JP2003034713A - Aqueous epoxy resin dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous epoxy resin dispersion excellent in one-pack storage stability, and a heat curable aqueous coating composition excellent in anticorrosive property, curability, impact resistance and adhesive property using the aqueous epoxy resin dispersion and a curing agent. SOLUTION: The aqueous epoxy resin dispersion which is a modified epoxy resin (E) dispersed in water and obtained by reacting a polyalkylene glycol modified epoxy resin (A), an epoxy group-containing resin (B) except for (A), a hydrazine derivative (C) having an active hydrogen and optionally an active hydrogen-containing compound (D) except for (C), wherein the polyalkylene glycol modified epoxy resin (A) is obtained by reacting a polyalkylene glycol (a) having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin (b), an active hydrogen-containing compound (c) and a compound having two or more active isocyanate groups in one molecule, and the heat curable aqueous coating composition comprising the aqueous epoxy resin dispersion and a curing agent are provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous epoxy resin dispersion which is excellent in one-component storage stability, and which uses the aqueous epoxy resin dispersion and a curing agent for corrosion resistance, curability and impact resistance. The present invention relates to a thermosetting aqueous coating composition having excellent adhesion and the like.

[0002]

2. Description of the Related Art In recent years, polymer aqueous dispersions of thermoplastic resins obtained by emulsion polymerization of acrylic, acryl-styrene, vinyl acetate, ethylene-vinyl acetate, etc. have been used for coatings, adhesives, It has come to be widely used in industrial applications such as an admixture for cement. But,
A film formed from these conventional polymer aqueous dispersions has insufficient adhesion to metals, wood, hardened cement, plastics and the like, and also has insufficient water resistance and heat resistance, and therefore, for example, in a wet state or high temperature. It often had peeling and blistering. In order to improve such defects of the polymer aqueous dispersion of the thermoplastic resin, it has been attempted to introduce a functional group into the polymer skeleton to form a crosslinked structure, but it is still not sufficient. Therefore, the use of an aqueous dispersion of a thermosetting resin, for example, an epoxy resin, in the above applications is being promoted.

JP-A-54-56700 describes a method of using a reaction product of a polyepoxide compound and a polyalkylene polyether polyol and a reaction product of a polyamine as a curing agent. In this case, the reaction product of the polyepoxide and the polyalkylene polyether polyol, which is to be reacted with the polyamine, has a large molecular weight, resulting in a slow curing of the epoxy resin composition.

JP-A-56-34767 describes a method in which a reaction product of a diepoxide and a polyamine is neutralized with an acidic substance to make it water-soluble, and this is used as a curing agent. In this case, the acidic substance remains in the cured product as described above, and the cured product becomes inferior in water resistance.

Japanese Unexamined Patent Publication (Kokai) No. 4-335020 describes a method of using a reaction product of a polyalkylene polyether polyol and diisocyanate with a polyamine as a curing agent. Also in this case, the reaction product of the polyalkylene polyether polyol and the diisocyanate has a large molecular weight, so that the curability as an epoxy resin composition becomes poor.

When the above-mentioned known curing agent is mixed with an aqueous dispersion of epoxy resin, the reaction between the active hydrogen of amine in the curing agent and the epoxy group in the epoxy resin dispersion gradually progresses in the mixture. However, there is a problem that the pot life is shortened because the viscosity of the mixed liquid increases or the fusibility of the coating film is insufficient.

[0007]

Means for Solving the Problems As a result of intensive studies to eliminate the drawbacks of the prior art, the present inventors have found that a polyalkylene glycol-modified epoxy resin, and an epoxy group-containing resin other than the modified epoxy resin, By using an aqueous epoxy resin dispersion obtained by dispersing a modified epoxy resin (E) obtained by reacting with a hydrazine derivative having active hydrogen in water, the above-mentioned drawbacks of the prior art can be solved.
It was found that the purpose was achieved. The present invention has been completed based on this new finding.

