JPH03182519A - Resin composition and water-based coating material for can interior using same - Google Patents

Abstract

PURPOSE:To obtain a resin composition useful as a water-based coating material for coating interiors of food cans by using a resin prepared by graft- polymerizing a specified advance epoxy resin with an addition-polymerizable monomer. CONSTITUTION:A resin obtained by graft-polymerizing an advance epoxy resin (A) [of a mol.wt. of 1500-29000, desirably 2500-9000 and an epoxy value >=0.006, desirably of 0.01-0.06; obtained by reacting 2,2-bis[p-(3-butoxy-2- glycidyloxypropyloxy)-phenyl]propane of the formula with optionally another polyglycidyl compound and a polyhydric phenol] with an addition-polymerizable monomer (B) containing 5-100wt.%, particularly 30-70wt.% monoethylenically unsaturated carboxylic acid) is used as a vinyl resin-modified epoxy resin composition useful for a water-based coating material for interiors of food cans. The amounts of components A and B used are desirably 10-95wt.%, particularly 50-90wt.% component A and 90-5wt.%, particularly 50-10wt.% component B.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel vinyl resin-modified epoxy resin composition and an epoxy resin emulsion obtained by seed polymerization in an emulsion of the epoxy resin composition. All of these are useful as water-based paints for coating the inner surfaces of edible cans for beverages, meat, vegetables, fruits, etc., and are especially low-temperature curing, as well as hygienic.
It produces a coating film with excellent properties such as reversibility, adhesion, processability, corrosion resistance, and chemical resistance, and also has excellent can production efficiency.

Conventional technology and its problems Conventionally, paints for the inside of cans that use organic solvents as solvents or dispersion media are not only unfavorable from the standpoint of environmental hygiene and fire safety, but also reduce the molecular weight of the base resin to maintain the appropriate viscosity of the paint. In order to solve these problems, there was a problem that the flavor of the food packed inside the container deteriorated.
Water-based paints for the inside of cans that contain no or almost no organic solvent are also being developed. The main water-based paints that have been developed so far include (i) self-emulsifying emulsion paints obtained by esterifying a carboxyl group-containing resin and an epoxy resin in the presence of a tertiary amine (Japanese Patent Application Laid-open No. 55-3481) ; (ii) Self-emulsifying emulsion paint obtained by graft polymerizing a vinyl heptamer containing a polymerizable unsaturated acid hetamine to an epoxy resin using a peroxide as a catalyst (JP-A-53 (in) a reaction product of an epoxy resin and (meth)acrylic acid, and an aromatic vinyl monomer a, β-
Self-emulsifying emulsion paint obtained by reacting (polymerizing) an alkyl ester of an ethylenically unsaturated carboxylic acid with a hexamer mixture consisting of acrylic acid or methacrylic acid (JP-A-58-198513, JP-A-Sho 60- 1
06805), etc.

However, the epoxy resins in the emulsion paints (i) to (ii) above are all bisphenol A type, and when used for the inside of cans to prevent flavor deterioration, the viscosity becomes significantly higher when the molecular weight is increased. It has defects. In other words, if the viscosity is high, it is difficult to carry out the above-mentioned aqueous reaction uniformly, and if a large amount of organic solvent is added to prevent this, the operations of water dispersion and subsequent removal of the organic solvent become complicated. When the resulting aqueous composition is applied to the inner surface of a can, the curing properties of the coating film are insufficient, resulting in problems such as easy deterioration of food hygiene, flavor, corrosion resistance, and adhesion.

Means for Solving the Problems The present inventors conducted extensive research to eliminate the above defects, and as a result, instead of bisphenol A type epoxy resin,
Epoxy resins obtained using specific glycidyl ether compounds do not have a significant increase in viscosity even if they have a high molecular weight, and therefore can be easily subjected to aqueous reactions and water dispersion. It was discovered that all of the above-mentioned coating film defects could be eliminated, and the present invention was developed.

That is, according to one embodiment of the present invention, 2゜2-bis(p-(3-butoxy-2-glycidyloxyprobyloxy)phenyl)propane (1), optionally other than the component (1) The polyglycidyl compound (2) obtained by reacting the polyhydric phenol (3) has a molecular weight of 1500 to 29000 and an epoxy value of 0.006.
A vinyl resin-modified epoxy resin composition obtained by graft polymerizing the above-mentioned advanced epoxy resin (A-1) and an addition-polymerizable 7-mer (B) containing a monoethylenically unsaturated carboxylic acid (4). (X) is provided.

