JP7188634B1 - Modified epoxy resin composition, aqueous coating agent - Google Patents

Abstract

An object of the present invention is to provide a modified epoxy resin composition that exhibits excellent antirust properties over a long period of time while maintaining properties such as excellent water resistance, hardness and water whitening resistance. SOLUTION: A reaction product (A ) and a monomer component (B) containing a polymerizable monomer (b1) having a carboxyl group, the modified epoxy resin composition having a primary hydroxyl value of 10 to 60 mgKOH/g. [Selection figure] None

Description

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

Conventionally, coating films obtained by water-based coating agents have inferior rust-preventing properties to solvent-based coating agents. A vinyl-modified epoxy ester obtained by polymerizing a compound is known (Patent Document 1). Since the modified epoxy ester uses epoxy resin as a raw material, it has relatively good rust resistance, and 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

However, as the application fields of water-based coating agents expand, the required performance of water-based coating agents increases, and there is a demand for improved levels of rust prevention and water resistance, and high initial hardness of the coating film. Such requirements cannot be satisfied with esters and the like. For example, the hardness of the coating film increases with the oxidative polymerization of the fatty acid component in the resin, but it takes several days for the hardness to reach the target value. A phenomenon in which a coating film prepared from a resin turns white when it is immersed in water (hereinafter referred to as water whitening) has also been a problem. Such water whitening resistance can be improved by increasing the ratio of the fatty acid component in the modified epoxy ester, but there is a problem that the initial coating film hardness is further reduced.

The present applicant also proposed a vinyl-modified epoxy resin composition which has a high initial coating film hardness and is less likely to whiten. A vinyl-modified epoxy resin aqueous solution (Patent Document 2) characterized by a copolymer neutralized product obtained by copolymerizing a group-containing vinyl monomer, and an aromatic epoxy resin and an aliphatic epoxy resin in combination. A vinyl-modified epoxy resin water-based product (Patent Document 3) is disclosed. However, these vinyl-modified epoxy resin water-based products are inferior in long-term (20 days or longer) antirust properties.

JP-A-11-269249 JP-A-2003-026739 JP-A-2005-120340

An object of the present invention is to provide a modified epoxy resin composition that exhibits excellent antirust properties over a long period of time while maintaining properties such as excellent water resistance, hardness and water whitening resistance.

The inventors of the present invention have extensively studied the raw material composition and physical properties of the reaction product of the intermediate, and have found that the above problems can be solved, and have completed the present invention. That is, the present invention relates to the following modified epoxy resin composition and aqueous coating agent.

1. a reaction product (A) comprising an epoxy resin (a1) containing a bisphenol-type epoxy resin, an amine (a2) containing a dialkanolamine and a chain aliphatic monoamine, and a polymerizable monomer (a3) having a glycidyl group;
A polymer comprising a monomer component (B) containing a polymerizable monomer (b1) having a carboxyl group as a component,
The dialkanolamine has an NH bond,
The chain aliphatic monoamine includes those having two NH bonds,
The component (a3) includes glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate and 1,2-epoxy. -At least one selected from the group consisting of 4-vinylcyclohexane,
The component (b1) is at least one selected from the group consisting of α,β-unsaturated monocarboxylic acids, α,β-unsaturated dicarboxylic acids, anhydrides of the above carboxylic acids and alkali metal salts of the above carboxylic acids. can be,
Calculated by (Equation 1)A modified epoxy resin composition having a primary hydroxyl value of 10 to 60 mgKOH/g.
(Formula 1) (primary hydroxyl value of modified epoxy resin composition) = (number of hydroxyl groups of alkanolamine) x (molecular weight of potassium hydroxide) / (solid weight of all constituent components)

2. 2. The modified epoxy resin composition according to item 1, wherein the amount of dialkanolamine used is 5 to 40% by weight based on 100% by weight of component (a2).

3. 3. The modified epoxy resin composition according to item 1 or 2, wherein the component (a2) further contains a monoalkanolamine having one N—H bond and/or a monoalkanolamine having two N—H bonds .

4. 3. The modified epoxy resin composition according to item 1 or 2, wherein the component (B) further contains styrenes (b2) and/or (meth)acrylate (b3).

5. 3. The modified epoxy resin composition according to item 3, wherein the component (B) further contains styrenes (b2) and/or (meth)acrylic acid ester (b3).

6. 2. The modified epoxy resin composition as described in 1 above, wherein the ratio [(A)/(B)] of components (A) and (B) is 60/40 to 99/1 in terms of solid weight.

7. An aqueous coating agent comprising the modified epoxy resin composition according to 1 or 2 above.

According to the modified epoxy resin composition of the present invention, while maintaining performance such as excellent water resistance, hardness and water whitening resistance, it also exhibits excellent rust prevention over a long period of time.