That is, the present invention has a number average molecular weight of 400 to
Obtained by reacting 20,000 polyalkylene glycol (a), bisphenol type epoxy resin (b), active hydrogen-containing compound (c) and compound (d) having two or more active isocyanate groups in one molecule. Polyalkylene glycol modified epoxy resin (A), epoxy group-containing resin (B) other than (A), hydrazine derivative (C) having active hydrogen, and, if necessary, active hydrogen-containing compound other than (C) The present invention provides an aqueous epoxy resin dispersion liquid obtained by dispersing a modified epoxy resin (E) obtained by reacting with (D) in water, and a thermosetting aqueous coating using the aqueous epoxy resin dispersion liquid. A composition is provided.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below.

The aqueous epoxy resin dispersion of the present invention comprises a polyalkylene glycol-modified epoxy resin (A),
Epoxy group-containing resin (B) other than (A), hydrazine derivative (C) having active hydrogen, and (C) if necessary
A modified epoxy resin (E) obtained by reacting with an active hydrogen-containing compound (D) other than the above is dispersed in water.

Polyalkylene glycol modified epoxy resin
Fat (A) The polyalkylene glycol-modified epoxy resin which is the component (A) of the present invention is a polyalkylene glycol (a), a bisphenol type epoxy resin (b), an active hydrogen-containing compound (c) and two or more in one molecule. It is obtained by reacting the compound (d) having an active isocyanate group.

Examples of the polyalkylene glycol (a) include polyethylene glycol, polypropylene glycol, polybutylene glycol, etc. Among them, polyethylene glycol is preferably used. The number average molecular weight of the polyalkylene glycol (a) is 400 to 20,000, preferably 500 to 10, from the viewpoint of the water dispersibility of the modified epoxy resin (D) to be obtained and the storability.
A range of 000 is suitable.

The bisphenol type epoxy resin (b)
Is a bisphenol-based compound having at least two epoxy groups in one molecule, and in particular, a diglycidyl ether of bisphenol obtained by a condensation reaction of a bisphenol-based compound and epihalohydrin, for example, epichlorohydrin is flexible and anticorrosive. It is suitable because it is easy to obtain a coating film excellent in

Representative examples of bisphenol compounds that can be used for preparing the epoxy resin (b) include bis (4-hydroxyphenyl) -2,2-propane and bis (4-hydroxyphenyl) -1,1-ethane. , Bis (4-hydroxyphenyl) -methane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-3-) t-butylphenyl) -2,2-propane and the like. Among the epoxy resins (b) formed using such a bisphenol-based compound, the bisphenol A type epoxy resin is particularly preferable in that a coating film excellent in flexibility and corrosion resistance can be obtained.

The epoxy resin (b) is generally in the range of about 310 to about 10,000, and particularly about 320 to about 2,000 from the viewpoint of production stability during production of the polyalkylene glycol-modified epoxy resin. It preferably has a number average molecular weight and has an epoxy equivalent of about 155 to 155.
It is preferably in the range of about 5,000, especially about 160 to about 1,000.

The active hydrogen-containing compound (c) used in the present invention is used for blocking the isocyanate group in the polyalkylene glycol-modified epoxy resin (A). Typical examples thereof include monohydric alcohols such as methanol, ethanol and diethylene glycol monobutyl ether; monovalent carboxylic acids such as acetic acid and propionic acid; monovalent thiols such as ethyl mercaptan, and other blocking agents. Are secondary amines such as diethylamine; primary amino groups of amine compounds containing one secondary amino group or hydroxyl group and one or more primary amino groups such as diethylenetriamine and monoethanolamine. , Compounds modified with aldimine, ketimine, oxazoline or imidazoline by heating with a ketone, aldehyde or carboxylic acid at a temperature of 100 to 230 ° C; oximes such as methylethylketoxime; phenols such as phenol and nonylphenol And the like. These compounds are generally 30 to 2,000, especially 3
It is desirable to have a molecular weight in the range of 0-200.

The above-mentioned compound (d) having two or more active isocyanate groups in one molecule is a compound having two or more, preferably two or three, isocyanate groups in one molecule. Those commonly used in manufacturing can be used as well. Examples of such a polyisocyanate compound (d) include aliphatic, alicyclic, and aromatic polyisocyanate compounds, and the following can be typically exemplified.