According to another aspect of the present invention, a radically reactive advanced epoxy resin (A-1) obtained by reacting the above-mentioned advanced epoxy resin (A-1) with the above-mentioned monoethylenically unsaturated carboxylic acid (4) A vinyl resin-modified epoxy resin composition (Y) obtained by copolymerizing -2) with the above-mentioned addition-polymerizable heptamer (B) is provided.

According to yet another aspect of the present invention, an epoxy resin obtained by seed polymerizing an ethylenically unsaturated monomer (C) in an emulsion system of the vinyl resin-modified epoxy resin (X) and/or (Y). An emulsion (Z) is provided.

According to yet another aspect of the present invention, there is provided a water-based paint for the inner surface of a can containing the vinyl resin-modified epoxy resin composition (X) or (Y) or the epoxy resin emulsion (z) as a main component.

One of the characteristics of the composition of the present invention is that 2,2-bis[
p-(3-butoxy-2-glycidyloxypropyloxy)phenyl]propane (1) is used, and its structural formula is as follows.

? 4HI The above component (1) has a lower viscosity than bisphenol A type diglycidyl ether and vinylphenol F type diglycidyl ether. The reason is that the component (1
) contains two highly flexible butoxy groups in its skeleton, and the distance between the benzene ring and oxirane ring, which occupy a large steric space, is wide, which is thought to increase the degree of freedom of the skeleton. . In addition, A-F and (Sueboxy resin) made using the component (1) can also be used as conventional bisphenol A (
Another advantage is that the viscosity is significantly lower than that of type F) epoxy resins, and the increase in viscosity is small even when the molecular weight increases. In addition to the above-mentioned reasons, this is also considered to be because the symmetry of the main chain skeleton of the resin decreases and the crystallization tendency decreases.

Therefore, such advanced epoxy resin (A-1)
When used, the reaction with the addition-polymerizable monomer (B) and the unsaturated carboxylic acid (4) can be easily carried out, and the resin compositions (X) and (Y) can be easily reacted without using a large amount of organic solvent. is obtained. Furthermore, since seed polymerization of the resin compositions (X) and/or (Y) in the emulsion system can be carried out uniformly without a significant increase in viscosity, the load on the stirring device etc. is also small. Furthermore, since large amounts of organic solvents are not used in these reaction steps, the step of recovering the solvent can also be omitted.

Furthermore, the water-based paint and epoxy emulsion (Z) containing the resin compositions (X) and (Y) as main components obtained in this way are particularly suitable as water-based paints for the inside of cans. Compared to Type F, it has better hardenability, food hygiene, flavor, processability, corrosion resistance, and adhesion.

The present invention will be explained in more detail below.

Advanced epoxy resin (A-1): Advanced epoxy resin (A-1) used in the present invention
) is 2,2-bis[p-(3-butoxy-2-glycidyloxypropyloxy)phenyl]propane (1)
It is an epoxy resin obtained by addition polymerization reaction of a polyglycidyl compound (2) other than the above component (1) and a polyhydric phenol (3) according to an advanced method, if necessary, and the resin has a molecular weight of 1500 to 29,000, preferably 2,500 to 9,000, and the epoxy value is 0.0
0.06 or more, preferably within the range of 0.01-0.06.

The polyglycidyl compounds other than component (1) of component (2) above are compounds having two or more glycidyl molecules per molecule, and are not essential for component (A-1).
) It is effective for increasing the molecular weight of Jffi and promoting the reaction with component (B) and component (4), and is particularly effective for polyglycidyl obtained using a compound having two or more phenolic hydroxyl groups in one molecule. Compounds are preferred. Specifically, examples of polyglycidyl compounds having two glycidyl groups in one molecule include glycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and 2.2-
diglycidyl ether of bis(4'-hydroxyphenyl)butane, diglycidyl ether of bisphenol S, diglycidyl ether of resorcinol, diglycidyl ether of hexahydrobisphenol A, diglycidyl ether of polyzolopyrene glycol, diglycidyl ether of neopentyl glycol glycidyl ether, heptalic acid diglycidyl ester, timer acid diglycidyl ester, diglycidyl ether of tetrabromobisphenol A,
Examples of polyglycidyl compounds having three or more glycidyl ether groups in one molecule include bisphenol hexafluoroacetone glycidyl ether, etc.
Examples include triglycidyl isocyanurate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl metaquinimendiamine, talesol novolak polyglycidyl ether, phenol novolak polyglycidyl ether, and epoxidized polybutadiene.

(3) ri! , minute polyhydric phenols are compounds having two or more phenolic hydroxyl groups in one molecule, such as bisphenol A1 bisphenol F12.2-bis(4'-hydroxyphenyl)butane, bisphenol S1 resorcinol, tetrabrome Bisphenol A
Examples include 1-bisphenol hexafluoroacetone, cresol novolak, resol novolaf, and the like.