The modified epoxy resin composition of the present invention comprises a specific reaction product (A) (hereinafter referred to as component (A)) and a polymerizable monomer (b1) having a carboxyl group (hereinafter referred to as component (b1)). It includes a polymer whose constituent component is the monomer component (B) (hereinafter referred to as component (B)). Each component will be described in detail below.

[About component (A)]
Component (A) includes an epoxy resin (a1) containing a bisphenol-type epoxy resin (hereinafter referred to as component (a1)), amines (a2) (hereinafter referred to as component (a2)), and a polymerizable compound having a glycidyl group. It is a reaction product composed of the monomer (a3) (hereinafter referred to as component (a3)).

Examples of bisphenol-type epoxy resins include reaction products of bisphenols and haloepoxides such as epichlorohydrin or 2-methylepichlorohydrin.

Bisphenols include phenol or 2,6-dihalophenol (hereinafter referred to as phenols), and reaction products of aldehydes (e.g., formaldehyde, acetaldehyde, etc.); phenols and ketones (e.g., acetone, acetophenone, cyclohexanone, benzophenone, etc.); oxidation reaction product of dihydroxyphenyl sulfide with peracid; etherification reaction product between hydroquinones; bisphenol A), bis(4-hydroxyphenyl)methane (bisphenol F), and the like. These may be used alone or in combination of two or more. Among them, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) is preferable from the viewpoint of excellent coating film hardness and rust resistance.

Commercially available products of component (a1) include, for example, “Epotote YD-011”, “Epotote YD-014”, “Epotote YD-017”, “Epotote YD-019”, “Epotote YD-128” (above, Japan manufactured by Tetsu Chemical & Materials Co., Ltd.) and the like.

The component (a1) may be used in combination with an epoxy resin other than the bisphenol type epoxy resin (hereinafter also referred to as other epoxy resin). By using other epoxy resins, the glass transition temperature and weight-average molecular weight of the modified epoxy resin composition can be adjusted, and the coating film tends to be excellent in rust resistance and water-resistant adhesion. Other epoxy resins include, for example, aliphatic epoxy resins and aromatic epoxy resins. These may be used alone or in combination of two or more.

Examples of aliphatic epoxy resins include resins containing glycidyl esters of aliphatic dibasic acids, glycidyl ethers of aliphatic polyols, glycidyl ethers of polyether polyols, and the like.

Aliphatic dibasic acids include, for example, sebacic acid, azelaic acid, dodecanoic acid, malonic acid, succinic acid, glutaric acid, adipic acid, 8,11-dimethyl-7,11-octadecadien-1,18-dicarboxylic acid. acid, 7-ethyloctadecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like.

Examples of aliphatic polyols include 1,4-butanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol and 1,10-decanediol. is mentioned.

Examples of polyether polyols include diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, heptaethylene glycol, octaethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, hexapropylene glycol, polyethylene glycol, polypropylene glycol, polyoxyethylene polyoxypropylene glycol, polybutylene glycol and the like. Examples of commercially available products include "Denacol EX-832", "Denacol EX-841", and "Denacol EX-931" (manufactured by Nagase ChemteX Corporation).

Examples of aromatic epoxy resins include cresol novolac epoxy resin, phenol novolak epoxy resin, triphenolmethane epoxy resin, triphenol ethane epoxy resin, trisphenol epoxy resin, diphenyl ether epoxy resin, and biphenyl epoxy resin. etc.

The ratio of the bisphenol-type epoxy resin to the other epoxy resin is preferably (bisphenol-type epoxy resin)/(other epoxy resin)=30/70 to 100/0 in terms of solid weight.

As the physical properties of component (a1), for example, the epoxy group concentration is preferably about 0.4×10 ⁻³ to 5.5×10 ⁻³ eq/g, and 0.5×10 ⁻³ to 3.5× About 10 ⁻³ eq/g is more preferable. The method for calculating the epoxy group concentration of the component (a1) is as described in JP-A-2019-137862.

The component (a2) contains a dialkanolamine and a chain aliphatic monoamine. By using these, a high molecular weight component (A) in which alkanol groups and chain aliphatic groups are incorporated in a well-balanced manner can be obtained, and when used as a coating film, it exhibits excellent rust prevention properties over a long period of time. easier.

A dialkanolamine is an amine with two alkanol groups. Although the type thereof is not particularly limited, dialkanolamine having an N—H bond (secondary dialkanolamine) is preferable from the viewpoint of reactivity with component (a1). Dialkanolamines (secondary dialkanolamines) having an NH bond include, for example, diethanolamine, di-n-propanolamine, diisopropanolamine, bis(2-hydroxybutyl)amine, bis(2-hydroxypentyl) amine, bis(2-hydroxyhexyl)amine and the like. These may be used alone or in combination of two or more. Among them, diethanolamine, di-n-propanolamine, and diisopropanolamine are more preferable because the coating film exhibits excellent antirust properties over a long period of time.