Hexamethylene diisocyanate (HMD
I), biuret compounds of HMDI, aliphatic polyisocyanate compounds such as isocyanurate compounds of HMDI; isophorone diisocyanate (IPDI), IP
Alicyclic polyisocyanate compounds such as biuret compounds of DI, isocyanurate compounds of IPDI, hydrogenated xylylene diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate; aromatic polyisocyanates such as tolylene diisocyanate and xylylene diisocyanate Compound.

Generally, it is appropriate that the mixing ratio of each component at the time of producing the polyalkylene glycol-modified epoxy resin (A) is within the following range.

Equivalent ratio of the hydroxyl group of (a) to the isocyanate group of (d): 1 / 1.2-1 to 1/10, preferably 1 /
1.5 to 1/5, more preferably 1 / 1.5 to 1/3,
Equivalent ratio of the hydroxyl group of (c) to the isocyanate group of (d): 1/2 to 1/100, preferably 1/3 to 1/5
0, more preferably 1/3 to 1/20, (a), (b)
And an equivalent ratio of the total amount of hydroxyl groups of (c) to the isocyanate group of (d): 1 / 1.5 or less, preferably 1 / 0.1
.About.1 / 1.5, more preferably 1 / 1.1-1 / 1.
1.

Epoxy group-containing resin (B) The epoxy group-containing resin which is the component (B) of the present invention is a resin other than the above-mentioned polyalkylene glycol-modified epoxy resin (A), which contains at least one epoxy group in the molecule. And, for example, an epoxy resin, a modified epoxy resin, an acrylic copolymer resin obtained by copolymerizing an epoxy group-containing monomer and another monomer, a polybutadiene resin having an epoxy group, a polyurethane resin having an epoxy group, and these The resin adducts or condensates may be used alone or in combination of two or more.

The above-mentioned epoxy resin is obtained by reacting polyphenols such as bisphenol A, bisphenol F and novolac type phenol with epihalohydrin such as epichlorohydrin to introduce a glycidyl group, or by further adding a glycidyl group-introduced reaction product to the reaction product. Aromatic epoxy resins obtained by reacting polyphenols to increase the molecular weight; further, aliphatic epoxy resins, alicyclic epoxy resins and the like can be mentioned. These can be used alone or in combination of two or more. You can It is preferable that these epoxy resins have a number average molecular weight of 1,500 or more, especially when it is necessary to form clothes at a low temperature.

Examples of the modified epoxy resin include resins obtained by reacting various modifying agents with the epoxy groups or hydroxyl groups in the above epoxy resin. For example, an epoxy ester resin reacted with a drying oil fatty acid; an epoxy acrylate resin modified with a polymerizable unsaturated monomer component containing acrylic acid or methacrylic acid; a urethane modified epoxy resin reacted with an isocyanate compound, etc. it can.

As the acrylic copolymer resin, an unsaturated monomer having an epoxy group and a polymerizable unsaturated monomer component essentially containing acrylic acid ester or methacrylic acid ester are solution polymerization method, emulsion polymerization method or suspension weight method. Examples of the resin synthesized by legal method,
Examples of the polymerizable unsaturated monomer component include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-, iso- or tert-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth)
Acrylic acid such as acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, or an alkyl ester of methacrylic acid having 1 to 24 carbon atoms; acrylic acid,
Methacrylic acid, styrene, vinyltoluene, acrylamide, acrylonitrile, N-methylol (meth) acrylamide, C1-C4 alkyl etherification product of N-methylol (meth) acrylamide, N, N-diethylaminoethyl methacrylate, etc. can be mentioned. . As the unsaturated monomer having an epoxy group, glycidyl methacrylate, glycidyl acrylate, 3,
There is no particular limitation as long as it has an epoxy group and a polymerizable unsaturated group such as 4-epoxycyclohexyl-1-methyl (meth) acrylate.

Further, the acrylic copolymer resin may be a resin modified with a polyester resin, an epoxy resin, a phenol resin or the like.

Particularly preferable as the epoxy group-containing resin (B) is a bisphenol A type epoxy resin which is a reaction product of bisphenol A and epiparohydrin, and the method for producing the resin is a matter well known in the art.

