Epototo YD-017", epoxy equivalent: 1850 g / eq)
-YD-019: Bisphenol A type epoxy resin (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name: "Epototo YD-019", epoxy equivalent: 2500 g / eq)
(A2) Ingredients-EHA: 2-ethylhexylamine (amine equivalent: 64.6 g / eq)
DBA: di-n-butylamine (amine equivalent: 129.3 g / eq)
-SA: Stearylamine (amine equivalent: 134.8 g / eq)
-MEA: Monoethanolamine (amine equivalent: 30.5 g / eq)
(A3) Ingredients-GMA: glycidyl methacrylate (epoxy equivalent: 142.2 g / eq)
[(B) component]
・ MAA: Methacrylic acid ・ AA: Acrylic acid ・ ATBS: Acrylamide-t-butylsulfonic acid ・ St: Styrene ・ MMA: Methyl methacrylate ・ 2EHA: 2-Ethylhexyl acrylate

Claims (8)

A vinyl-modified epoxy resin composition containing a polymer containing the following (A) and (B) as constituents.
(A) A modified epoxy resin comprising an epoxy resin (a1) containing a bisphenol type epoxy resin, amines (a2) and a glycidyl group-containing vinyl monomer (a3), and having an amine value of 15 to 85 mgKOH / g. (B) Monomer component containing a sulfone group-containing vinyl monomer (b2) (excluding the case where a carboxyl group-containing vinyl monomer (b1) is contained). A vinyl-modified epoxy resin composition containing a polymer containing the following (A) and (B) as constituents (excluding those containing an acrylic resin emulsion) .
(A) A reaction product composed of an epoxy resin (a1) made of a bisphenol type epoxy resin, amines (a2) containing an alkanolamine , and a glycidyl group-containing vinyl monomer (a3), having an amine value of 15 to 85 mgKOH / g. Yes, a modified epoxy resin (B) carboxyl group-containing vinyl monomer (b1 ) having an epoxy group concentration of (a1) of 1.47 × 10 ^-3 to 2.5 × 10 ^-3 eq / g is included. The usage ratio of the component (a1), the component (a2) and the component (a3) is {(the number of epoxy groups of the component (a1)) + (the number of epoxy groups of the component (a3))} / (the amino group of the component (a2)). The vinyl-modified epoxy resin composition according to claim 1 or 2 , wherein the number of active hydrogens) = 100/120 to 100/80. (A1) The vinyl-modified epoxy resin composition according to claim 1 , wherein the epoxy group concentration of the component is 0.4 × 10 ^-3 to 3.5 × 10 ^-3 eq / g. The vinyl-modified epoxy resin composition according to claim 1 , wherein the component (a2) contains an alkanolamine. The vinyl-modified epoxy resin composition according to any one of claims 1 to 5 , wherein the component (B) further contains styrenes (b3) and / or (meth) acrylic acid ester (b4). The vinyl-modified epoxy according to any one of claims 1 to 6 , wherein the ratio of the component (A) and the component (B) used [(A) / (B)] is 60/40 to 99/1 in terms of solid content weight. Resin composition. An aqueous coating agent containing the vinyl-modified epoxy resin composition according to any one of claims 1 to 7 .