The amount of dialkanolamine used when the component (a2) is 100% by weight is preferably 5 to 40% by weight, and 7 to 30% by weight, because the coating film exhibits excellent rust prevention properties over a long period of time. % is more preferred.

A chain aliphatic monoamine is a monoamine having one or more non-cyclic hydrocarbon groups (alkyl group, alkenyl group, alkynyl group) in the molecule. Although the type thereof is not particularly limited, in terms of reactivity with component (a1), chain aliphatic amines having one or two N—H bonds, namely monoalkylamines, monoalkenylamines, dialkylamines, Dialkenylamines are preferred. These may be used alone or in combination of two or more.

Examples of monoalkylamines include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, s-butylamine, t-butylamine, n-pentylamine, isopentylamine, n-hexylamine, n-heptylamine, n-octylamine, isooctylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, isodecylamine, n-undecylamine, n-dodecylamine (n-laurylamine), n- tridecylamine, n-tetradecylamine (n-myristylamine), n-pentadecylamine, n-hexadecylamine (n-palmitylamine), n-heptadecylamine, n-octadecylamine (n-stearylamine ), isooctadecylamine (isostearylamine), and the like. These may be used alone or in combination of two or more.

Monoalkenylamines include vinylamine, allylamine, butenylamine, pentenylamine, hexenylamine, heptenylamine, octenylamine, nonenylamine, decenylamine, undecenylamine, dodecenylamine, tridecenylamine, tetradecenylamine, pentadecenylamine, hexadecenylamine. , heptadecenylamine, octadecenylamine (oleylamine etc.), nonadecenylamine, icosenylamine, dodecenylamine and the like. These may be used alone or in combination of two or more. In addition, the position of the carbon-carbon double bond of these monoalkenylamines is not particularly limited, and their structural isomers can be freely used.

Dialkylamines include dimethylamine, N-ethylmethylamine, diethylamine, N-ethyl-N-(n-propyl)amine, di-n-propylamine, n-propylisopropylamine, diisopropylamine, di-n-butylamine, diisobutyl Amine, di-s-butylamine, di-t-butylamine, Nn-butylethylamine, Ns-butylethylamine, Nt-butylethylamine, Nn-butylpropylamine, Ns-butylpropylamine, N -t-butylpropylamine, Nt-butylisopropylamine, dipentylamine (diamylamine), diisopentylamine (diisoamylamine), dihexylamine, diheptylamine, dioctylamine, bis(2-ethylhexyl)amine, dinonylamine , didecylamine, diundecylamine, didodecylamine (dilaurylamine), ditridecylamine, ditetradecylamine (dimyristylamine), dipentadecylamine, dihexadecylamine (dipalmitylamine), diheptadecylamine , dioctadecylamine (distearylamine) and the like. These may be used alone or in combination of two or more.

The dialkenylamines include divinylamine, diallylamine, dibutenylamine, dipentenylamine, dihexenylamine, diheptenylamine, dioctenylamine, dinonenylamine, didecenylamine, diundecenylamine, didodecenylamine, ditridecenylamine, di tetradecenylamine, dipentadecenylamine, dihexadecenylamine, diheptadecenylamine, dioctadecenylamine, dinonadecenylamine, diicosenylamine, didodecenylamine and the like. Further, the position of the carbon-carbon double bond of these dialkenylamines is not particularly limited, and structural isomers thereof can be freely used.

Among these chain aliphatic monoamines, monoalkylamines, monoalkenylamines, and dialkylamines are more preferable because the coating film exhibits excellent antirust properties over a long period of time.

The amount of the chain aliphatic monoamine used when the component (a2) is 100% by weight is preferably 50 to 95% by weight, and 60 to 92% by weight is more preferred.

Moreover, the (a2) component may further contain a monoalkanolamine. The type is not particularly limited, but from the viewpoint of reactivity with component (a1), monoalkanolamine having one N—H bond (secondary monoalkanolamine), monoalkanol having two N—H bonds Amines (primary monoalkanolamines) are preferred.

Examples of monoalkanolamines (secondary monoalkanolamines) having one NH bond include N-methylethanolamine, N-ethylethanolamine, Nn-propylethanolamine, N-isopropylethanolamine, Nn-butylethanolamine, N-isobutylethanolamine, Ns-butylethanolamine, Nt-butylethanolamine, N-phenylethanolamine, N-benzylethanolamine, N-methylbutanolamine, N- ethylbutanolamine, Nn-propylbutanolamine, N-isopropylbutanolamine, N-butylbutanolamine, N-isobutylbutanolamine and the like. These may be used alone or in combination of two or more.

Examples of monoalkanolamines (primary monoalkanolamines) having two NH bonds include monomethanolamine, monoethanolamine, monopropanolamine, 1-amino-2-propanol, 2-amino-1- propanol, 2-amino-2-methyl-1-propanol, 4-amino-1-butanol, 5-amino-1-pentanol, 6-amino-1-hexanol and the like. These may be used alone or in combination of two or more.

