Vinyl-modified epoxy resin composition, water-based coating agent

Abstract

To provide a vinyl-modified epoxy resin composition that gives an aqueous coating being well dispersible in water and having excellent dryability.SOLUTION: A vinyl-modified epoxy resin composition contains a polymer having the following (A) and (B) as essential reaction components: (A) a modified epoxy resin that is a reaction product comprising an epoxy resin containing a bisphenol-type epoxy resin (a1), an amine (a2) and a glycidyl group-containing vinyl monomer (a3); and (B) a monomer component containing a methacrylamide (b1).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a vinyl-modified epoxy resin composition and an aqueous coating agent. [Background technology]

[0002] Conventionally, coating films obtained using water-based coating agents have inferior rust-preventive properties compared to solvent-based coating agents, but vinyl-modified epoxy esters obtained by polymerizing vinyl monomers in the presence of fatty acid-modified epoxy esters have been publicly known as coatings with improved rust-preventive properties (Patent Document 1). The vinyl-modified epoxy esters use epoxy resins as raw materials, and therefore have relatively good rust-preventive properties, 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.

[0003] However, as the application fields of the aqueous coating agent expand, the performance requirements for the aqueous coating agent also increase, and there is a demand for improved rust prevention and water resistance, as well as high initial hardness of the coating film, which the vinyl-modified epoxy ester and the like cannot satisfy. For example, the hardness of the coating film increases with the oxidative polymerization of the fatty acid component in the resin, but it takes a long time to dry, and even if a coating film is obtained, it takes several days for the hardness to reach the target value, so scratches at the initial stage of coating film formation are likely to be a problem, and the phenomenon that the coating film prepared from the resin whitens when immersed in water (hereinafter referred to as water-resistant whitening) has also been a problem. Such water-resistant whitening can be 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 reduced.

[0004] Therefore, the present applicant proposed an aqueous vinyl-modified epoxy resin comprising an aromatic epoxy resin and an aliphatic epoxy resin in combination, as a vinyl-modified epoxy resin composition that can be dried in a short time (has excellent drying properties), gives a coating film with high hardness, and is not easily whitened by water (Patent Document 2). However, this aqueous vinyl-modified epoxy resin is difficult to disperse in water when preparing an aqueous coating agent, and further has poor drying properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-269249 [Patent Document 2] JP 2005-120340 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a vinyl-modified epoxy resin composition which disperses well in water and gives an aqueous coating agent which has excellent drying properties. [Means for solving the problem]

[0007] As a result of extensive investigations, the present inventors have found that a vinyl-modified epoxy resin composition copolymerized with a vinyl monomer having a specific functional group can solve the above-mentioned problems, and have thus completed the present invention. That is, the present invention relates to the following vinyl-modified epoxy resin composition and aqueous coating agent.

[0008] 1. A vinyl-modified epoxy resin composition comprising a polymer having the following (A) and (B) as essential reaction components: (A) A modified epoxy resin which is a reaction product of an epoxy resin (a1) containing a bisphenol-type epoxy resin, an amine (a2) and a glycidyl group-containing vinyl monomer (a3). (B) Monomer component containing (meth)acrylamide (b1)

[0009] 2. A vinyl-modified epoxy resin composition according to item 1 above, wherein the component (a2) contains an alkanolamine.

[0010] 3. A vinyl-modified epoxy resin composition according to item 1 or 2 above, wherein the component (b1) is at least one member selected from the group consisting of N,N-dialkyl(meth)acrylamide, N,N-dialkylaminoalkyl(meth)acrylamide, and diacetone(meth)acrylamide.

[0011] 4. The vinyl-modified epoxy resin composition according to any one of items 1 to 3, wherein the amount of the component (b1) used is 0.4 to 30 parts by weight, in terms of non-volatile weight, per 100 parts by weight of the component (A).

[0012] 5. The vinyl-modified epoxy resin composition according to any one of items 1 to 4 above, wherein the component (B) further contains a carboxyl group-containing vinyl monomer and / or an ester thereof (b2).

[0013] 6. The vinyl-modified epoxy resin composition according to item 5 above, wherein the ratio of the components (b1) and (b2) used is (b1) / (b2)=0.01 to 30, in terms of non-volatile weight.