The addition polymerization reaction using the above components (1) to (3) is (1)
For 1 mole of total epoxy groups of gt and component (2),
(3) Blend the components so that the total phenolic hydroxyl groups are 0-5 to 1.5 moles, preferably 0.8 to 1.2 moles, and heat in the presence of a catalyst at a temperature of about 0°C to about 200°C. The final reaction product (A-1) is preferably carried out at a temperature of
) The addition polymerization reaction is continued until the molecular weight of the component falls within the range of 1,500 to 29,000. Furthermore, when using component (2), 90% by weight based on the total amount with component (1) a.
Hereinafter, it is particularly preferable to use it in an amount of 70% by weight or less.

In this addition polymerization reaction, when the molar ratio of epoxy group/phenolic hydroxyl group approaches 1.0, a high molecular weight component (A-1) having approximately equal moles of both groups is obtained, and 1.0
The larger the size, the more epoxy groups (A-1)
The 5E content increases, making it difficult to increase the molecular weight.1. When it is smaller than O, it has a phenolic hydroxyl group (A-1
) The number of components increases, making it difficult to increase the molecular weight.

If the molecular weight of component (A-1) is less than 1,500, the resulting composition will form a coating film with poor corrosion resistance and processability, whereas if the molecular weight is greater than 29,000, the resulting composition will form a coating film with extremely strong internal stress. This is not preferable as it tends to form. In addition, if the epoxy value of component (A-1) is less than 0.006, there will be a large amount of unreacted components that do not chemically react with component (B) during the next reaction with component (B), etc., which is preferable. do not have.

Examples of catalysts that can be used in the addition polymerization reaction include sodium hydroxide, potassium hydroxide, lithium hydroxide,
Barium hydroxide, calcium hydroxide, sodium carbonate,
Alkali metal or alkaline earth metal salts such as calcium carbonate; amines such as n-butylamine, tri-n-butylamine, triethanolamine, pyridine, or quaternary ammonium salts such as tetraethylammonium bromide; l-methyl Imidazole, 2-methylimidazole, 2-ethyl-4-methyl-imidazole, 1.2
Examples include imidazole-based compounds such as -dimethyl-imidazole; phosphonium compounds, and the like. The amount of catalyst used varies depending on the type of catalyst, type of (1) to (3) J*, combination, etc., but generally (1) to (3) J
It is preferably 10% by weight or less based on the total solid content of ffi.

In addition, in this addition polymerization reaction, the product [A-tfR
If necessary, the reaction may be carried out in an organic solvent in order to increase the reactivity of the reaction mixture, prevent thickening and gelation during the reaction, and conduct the reaction uniformly. Organic solvents that can be used include:
(1) to (3) g of the catalyst and reaction products are preferably dissolved; specifically, aromatic hydrocarbons such as toluene and xylene; hydroxyl groups such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether are preferred Ethers not containing; esters such as ethyl acetate and butyl acetate; and ketones such as acetone and methyl ethyl ketone.

Furthermore, the following formula (i) ~ (V) HO-R, -... (i) HO-CmHzm O-R*" (u) HO-C+o
H1m-0-CmH, a+-0-R1...(ii)H
O(CmH, mo-)-H+ * * (iv) n HO(CmHx mOV R+ ... (iv) In each of the above formulas, %R1 represents an alkyl group having 1 to 12 carbon atoms, and R2 is a carbon atom Alcohol-based solvents, cellosolve-based solvents, calpitol-based solvents, which represent several 1 to 6 alkyl groups, and m and n are each integers of 1 to 6;
It is also possible to use solvents with hydroxyl groups such as ether solvents, but these solvents alone may inhibit the increase in molecular weight of component (A-1), so these solvents should not be used in combination with the above-mentioned organic solvents. It is desirable to do so.

Vinyl resin-modified epoxy resin assembly (X) Two vinyl resin-modified epoxy resin assembly (X) of the present invention is the above (AI
) component and an addition polymerizable monomer (B) containing a monoethylenically unsaturated carboxylic acid (4) are graft-polymerized.

Specifically, it can be carried out, for example, by graft polymerizing component (B) in an organic solvent solution or dispersion of component (A-1) in the presence of a free radical generator. It is presumed that this grafting occurs when the free radical withdraws the proton on the (A-1)t, fragmentation skeleton, and can be efficiently achieved by increasing the concentration of the radical initiator, the concentration of the reaction components, and the reaction temperature. Although the reaction progresses, unreacted components (A-1) and (B) component polymers are thought to coexist.