The compounding ratio of the polyalkylene glycol-modified epoxy resin (A) and the epoxy group-containing resin (B) is (A) / (B) = 90/5 to 60 / as a non-volatile content weight ratio.
40, preferably (A) / (B) = 80/20 to 65 /
The range of 35 is suitable from the viewpoint of good water dispersibility and corrosion resistance of the obtained film.

Hydrazine Derivative Having Active Hydrogen (C) The hydrazine derivative having active hydrogen, which is the component (C) of the present invention, has excellent corrosion resistance of the film obtained by using the aqueous epoxy resin dispersion of the present invention. Although essential for the expression, a part of it can be replaced with an active hydrogen-containing compound (D) other than the hydrazine derivative.

Specific examples of the hydrazine derivative having active hydrogen include carbohydrazide, propionic acid hydrazide, salicylic acid hydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, thiocarbohydrazide, 4,4. Hydrazide compounds such as ′ -oxybisbenzenesulfonyl hydrazide, benzophenone hydrazone and aminopolyacrylamide; pyrazole compounds such as pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone and 3-amino-5-methylpyrazole; 1 , 2,4-triazole, 3-amino-1,2,
4-triazole, 4-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 5
-Amino-3-mercapto-1,2,4-triazole, 2,3-dihydro-3-oxo-1,2,4-triazole, 1H-benzotriazole, 1-hydroxybenzotriazole (monohydrate), 6-methyl-8-hydroxytriazolopyridazine, 6-phenyl-8-hydroxytriazolopyridazine, 5-hydroxy-7-
Triazole compounds such as methyl-1,3,8-triazaindolizine; 5-phenyl-1,2,3,4-tetrazole, 5
-Terazole compounds such as mercapto-1-phenyl-1,2,3,4-tetrazole; 5-amino-2-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole And other thiadiazole compounds; maleic hydrazide, 6-methyl-3-pyridazone, 4,5-dichloro-3-pyridazone, 4,5-dibromo-3-pyridazone, 6-methyl-4,5-dihydro-3-pyridazone And other pyridazine compounds.

Among these, 5-membered ring or 6-membered ring
Pyrazole compounds and triazole compounds having a membered ring cyclic structure and having a nitrogen atom in the cyclic structure are particularly preferable from the viewpoint of corrosion resistance and the like. These hydrazine derivatives can be used alone or in combination of two or more.

Examples of the active hydrogen-containing compound (D) other than the hydrazine derivative include primary or secondary amine compounds having active hydrogen; ammonia; organic acids such as carboxylic acids; hydrogen halides such as hydrogen chloride. Examples thereof include alcohols, thiols, hydrazine derivatives having no active hydrogen, or quaternary chlorinating agents which are a mixture of a tertiary amine and an acid, and one or more of these can be used.

In particular, when an amine compound is used, acetic acid,
It is possible to improve water dispersibility by neutralization with phosphoric acid or the like, or with an organic acid such as dicarboxylic acid or carboxylic acid anhydride, by neutralization with a tertiary amine or the like.

Typical examples of the amine compound having activated hydrogen include the following. (1) A primary amino group of an amine compound containing one secondary amino group such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, and methylaminopropylamine, and one or more primary amino groups, a ketone, Aldehydes or carboxylic acids and eg 1
A compound modified by heating to a temperature of about 00 to 230 ° C. to give an aldimine, ketimine, oxazoline, or imidazoline; (2) diethylamine, diethanolamine, di-n-
Or a second such as -ios-propanolamine, N-methylethanolamine, N-ethylethanolamine
Secondary monoamine compound; (3) secondary amine-containing compound obtained by adding monoalkanolamine such as monoethanolamine and dialkyl (meth) acrylamide by Michael addition reaction; (4) monoethanolamine, neopentanolamine , 2-aminopropanol, 3-aminopropanol, 2-hydroxy-2 '(aminopropoxy) ethyl ether, and other compounds obtained by modifying the primary amine group of alkanolamine with ketimine.