Among them, monoalkanolamine having two N—H bonds (primary monoalkanolamine) is preferable, and monomethanolamine and monoethanolamine are preferable, since the coating film exhibits excellent antirust properties over a long period of time. more preferred.

The amount of monoalkanolamine used when the component (a2) is 100% by weight is preferably 15% by weight or less, and 8% by weight or less, because the coating film exhibits excellent rust prevention properties over a long period of time. more preferred.

In addition, the component (a2) may further contain a chain aliphatic diamine, an alicyclic amine, or an aromatic amine.

Chain aliphatic diamines include, for example, ethylenediamine, 1,3-propanediamine, propane-1,2-diamine, 1,2-butanediamine, 1,3-butanediamine, 1,4-butanediamine, 1, 2-pentanediamine, 1,3-pentanediamine, 1,4-pentanediamine, 1,5-pentanediamine, 1,2-hexanediamine, 1,3-hexanediamine, 1,4-hexanediamine, 1,5 -hexanediamine, 1,6-hexanediamine, trimethylhexanediamine and the like. These may be used alone or in combination of two or more. The amount of chain aliphatic diamine to be used is preferably 10% by weight or less, more preferably 5% by weight or less, based on 100% by weight of component (a2).

Cycloalicyclic amines include, for example, cyclopentylamine, cyclohexylamine, 2-methylcyclohexylamine, 3-methylcyclohexylamine, 4-methylcyclohexylamine, cycloheptylamine, cyclooctylamine and other cycloalkyl monoamines; N-methylcyclopentyl N-alkylcycloalkyl monoamines such as amines, N-ethylcyclopentylamine, N-methylcyclohexylamine, N-ethylcyclohexylamine; 1,2-cyclopentanediamine, 1,3-cyclopentanediamine, 1,2-cyclohexanediamine , 1,3-cyclohexanediamine, 1,4-cyclohexanediamine and isophoronediamine. These may be used alone or in combination of two or more. The amount of the alicyclic amine used is preferably 20% by weight or less, more preferably 10% by weight or less, based on 100% by weight of component (a2).

Examples of aromatic amines include aniline, methylaniline, dimethylaniline, ethylaniline, n-propylaniline, isopropylaniline, n-butylaniline, isobutylaniline, n-pentylaniline, n-hexylaniline, nonylaniline and dodecylaniline. , benzylamine, phenethylamine and the like. These may be used alone or in combination of two or more. The amount of the aromatic amine used is preferably 20% by weight or less, more preferably 10% by weight or less, based on 100% by weight of component (a2).

Component (a3) is a polymerizable monomer having a glycidyl group, and is a component for facilitating addition of component (B) by introducing the structure into component (A). Examples of 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, and these may be used alone or in combination of two or more. Among them, glycidyl acrylate and glycidyl methacrylate are preferred.

The ratio of components (a1), (a2) and (a3) used is {(number of epoxy groups in component (a1)) + (number of epoxy groups in component (a3))}/(amino groups in component (a2) active hydrogen number) is about 100/120 to 100/80, preferably about 100/110 to 100/90, more preferably about 100/105 to 100/95. By setting it as the said range, (A) component is obtained at a high yield and it becomes easy to exhibit the outstanding coating film performance. The method for calculating the number of epoxy groups and the number of active hydrogens of amino groups is as described in JP-A-2019-137862.

Moreover, you may use a polyisocyanate for the structural component of (A) component as needed.

Examples of polyisocyanates include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates. These may be used alone or in combination of two or more.

Examples of aromatic polyisocyanates include xylylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyl isocyanate, and dialkyldiphenylmethane. diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, orthotoluidine diisocyanate, polyphenylpolyisocyanate and the like. These may be used alone or in combination of two or more.

Examples of aliphatic polyisocyanates include butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and lysine diisocyanate. These may be used alone or in combination of two or more.

Examples of alicyclic polyisocyanates include cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, and isophorone diisocyanate. These may be used alone or in combination of two or more.

The amount of polyisocyanate used is preferably about 0.005 to 2, more preferably about 0.05 to 0.5, in terms of {number of isocyanate groups in polyisocyanate}/{number of hydroxyl groups in components (a1) to (a3)}. is more preferred. The method for calculating the number of isocyanate groups and the number of hydroxyl groups is as described in JP-A-2019-137862.

Component (A) can be obtained by various known production methods using components (a1), (a2) and (a3) and, if necessary, epoxy resins other than (a1) and polyisocyanate. . As production conditions, for example, the reaction temperature is usually 50 to 250°C, preferably 80 to 150°C. Further, the reaction time is, for example, usually 3 to 12 hours, preferably 3 to 8 hours.