[0014] 7. An aqueous coating agent comprising the vinyl-modified epoxy resin composition according to any one of items 1 to 6 above. Effect of the Invention

[0015] The vinyl-modified epoxy resin composition of the present invention disperses well in water and dries quickly when used to prepare an aqueous coating agent, and the coating film prepared using the aqueous coating agent has excellent primary adhesion, water-whitening resistance, and water-resistant adhesion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The vinyl-modified epoxy resin composition of the present invention contains a polymer having as its constituent components (A) a specific modified epoxy resin (hereinafter referred to as component (A)) and (B) a specific monomer component (hereinafter referred to as component (B)). Each component will be described in detail below.

[0017] [About component (A)] Component (A) is a reaction product of an epoxy resin (a1) (hereinafter referred to as component (a1)) containing a bisphenol-type epoxy resin, an amine (a2) (hereinafter referred to as component (a2)), and a glycidyl group-containing vinyl monomer (a3) ​​(hereinafter referred to as component (a3)).

[0018] The bisphenol type epoxy resin is not particularly limited, and examples thereof include reaction products of bisphenols and haloepoxides such as epichlorohydrin or 2-methylepichlorohydrin.

[0019] The bisphenols are not particularly limited, and include reaction products of phenol or 2,6-dihalophenol (hereinafter referred to as phenols) and aldehydes (e.g., formaldehyde, acetaldehyde, etc.); reaction products of phenols and ketones (e.g., acetone, acetophenone, cyclohexanone, benzophenone, etc.); oxidation reaction products of dihydroxyphenyl sulfide with peracid; etherification reaction products of hydroquinones; and more specifically, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), bis(4-hydroxyphenyl)methane (bisphenol F), etc. may be mentioned. These may be used alone or in combination of two or more. Among them, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) is preferred from the viewpoint of excellent hardness and rust prevention of the coating film.

[0020] The component (a1) may contain an epoxy resin other than the bisphenol type epoxy resin (hereinafter, also referred to as other epoxy resin). By using the other epoxy resin, the glass transition temperature and weight average molecular weight of the vinyl-modified epoxy resin composition can be adjusted, and the coating film tends to have excellent rust prevention and water-resistant adhesion. Specific examples of the other epoxy resin include, but are not limited to, aliphatic epoxy resins and aromatic epoxy resins. These may be used alone or in combination of two or more.

[0021] The aliphatic epoxy resin is not particularly limited, and examples thereof include resins containing glycidyl esters of aliphatic dibasic acids, glycidyl ethers of aliphatic polyols, and glycidyl ethers of polyether polyols.

[0022] The aliphatic dibasic acid is not particularly limited, and examples thereof include sebacic acid, azelaic acid, dodecanoic acid, malonic acid, succinic acid, glutaric acid, adipic acid, 8,11-dimethyl-7,11-octadecadiene-1,18-dicarboxylic acid, 7-ethyloctadecanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid.

[0023] The aliphatic polyol is not particularly limited, and examples thereof include 1,4-butanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol.

[0024] The polyether polyol is not particularly limited, and examples thereof 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, and polybutylene glycol.

[0025] The aromatic epoxy resin is not particularly limited, and examples thereof include cresol novolac type epoxy resins, phenol novolac type epoxy resins, triphenol methane type epoxy resins, triphenol ethane type epoxy resins, trisphenol type epoxy resins, diphenyl ether type epoxy resins, and biphenyl type epoxy resins.

[0026] The ratio of the bisphenol type epoxy resin and the other epoxy resins used is not particularly limited, but is preferably (bisphenol type epoxy resin) / (other epoxy resin)=about 30 / 70 to 100 / 0 in terms of non-volatile weight.

[0027] The physical properties of the (a1) component include an epoxy group concentration of 0.4×10 -3 ~3.5×10 -3 eq / g is preferable, and 0.5×10 -3 ~2.5×10 -3 eq / g is more preferable, and 0.8×10 -3 ~2.1×10 -3 When an epoxy group concentration in this range is used, the coating film will have high hardness and excellent rust prevention properties when reacted with component (a2).