The quaternary chlorinating agent is a mixture of a hydrazine derivative having no active hydrogen or a tertiary amine with an acid, and the hydrazine derivative having no active hydrogen or the tertiary amine is an epoxy group by itself. Since it has no reactivity with, it is a mixture with an acid so that it can react with an epoxy group. The quaternary chlorinating agent reacts with the epoxy group in the presence of water, if necessary, to form a quaternary salt with the epoxy group-containing resin. The acid used to obtain the quaternary chlorinating agent may be any of organic acids such as acetic acid and lactic acid, and inorganic acids such as hydrochloric acid. Examples of the hydrazine derivative having no active hydrogen used for obtaining the quaternary chlorinating agent include, for example, 3,6-dichloropyridazine,
Examples of the tertiary amine include dimethylethanolamine, triethylamine, trimethylamine, triisopropylamine, methyldiethanolamine and the like.

Modified epoxy resin (E) Polyalkylene glycol modified epoxy resin (A) for obtaining modified epoxy resin (E), epoxy group-containing resin (B), hydrazine derivative (C) having active hydrogen, and active hydrogen content The reaction with the compound (D) is usually 10 to 300.
C., preferably 50 to 150.degree. C. for about 1 to 8 hours.

This reaction may be carried out by adding an organic solvent, and the type of organic solvent used is not particularly limited. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, dibutyl ketone, cyclohexanone; ethanol, butanol, 2-ethylhexyl alcohol, benzyl alcohol, ethylene glycol, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether. , Alcohols and ethers containing hydroxyl groups such as propylene glycol, propylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether; esters such as ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate; toluene, xylene Such as aromatic hydrocarbons It can be used one or two or more thereof. Of these, ketone-based or ether-based solvents are particularly preferable from the viewpoints of solubility with epoxy resin, film-forming property, and the like. The polyalkylene glycol-modified epoxy resin (A) and the epoxy group-containing resin (B) and the hydrazine derivative (C) having active hydrogen are mixed in the polyalkylene glycol-modified epoxy resin (A) and the epoxy group-containing resin (B). The equivalent ratio of the active hydrogen group in the hydrazine derivative (C) to the epoxy group is 0.01 to 10, preferably 0.1 to 8, and more preferably 0.2 to 4 for corrosion resistance and water. It is suitable in terms of dispersibility.

Although a part of the hydrazine derivative (C) can be replaced with the active hydrogen-containing compound (D),
The amount to be replaced is 90 mol% or less, preferably 70
From the viewpoint of corrosion resistance and adhesiveness, it is suitable to be in the range of mol% or less, more preferably 10 to 60 mol%.

The aqueous epoxy resin dispersion according to the present invention can be used as a raw material for an undercoat, a filler, a sealing material, a protective coating, a coating material, a sealing material, a mortar and a coating material. Next, a thermosetting aqueous coating composition using the aqueous epoxy resin dispersion will be described.

Thermosetting Aqueous Coating Composition The aqueous epoxy resin dispersion of the present invention can be applied and dried as it is to form a film having good adhesion to metal, wood, etc., but a more dense barrier film is formed. In order to achieve this, the curing agent (F) is added to the aqueous epoxy resin dispersion liquid
It is desirable that the organic film is heat-cured by blending.
As the curing agent (F), a polyisocyanate compound,
Examples thereof include amino resin compounds.

The polyisocyanate compound is a compound having at least two isocyanate groups in one molecule, and is an aliphatic isocyanate compound, an alicyclic isocyanate compound (including a heterocycle), an aromatic isocyanate compound; these isocyanates. Examples thereof include compounds obtained by partially reacting a compound with a polyhydric alcohol, and some or all of the isocyanate groups in these polyisocyanate compounds may be blocked with a blocking agent.

Examples of the polyisocyanate compound include the followings. m- or p-phenylene diisocyanate, 2,
4- or 2,6-tolylene diisocyanate, o- or p-xylylene diisocyanate, hexamethylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate The above compounds alone or a mixture thereof and a polyhydric alcohol (ethylene glycol, propylene glycol, etc. Dihydric alcohols; trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric alcohols such as pentaerythritol; hexahydric alcohols such as sorbitol and dipentaerythritol), and the reaction product of at least one molecule. A compound in which two isocyanates remain. These polyisocyanate compounds may be used alone or in combination of two or more.