The addition polymerizable monomer (B) contains a monoethylenically unsaturated carboxylic acid (4), and its composition ratio is 5 to 100% by weight of the component (4) in the component (B), especially 3% by weight.
It is preferable that the content is 0 to 70% by weight, with the remainder being at least one other polymerizable monomer.

The (4) g portion of monoethylenically unsaturated carboxylic acid is 1
A compound that has one or more carboxyl groups and one or more polymerizable unsaturated bonds in its molecule, such as acrylic acid,
Methacrylic acid, crotonic acid, itaconic acid, maleic acid,
7 malic acid, etc., and these can be used alone or in combination of two or more.

In addition, in the (B) ffi component, other polymerizable monomers that can be used together with the (4) rR component include the following ■
Examples of ~@ are listed.

■ Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, i-butyl acrylate, i-butyl methacrylate, tart-butyl acrylate, tart-butyl methacrylate,
The number of carbon atoms of acrylic acid or methacrylic acid such as cyclohexyl acrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, decyl acrylate, etc. is 1 or more 24 alkyl or cycloalkyl esters: @acrylamide, methacrylamide, N-methylacrylamide, N-
Ethyl methacrylamide, diacetone acrylamide,
N-methylol acrylamide, N-methylol methacrylamide, N-methoxymethyl acrylamide, N-
Functional acrylic or methacrylamide such as butoxymethylacrylamide; ■ Styrene, vinyltoluene, vinyl propionate,
a-methylstyrene, vinyl acetate, acrylonitrile,
Vinyl monomers such as methacrylonitrile, vinyl propionate, vinyl bivalate, beoba monomer (Shell Chemicals); @ acrylics such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, etc. Hydroxyalkyl esters having 1 to 8 carbon atoms of acid or methacrylic acid; etc.

The ratio of the (A-1) Tit content and the CB) component to be used is not particularly limited, but generally, based on the total solid content of both components, the (A-1) component is 10 to 95% by weight, particularly 50 to 95% by weight. 90
% by weight, and CB) g content from 90 to 5% by weight, especially 50
It is preferably within the range of 10 to 10% by weight.

The above graft polymerization reaction can usually be carried out in an organic solvent in the presence of a free radical generator, and the organic solvents used include (A-1) 5It, (B) lff1
It is preferable to use solvents that can dissolve the component, its polymer, and component (X), such as solvents represented by the above formulas (i) to (v), and aromatic hydrocarbons such as toluene and xylene;
Esters such as ethyl acetate and butyl acetate; ketones such as acetone and methyl ethyl ketone; Examples of free radical generators include benzoyl peroxide, barbutyl ophtate, t-butyl hydroperoxide, azobisisobutyronitrile, azobisvaleronitrile, 2.2' azobis(2
-aminopropane) hydrochloride, etc. can be used, and the amount used varies depending on the type of monomer, solvent, catalyst, combination thereof, reaction temperature, reaction concentration, grafting efficiency, etc., but generally 100 parts by weight of component (B) It is preferably used in a proportion of 0.5 to 5 parts by weight.

The vinyl resin-modified epoxy resin composition (X) of the present invention is
It is preferable that the acid value is in the range of 10 to 200, particularly 15 to 80.

Although the composition (X) can be used as a paint as it is, it is preferable to remove the organic solvent if necessary, neutralize it, and then dissolve or disperse it in water to make it water-based and use it for coating the inside of a can.

Vinyl resin-modified epoxy resin composition (Y) Second, the vinyl resin-modified epoxy resin composition (Y) is a radically reactive advanced epoxy resin obtained by reacting 1 g of (4) with component (A-1). In addition to (A-2), the above (
It can be obtained by copolymerizing component B).

(A-2) #: Min is (A-1) component noepoxy group (
4) A polymerizable unsaturated bond is introduced by reacting the carboxyl groups of the components. Therefore, component (A-1) preferably has an average of 0.2 or more, particularly 0.5 or more, epoxy groups per molecule. The reaction between the two components is such that the epoxy group in component (A-1)/carboxyl group in component (4) is usually 110.1 to 115.0. Preferably, the ratio is within the range of 110.5 to 1/2.0, and an esterification catalyst (e.g., n-butylamine,
The reaction can be carried out by controlling the epoxy value of the reactants and controlling the reaction to the desired reaction point in the presence of tetraethylammonium bromide, dibutyl oxide, etc., usually at a temperature of 50 to 200°C. (A-2) A suitable number of polymerizable unsaturated bonds to be introduced into the atom is an average of 0.2 to 1.5 per molecule.