In the production method, a hydrophilic organic solvent may be used. Examples of hydrophilic organic solvents include alkylene glycol monoethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-butyl ether, and propylene glycol mono-t-butyl ether; diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, and dipropylene. dialkylene glycol monoethers such as glycol methyl ether; alkoxy alcohols such as 3-methoxybutanol and 3-methoxy-3-methylbutanol; cellosolves such as methyl cellosolve, ethyl cellosolve, n-butyl cellosolve, t-butyl cellosolve; cellosolve acetate such as ethyl cellosolve acetate; aliphatic monoalcohols such as isopropyl alcohol and n-butyl alcohol; These may be used alone or in combination of two or more. Moreover, after manufacturing the component (A), the hydrophilic solvent may be added. The amount of hydrophilic organic solvent used is preferably adjusted so that the reaction concentration is about 30 to 80% by weight.

[About component (B)]
Component (B) is a monomer component containing a polymerizable monomer (b1) having a carboxyl group (hereinafter referred to as component (b1)), and the modified epoxy resin composition is easily dispersed in water.

Component (b1) includes, for example, α,β-unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; saturated dicarboxylic acids; anhydrides of the carboxylic acids; alkali metal salts such as sodium salts and potassium salts of the carboxylic acids; These may be used alone or in combination of two or more. Among them, (meth)acrylic acid, maleic acid, fumaric acid, and itaconic acid are preferable, and methacrylic acid and acrylic acid are more preferable, because the modified epoxy resin composition is well dispersed in water.

The amount of component (b1) used is preferably about 0.1 to 20 parts by weight, preferably 1 to 20 parts by weight, per 100 parts by weight of component (A), because the modified epoxy resin composition is well dispersed in water. About 10 parts by weight is more preferable.

(b1) When using a component, you may use carbodiimide as needed.

Carbodiimides include, 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-diisopropylphenylenecarbodiimide), poly(isopropylphenylenecarbodiimide), N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, N,N'-diisopropylphenylcarbodiimide, N-ethyl-N'-( 3-dimethylaminopropyl)-carbodiimide hydrochloride and the like. Commercially available products include "Carbodilite E-02", "Carbodilite V-02", and "Carbodilite V-04" (manufactured by Nisshinbo Chemical Co., Ltd.). These may be used alone or in combination of two or more.

The amount of carbodiimide used is preferably about 0.005 to 2, more preferably about 0.05 to 0.5, in terms of {number of imide groups in carbodiimide}/{number of cacarboxyl groups in component (b1)}.

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

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

Further, as the component (B), styrenes (b2) (hereinafter referred to as the (b2) component) and/or (meth)acrylic acid esters (b3) (hereinafter referred to as the (b3) component) may be used. good.

Examples of component (b2) include styrene, α-methylstyrene, t-butylstyrene, dimethylstyrene, acetoxystyrene, hydroxystyrene, vinyltoluene, and chlorovinyltoluene. These may be used alone or in combination of two or more.

The amount of component (b2) used is preferably about 0.1 to 40 parts by weight, more preferably about 1 to 20 parts by weight, per 100 parts by weight of component (A).

Component (b3) includes, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, Isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, (meth)acrylate isohexyl acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, ( n-decyl meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate and the like. These may be used alone or in combination of two or more. Among them, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Lauryl (meth)acrylate is preferred.

The amount of component (b3) used is preferably about 0.1 to 40 parts by weight, more preferably about 1 to 20 parts by weight, per 100 parts by weight of component (A).
degree is more preferred.

Furthermore, as the component (B), a monomer component (b4) (hereinafter referred to as component (b4)) other than the components (b1) to (b3) may be used, if necessary. Examples of component (b4) include sulfones such as styrenesulfonic acid, methallylsulfonic acid, methallyloxybenzenesulfonic acid, allyloxybenzenesulfonic acid, acrylamido-2-methylpropanesulfonic acid, and acrylamido-t-butylsulfonic acid. Polymerizable monomers having an acid group; vinyl carboxylates such as vinyl acetate and vinyl propionate; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, (Meth)acrylic acid hydroxyalkyl esters such as 7-hydroxyheptyl (meth)acrylate and 8-hydroxyoctyl (meth)acrylate; (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl ( (meth)acrylamides such as meth)acrylamide and N-ethyl-N-methyl(meth)acrylamide; and (meth)acrylonitrile. These may be used alone or in combination of two or more.

The amount of component (b4) used is preferably about 0.1 to 40 parts by weight per 100 parts by weight of component (A).

Solution polymerization is preferred as the method for polymerizing the components (A) and (B). The conditions are, for example, a temperature of about 60 to 150° C., preferably about 70 to 140° C., and a time of about 1 to 8 hours, preferably about 2 to 6 hours, in the presence of a polymerization initiator. Moreover, the above-mentioned organic solvent may be used in the system.

The ratio of the components (A) and (B) is preferably (A )/(B)=60/40 to 99/1, more preferably 70/30 to 97/3, still more preferably 80/20 to 95/5.

Examples of polymerization initiators include azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile, benzoyl peroxide, cumene hydroperoxide, Organic peroxides such as t-butyl hydroperoxide, t-butyl peroxy-2-ethylhexanoate, dicumyl peroxide, lauroyl peroxide, and the like are included. These may be used alone or in combination of two or more.

