JPH09302303A - Aqueous dispersion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous dispersion composition, comprising an ionomer resin, a modified resin and/or a reactional product of both the resins, having good adhesion to a substrate and a coating material and capable of forming a coating film excellent in alkali- and water resistant adhesions, etc. SOLUTION: This aqueous dispersion composition comprises (A) an ionomer resin, (B) a modified epoxy resin and/or (C) a reactional product of both the components A with B at (99/1) to (50/50) weight compositional ratio of the component A/(components B and C). The component A is preferably a polymer, comprising a polymeric main chain composed of a hydrocarbon and having carboxyl groups in the side chain and at least a part of the carboxyl groups are neutralized with a metallic ion. The composition B is preferably a resin prepared by neutralizing, e.g. a chemical reactional product of an aromatic epoxy resin with a monovalent active hydrogen-containing compound and a carboxyl group-containing acrylic resin with a basic compound and self- emulsifying the resultant neutralized product in water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ionomer resin- and modified epoxy resin-based aqueous dispersion composition, and more specifically, as a coating composition for metals, particularly an organic composite-coated steel sheet coating composition, PCM. The present invention relates to a self-emulsifying aqueous dispersion composition which forms a coating film excellent as a steel sheet paint and a can inner surface paint.

[0002]

2. Description of the Related Art Ionomer resins such as partially neutralized products obtained by neutralizing a part of a carboxyl group of an ethylene-methacrylic acid copolymer in a side chain with a metal cation are used as various base materials, especially metal. It is well known that it has good adhesion. Further, since a coating film made of this ionomer resin has excellent water resistance and moisture resistance, it is also known to use this ionomer resin as an anticorrosive agent for metal base materials. Further, it is known that the ionomer resin can be used as an aqueous dispersion because it can be easily dispersed in water. Therefore, the aqueous dispersion containing the ionomer resin is applied to a substrate such as a metal, for example, a steel plate to form a rust preventive layer made of the ionomer resin to manufacture a rust preventive steel plate.

By the way, in recent years, with the diversification and high-grade use of rust-preventing steel sheets, the rust-preventing steel sheets which have been used only by applying the rust-preventive agent to the base material have been used for the purpose of coloring. Further, there has been an increasing demand for forming a coating film made of a curable resin such as paint.

However, the rust preventive layer made of an ionomer resin has poor adhesion to a coating film made of a curable resin such as a paint, and even if a paint or the like is overcoated on the coating film of the ionomer resin, it is satisfactory. A coating film having adhesiveness could not be obtained.

In order to ameliorate this problem, the present inventors firstly prepared an aqueous solution containing an aqueous dispersion of an ionomer resin and an epoxy compound as main components and having a good adhesiveness with a top coating composition. A dispersion composition has been proposed (Japanese Patent Laid-Open No. Hei 5 (1999) -53977)
-286072).

[0006]

The coating film formed from the above aqueous dispersion composition showed good paint adhesion. However, when it is subjected to alkali cleaning, which is often carried out during the treatment of steel sheet, it is difficult to solve the problems. It had a drawback that the adhesiveness with paint was lowered. Therefore, an object of the present invention is to provide an aqueous dispersion composition which has good adhesion to a base material and a coating material, and particularly to form a coating film excellent in alkali resistance adhesion, water resistance adhesion, and moisture resistance adhesion. Especially.

[0007]

To solve the above problems, the present invention provides an ionomer resin (A) and a modified epoxy resin (B), and / or an ionomer resin (A) and a modified epoxy resin (B). The present invention provides an aqueous dispersion composition containing the reaction product (C), and having a weight composition ratio of (A) / {(B) + (C)} = 99/1 to 50/50.

The ionomer resin (A) is composed of a polymer main chain composed of a hydrocarbon and has a carboxyl group in a side chain, and at least a part of the carboxyl group is neutralized with a metal cation, so that Provided is an emulsified aqueous dispersion composition.

In particular, the modified epoxy resin (B) is
It is intended to provide an aqueous dispersion composition obtained by neutralizing any of the following (1) to (4) with a basic compound (J) and self-emulsifying in water. (1) Chemical reaction product (G) of aromatic epoxy resin (D), monovalent active hydrogen group-containing compound (E), and carboxyl group-containing acrylic resin (F) (2) Chemical reaction A mixture (I-1) obtained by adding an aromatic epoxy resin (D) to the product (G) (3) A mixture obtained by adding an aromatic polyol resin (H) to the chemical reaction product (G) (I- 2) (4) A mixture (I-3) in which an aromatic epoxy resin (D) and an aromatic polyol resin (H) are added to the chemical reaction product (G).