The above reaction of the same components can be carried out without a solvent or in an organic solvent, and the solvent that can be used is the reactant (A-
1) component, (4) component, reaction catalyst and product (
An organic solvent that dissolves or disperses component A-2) is preferred, and specific examples thereof include organic solvents selected from those exemplified for the synthetic leather component (X).

Composition (Y) is obtained by radical copolymerizing component (B) Ii with component (A-2).

The composition ratio of component (A-2) and component (B) is based on the total solid weight of the same components, with component (A-2) ranging from 10 to 9
0%, preferably 50-90%, and 10-90%,
Preferably it is within the range of 10 to 50%.

Specifically, it is preferable to copolymerize the (A-2) Jffi component and the (B) component in the presence of an organic solvent and a free radical generator. (B) As the ffi component, organic solvent, and 7-aryl radical generator, those mentioned above can be used.

The vinyl resin-modified epoxy resin (Y) of the present invention has an acid value of 1O to 200. In particular, it is preferable to adjust the value within the range of 15 to 80.

Component (Y) can be used even if it is dissolved or dispersed in an organic solvent, but particularly preferably, it can be used after being dissolved or dispersed in water after being neutralized by a conventional method if necessary.

The above <X> a and (Y) components can be dissolved or dispersed in water as they are if they have a high acid value, but they can be water-dispersed by neutralizing the carboxyl groups in the components with a basic compound. or water solubilization can be easily carried out. The aqueous dispersion or aqueous dispersion prepared in this manner may be hereinafter collectively referred to as "emulsion J" or "aqueous dispersion."

As the basic compound as a neutralizing agent, those known per se can be used, and preferred specific examples include those of the general formula RsR
aRsN [wherein R1 and R1 are 1 in the alkyl moiety]
or a substituted or unsubstituted monovalent alkyl group containing 2 carbon atoms, and R, is 1 to 4 (substituted containing El carbon atoms).

or unsubstituted m alkyl],
At least one selected from the group consisting of N-methylpyrrolidine, N-methylmorpholine, pyridine, N-methylvirol, N-methylpiperidine, and mixtures thereof.
Seeds can be given. Examples of compounds of the above formulas R, R, RsN include trimethylamine, dimethylethanolamine (dimethylaminoethanol), methyljethanolamine, methylethanolamine, dimethylethylamine,
dimethylpropylamine, dimethyl-3-hydroxy-
Examples include 1-propylamine, dimethylbenzylamine, dimethyl-2-hydroxy-1-propylamine, diethylmethylamine, dimethyl-1-hydroxy-2-propylamine, and mixtures thereof. Most preferably trimethylamine or dimethylethanolamine is used.

Neutralization is usually preferably carried out at a neutralization equivalent of 0.1 to 2.0.

When neutralized in this way, (X) Jffi and (Y)
The components are self-emulsifying and dissolve or disperse in water, so it is not necessarily necessary to use emulsifiers or dispersants.

The particle size of the component (X) and component (Y) in these aqueous dispersions is preferably 1 μm or less.

In addition, (X) component and (Y)! i1. This method also has the advantage that the viscosity of the system does not increase significantly during the phase transformation from W2O type to O/W type, so that no excessive load is placed on manufacturing equipment.

In aqueous conversion of component (X) and component (Y), generally the higher the acid value and neutralization equivalent of the surrounding components, the easier it is to obtain a water-soluble product or an emulsion having a small particle size.

Epoxy resin emulsion (Z): Furthermore, the epoxy resin emulsion (Z) in the present invention
) is obtained by seed polymerizing the ethylenically unsaturated monomer (C) in an emulsion (aqueous dispersion) containing 51 tons of the component (X) and/or (Y).

Seed polymerization can be carried out by polymerizing monomer CC) inside or near the particles of component (X) and/or component (Y) in the aqueous dispersion.

The aqueous dispersion of component (X) and component (Y) can be obtained by appropriately selecting the molecular weight, acid value, degree of neutralization, composition, etc. of the components, and the size of the dispersed particles in water is 1 μm. The following are suitable. When the ethylenically unsaturated monomer (C) is mixed into this aqueous dispersion, the monomer (C) concentrates in and near the dispersed particles. This tendency increases as the monomer (C) becomes more lipophilic. When heated there, the monomer (C
) polymerization (seed polymerization) is performed.

Ethylenically unsaturated monomer (C) capable of seed polymerization
As such, one or more types of heptamers mentioned for the addition-polymerizable heptamers (B) are used, and among these, hydrophobic heptamers are preferred. This seed polymerization is suitably carried out in the presence of a free radical generator as described above.