The amount of the polymerization initiator used is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight, per 100 parts by weight of components (A) and (B) combined.

Examples of the organic solvent include those listed in the section of the method for producing component (A). The amount of the organic solvent used may be adjusted so that the reaction concentration is about 30 to 90% by weight. The polymer obtained by the above production method may contain a solvent, but it is preferable that the content is less than 20% by weight by appropriately removing the solvent by distillation under reduced pressure or the like.

When the polymer obtained by the above production method is used in an aqueous coating agent, water is added to dissolve or disperse the polymer. It is preferably neutralized with a base (that is, converted into a base-neutralized vinyl-modified epoxy resin composition). The pH after neutralization is preferably 7-10. Examples of the base used as the neutralizing agent 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. Among them, ammonia and amine are preferable because they are easily volatilized during drying.

The modified epoxy resin composition of the present invention optionally contains additives such as surface conditioners, surfactants, ultraviolet absorbers, antioxidants, antifoaming agents, wetting agents, and rust preventives. But it's okay. These may be used alone or in combination of two or more.

As the physical properties of the modified epoxy resin composition of the present invention, the primary hydroxyl value (unit: mgKOH/g) is important in order to exhibit excellent rust prevention even for a long period of time. , the molecular weight of potassium hydroxide (Mw. 56.11), and the solid content weight of all constituent components, it can be obtained by (Equation 1).
(Formula 1) (primary hydroxyl value of modified epoxy resin composition)
= (number of hydroxyl groups of alkanolamine) x (molecular weight of potassium hydroxide) / (solid weight of all constituent components)

The number of hydroxyl groups in alkanolamine is represented by the product of the number of moles of alkanolamine and the number of hydroxyl groups. For example, the number of hydroxyl groups in 0.8 mol of diethanolamine is 0.8×2=1.6 because the number of hydroxyl groups in diethanolamine is 2. Further, the number of hydroxyl groups in 0.5 mol of monoethanolamine is 0.5×1=0.5 because the number of hydroxyl groups in monoethanolamine is 1. When a plurality of alkanolamines are used, the number of hydroxyl groups of each alkanolamine is calculated and added together.

When polyisocyanate is used, it can react with the hydroxyl groups of alkanolamine, so the value obtained by subtracting the number of isocyanate groups of polyisocyanate calculated by the above method from the number of hydroxyl groups of alkanolamine is the net number of alkanolamine. number of hydroxyl groups.

Further, the solid content weight of all constituent components is the sum of the charged weight of each constituent component forming component (A) and each monomer component belonging to component (B) in terms of solid content (the same shall apply hereinafter).

The primary hydroxyl value is 10 to 60 mgKOH/g. When the primary hydroxyl value is within this range, the coating film tends to exhibit excellent antirust properties over a long period of time. From the same point of view, the primary hydroxyl value is preferably 10 to 60 mgKOH/g, more preferably 12 to 50 mgKOH/g, even more preferably 15 to 45 mgKOH/g.

In addition, as other physical properties of the modified epoxy resin composition, the total hydroxyl value is preferably 150 to 280 mgKOH/g, more preferably 150 to 280 mgKOH/g, because the coating film tends to exhibit excellent antirust properties over a long period of time. is 170-260 mgKOH/g, more preferably 190-240 mgKOH/g. The total hydroxyl value (unit: mhKOH/g) is the number of hydroxyl groups in the modified epoxy resin composition, the molecular weight of potassium hydroxide (Mw.56.11), and the solid content of all constituent components of the modified epoxy resin composition. It can be obtained by (Equation 2) using the partial weight.
(Formula 2) (total hydroxyl value of modified epoxy resin composition)
= (number of hydroxyl groups in the modified epoxy resin composition) x (molecular weight of potassium hydroxide) / (solid weight of all constituent components)

The number of hydroxyl groups in the modified epoxy resin composition is determined by the sum of the numbers of hydroxyl groups in the components (a1) to (a3). The number of hydroxyl groups in component (a1) can be calculated by multiplying the charged molar amount of component (a1) by the number of hydroxyl groups per molecule including hydroxyl groups generated when the epoxy groups in component (a1) are ring-opened. In addition, when the (a1) component contains a plurality of components, the number of hydroxyl groups of the (a1) component is the total number of hydroxyl groups of each component. The number of hydroxyl groups of component (a3) is also the same. The number of hydroxyl groups in component (a2) is as described above.

When polyisocyanate is used, it can react with these hydroxyl groups. It is the net number of hydroxyl groups in the modified epoxy resin composition.

Furthermore, the weight-average molecular weight (polystyrene conversion value by gel permeation chromatography) of the modified epoxy resin composition is preferably about 10,000 to 250,000, and 40, from the viewpoint of excellent hardness and rust resistance of the coating film. ,000 to 200,000 is more preferable. In addition, the solid content concentration is preferably 30 to 45% by weight.