An aqueous dispersion composition in which the aromatic epoxy resin (D) has an average of 1.1 to 2.0 epoxy groups in one molecule and a number average molecular weight of 700 or more, preferably 1400 or more. It is to provide things.

The carboxyl group-containing acrylic resin system (F) has a number average molecular weight of 300 to 60,000, at least 25% by weight of carboxylic acid units and 25 to 450.
It is intended to provide an aqueous dispersion composition having an acid value of KOHmg / 1g (converted to 100% of resin).

The aqueous dispersion composition of the present invention will be described in detail below. The aqueous dispersion composition of the present invention comprises an ionomer resin (A) and a modified epoxy resin (B), and / or
Alternatively, it is composed of a reaction product (C) of an ionomer resin (A) and a modified epoxy resin (B). That is, the aqueous dispersion composition of the present invention has any one of A + B, A + B + C, and C configurations.

The ionomer resin which is the component (A) of the aqueous dispersion composition is composed of a polymer main chain mainly composed of hydrocarbons and has a carboxyl group in the side chain, and at least a part of the carboxyl group is present. It is a polymer neutralized with a metal cation. As an example of this ionomer resin (A), a partially neutralized product obtained by neutralizing at least a part of the contained carboxyl group with a metal cation, which is a polymer of an α-olefin and an unsaturated carboxylic acid, is shown. it can.
Examples of the α-olefin include ethylene and propylene, but ethylene can be particularly mentioned. That is,
A preferable example of the ionomer resin (A) is a partially neutralized product of a polymer of ethylene and an unsaturated carboxylic acid, in which at least a part of the contained carboxyl group is neutralized with a metal cation. The ethylene-unsaturated carboxylic acid copolymer constituting the main skeleton of the ionomer resin (A) given as a suitable example may be a random copolymer or a graft copolymer of an unsaturated carboxylic acid onto polyethylene. Good and a random copolymer is preferable in terms of transparency.

Examples of the unsaturated carboxylic acid which is a component of the ethylene-unsaturated carboxylic acid copolymer include unsaturated carboxylic acids having 3 to 8 carbon atoms. Specific examples of the unsaturated carboxylic acid having 3 to 8 carbon atoms include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, isocrotonic acid, citraconic acid, allyl succinic acid,
Mesaconic acid, glutaconic acid, nadic acid (endocis-
2,2,1-hept-2-ene-5,6-dicarboxylic acid), methyl nadic acid, tetrahydrophthalic acid, methyl hexahydrophthalic acid and the like. Among these, acrylic acid and methacrylic acid are preferable, and methacrylic acid is particularly preferable.

The ethylene-unsaturated carboxylic acid copolymer constituting the main skeleton of the ionomer resin (A) is
A third component may be included in addition to ethylene and unsaturated carboxylic acid. Examples of the third component include unsaturated carboxylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate and isobutyl (meth) acrylate, and vinyl esters such as vinyl acetate.

The ethylene content of the ethylene-unsaturated carboxylic acid copolymer is usually 95 to 60% by weight.
And preferably 92 to 75% by weight. If the ethylene content is 95% by weight or less, the porosity is good, and 60
It is preferable for the coating film to be not less than wt% because the corrosion resistance and solvent resistance do not deteriorate. The content of unsaturated carboxylic acid is usually 5 to 40% by weight, and particularly 8 to 2%.
It is preferably in the range of 5% by weight. When the ethylene-unsaturated carboxylic acid copolymer contains the third component, the third component is present in an amount of 40% by weight or less,
It is desirable in terms of solvent resistance.

In the ionomer resin (A) of the present invention, the metal cation neutralizing at least a part of the carboxyl group in the side chain of the ethylene-unsaturated carboxylic acid copolymer is, for example, 1 to 3. Monovalent metal cations are preferable, and monovalent metal cations are preferable from the viewpoint that an ionomer resin having good emulsifying property can be obtained. This one
Among the valent metal cations, sodium and potassium are particularly preferable.

The ratio of the carboxyl groups neutralized with a metal cation to all the carboxyl groups in the side chain of the ethylene-unsaturated carboxylic acid copolymer, that is, the degree of neutralization, is excellent in the adhesion of the coating film, and From the viewpoint of obtaining an aqueous dispersion having good stability, it is usually about 20 to 100%, preferably 30 to 80%.

This ionomer resin (A) is based on ASTM
MFR (190 ° C) according to D 1238 is 0.05
It is preferably about 100 g / 10 min, and particularly,
It is preferably 0.1 to 50 g / 10 min.