The polymerization conditions such as temperature and time for seed polymerization vary depending on the type of monomer used, the type of initiator, etc., but usually the reaction temperature is within the range of about 30 to about 100°C, and the polymerization time is about 30°C.
The time can be approximately 0 minutes to 10 hours.

Nanatsuma (C) is generally (X) and/or (Y)
1 to 300 parts by weight per 100 parts by weight of solid content for g,
It is preferably within the range of 10 to 150 parts by weight.

The epoxy resin emulsion (Z) obtained by such seed polymerization is effective in reducing costs because the proportions of components (A-1) and (A-2) used can be reduced.

Vinyl resin-modified epoxy resin (X) in the present invention, (
Y) and the epoxy resin emulsion (Z) obtained using these, the secondary hydroxyl group in the skeleton of the advanced epoxy resin (A-1) and the monoethylenically unsaturated acid ( Although it is possible to form a cured coating film by reaction with carboxyl groups based on 4), urea resin,
By mixing a curing agent such as a melamine resin or a phenol resin (these also include methylol compounds and alkyl ether compounds), it becomes possible to form a coating film with improved curability, corrosion resistance, etc.

Furthermore, the vinyl resin modified epoxy resin (X), (Y
) and epoxy resin emulsion (Z) include polyester resin, polybutadiene and its modified resin, vinyl chloride-vinyl acetate copolymer, maleic anhydride-styrene copolymer, maleic anhydride-vinyl methyl ether copolymer, ethylene - It is also possible to mix an acrylic acid copolymer, an ethylene-methacrylic acid copolymer, etc. as appropriate.

Vinyl resin-modified epoxy resin (X) and (Y
) are preferably used after being dissolved or dispersed in an organic solvent and/or water, and furthermore, these and the epoxy resin emulsion (Z) are preferably used as a paint. Among these, it is most preferable to use an aqueous compound using water as a solvent or dispersion medium as the composition for coating the inner surface of a food can. The material for cans is aluminum plate, steel plate, or plated steel plate whose surface is plated with zinc, chromium, tin, aluminum, etc., or the surface of steel plate is chemically treated with chromic acid, iron phosphate, or zinc phosphate. Treated steel plates etc. can be used. The inner surface of the can can be coated by, for example, roll coating, spray coating, brush coating, spraying, dipping, or the like. The coating film thickness is usually suitably within the range of 5 to 30 microns based on the cured coating film. The baking of the coating is generally carried out at a temperature of about 150 to about 220°C, preferably about 1
It can be carried out at 80 to about 200°C for about 30 to about 600 seconds, preferably about 60 to about 300 seconds.

The above vinyl resin modified epoxy resin composition (X) of the present invention
, (Y) and the epoxy resin emulsion (Z) are all based on the component (A-1) containing the above (1) Based on this, the ms product (X), component (A-2), and composition (Y) can be produced (stirred) with little increase in viscosity during production (reaction).
The load on the equipment is reduced, and the amount of organic solvent used in the aqueous compound can be reduced, making it possible to reduce costs and improve production efficiency. Furthermore, the vinyl resin-modified epoxy resin compositions (X), (Y) and epoxy resin emulsion (z) of the present invention have excellent compatibility with the curing agent, and the viscosity increases during heat curing of the coating film. Because the coating is gentle, it is possible to form a uniform and efficient coating film with high crosslinking density, resulting in improved flavor properties, corrosion resistance, hygiene, chemical resistance, boiling water resistance, processability, and adhesion. .

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. All parts and percentages in Examples and Comparative Examples are based on weight unless otherwise specified.

■, Production example 1, advanced epoxy resin [(A-1)ffi portion]
Distribution: Place the first component shown below into a reaction container and heat under a nitrogen stream.
The reaction was carried out at 60°C. The reaction was performed with an epoxy value (solid content of 10
molar equivalent of epoxy group per 0g) and solution viscosity (25℃
Gardner-Holdt viscosity of butylcarpitol solution). The reaction took about 6 hours.

Table 1 In Table 1, (*1): 2,2-bis(p-(3-butoxy-2-
The amount of glycidyloxyglobioxy)phenyl)propane, the epoxy equivalent is 315, and the nonvolatile content is 10.
It is 0%.

(Car 2): (2-1) is diglycidyl ether of bisphenol A (epoxy equivalent: 186, non-volatile content: 1OO%)
, (2-2) is diglycidyl ether of bisphenol F (epoxy equivalent: 164, non-volatile content: 100%).

(*3): (3-1) is bisphenol A (hydroxyl group 1
14, nonvolatile content 100%), (3-2) is bisphenol F (hydroxyl value 100, nonvolatile content 100%).