In addition, the viscosity at a solid content concentration of 33% by weight and a temperature of 25° C. is preferably 200 to 4000 mPa·s, more preferably 400 to 3000 mPa·s.

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

In the preparation of the aqueous coating agent of the present invention, for example, coloring pigments such as carbon black and titanium oxide; extender pigments such as talc, calcium carbonate and barium sulfate; rust preventives such as aluminum phosphomolybdate, zinc phosphate and zinc oxide; Pigments; metal compounds such as cobalt compounds, nickel compounds and zirconium compounds; silane coupling agents, colloidal silica and the like can be appropriately blended. In addition, if necessary, curing agents such as melamine resins, urea resins, isocyanates, blocked isocyanates, and carbodiimides, additives such as colorants, plasticizers, and rust preventives, and the aforementioned organic solvents may be appropriately added. . The solid content concentration of the aqueous coating agent is preferably 20 to 80% by weight, more preferably 30 to 60% by weight.

As physical properties of the aqueous coating agent of the present invention, for example, the viscosity at a solid content concentration of 30 to 60% by weight and a temperature of 25° C. is usually about 10 to 500 mPa·s, preferably about 50 to 300 mPa·s.

Hereinafter, the present invention will be described in more detail through examples and comparative examples. In addition, the technical scope of the present invention is not limited by those descriptions. "Parts" and "%" in the examples are by weight unless otherwise specified.

(viscosity)
A solution of the modified epoxy resin composition having a solid content concentration of 33% was allowed to stand in a constant temperature bath at a temperature of 25°C, and then the viscosity was measured with a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.).

(Total hydroxyl value and primary hydroxyl value)
The total hydroxyl value of the modified epoxy resin composition was calculated from Equation 2, and the primary hydroxyl value was calculated from Equation 1.
(Formula 2) (total hydroxyl value of modified epoxy resin composition)
= (number of hydroxyl groups in the modified epoxy resin composition) x (molecular weight of potassium hydroxide) / (solid weight of all constituent components)
(Formula 1) (primary hydroxyl value of modified epoxy resin composition)
= (number of hydroxyl groups of alkanolamine) x (molecular weight of potassium hydroxide) / (solid weight of all constituent components)

Example 1
200 parts of t-butyl cellosolve, bisphenol A type epoxy resin (trade name: "Epotato YD-014", epoxy equivalent: 950 g / eq, day 300 parts of Tetsu Chemical & Materials Co., Ltd.) and 6 parts of glycidyl methacrylate were added and dissolved at 120° C. under a stream of nitrogen, and then 9.4 parts of diethanolamine and 36.2 parts of stearylamine were added and allowed to react for 7 hours. A product (A-1) was obtained. Next, a mixture of 15.0 parts of acrylic acid, 10.0 parts of styrene, 10.0 parts of methyl acrylate and 4 parts of t-butylperoxy-2-ethylhexanoate was charged into the dropping funnel, and the reaction system was was added dropwise over 1 hour, and the mixture was kept warm for 3 hours. After cooling to 80° C., 19 parts of triethylamine and 560 parts of water were sequentially added and mixed to obtain a modified epoxy resin composition having a solid content of 33% and a pH of 9.5. The physical properties are shown in Table 1 (the same applies hereinafter).

Examples 2-15, Comparative Examples 1-5
The compositions shown in Table 1 were synthesized in the same manner as in Example 1 to obtain modified epoxy resin compositions.

(Preparation of aqueous coating agent)
Aqueous coating agents were prepared by kneading mixtures having the compositions shown below with a paint shaker. The resulting water-based coating material is applied onto a degreased dull steel plate (SPCC-SD, 0.8×70×150 mm) (hereinafter referred to as SPCC-SD) so that the film thickness after drying is 25 to 30 μm. It was applied by a coater, forcedly dried at a temperature of 80°C for 20 minutes, and then allowed to stand for 6 days in an environment of a temperature of 23°C and a humidity of 60% to prepare a coating film. Using the obtained coating film, the following tests were performed.

(composition)
Each modified epoxy resin composition 200 parts Talc 38 parts Carbon black 4 parts Zinc oxide 8 parts Zinc phosphate rust preventive pigment 2.8 parts Calcium carbonate 18 parts Ion-exchanged water 10 parts

(Evaluation test of coating film)
(1) Pencil hardness Conforming to JIS K5600-5-4. Table 1 shows the evaluation results. (same below)

(2) Primary Adhesion According to JIS K5600-5-6, the cross-cut adhesion when peeling off the coating film cured for 6 days in an environment of 23 ° C. and 60% humidity after coating is taken as 100. evaluated.

(3) Water-resistant Adhesion The test was conducted according to JIS K5600-6-2, and the cross-cut adhesion was evaluated as 100 when the coating film was immersed in hot water at a temperature of 40° C. for 10 days and peeled off.