The ionomer resin (A) is produced by, for example, copolymerizing ethylene, an unsaturated carboxylic acid and, if necessary, the third component by a high pressure radical polymerization method,
A method of neutralizing the carboxyl group of the obtained ethylene-unsaturated carboxylic acid copolymer with the compound having a metal cation, graft-copolymerizing an unsaturated carboxylic acid with polyethylene, and then subjecting the carboxyl group of the obtained copolymer to It can be carried out according to the method of neutralizing with the compound having the metal cation. In this production, required components may be supplied to an extruder and melt-kneaded to react, or the reaction may be performed in an appropriate solution.

An aqueous dispersion of this ionomer resin (A) can be easily prepared. For example, 1 to water
It can be prepared by a method in which the ionomer resin (A) having a solid content of 60% by weight is mixed, heated and melted at a temperature of 100 to 270 ° C., and dispersed.

The modified epoxy resin which is the component (B) of the aqueous dispersion composition of the present invention is one of the following (1):
To (4) are neutralized with the basic compound (J) and self-emulsified in water. (1) Chemical reaction product (G) of aromatic epoxy resin (D), monovalent active hydrogen group-containing compound (E), and carboxyl group-containing acrylic resin (F) (2) Chemical reaction A mixture (I-1) obtained by adding an aromatic epoxy resin (D) to the product (G) (3) A mixture obtained by adding an aromatic polyol resin (H) to the chemical reaction product (G) (I- 2) (4) A mixture (I-3) in which an aromatic epoxy resin (D) and an aromatic polyol resin (H) are added to the chemical reaction product (G).

The aromatic epoxy resin (D) is not particularly limited as long as it has an aromatic hydrocarbon in the resin skeleton, but is bisphenol A type epoxy resin, bisphenol AD type epoxy resin, bisphenol F type epoxy resin, novolac. Type epoxy resin and the like. Among these, bisphenol A type epoxy resin is preferable. These aromatic epoxy resins (D), which are raw materials of the modified epoxy resin (B), usually have an average of 1.1 to 2.0 epoxy groups in one molecule and a number average molecular weight of 700. Or more, preferably 1400 or more. Phenols, especially bisphenol A, are useful when it is necessary to increase the molecular weight of the aromatic epoxy resin (D). By using an excess amount of bisphenol A with respect to the concentration of the epoxy groups of the raw material epoxy resin, the molecular weight can be increased.

As the monovalent active hydrogen group-containing compound (E) used in the present invention, acrylic acid, methacrylic acid; dehydrated castor oil fatty acid, linseed oil fatty acid and the like having a conjugated double bond; acetic acid, propionic acid, etc. Saturated fatty acids; secondary aliphatic amine alcohols and the like. Among these, acrylic acid and methacrylic acid are preferable.

The carboxyl group-containing acrylic resin (F) used in the present invention comprises (i) a carboxyl group-containing vinyl monomer, (ii) an aromatic vinyl monomer, and (ii)
i-1) At least one monomer selected from the group consisting of alkyl esters of α, β-ethylenically unsaturated carboxylic acids, (iii-2) hydroxyalkyl esters and (iii-3) N-hydroxyalkylamides. And combining these monomers or a mixture thereof in an equivalent ratio in which the final polymer has a carboxyl group, and using an ordinary radical polymerization initiator such as azobisisobutyronitrile or benzoyl peroxide in an organic solvent, 60 ~ 15
It can be obtained by polymerizing or copolymerizing at a temperature of 0 ° C.

Vinyl monomer containing carboxyl group (i)
Examples thereof include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid and the like. Among these, acrylic acid or methacrylic acid is preferable. Examples of the aromatic vinyl monomer (ii) include styrene-based monomers such as styrene, vinyltoluene, 2-methylstyrene, t-butylstyrene and chlorostyrene. Among these, styrene is preferable.

Examples of the alkyl ester of α, β-ethylenically unsaturated carboxylic acid (iii-1) include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate and acrylic acid. Acrylic esters such as n-amyl, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate, dodecyl acrylate, and methyl methacrylate, propyl methacrylate, methacryl Acid n-butyl, isobutyl methacrylate, n-amine methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n methacrylate
-Methacrylic acid esters such as octyl, decyl methacrylate, dodecyl methacrylate and the like can be mentioned. Among these, ethyl acrylate is preferable.

Examples of the hydroxyalkyl ester (iii-2) of α, β-ethylenically unsaturated carboxylic acid include hydroxyalkyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate. Examples thereof include ester monomers. Among these, hydroxyethyl methacrylate is preferable.