Examples of the blocking agent include aliphatic monoalcohols such as methanol, ethanol, propanol, butanol and octyl alcohol; monoethers of ethylene glycol and / or diethylene glycol such as methyl, ethyl and propyl (n -, Iso), butyl (n-, iso, sec) and other monoethers; phenol, cresol and other aromatic alcohols; acetoxime, methyl ethyl ketone oxime and other oximes, and the like can be used.
By reacting one or more species with the polyisocyanate compound, a polyisocyanate compound that is stably protected at least at room temperature can be obtained.

Examples of the amino resin include a methylolated amino resin obtained by the reaction of an aldehyde with an amino component such as melamine, urea, benzoguanamine, acetoguanamine, steroganamin, spiroguanamine, and dicyandiamide. Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Further, it is also possible to use those obtained by etherifying this methylolated amino resin with a suitable alcohol, and examples of the alcohol used for the etherification include methyl alcohol, ethyl alcohol,
n-propyl alcohol, i-propyl alcohol, n
-Butyl alcohol, i-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like can be mentioned. As the amino resin, a methylolated melamine resin in which at least a part of a methylol group is alkyl etherified is preferable.

The compounding amount of the curing agent (F) with respect to the modified epoxy resin (E) is (E) /
(F) = 95/5 to 55/45, preferably (E) /
It is suitable to mix (F) = 90/10 to 65/35 from the viewpoints of adhesion of the film to the material and suitability for topcoating.

In addition, it is desirable to use known cure promoting catalysts to increase low temperature crosslinkability. Examples of the curing acceleration catalyst when a polyisocyanate compound is used as the curing agent include N-ethylmorpholine, dibutyltin dilaurate, cobalt naphthenate, stannous chloride,
Zinc naphthenate, bismuth nitrate, etc. can be used. When an amino resin is used as the curing agent, for example, phosphoric acid, a sulfonic acid compound, or an amine neutralized product of a sulfonic acid compound is preferably used as the curing acceleration catalyst. Typical examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and the like. The amine in the amine-neutralized product of the sulfonic acid compound may be a primary amine, a secondary amine, or a tertiary amine.

Further, resins such as acrylic, alkyd, and polyester may be mixed and used for the purpose of slightly improving physical properties such as adhesion.

In the thermosetting aqueous coating composition of the present invention, in addition to the above-mentioned resins, if necessary, a coloring pigment, an anticorrosive pigment, an extender pigment, a curing catalyst, an interface, which are usually used in the field of paints, may be added. An activator and other additives can also be added.

The above aqueous coating composition can be applied to the substrate by a suitable method such as brush coating, roller coating, spray coating, spatula coating, press coating, doctor blade coating, electrodeposition coating or dip coating.

The effects of the present invention are as follows:
A thermosetting aqueous coating composition that is excellent in liquid storage stability and that uses the aqueous epoxy resin dispersion and a curing agent is excellent in corrosion resistance, curability, impact resistance, adhesion and the like. .

[0049]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In the following, "part" and "%"
All are based on weight.

Polyalkylene glycol modified epoxy resin
Manufacture of fat Manufacturing example 1 1688 g of polyethylene glycol having a number average molecular weight of 4,000 and 539 g of methyl ethyl ketone were added to a glass 4-necked flask equipped with a thermometer, a stirrer, and a cooling tube.
After stirring and mixing at 0 ° C. for uniform transparency, 171 g of tolylene diisocyanate was added and reacted for 2 hours, then 1121 g of Epicoat 834X90 (epoxy resin, manufactured by Shell Japan Co., Ltd., epoxy equivalent 250), diethylene glycol triethyl 66 g of ether and 1.1 g of a 1% dibutyltin dilaurate solution were added, and the reaction was continued for 2 hours. After that, the temperature was raised to 80 ° C. and the reaction was carried out for 3 hours, and it was confirmed that the isocyanate value was 0.6 or less. After that, the temperature was raised to 90 ° C., and methyl ethyl ketone was removed by vacuum distillation until the solid content concentration became 81.7%. After the removal, 659 g of propylene glycol monomethyl ether and 270 g of deionized water were added and diluted to obtain a polyethylene glycol-modified epoxy resin solution A1 having a solid content concentration of 76%.