(4) Water-whitening resistance Each water-based coating agent is coated on SPCC-SD with a bar coater so that the film thickness after drying is 25 to 30 μm, and forcedly dried at a temperature of 80 ° C. for 20 minutes. A coating film was prepared by allowing it to stand for 6 days in an environment with a temperature of 23° C. and a humidity of 60%. In accordance with JIS K5600-6-2, the appearance of the coating film immersed in hot water at a temperature of 40° C. for 10 days was visually observed. Evaluation criteria are shown below.
(Evaluation criteria)
○: Not whitened △: Slightly whitened ×: Completely whitened

(5) Anti-corrosion property It was measured according to JIS K5600-7-9 and indicated by the cellophane tape peeling width (mm) after 10 days, 20 days and 30 days of the salt spray test.

[(A) component]
(a1) Component YD-014: Bisphenol A type epoxy resin (trade name “Epotote YD-014”, Mw.1400, epoxy equivalent: 950 g / eq, number of hydroxyl groups per molecule before ring opening: 3.7 ( After ring opening: 5.7), manufactured by Nippon Steel Chemical & Materials Co., Ltd.)
・EX-841: polyethylene glycol diglycidyl ether (trade name “Denacol EX-841”, Mw.744, epoxy equivalent: 372 g/eq, number of hydroxyl groups per molecule before ring opening: 0 (after ring opening: 2) , manufactured by Nagase ChemteX Corporation)
・EX-931: polypropylene glycol diglycidyl ether (trade name “Denacol EX-931”, Mw.940, epoxy equivalent: 472 g/eq, number of hydroxyl groups per molecule before ring opening: 0 (after ring opening: 2) , manufactured by Nagase ChemteX Corporation)
・ YD-011: Bisphenol A type epoxy resin (trade name “Epotato YD-011”, Mw.900, epoxy equivalent: 475 g / eq, number of hydroxyl groups per molecule before ring opening: 2 (after ring opening: 4) , NIPPON STEEL CHEMICAL & MATERIAL CO., LTD.)
(a2) component DEA: diethanolamine (molecular weight: 105.1, number of hydroxyl groups: 2)
・DIPA: diisopropanolamine (molecular weight: 133.2, number of hydroxyl groups: 2)
・MEA: monoethanolamine (molecular weight: 61, number of hydroxyl groups: 1)
- SA: stearylamine (molecular weight: 269.6)
・ OA: n-octylamine (molecular weight: 129.2)
- OLA: oleylamine (molecular weight: 267.5)
・DBA: di-n-butylamine (molecular weight: 129.3)
(a3) component GMA: glycidyl methacrylate (epoxy equivalent: 142.2 g/eq, number of hydroxyl groups per molecule before ring opening: 0 (after ring opening: 1))
[(B) Component]
・AA: acrylic acid ・St: styrene ・MA: methyl acrylate

Claims (7)

a reaction product (A) comprising an epoxy resin (a1) containing a bisphenol-type epoxy resin, an amine (a2) containing a dialkanolamine and a chain aliphatic monoamine, and a polymerizable monomer (a3) having a glycidyl group;
A polymer comprising a monomer component (B) containing a polymerizable monomer (b1) having a carboxyl group as a component,
The dialkanolamine has an NH bond,
The chain aliphatic monoamine includes those having two NH bonds,
The component (a3) includes glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate and 1,2-epoxy. -At least one selected from the group consisting of 4-vinylcyclohexane,
The component (b1) is at least one selected from the group consisting of α,β-unsaturated monocarboxylic acids, α,β-unsaturated dicarboxylic acids, anhydrides of the above carboxylic acids and alkali metal salts of the above carboxylic acids. can be,
A modified epoxy resin composition having a primary hydroxyl value of 10 to 60 mgKOH/g as determined by (Formula 1) .
(Formula 1) (primary hydroxyl value of modified epoxy resin composition) = (number of hydroxyl groups of alkanolamine) x (molecular weight of potassium hydroxide) / (solid weight of all constituent components) 2. The modified epoxy resin composition according to claim 1, wherein the amount of dialkanolamine used is 5 to 40% by weight based on 100% by weight of component (a2). 3. The modified epoxy resin composition according to claim 1, wherein the component (a2) further comprises a monoalkanolamine having one NH bond and/or a monoalkanolamine having two NH bonds . 3. The modified epoxy resin composition according to claim 1, wherein the component (B) further contains styrenes (b2) and/or (meth)acrylic acid esters (b3). 4. The modified epoxy resin composition according to claim 3, wherein the component (B) further contains styrenes (b2) and/or (meth)acrylates (b3). 2. The modified epoxy resin composition according to claim 1, wherein the ratio [(A)/(B)] of components (A) and (B) is 60/40 to 99/1 in terms of solid weight. An aqueous coating agent comprising the modified epoxy resin composition according to claim 1 or 2 .