N of α, β-ethylenically unsaturated carboxylic acid
Examples of -hydroxyalkylamide (iii-3) include N-substituted (meth) acrylic monomers such as N-methylol (meth) acrylamide and N-butoxymethyl (meth) acrylamide.

In the above carboxyl group-containing acrylic resin (F), the amount of the carboxyl group-containing vinyl monomer is preferably 25 to 75% by weight based on the total amount of the monomers. Within this range, the dispersion stability in an aqueous medium, the solvent resistance of the applied coating film, and the flavor property when used on the inner surface of a can are good. In addition, the viscosity of the copolymer during production is appropriate and production is easy, and particularly when used for an organic composite-coated steel sheet, it has good corrosion resistance such as a salt spray test.

The carboxyl group-containing acrylic resin (F) has a weight average molecular weight of 2,000 to 60,000, preferably 5,000 to 20,000. When the weight average molecular weight is within the above range, the crosslink density of the coating film is appropriate and the processability is good, and gelation is not caused during the reaction with the aromatic epoxy resin (D) and the monovalent active hydrogen group-containing compound (E). It won't wake up. Moreover, the acid value is 25 to 25 in terms of solid content.
450KOHmg / 1g (100% conversion of resin), preferably 20
Those of 0 to 350 KOHmg / 1g are suitable.

In the present invention, the chemical reaction product (G) of the aromatic epoxy resin (D), the monovalent active hydrogen group-containing compound (E) and the carboxyl group-containing acrylic resin (F) is ammonia or In the presence or absence of an amine catalyst, the component (D), the component (E) and the component (F) are equivalent to the active hydrogen group of the component (E) and the epoxy group of the component (D) in an equivalent ratio. 0.2 <(E) / (D) <0.
8; 0.5 <(D) / (F) <5 by solid weight ratio;
Reaction temperature is 70 ° C to 160 ° C, preferably 100 ° C to 1
It can be obtained by reacting in the range of 40 ° C.

As described above, the aromatic polyol resin (H) used in the mixture (I) of the present invention is the component to be mixed with the modified epoxy resin (B) of the present invention (3) and (4). And is obtained by modifying the epoxy group of an aromatic epoxy resin with a sealant. The aromatic epoxy resin as a raw material is not particularly limited as long as it has an aromatic hydrocarbon in the resin skeleton, but bisphenol A
Epoxy resin, bisphenol AD epoxy resin,
Examples include bisphenol F type epoxy resin and novolac type epoxy resin. The aromatic epoxy resin used as the raw material is usually 1.1 to 2.
It has 0 epoxy groups and has a number average molecular weight of 700 or more, preferably 1400 or more.

The sealing agent used is not particularly limited as long as it seals the epoxy group of the aromatic epoxy resin. For example, phenols, carboxylic acids, primary amines, secondary amines, Examples thereof include those having a reactive hydrogen atom such as mercaptans, alcohols and water, and those having no reactive hydrogen atom such as a nucleophilic reagent such as an alkyl halide, a Grignard reagent and an alkyl lithium.

Specific examples of the sealant used include phenols such as bisphenol A, alkyl monophenol, and resorcinol. Carboxylic acids, as monocarboxylic acid compounds, aromatic carboxylic acids such as benzoic acid, palmitic acid, lauric acid, myristic acid, saturated aliphatic carboxylic acids such as stearic acid, castor oil fatty acid, soybean oil fatty acid, tall oil fatty acid, Examples include animal and vegetable oil fatty acids such as flaxseed oil fatty acid and cottonseed oil fatty acid. As a polycarboxylic acid compound, glutaric acid, maleic acid,
Examples thereof include adipic acid, succinic acid, trimellitic acid, pyromellitic acid, glycolic acid and tartaric acid. Also, the first
Examples of primary amines and secondary amines include hydroxylamines such as ethanolamine and diethanolamine as examples of primary amines, and alkylamines such as propylamine, ethylamine, dipropylamine and diethylamine are secondary amines. Take as an example.

When it is necessary to increase the molecular weight of the aromatic epoxy resin modified with the sealing agent in order to obtain the aromatic polyol resin (H) when selecting the sealing agent to be used, the sealing agent is Phenols, especially bisphenol A, are useful as the stopping agent. By using an excess amount of bisphenol A with respect to the concentration of the epoxy group of the aromatic epoxy resin, it is possible to increase the molecular weight and seal the epoxy group of the aromatic epoxy resin. Further, when it is not necessary to increase the molecular weight, a monocarboxylic acid compound and primary and secondary amines as a sealing agent are useful because they have high reactivity with an epoxy group. The sealant used may be not only one type, but may be a combination of two or more types.