[0028] The epoxy group concentration of the component (a1) is expressed as the number of epoxy groups contained per gram of the component (a1).

[0029] When one type of component (a1) is used, the epoxy group concentration is calculated as the reciprocal of the epoxy equivalent (= 1 / epoxy equivalent of component (a1)).

[0030] When two types of (a1) components are used, the epoxy group concentration of the (a1) component is calculated from the charge weight and epoxy equivalent of each component according to formula 1. The two types of (a1) components are referred to as (a1-1) component and (a1-2) component, respectively.

[0031] (Formula 1) JPEG0007631998000001.jpg9138

[0032] Similarly, when n types of component (a1) are used, the epoxy group concentration of component (a1) is calculated from (Equation 2).

[0033] (Formula 2) JPEG0007631998000002.jpg10163JPEG0007631998000003.jpg16148

[0034] The component (a2) is not particularly limited, and various known amines can be used. Examples include alkanolamines, aliphatic amines, alicyclic amines, aromatic amines, etc. These may be used alone or in combination of two or more. By using the component (a2), a highly polymerized component (A) is obtained, which imparts rust prevention and water-resistant adhesion when formed into a coating film.

[0035] The alkanolamine is not particularly limited, and examples thereof include primary alkanolamines such as monoethanolamine and monoisopropanolamine, secondary alkanolamines such as diethanolamine, diisopropanolamine, di-2-hydroxybutylamine, N-methylethanolamine, N-ethylethanolamine and N-benzylethanolamine, and tertiary alkanolamines such as triethanolamine and tripropanolamine. These may be used alone or in combination of two or more.

[0036] The aliphatic amine is not particularly limited, and examples thereof include primary aliphatic monoamines such as ethylamine, n-propylamine, n-butylamine, n-hexylamine, n-octylamine, n-laurylamine, n-stearylamine, n-palmitylamine, n-oleylamine, and 2-ethylhexylamine; secondary aliphatic monoamines such as diethylamine, di-n-propylamine, and di-n-butylamine; and aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 2,2,4-trimethylhexanediamine, 2,4,4-trimethylhexanediamine, and isophoronediamine. These may be used alone or in combination of two or more.

[0037] The alicyclic amine is not particularly limited, and examples thereof include cyclopentylamine, cyclohexylamine, norbornylamine, etc. These may be used alone or in combination of two or more kinds.

[0038] The aromatic amine is not particularly limited, and examples thereof include toluidine, xylidine, cumidine (isopropylaniline), hexylaniline, nonylaniline, dodecylaniline, benzylamine, phenethylamine, etc. These may be used alone or in combination of two or more kinds.

[0039] Among these (a2) components, it is preferable to include an alkanolamine, and more preferable to include monoethanolamine, in order to provide a coating film with excellent hardness. When an alkanolamine is used, the amount used is not particularly limited, and is usually 1 to 90% by weight, and preferably 1 to 60% by weight, with the total of the (a2) components being 100% by weight. By setting the amount within this range, the coating film has excellent primary adhesion and water-resistant adhesion.

[0040] The (a3) ​​component is not particularly limited, and various known ones can be used. Examples of the (a3) ​​component include glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate, 1,2-epoxy-4-vinylcyclohexane, etc., which may be used alone or in combination of two or more. Among them, glycidyl acrylate and glycidyl methacrylate are preferred.

[0041] The ratio of the (a1) component, the (a2) component, and the (a3) ​​components used, {(the number of epoxy groups in the (a1) component)+(the number of epoxy groups in the (a3) ​​component)} / (the number of active hydrogens in the amino groups in the (a2) component), is about 100 / 120 to 100 / 80, preferably about 100 / 110 to 100 / 90, and more preferably about 100 / 105 to 100 / 95. By keeping it within this range, the (A) component can be obtained in high yield, and excellent coating film performance can be easily exhibited.

[0042] The number of epoxy groups in component (a1) is the value obtained by dividing the charged weight of component (a1) by the epoxy equivalent of component (a1). When n types of components (a1), namely components (a1-1), (a1-2), ..., (a1-n), are used as component (a1), the number of epoxy groups is calculated from (Equation 3).