Production Example 2 In Production Example 1, the number average molecular weight was 1 instead of 1688 g of polyethylene glycol having a number average molecular weight of 4,000.
The reaction was performed in the same manner as in Production Example 1 except that 4,220 g of 10,000 polyethylene glycol was used to obtain a polyethylene glycol-modified epoxy resin solution A2 having a solid content concentration of 76%.

Preparation of Aqueous Epoxy Resin Dispersion Example 1 EP0100 (produced by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 1,000) (2,029 g) and propylene glycol monobutyl ether (697 g) were charged in a four-necked flask,
The temperature was raised to 10 ° C. and the epoxy resin was completely dissolved in 1 hour. Polyethylene glycol modified epoxy resin solution A1, 1,180 g, 3-amino-1,2,
4-triazole (molecular weight 84) 311.7 g was added,
The reaction was carried out at 100 ° C for 5 hours. After the reaction, 719.6 g of propylene glycol monobutyl ether was added to obtain a modified resin. Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion B1 having a solid content concentration of 40%.

The resulting aqueous epoxy resin dispersion B2 was added to 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Example 2 In Example 1, 130 g of 3-amino-1,2,4-triazole was added to diethanolamine (molecular weight: 10
A modified resin was obtained by performing the reaction in the same manner as in Example 1 except that the modified resin was replaced by 5). Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion B2 having a solid content concentration of 40%.

The resulting aqueous epoxy resin dispersion B2 was added to 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Example 3 In Example 1, 197 g of 3-amino-1,2,4-triazole was replaced with diethanolamine (molecular weight: 10).
A modified resin was obtained by performing the reaction in the same manner as in Example 1 except that the modified resin was replaced by 5). Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion B3 having a solid content concentration of 40%.

The resulting aqueous epoxy resin dispersion B2 was added to 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Example 4 In Example 1, the polyethylene glycol-modified epoxy resin solution A1 / EP1004 (produced by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 1,000) was used in a solid content ratio of 85/1.
A modified resin was obtained by carrying out the reaction in the same manner as in Example 1 except that the modified resin was used. Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion B4 having a solid content concentration of 40%.

The resulting aqueous epoxy resin dispersion B2 was added to 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Example 5 In Example 1, the polyethylene glycol-modified epoxy resin solution A1 / EP1004 (produced by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 1,000) was used as a solid content ratio of 60/4.
A modified resin was obtained by performing the reaction in the same manner as in Example 1 except that the modified resin was used instead of 0. Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion B5 having a solid content concentration of 40%.

The resulting aqueous epoxy resin dispersion B2 was mixed with 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Example 6 A modified resin was obtained in the same manner as in Example 1 except that the polyethylene glycol modified epoxy resin solution A2 was used in place of the polyethylene glycol modified epoxy resin solution A1. Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion B6 having a solid content concentration of 40%.

The resulting aqueous epoxy resin dispersion B2 was added to 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Production Example of Aqueous Epoxy Resin Dispersion for Comparative Example Production Example 3 In Example 1, 311.7 g of 3-amino-1,2,4-triazole was added to diethanolamine (molecular weight: 105).
A modified resin was obtained by carrying out the reaction in the same manner as in Example 1 except that the amount was replaced with 333 g. Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion C1 having a solid content concentration of 40%.

The resulting aqueous epoxy resin dispersion C1 was mixed with 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Production Example 4 Polyethylene glycol-modified epoxy resin solution A1 / EP1004 (produced by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 1,000) in Example 1 was used in a solid content ratio of 60/4.
A modified resin was obtained by performing the reaction in the same manner as in Example 1 except that the modified resin was used instead of 0. Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion C2 having a solid content concentration of 40%.

The obtained aqueous epoxy resin dispersion C2 was mixed with 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Production Example 5 Polyethylene glycol-modified epoxy resin solution A1 / EP1004 (produced by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 1,000) in Example 1 was used in a solid content ratio of 98/2.
A modified resin was obtained by carrying out the reaction in the same manner as in Example 1 except that the modified resin was used. Water was mixed with the modified resin to obtain an aqueous epoxy resin dispersion C3 having a solid content concentration of 40%.

The obtained aqueous epoxy resin dispersion C3 was mixed with 4
After being stored in a thermostatic chamber at 0 ° C. for 1 month, there was almost no change in appearance and viscosity of the dispersion, which was good.