The amount of the sealant used is such that the number average molecular weight of the entire modified epoxy resin (B) containing the aromatic polyol resin (H) is 350 to 40,000, preferably 1400 to 2
0000, an average of 0 to 0.4 epoxy groups in one molecule,
It is preferably used in an amount of 0 to 0.2 and primary hydroxyl groups in an average of 0.01 to 4.0, preferably 0.5 to 3.5 in one molecule. It is preferable that the number average molecular weight of the modified epoxy resin (B) containing the aromatic polyol resin (H) is in the above range because the corrosion resistance is good. Further, when the epoxy group is in the above range, destabilization of the aqueous dispersion composition and deterioration of the coating film due to the ring-opening reaction of the epoxy group can be prevented, which is more preferable. Further, when the primary hydroxyl group is in the above range, generation of a microgel body having a network structure due to an excessive esterification reaction can be suppressed, which is more preferable.

In the present invention, the mixtures (I-1) to (I-
The weight ratio in 3) is selected from the following range. Here, the description of post-mixing (D) means that the component (D) as a raw material of the chemical reaction product (G) is not included. (G) + (H) + Post-mixing (D) = 100 0 <(H) + Post-mixing (D) ≦ 80 0 <Post-mixing (D) ≦ 80 Preferably, 1 ≦ (H) + Post-mixing (D ) ≦ 80 1 ≦ Post-mixing (D) ≦ 80 More preferably, 30 ≦ (H) + Post-mixing (D) ≦ 70 20 ≦ Post-mixing (D) ≦ 70 (H) is preferably 0 ≦ (H ) ≦ 50, more preferably 0 ≦ (H) ≦ 40

When the aromatic epoxy resin (D) and / or the aromatic polyol resin (H) is added to and mixed with the chemical reaction product (G), all the resins of the carboxyl group-containing acrylic resin (F) are mixed. The weight percentage is reduced, thus reducing the free carboxyl groups after the curing reaction and increasing the gel fraction. This has the effect of improving the physical properties of the coating film, such as chemical resistance and adhesion.

The excess carboxyl groups in the chemical reaction product (G) and the mixtures (I-1) to (I-3) are
Neutralize with basic compound (J). The modified epoxy resin (B) of the present invention is obtained by neutralizing and self-emulsifying in water. The modified epoxy resin (B) is the ionomer resin (A) of the present invention and / or the reaction product (C) of the ionomer resin (A) and the modified epoxy resin (B).
Together, it constitutes the aqueous dispersion composition of the present invention.

Ammonia or amines can be used as the basic compound (J), and the excess carboxyl groups in the chemical reaction product (G) and the mixtures (I-1) to (I-3) can be used. Neutralize to give ammonium or amine salts. Preferably, ammonia or amines are added in amounts such that the final composition has a pH of 5-11.

The amines used are, for example, ethylamine,
Alkylamines such as butylamine, diethylamine, trimethylamine, triethylamine, butylamine;
2-dimethylaminoethanol, diethanolamine,
Alcohol amines such as triethanolamine, aminomethyl propanol and dimethylaminomethyl propanol; morpholine and the like are used. Also, polyamines such as ethylenediamine and diethylenetriamine can be used. Of these, 2-dimethylaminoethanol is preferable.

The modified epoxy resin (B) of the present invention is used by adding an aqueous medium to disperse and self-emulsifying. Here, the aqueous medium means water alone having at least 10% by weight or more of water, or a mixture of water and a hydrophilic organic solvent, and examples of the hydrophilic organic solvent include methanol, ethanol, isopropanol, n-butanol, and Alkyl alcohols such as sec-butanol, tert-butanol and isobutanol; ether alcohols such as methyl cellosolve, ethyl solve, propyl cellosolve, butyl cellosolve, methyl carbitol, ethyl carbitol, propylene glycol monomethyl ether and propylene glycol monoethyl ether; Ether esters such as methyl cellosolve acetate and ethyl cellosolve acetate; dioxane, dimethylformamide, diacetone alcohol and the like are used. Of these, n-butanol, butyl cellosolve and propylene glycol monomethyl ether are preferable.

In the modified epoxy resin (B) of the present invention, the chemical reaction product (G), the mixture (I-1), (I-2) or (I-3) is neutralized with the basic compound (J). The ratio of the mashed one and the aqueous medium such as water is 5/95 to 70/3.
0, preferably 20/80 to 50/50. The reason why the content is within the range is to improve the stability of the aqueous dispersion. After emulsification, the amount of the aqueous medium used can be reduced, if necessary, by distillation under reduced pressure or the like, or the amount of the aqueous medium can be increased by additional addition. Therefore, the above range limits the final composition ratio. It is not a thing, but a ratio in the manufacturing process.