[0043] (Formula 3) JPEG0007631998000004.jpg5135

[0044] The number of epoxy groups in the component (a3) ​​can be calculated in the same manner as the calculation of the number of epoxy groups in the component (a1) described above.

[0045] The number of active hydrogen atoms in the amino group of the (a2) component is the weight of the (a2) component divided by the amine equivalent of the (a2) component. When there are multiple (a2) components, the number of active hydrogen atoms is calculated from (Equation 4).

[0046] (Formula 4) JPEG0007631998000005.jpg5134

[0047] Furthermore, polyisocyanate may be used as a constituent of component (A) if necessary.

[0048] The polyisocyanate is not particularly limited, and examples thereof include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, blocked isocyanates, etc. These may be used alone or in combination of two or more kinds.

[0049] The aromatic polyisocyanate is not particularly limited, and examples thereof include xylylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, orthotoluidine diisocyanate, polyphenyl polyisocyanate, etc. These may be used alone or in combination of two or more.

[0050] The aliphatic polyisocyanate is not particularly limited, and examples thereof include butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, etc. These may be used alone or in combination of two or more kinds.

[0051] The alicyclic polyisocyanate is not particularly limited, and examples thereof include cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatemethyl)cyclohexane, methylcyclohexane diisocyanate, isophorone diisocyanate, etc. These may be used alone or in combination of two or more.

[0052] 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 examples thereof include phenol-based blocking agents such as phenol and cresol; oxime-based blocking agents such as methyl ethyl ketone oxime and acetone oxime; lactam-based blocking agents such as ε-caprolactam and γ-butyrolactam; active methylene-based blocking agents such as ethyl acetoacetate, acetylacetone, and ethyl malonate; alcohol-based blocking agents such as methanol and ethanol; and other amine-based blocking agents, imine-based blocking agents, imide-based blocking agents, imidazole-based blocking agents, and mercaptan-based blocking agents. These may be used alone or in combination of two or more.

[0053] The amount of polyisocyanate used is not particularly limited, but the ratio of {the number of isocyanate groups in the polyisocyanate} / {the number of hydroxyl groups in components (a1) to (a3)} is preferably about 0.005 to 2, and more preferably about 0.05 to 0.5.

[0054] The number of isocyanate groups in a polyisocyanate is the value obtained by multiplying the molar amount of the polyisocyanate charged by the number of isocyanate groups per molecule of the polyisocyanate. When a plurality of polyisocyanates are used, the number of isocyanate groups is the sum of the numbers of isocyanate groups in each component.

[0055] The number of hydroxyl groups in component (a1) can be calculated by multiplying the molar amount of component (a1) charged by the number of hydroxyl groups per molecule, including the hydroxyl groups generated when the epoxy groups in component (a1) are ring-opened. When component (a1) contains multiple components, the number of hydroxyl groups in component (a1) is the sum of the numbers of hydroxyl groups in each component. The same applies to the number of hydroxyl groups in component (a3).

[0056] The number of hydroxyl groups in component (a2) can be calculated by multiplying the molar amount of component (a2) charged by the number of hydroxyl groups per molecule of component (a2). When component (a2) contains multiple components, the number of hydroxyl groups in component (a2) is the sum of the numbers of hydroxyl groups in each component.

[0057] The (A) component can be obtained by various known production methods using the (a1), (a2) and (a3) ​​components, and, if necessary, an epoxy resin other than (a1) and a polyisocyanate. The production conditions are not particularly limited, and for example, the reaction temperature is usually about 50 to 250° C., and preferably about 80 to 150° C. The reaction time is also not particularly limited, and depending on the reaction temperature, for example, it is usually about 3 to 12 hours, and preferably 3 to 8 hours.

[0058] In the above-mentioned production method, various known solvents can be used. The solvent is not particularly limited, and examples thereof include 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; ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-butyl ether, and propylene glycol mono t-butyl ether; cellosolves such as methyl cellosolve, ethyl cellosolve, n-butyl cellosolve, and t-butyl cellosolve; and 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 may be used as dilution solvents without any problems. 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.

[0059] The physical properties of the obtained component (A) include an amine value of usually 15 to 90 mgKOH / g, and preferably 40 to 60 mgKOH / g, where the amine value is a value measured in accordance with JIS K-7237.