Put the component (A-1) into a reaction container and heat it at 110°C under a stream of air to fully dissolve it, then add the component (4) and the catalyst,
A radically reactive advanced epoxy resin (A
-2) was obtained.

The names and amounts of these components (A-1), (4) and the catalyst, and the properties of the obtained component (A-2) are shown in Table 2 below.

■, Example 1, Vinyl resin modified epoxy resin composition (X) Component (A-1) and solvent were placed in a reaction vessel at 110°C under a nitrogen stream.
When the A-1) component is sufficiently dissolved, the (B) component is dropped into the reaction system at 110°C over a period of 3 hours, and after the dropwise addition is completed, the mixture is maintained at the same temperature for 2 hours to form a vinyl resin-modified epoxy composition. A solution of product (X) was obtained.

The names and amounts of the component (A-1), component (B) and solvent, and the properties of the resulting composition (X) are shown in Table 3 below.

Table 3 (*l) 75% water wet product 2, vinyl resin modified epoxy resin composition (Y) Half of the solvent was placed in a reaction vessel and heated to 100°C under a nitrogen stream.
Next, component (A-2), component (B), the remainder of the solvent, etc. were added dropwise into the reaction system over a period of 3 hours, and after the addition was completed, the same temperature was maintained for 2 hours to form a vinyl resin-modified epoxy resin composition. A product (Y) solution was obtained.

These (A-2) It, minutes, names and blending amounts of component (B) and solvent, performance of the obtained composition (Y), etc. are shown in Table 4 below.

Table 4 ($1) 75% water wet composition 140 parts of each of the compositions (X-1) to (X-4) and (Y-1) to (Y-4) obtained in the above examples were added with dimethyl ethanol. An amine was added to completely neutralize the mixture, and water was added to obtain an aqueous dispersion with a nonvolatile content of 20%.

4. Epoxy resin emulsion (Z) 500 parts of the above aqueous compound was heated to 80°C, and ethylenic Kibushiwa Shichitsummer (C) and azobisisobutyronitrile were added dropwise over 3 hours. The emulsion (z) was obtained by aging at room temperature for 3 hours and seed polymerization.

The names and amounts of these components were as shown in Table 5.

Table 5 In Table 5, both compositions (X) and (Y) are aqueous dispersions with a non-volatile content of 20%, and ethylenic Kibushi Kazutsummer (e) has a styrene/n-butyl acrylate ratio of 80%.
/20 (parts).

5. Compositions (X-1) to (X-1) obtained in Examples 38 and 4 above
The aqueous dispersions and emulsions (Z) of X-4) and (Y-1) to (Y-4) were applied to objects to be coated, and the performance of the cured coating films was also investigated.

Specifically, these aqueous compositions were coated on a tin plate using a bar coater so that the cured coating film had a thickness of 15 to 20 μm, and the coating film was cured by heating at 200° C. for 10 minutes. The performance test results of the coating film are shown in Table 6 below.

In Table 6, Examples or comparative examples marked with "○" in the component column (1) use Hytanol 4010 as a curing agent (Hitachi Chemical Co., Ltd. product name, Phenol Resin J), and the resin in the composition. This indicates that 10 parts by weight of the solid content was blended per 100 parts by weight of the solid content. Note that the "-" on the same side indicates that no curing agent was blended.

■ Comparative example! , 3.5.7.9.11, 13 and 15
(x -1)', (Y-1)' and (2-3
)' is (X-1), (Y-1), (Z-1) in Example
and advanced epoxy resin (A
-1) Replace -1 with an advanced epoxy resin with an epoxy value of 0.026, a solution viscosity of Z6, and a molecule of approximately 5500 synthesized from 200 parts of diglycidyl ether of bisphenol A, 114 parts of bisphenol A, and 1 part of tetrabutylammonium bromide. The acrylic modification reaction of this advanced epoxy resin was carried out in n-butanol solution for 40 minutes.
(X-1) and (Y-
This is an aqueous dispersion composition obtained by neutralizing in the same manner as 1), (Z-1) and (Z-3), adding water and dispersing, and removing excess butanol under reduced pressure as required.

■ Comparative examples 2.4.6.8.10.12.14 and 1
(X-2)', (Y-2)', (Z-2)' used in 6
and (Z-4)' are (X-2) and (Y-2) in Example
), (Z-2) and (z-4), the advanced epoxy resin (A-1)-2 was mixed with 175 parts of diglycidyl ether of bisphenol F, 100 parts of bisphenol F,
Synthesized from 1 part of tetrabutylammonium bromide and epoxy value 0.026, solution viscosity Zn molecular weight approximately 5
(x-2), (Y-2), except that the acrylic modification reaction of this advanced epoxy resin was carried out at 50% in n-butanol solution.
), (Z-2) and (Z-4), neutralized by adding water and dispersing, and removing excess n-butanol under reduced pressure as necessary.