The aqueous dispersion composition of the present invention comprises the above ionomer resin (A), modified epoxy resin (B), and / or
Alternatively, it is an aqueous dispersion containing the reaction product (C) of the ionomer resin (A) and the modified epoxy resin (B).

As a method of producing the aqueous dispersion composition of the present invention, a method of mixing the aqueous dispersion of the ionomer resin (A) and the aqueous dispersion of the modified epoxy resin (B) at room temperature to 80 ° C. is preferable. The weight composition ratio of the resulting aqueous dispersion composition is; (A) / {(B) + (C)} = 99/1 to 50/5
0 ;; (A) / (B) = 9 when component (C) is not included
9/1 to 50/50; more preferably 90/1
It is preferably in the range of 0 to 60/40. When the proportion of the ionomer resin (A) is more than the above range, the adhesion to the topcoat paint and the alkali resistance of the coating film are deteriorated, while when the proportion of the ionomer resin (A) is less than the above range. , The moisture resistant adhesion of the coating film decreases.

In addition to (A), (B) and (C) described above, the aqueous dispersion composition of the present invention may contain other components such as various resins and compounding agents, if necessary, to defeat the purpose of the present invention. You may contain in the range which does not exist. Other components include, for example, water-soluble melamine resins, hexamethoxymethylmelamine, methylolated benzoguanamine resins, methylolated urea resins, and other water-soluble amino resins for improving the strength of coating films; curing agents such as phenol resins; Organic additives such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, polyethylene oxide, polyacrylamide, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose are used to improve the stability of the aqueous dispersion composition and adjust the viscosity. Adhesives; inorganic thickeners such as silicon dioxide, activated clay, bentonite; surfactants for improving the stability of aqueous dispersion compositions such as nonionic surfactants and anionic surfactants; films obtained Improves rust prevention ability Water-soluble polyvalent metal salts such as because of strontium chromate;
Other rust preventives, fungicides, UV absorbers, heat stabilizers, foaming agents, titanium white, red iron oxide, phthalocyanine, carbon black, pigments such as permanent yellow, calcium carbonate, magnesium carbonate, barium carbonate, talc, hydroxide. Aluminum, calcium sulfate, kaolin,
Examples thereof include fillers such as mica, asbestos, mica and calcium silicate.

The viscosity of the aqueous dispersion composition of the present invention is from 30 to 20 from the viewpoint of coating workability for forming a rust preventive layer.
It is suitable to be about 00 cps, preferably 50 to 1500 cps.

The aqueous dispersion composition of the present invention is applied onto a substrate, dried and cured to form a film. The application of the aqueous dispersion composition can be carried out by a method such as spraying, curtain, flow coater, roll coater, brush coating and dipping. After applying the aqueous dispersion composition, it may be naturally dried, but baking is preferably performed. The baking temperature is 80 to 250 ° C., and the film having good performance is formed by heating for 10 seconds to 30 minutes.

The substrate to be coated is not particularly limited, but suitable examples include untreated steel sheets, zinc-nickel steel sheets, zinc-iron sheets, tin plates, non-chromated steel sheets, and other treated steel sheets.

The paint to be applied is not particularly limited,
Examples thereof include melamine alkyd paint and urethane paint.

[0052]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, "part" and "%" in the text mean "part by weight" and "% by weight", respectively.

<Preparation of coated plate> Ionomer resin (A)
And / or a modified epoxy resin (B) and / or an aqueous dispersion composition containing a reaction product (C) of an ionomer resin (A) and a modified epoxy resin (B) is added to water so that the solid content becomes 10%. Was added and mixed to prepare. Using a No. 5 bar coater, apply this to a 0.8 mm thick coating type chromate-galvanized steel sheet and reach a maximum temperature of 120 ° C.
And baked for 20 seconds to cure. The thickness of the coating film is about 1
It was 2 μm. Further, using a No. 60 bar coater, Amylak (made by Kansai Paint Co., Ltd .: melamine alkyd paint) was applied, and baked at 130 ° C. for 20 minutes to cure. The thickness of the coating film was about 35 to 40 μm.