[0060] [About component (B)] The component (B) is a monomer component containing (meth)acrylamide (b1) (hereinafter referred to as the component (b1)). When the component (b1) is used, the vinyl-modified epoxy resin composition is easily dispersed in water when preparing an aqueous coating agent. In addition, the hardness, water-whitening resistance, and water-resistant adhesion of the coating film are also easily improved.

[0061] Examples of the (b1) component include N-alkyl (meth)acrylamides such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, Nn-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, and N-tert-butyl (meth)acrylamide; N,N-dialkyl acrylamides such as N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, and N,N-diisopropyl (meth)acrylamide; N,N-dialkyl amino alkyl (meth)acrylamides such as N,N-dimethylamino methyl (meth)acrylamide, N,N-dimethylamino ethyl (meth)acrylamide, N,N-dimethylamino propyl (meth)acrylamide, and N,N-dimethylamino isopropyl (meth)acrylamide; (meth)acrylamides having a hydroxyl group such as N-methylol (meth)acrylamide and N-hydroxyethyl (meth)acrylamide; methacrylamide, acrylamide, and diacetone (meth)acrylamide. These may be used alone or in combination of two or more. Among these, N,N-dialkyl(meth)acrylamide, N,N-dialkylaminoalkyl(meth)acrylamide and diacetone(meth)acrylamide are preferred, and N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide and diacetone(meth)acrylamide are more preferred, since the vinyl-modified epoxy resin composition is easily dispersed in water when preparing an aqueous coating agent and a coating film can be obtained in a short time.

[0062] The amount of component (b1) used is preferably about 0.4 to 30 parts by weight, and more preferably about 0.8 to 10 parts by weight, based on the non-volatile weight of component (A), from the viewpoint of good dispersion of the vinyl-modified epoxy resin composition in water when preparing an aqueous coating agent.

[0063] The component (B) may further contain a carboxyl group-containing vinyl monomer and / or its ester (b2) (hereinafter referred to as component (b2)) as a monomer component.

[0064] Among the (b2) components, examples of the carboxyl group-containing vinyl monomer include α,β-unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; α,β-unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, muconic acid and citraconic acid; anhydrides of the above carboxylic acids; and alkali metal salts of the above carboxylic acids such as sodium salts and potassium salts. 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 preferred, and methacrylic acid and acrylic acid are more preferred, from the viewpoint that the vinyl-modified epoxy resin composition disperses well in water when preparing an aqueous coating agent.

[0065] Among the (b2) components, examples of esters of carboxyl group-containing vinyl monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, etc., which may be used alone or in combination of two or more. Among these, methyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and t-butyl (meth)acrylate are preferred from the viewpoint of the excellent water-resistant adhesion of the coating film.

[0066] The amount of component (b2) used is preferably about 1 to 40 parts by weight, and more preferably about 1 to 10 parts by weight, based on 100 parts by weight of component (A), in terms of non-volatile weight, from the viewpoint of good dispersion of the vinyl-modified epoxy resin composition in water when preparing an aqueous coating agent.

[0067] In addition, the ratio of the (b1) component to the (b2) components used is preferably (b1) / (b2)=0.01 to 30, more preferably (b1) / (b2)=0.02 to 10, and even more preferably 0.05 to 2, in terms of non-volatile weight, from the viewpoint of good dispersion of the vinyl-modified epoxy resin composition in water when preparing an aqueous coating agent.

[0068] When the component (b2) is used, a carbodiimide may be used as necessary.

[0069] Examples of carbodiimides include 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, etc. 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.

[0070] The amount of carbodiimide used is preferably about 0.005 to 3, and more preferably about 0.05 to 2, in terms of the ratio of {the number of imide groups in the carbodiimide} / {the number of carboxylic acid groups in the component (b1)}.

[0071] The number of imide groups in a carbodiimide is the molar amount of the carbodiimide charged multiplied by the number of imide groups per molecule of the carbodiimide. When a plurality of carbodiimides are used, the number of imide groups is the sum of the numbers of imide groups in each component.

[0072] The number of carboxylic acid groups in component (b2) is the molar amount of component (b2) multiplied by the number of carboxylic acid groups per molecule of component (b2). When multiple components (b2) are used, the number of carboxylic acid groups is the sum of the numbers of carboxylic acid groups in each component.