(2) Curability: The cured coating film separated from the object to be coated was subjected to solvent extraction for 3 hours under refluxing methyl ethyl ketone, and evaluated by the change in weight of the remaining coating film after solvent extraction.

◎ 100-97% 0 96-90% △ 89-80% × 79% or less■ Corrosion resistance: Cut the coated plate into 150 x 70 mm, cross-cut the coated film to reach the substrate, and then place it in a salt spray test device. After 4 weeks, the sample was taken out and the width of rust on one side from the cut portion was measured.

@ 0 to less than 1 mm ○ 1 to less than 2 mm △ 2 to less than 6 m country
After being immersed in water for -60 minutes, the coating film was dried at room temperature, a cellophane adhesive tape was attached to the coating surface, and the coating surface was evaluated after being strongly peeled off.

◎ No peeling at all O Very slight peeling Δ Slight peeling × Significant peeling ■ Adhesiveness: Using a knife, make 11 vertical and horizontal cuts on the coating surface with a width of approximately 1.5 mm in a grid pattern. A cellophane adhesive tape of 24 types was adhered to the sample, and when it was strongly peeled off, the number of remaining adhered goblets was observed.

◎ 100 pieces 0 95-99 pieces Δ 80-94 pieces × 79 pieces or less ■ Impact resistance: Cut the coated plate into 40 mm x 50 mm, and fold it in half so that the test area is 40 mm with the coated film on the outside. , sandwich two pieces of Tin 7 Lee steel with a thickness of 0.23+nm between the two folded test pieces, drop a 3kg weight from a height of 42cm onto the folded part, and then apply a 6.5V x 6 piece to the folded tip. Electricity was applied for seconds, and the current value (mA) in a 2 cm width of the processed area was measured.

◎ 0 to less than 1 O 1 to less than 3 Δ 3 to less than 1 O x 10 or more ■ Tensile workability: The elongation rate of the cured coating film is
The measurement was performed using Tensilon UTN n-2 (N, Toyo Baldwin Co., Ltd. Ura, trade name). The tensile speed was 5 mm/ll1n at 20°C, and the workability was evaluated based on the average elongation rate of the 1O sample.

Elongation rate 0-10%: × 11%-20%: △ 21-30%: 0 31% or more: ◎ [Phase] 7 Labor resistance: Each aqueous coating composition was applied to the inner surface of the can, and 5% was applied at 200°C. After heating for a minute to harden (
The can was filled with 250 ml of activated carbon-treated tap water, sealed, and sterilized at 100°C for 30 minutes, stored at 37°C for 4 months, and then subjected to a flavor test.

■ No change at all ○ Very slight change △ Slight change × Significant change ■ Hygiene: A can made from the painted tin plate was filled with 250 m12 of deionized exchanged water, sealed, and sealed for 60 minutes.
C. for 30 minutes and 100.degree. C. for 30 minutes and measured according to the test method described in the Food Sanitation Law. The amount of potassium permanganate consumed was expressed in ppm.

◎ 0 to less than 2 02-less than 5 Δ 5 to less than 10 × 10 or more

Claims (1)

[Scope of Claims] 1,2,2-bis(p-(3-butoxy-2-glycidyloxypropyloxy)phenyl)propane (1),
An advanced epoxy resin having a molecular weight of 1,500 to 29,000 and an epoxy value of 0.006 or more, obtained by reacting a polyglycidyl compound (2) other than the component (1) and a polyhydric phenol (3) as necessary. (
A vinyl resin-modified epoxy resin composition obtained by graft polymerizing A-1) and an addition polymerizable monomer (B) containing a monoethylenically unsaturated carboxylic acid (4). 2. Advanced epoxy resin according to claim 1 (A-1
) and a monoethylenically unsaturated carboxylic acid (4). A vinyl resin obtained by copolymerizing an addition polymerizable monomer (B) with a radically reactive advanced epoxy resin (A-2) obtained by reacting a monoethylenically unsaturated carboxylic acid (4) with Modified epoxy resin composition. 3. An epoxy resin emulsion obtained by seed polymerizing an ethylenically unsaturated monomer (C) in an emulsion system of the vinyl resin-modified epoxy resin composition according to claim 1 and/or 2. 4. A water-based paint for the inside of a can, which contains the vinyl resin-modified epoxy resin according to claim 1 or 2 or the epoxy resin emulsion according to claim 3 as a main component.