In the following examples, coating films were evaluated for the following items. <Initial Adhesion> A test piece having a grid pattern was prepared in accordance with the method of the grid pattern test described in JIS K 5400, and an adhesive tape (manufactured by Nichiban Co., Ltd .: trade name Cellotape) was used as the test piece. After sticking on the cross, quickly pull the adhesive tape in the direction of 90 ° to peel it off,
The number of cross-cuts not peeled out of 00 was counted, and the value of (the number of cross-cuts not peeled) / 100 was used as an index for the evaluation of adhesion.

<Water-resistant adhesion> The coated plate is immersed in water at 40 ° C for 20 minutes.
After soaking for 0 hour, the above-mentioned cross-cut test was conducted.

<Alkali Resistance Adhesion> In the production of a coated plate, a test piece was prepared by coating the aqueous dispersion composition and not coating the top coating composition. The test piece was immersed in 2% sodium silicate water having a pH of 10 or more at 60 ° C. for 2 minutes, immediately washed with water for 30 seconds, dried with nitrogen gas, and then subjected to the cross-cut test.

<Moisture-Resistant Adhesion> In the production of a coated plate, a test piece was prepared by coating the aqueous dispersion composition and not coating the top coating composition. The test piece was placed in an atmosphere of 80 ° C. and a humidity of 95% for 48 hours, and then the cross-cut test was performed.

<Rust generation rate> In the production of a coated plate, a test piece was prepared by coating the aqueous dispersion composition and not coating the top coating, and after performing the moisture resistance test, the area where rust was generated was measured. . The results are shown as a ratio (%) of the area where rust is generated to the entire area.

Reference Example 1 Preparation of Aqueous Dispersion of Ionomer Resin (A) Ethylene-methacrylic acid copolymer (MFR (190
℃): 60g / 10min, methacrylic acid content: 20
%) 275 parts, water 725 parts, and sodium hydroxide 13 parts were charged into a 1.5-liter autoclave equipped with two turbine blades, and stirred and heated to 150 ° C. After continuing stirring at 150 ° C. for 2 hours, the temperature was lowered to obtain an aqueous dispersion of the ionomer resin (A). The obtained aqueous dispersion had a solid content concentration of 27% and a viscosity of 200 cps.

Reference Example 2 Preparation of Aqueous Dispersion of Modified Epoxy Resin (B) [1] to [3] [1] Preparation of Acrylic Resin (F) Solution Containing Carboxyl Group Four-necked gas substituted with nitrogen gas A flask was charged with 500 parts of ethylene glycol monobutyl ether, and 150 to 1
Heated to 60 ° C. While maintaining this temperature, styrene 10
4 parts, ethyl acrylate 50 parts, methacrylic acid 313
Parts, 33 parts of 2-hydroxyethyl methacrylate, and 5.5 parts of dicumyl peroxide were mixed to prepare a uniform solution.
The mixture was gradually applied to a four-necked flask over a period of time, and after completion of the application, the mixture was further stirred at 150 to 160 ° C. for 6 hours. afterwards,
Further, 250 parts of ethylene glycol monobutyl ether was added and dissolved, and when cooled to room temperature, an acid value (resin 100% conversion) 307 KOHmg / 1g, solid content 40%
To obtain a carboxyl group-containing acrylic resin (F) solution. Weight average molecular weight is about 8000 and carboxylic acid unit is 5
7%.

[2] Preparation of Aromatic Polyol Resin (H) Solution 1000 parts of bisphenol A type epoxy resin (number average molecular weight of about 3200, epoxy equivalent of about 2700) and xylene of 200 parts were placed in a four-necked flask substituted with nitrogen gas. Was gradually heated to raise the internal temperature to 120 ° C., stirred for 1 hour to completely dissolve it, and then gradually heated to 150 ° C. After reaching 150 ° C, diethanolamine 38.9
The parts were put down for 1 hour and reacted for an additional 6 hours. Then, ethylene glycol monobutyl ether 492.
After 6 parts were added and dissolved, the mixture was cooled to room temperature to obtain an aromatic polyol resin (H) solution having an epoxy equivalent of 30,000 or more and a solid content of 60%. The number average molecular weight was 3,300, and the average number of epoxy groups in one molecule was 0.1 or less.