Production of Thermosetting Aqueous Coating Composition Examples 7 to 12 and Comparative Examples 4 to 6 The above Examples 1 to 6 and Comparative Example 1 with the composition shown in Table 1.
Each of the thermosetting aqueous coating compositions was obtained by mixing the aqueous epoxy resin dispersion liquid obtained in any one of 3 to 3 with a curing agent.

Preparation of Test Coated Plate The surface of an untreated cold-rolled steel plate having a plate thickness of 0.5 mm was subjected to alkali degreasing treatment, washed with water and dried, and then each thermosetting aqueous coating composition of Examples and Comparative Examples was dried to a film thickness of 2 μm. Was applied with a bar coater so that the maximum plate temperature reached 180 ° C. and dried for 15 seconds.

Coating Film Performance Test Each of the prepared test pieces was evaluated using the following test methods, and the results shown in Table 1 were obtained.

Test method Appearance of coating film: The appearance of the treated film was visually evaluated, and a rating was given according to the following criteria. ◯: Uniform Δ: Partial unevenness X: Entire surface unevenness

Adhesion: JIS K5400 8.5.2.
Judgment was made by the cross-cut tape method (clearance interval 1 mm) described in 1 above, and scores were given according to the following criteria. 5: No peeling 4: Peeling area of less than 5% 3: Peeling area of 5% or more and less than 20% 2: Peeling area of 20% or more and less than 50% 1: Peeling area of 50% or more.

Corrosion resistance: The test was carried out according to the JIS Z2371 salt spray test method. The test time was 24, 48 and 72 hours, and the evaluation was made according to the following criteria. 5: No red rust or blisters on the coated surface 4: Red rust or blisters occurrence rate is less than 10% 3: Red rust or blisters occurrence rate is 10% or more and less than 30% 2: Red rust or blisters occurrence rate Is 30% or more and less than 50% 1: occurrence rate of red rust or blisters is 50% or more.

[0076]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 161/20 C09D 161/20 163/00 163/00 175/04 175/04 F term (reference) 4J002 CC13Y CC16Y CC18Y CC19Y CD20W CD20X DE026 ER007 FD14Y FD147 4J036 AD08 AD15 AD21 AF06 AK03 AK08 CA02 CA06 CB04 CB05 CB10 DB12 DB02 DB02 DB02 DB02 DB02 DB02 DB02 DB02 DB202 DB202 DB02 DB202 DB02 DB202 DB02 DB202 DB02 DB02 DB202 DB02 DB202 DB02 DB202 DB202 MA08 MA10 MA14 NA03 NA11 NA12 NA24

Claims (6)

[Claims] 1. A polyalkylene glycol (a) having a number average molecular weight of 400 to 20,000, a bisphenol type epoxy resin (b), an active hydrogen-containing compound (c) and two or more active isocyanate groups in one molecule. A polyalkylene glycol-modified epoxy resin (A) obtained by reacting the compound (d) with, an epoxy group-containing resin (B) other than (A), a hydrazine derivative (C) having active hydrogen, and, if necessary, (A), an aqueous epoxy resin dispersion obtained by dispersing a modified epoxy resin (E) obtained by reacting with an active hydrogen-containing compound (D) other than (C) in water. 2. The epoxy group-containing resin (B) is 1,500.
The aqueous epoxy resin dispersion liquid according to claim 1, which has a number average molecular weight of 10,000 or more and 10,000 or less and an epoxy equivalent of 150 or more and 5,000 or less. 3. An active hydrogen-containing compound (D) other than (C)
Is a secondary amine or a dibasic acid, and a part or all of the amino groups or acid groups in the obtained modified epoxy resin (E) is neutralized with a neutralizing agent and dispersed in water. Claim 3
The aqueous epoxy resin dispersion described in 1. 4. The aqueous epoxy resin dispersion liquid according to claim 1, wherein the polyalkylene glycol is polyethylene glycol. 5. A thermosetting aqueous coating composition comprising the aqueous epoxy resin dispersion according to any one of claims 1 to 4 and a curing agent. 6. The thermosetting aqueous coating composition according to claim 5, wherein the curing agent is an optionally blocked polyisocyanate compound and / or an amino resin.