[0073] The component (B) may contain a monomer component (b3) (hereinafter referred to as component (b3)) other than the components (b1) and (b2) as necessary. Examples of the component (b3) include sulfonic acids such as styrenesulfonic acid, methallyl sulfonic acid, methallyloxybenzenesulfonic acid, allyloxybenzenesulfonic acid, acrylamido-2-methylpropanesulfonic acid, and acrylamido-t-butylsulfonic acid; sulfo group-containing vinyl monomers such as alkali metal salts (e.g., sodium salts and potassium salts) of these sulfonic acids; Styrenics such as styrene, α-methylstyrene, t-butylstyrene, dimethylstyrene, acetoxystyrene, hydroxystyrene, vinyltoluene, and chlorovinyltoluene; Examples of the vinyl acetate include vinyl acetate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, and (meth)acrylonitrile. These may be used alone or in combination of two or more.

[0074] The amount of component (b3) used is preferably 40 parts by weight or less, and more preferably 20 parts by weight or less, per 100 parts by weight of component (A), from the viewpoint of good dispersion of the vinyl-modified epoxy resin composition in water when preparing an aqueous coating agent.

[0075] The polymerization method of the (A) component and the (B) component is not limited, but a solution polymerization method is preferred. The conditions are not particularly limited, and for example, in the presence of a polymerization initiator, the temperature is about 60 to 150°C, preferably about 70 to 140°C, and the time is about 1 to 8 hours, preferably about 2 to 6 hours. A solvent may also be used in the system.

[0076] The polymerization initiator is not particularly limited, and examples thereof include azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile, and organic peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-butylperoxy-2-ethylhexanoate, dicumyl peroxide, and lauroyl peroxide, which may be used alone or in combination of two or more kinds.

[0077] The amount of the polymerization initiator used is not particularly limited, but is preferably about 1 to 10 parts by weight per 100 parts by weight of the total of the components (A) and (B).

[0078] The solvent is not particularly limited, and examples thereof include those listed in the section on the production method of 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. The polymer obtained by the above production method may contain a solvent, but it is preferable to remove the solvent by distillation under reduced pressure or the like, so that the content is less than 20% by weight.

[0079] The vinyl-modified epoxy resin composition obtained by the above-mentioned production method may be neutralized with an acid or a base.

[0080] Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, etc., and organic acids such as formic acid, acetic acid, citric acid, malic acid, tartrate, aspartic acid, etc. Examples of the base include ammonia, amines such as methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, N,N-dimethylethanolamine, etc., and hydroxides of alkali metals such as potassium hydroxide, sodium hydroxide, etc., which may be used alone or in combination of two or more kinds.

[0081] When used as an aqueous coating agent, the vinyl-modified epoxy resin composition of the present invention is dissolved or dispersed by adding water, and in order to facilitate dissolution or dispersion in water, it is preferable that the resin composition is neutralized with a base (i.e., the vinyl-modified epoxy resin composition is neutralized with a base). The pH after neutralization is preferably about 7 to 10. In addition, as such a base, ammonia and amines are preferable, and ammonia is more preferable, because they are easily volatilized during drying.

[0082] The physical properties of the vinyl-modified epoxy resin composition of the present invention are not particularly limited, but for example, from the viewpoint of excellent hardness of the coating film, the weight average molecular weight (polystyrene equivalent value by gel permeation chromatography) is preferably about 10,000 to 250,000, more preferably about 20,000 to 200,000. The non-volatile content is not particularly limited and may be appropriately determined in consideration of the viscosity, but is usually about 30 to 45% by weight.

[0083] The viscosity at a non-volatile content of 35% by weight and a temperature of 23° C. is usually about 800 to 4000 mPa·s, and preferably about 1000 to 3000 mPa·s.

[0084] The aqueous coating agent of the present invention contains the vinyl-modified epoxy resin composition. The aqueous coating agent of the present invention can be applied to paints, surface treatment agents, etc. for various raw materials such as wood, paper, fiber, plastics, ceramics, iron, and non-ferrous metals.