[3] Preparation of Aqueous Dispersion of Modified Epoxy Resin (B) Bisphenol A having a number average molecular weight of about 3700 and an epoxy equivalent of about 2150 was placed in a four-neck flask purged with nitrogen gas.
Type epoxy resin 300 parts, methacrylic acid 5.7 parts, carboxyl group-containing acrylic resin (F) solution (solid content 40%) 375 parts previously prepared, ethylene glycol monobutyl ether 225 parts were charged and gradually heated. After raising the internal temperature to 120 ° C and stirring for 1 hour to completely dissolve it,
It was cooled slowly to 110 ° C. After reaching 110 ° C., 61.8 parts of dimethylaminoethanol was added. further,
The reaction was carried out at 110 ° C. for 1 hour to obtain a chemical reaction product (G). Acid value (100% conversion of resin) at this time is 92KOHmg /
1 g. Next, a bisphenol A type epoxy resin 35 having a number average molecular weight of about 3700 and an epoxy equivalent of about 2150.
0 parts, 500 parts of the aromatic polyol resin (H) solution (solid content 40%) prepared above, and 600 parts of propylene glycol monomethyl ether were added, and the mixture was stirred at 100 ° C. for 1 hour to completely dissolve it, and then ion The emulsion was emulsified using a disperser while gradually adding 2933 parts of exchanged water. Solid content 2
A 0% milky white dispersion was obtained. Then, the solvents ethylene glycol monobutyl ether and propylene glycol monomethyl ether were distilled off under reduced pressure, and ion-exchanged water was added every time the solid content exceeded 40% until the total amount of the solvent became 10% or less, and the solvent was distilled off under reduced pressure. Prepared. The obtained aqueous dispersion had a solid content of 27%, a viscosity of 25 cps and a solvent content of 9
% Or less.

Example 1 An aqueous dispersion of the ionomer resin (A) prepared in Reference Example 1 and an aqueous dispersion of the modified epoxy resin (B) prepared in Reference Example 2 were mixed at a weight ratio of 70/30. Was mixed and used as a sample. Using this, a coated plate was prepared in the above-mentioned manner, and the adhesion was evaluated. The results are shown in Table 1.

<Comparative Example 1> An aqueous dispersion of the ionomer resin (A) prepared in Reference Example 1 was used as a sample to prepare a coated plate, and the adhesion was evaluated. The results are shown in Table 1.

Comparative Example 2 The water dispersion of the ionomer resin (A) prepared in Reference Example 1 and the water dispersion of the modified epoxy resin (B) prepared in Reference Example 2 were mixed at a weight ratio of 30/70. Then, as a sample, a coated plate was prepared using this, and the adhesion was evaluated. The results are shown in Table 1.

<Comparative Example 3> An aqueous dispersion of the ionomer resin (A) prepared in Reference Example 1 and tetraethylene glycol diglycidyl ether (Nagase Chemicals: EX-82).
The water dispersion of 1) was mixed at a weight ratio of 90/10 to prepare a sample. A coated plate was prepared using this and the adhesion was evaluated. The results are shown in Table 1.

[0067]

[0068]

EFFECTS OF THE INVENTION The aqueous dispersion composition of the present invention forms a coating film having excellent adhesion to a substrate and a coating material, in particular, alkali resistance adhesion, water resistance adhesion, and moisture resistance adhesion.

Claims (5)

[Claims] 1. An ionomer resin (A) and a modified epoxy resin (B), and / or a reaction product (C) of an ionomer resin (A) and a modified epoxy resin (B), the weight composition ratio of which is: A) / {(B) + (C)} = 99/1 to 50/50 The aqueous dispersion composition. 2. The ionomer resin (A) comprises a polymer main chain composed of a hydrocarbon, has a carboxyl group in a side chain, and at least a part of the carboxyl group is neutralized with a metal cation, The aqueous dispersion composition according to claim 1, which is emulsified in water. 3. The modified epoxy resin (B) is characterized in that any of the following (1) to (4) is neutralized with a basic compound (J) and self-emulsified in water. The aqueous dispersion composition according to claim 1. (1) Chemical reaction product (G) of aromatic epoxy resin (D), monovalent active hydrogen group-containing compound (E), and carboxyl group-containing acrylic resin (F) (2) Chemical reaction A mixture (I-1) obtained by adding an aromatic epoxy resin (D) to the product (G) (3) A mixture obtained by adding an aromatic polyol resin (H) to the chemical reaction product (G) (I- 2) (4) A mixture (I-3) in which an aromatic epoxy resin (D) and an aromatic polyol resin (H) are added to the chemical reaction product (G). 4. The aromatic epoxy resin (D) has an average of 1.1 to 2.0 epoxy groups in one molecule and a number average molecular weight of 700 or more, preferably 1400 or more. The aqueous dispersion composition according to any one of 1 to 3. 5. The carboxyl group-containing acrylic resin (F) comprises a number average molecular weight of 300 to 60,000, at least 25% by weight of carboxylic acid units, and 25 to 45.
The aqueous dispersion composition according to any one of claims 1 to 3, which has an acid value of 0 KOHmg / 1g (converted to 100% of resin).