[0085] In preparing the aqueous coating agent of the present invention, color pigments such as carbon black and titanium oxide; extender pigments such as talc, calcium carbonate, and barium sulfate; rust-preventive pigments such as aluminum phosphomolybdate, zinc phosphate, and zinc oxide; 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, hardeners such as melamine resins, urea resins, isocyanates, blocked isocyanates, and carbodiimides, and additives such as various known solvents, colorants, plasticizers, and rust inhibitors may be blended as necessary. The non-volatile content of the aqueous coating agent is not particularly limited, but is preferably about 5 to 80% by weight, and more preferably about 10 to 60% by weight.

[0086] The physical properties of the aqueous coating agent of the present invention are not particularly limited, and for example, the nonvolatile content is 20 to 60% by weight, and the viscosity at a temperature of 23° C. is usually about 10 to 500 mPa·s, preferably about 50 to 300 mPa·s. EXAMPLES

[0087] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. In each example and comparative example, parts or percentages are by weight.

[0088] Example 1 A reaction apparatus equipped with a stirrer, a cooler, a thermometer, and a nitrogen gas inlet tube was charged with 80 parts of t-butyl cellosolve, 70 parts of YD-014 (manufactured by Nippon Steel Chemical & Material Co., Ltd., trade name: "Epotohto YD-014", epoxy equivalent: 950 g / eq), 130 parts of YD-011 (manufactured by Nippon Steel Chemical & Material Co., Ltd., trade name: "Epotohto YD-011", epoxy equivalent: 475 g / eq), and 1 part of glycidyl methacrylate, and dissolved at 120°C under a nitrogen stream. Then, 2.0 parts of monoethanolamine, 4.0 parts of diethanolamine, 4.0 parts of di-n-butylamine, and 30.0 parts of stearylamine were added and reacted for 7 hours to obtain a modified epoxy resin (A-1). Next, a mixture of 8 parts of acrylic acid, 6 parts of n-butyl acrylate, 3 parts of methyl methacrylate, 4 parts of glycidyl methacrylate, and 15 parts of t-butylperoxy-2-ethylhexanoate was charged into the dropping funnel, dropped into the reaction system over 1 hour, and kept warm for 3 hours. After cooling to 80°C, 5 parts of an aqueous ammonia solution (non-volatile content: 28%) and 370 parts of water were added and mixed in order to obtain a vinyl-modified epoxy resin composition with a non-volatile content of 35%. The physical properties of the composition are shown in Table 1 (same below).

[0089] [Weight average molecular weight of vinyl-modified epoxy resin composition] Equipment: HLC-8220 (Tosoh Corporation) Column: TSKgel α-2500×1, α-3000×1 Separation solvent: DMF (containing LiBr 5mmol / kg), Flow rate: 1ml / min Temperature: 40℃ Standard: Polystyrene

[0090] Examples 2 to 6, Comparative Example 1 Using the compositions shown in Table 1, synthesis was carried out in the same manner as in Example 1 to obtain vinyl-modified epoxy resin compositions.

[0091] (dryness) The coating was applied to a degreased dull steel plate (product name: "SPCC-SD", 0.8 x 70 x 150 mm) (hereinafter referred to as SPCC-SD) using a bar coater so that the film thickness after drying would be 15 to 20 μm, and the coating was dried at room temperature. The time it took for the coating to leave no mark when lightly touched with a finger (touch-drying time) was recorded. The drying property was evaluated according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) ○: Less than 10 minutes △: More than 10 minutes and less than 20 minutes ×: More than 20 minutes

[0092] (Preparation of aqueous coating agent) The mixtures of the compositions shown below were mixed in a paint shaker to prepare water-based coating agents. The obtained water-based coating agents were applied to SPCC-SD with a bar coater so that the film thickness after drying would be 25 to 30 μm, and after forced drying (80°C x 20 minutes), the coating was left for 6 days in an environment with a temperature of 20°C and a humidity of 60% to prepare a coating film. The obtained coating film was used for the following tests.

[0093] (composition) Epoxy resin composition of each Example and Comparative Example: 200 parts Talc 38 parts Carbon black 4 parts Zinc oxide 2.7 parts Zinc phosphate-based anti-rust pigment 8 parts Calcium carbonate 18 parts Ion-exchanged water 5 parts

[0094] (Paint film evaluation test) (1) Dispersibility The particle size of each of the water-based coating agents mixed in the above composition was measured using a grind gauge (manufactured by Taiyu Kizai Co., Ltd.) and evaluated according to the following criteria. The results are shown in Table 1 (same below). (Evaluation Criteria) ○: Less than 20μm △: 20μm or more and less than 50μm ×: 50μm or more (2) Pencil hardness The hardness of the coating was measured in accordance with JIS K5600-5-4.

[0095] (3) Primary adhesion The test was carried out in accordance with JIS K5600-5-6, and the coating film was aged for 6 days in an environment of 23°C and 50% humidity after application, and then peeled off, and the cross-cut adhesion was evaluated as 100. The aqueous coating agent prepared using the vinyl-modified epoxy resin composition of Comparative Example 1 was not evaluated (the same applies below).

[0096] (4) Water-resistant adhesion The test was carried out in accordance with JIS K5600-6-2. The coating film was immersed in warm water at 40° C. for 10 days and then peeled off, and the cross-cut adhesion was evaluated as 100.

[0097] (5) Water-whitening resistance Each aqueous coating agent was applied to SPCC-SD with a bar coater so that the film thickness after drying would be 25 to 30 μm, and the coating was forced to dry for 20 minutes in a circulating air dryer at 100°C, and then left to stand for 6 days in an environment with a temperature of 20°C and a humidity of 60% to prepare a coating film. In accordance with JIS K5600-6-2, the appearance of the coating film was visually observed after immersion in warm water at a temperature of 40°C for 10 days. The evaluation criteria are as follows. (Evaluation Criteria) ○: No whitening △: Partially bleached ×: Completely bleached

[0098] [Table 1]

[0099] [Component (A)] Component (a1) YD-014: Bisphenol A type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., product name: "Epotohto YD-014", epoxy equivalent: 950g / eq) YD-011: Bisphenol A type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., product name: "Epotohto YD-011", epoxy equivalent: 475g / eq) (a2) Component MEA: Monoethanolamine (amine equivalent: 30.5g / eq) DEA: Diethanolamine (amine equivalent: 105.1g / eq) DBA: Di-n-butylamine (amine equivalent: 129.3g / eq) SA: Stearylamine (amine equivalent: 134.8g / eq) (a3) Component GMA: Glycidyl methacrylate (epoxy equivalent: 142.2g / eq) [(B) Component] (b1) Component ·DAAM: Diacetone acrylamide ·DMAA: N,N-Dimethylacrylamide ·DMAPAA: N,N-Dimethylaminopropylacrylamide (b2) Component ·AA: Acrylic acid ·BA: n-Butyl acrylate MMA: Methyl methacrylate [others] NH3: Ammonia solution (non-volatile content: 28%) TEA: Triethylamine

Claims

1. A vinyl-modified epoxy resin composition comprising a polymer having the following (A) and (B) as essential reaction components: (A) A modified epoxy resin which is a reaction product of an epoxy resin (a1) containing a bisphenol-type epoxy resin, an amine (a2) and a glycidyl group-containing vinyl monomer (a3). (B) a monomer component containing at least one (meth)acrylamide (b1) selected from the group consisting of N,N-dialkyl(meth)acrylamide, N,N-dialkylaminoalkyl(meth)acrylamide, and diacetone(meth)acrylamide; The amount of component (b1) used is 0.4 to 30 parts by weight, in terms of non-volatile weight, per 100 parts by weight of component (A).

2. 2. The vinyl-modified epoxy resin composition according to claim 1, wherein the component (a2) comprises an alkanolamine.

3. 3. The vinyl-modified epoxy resin composition according to claim 1, wherein the component (B) further comprises a carboxyl group-containing vinyl monomer and / or an ester thereof (b2).

4. 4. The vinyl-modified epoxy resin composition according to claim 3, wherein the ratio of the components (b1) and (b2) used is (b1) / (b2)=0.01 to 30, in terms of non-volatile weight.

5. An aqueous coating agent comprising the vinyl-modified epoxy resin composition according to any one of claims 1 to 4.

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