JP2818457B2 - Resin composition and water-based paint for inner surface of can using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel vinyl resin-modified epoxy resin composition and an epoxy resin emulsion obtained by subjecting the epoxy resin composition to seed polymerization in an emulsion. All of these are useful as water-based paints for coating the inner surfaces of edible cans such as drinks, meats, vegetables and fruits, and have a low-temperature curing property, and are particularly hygienic,
It forms a coating film with excellent properties such as flavor, adhesion, processability, corrosion resistance and chemical resistance, and is also excellent in can production efficiency.

2. Description of the Related Art Conventionally, paints for inner surfaces of cans that use an organic solvent as a solvent or a dispersion medium are not only unfavorable from the viewpoint of environmental hygiene and fire safety, but if the molecular weight of the substrate resin is reduced in order to maintain an appropriate viscosity of the paint, the There is a problem that the flavor and the like of the food filled therein are reduced. In order to solve these problems, a water-based paint for the inner surface of a can containing no or almost no organic solvent has been developed. The main water-based paints that have been developed include, for example, (i) a self-emulsifying emulsion paint obtained by esterifying a carboxyl group-containing resin and an epoxy resin in the presence of a tertiary amine (Japanese Patent Laid-Open No. (Ii) Self-emulsifying emulsion paints obtained by graft-polymerizing a vinyl monomer containing a polymerizable unsaturated acid monomer onto an epoxy resin using a peroxide as a catalyst (JP-A-53-1285). And (iii) a reaction product of an epoxy resin and (meth) acrylic acid, and a monomer mixture comprising an aromatic vinyl monomer, an alkyl ester of an α, β-ethylenically unsaturated carboxylic acid, acrylic acid or methacrylic acid. React (polymerization)
Self-emulsifying emulsion paint obtained by
-198513, JP-A-60-106805).

However, the epoxy resins in the emulsion coatings (i) to (iii) are all bisphenol A type, and the viscosity becomes extremely high when the molecular weight is increased to prevent deterioration of flavor and the like for the inner surface of the can. It has the defect of. That is, if the viscosity is high, it is difficult to make the aqueous reaction uniform, and if a large amount of an organic solvent is blended to prevent it, the operation of water dispersion and subsequent removal of the organic solvent becomes complicated, and When the resulting aqueous composition is applied to the inner surface of a can, the curability of the coating film is insufficient, so that there are problems such as deterioration of food hygiene, flavor, corrosion resistance, adhesion and the like.

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned defects, and as a result, an epoxy resin obtained by using a specific glycidyl ether compound instead of bisphenol A type epoxy resin is However, even if the molecular weight is high, the viscosity does not significantly increase, so that an aqueous reaction or water dispersion can be easily performed, and when used for coating the inner surface of a can, all of the above-mentioned coating film defects can be eliminated. The present invention has been completed.

That is, according to one embodiment of the present invention, 2,2-bis (p- (3-butoxy-2-glycidyloxypropyloxy) phenyl) propane (1) and, if necessary, components other than the component (1) An advanced epoxy resin (A-1) having a molecular weight of 1500-29000 and an epoxy value of 0.006 or more obtained by reacting a polyglycidyl compound (2) and a polyhydric phenol (3), and a monoethylenically unsaturated carboxylic acid There is provided a vinyl resin-modified epoxy resin composition (X) obtained by graft-polymerizing an addition polymerizable monomer (B) containing an acid (4).

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

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

One of the features of the composition of the present invention is that 2,2-bis [p- (3-butoxy-2-glycidyloxypropyloxy) phenyl] propane (1) is a component of the advanced epoxy resin (A-1). ), Whose structural formula is as follows:

The component (1) has a lower viscosity than bisphenol A-type diglycidyl ether and furthermore biphenol F-type diglycidyl ether. The reason is that the component (1) has two butoxy groups with excellent flexibility in its skeleton, and furthermore, the space between the benzene ring and the oxirane ring, which occupy a large space sterically, is wide and the skeleton is free. The degree may increase. Further, the advanced epoxy resin using the component (1) is also a conventional bisphenol A
There is an advantage that the viscosity is significantly lower than that of the (or F) type epoxy resin, and the increase in viscosity is small even when the molecular weight is high. This is because, in addition to the above-mentioned reasons, the symmetry of the main chain skeleton of the resin may decrease, and the tendency of crystallization may decrease.

Therefore, such advanced epoxy resin (A-
When 1) is 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 (X) can be prepared without using a large amount of an organic solvent. Y) is obtained. Further, the seed polymerization of the resin composition (X) and / or (Y) in the emulsion system can be carried out uniformly without significantly increasing the viscosity, so that the load on the stirrer or the like is small. Further, since a large amount of the organic solvent is not used in these reaction steps, the solvent recovery step can be omitted.

Further, the water-based paint and the epoxy emulsion (Z) containing the resin compositions (X) and (Y) as main components thus obtained are particularly suitable as a water-based paint for the inner surface of a can, and the conventional bisphenol A Type and F type,
It has excellent curability, food hygiene, flavor, processability, corrosion resistance and adhesion.

 Hereinafter, the present invention will be described in more detail.

Advanced epoxy resin (A-1): Advanced epoxy resin (A-
1) is 2,2-bis [p- (3-butoxy-2-glycidyloxypropyloxy) phenyl] propane (1), and if necessary, a polyglycidyl compound (2) other than the component (1), And an epoxy resin obtained by subjecting a polyhydric phenol (3) to an addition polymerization reaction by an advance method, wherein the resin has a molecular weight of 1500 to 29,000, preferably
It can be from 500 to 9000 and the epoxy value can be in the range of 0.006 or more, preferably 0.01 to 0.06.

The polyglycidyl compound other than the component (1) of the component (2) is a compound having two or more glycidyls per molecule and is not essential for the component (A-1), but is not essential for the component (A-1).
It is effective for increasing the molecular weight of the component (1), accelerating the reaction with the component (B) or the component (4), and in particular, polyglycidyl obtained by using a compound having two or more phenolic hydroxyl groups in one molecule. Compounds are preferred. Specifically, examples of the polyglycidyl compound having two glycidyl groups in one molecule include glycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and 2,2-bis (4′-hydroxyphenyl). Diglycidyl ether of butane, diglycidyl ether of bisphenol S, diglycidyl ether of resorcinol, diglycidyl ether of hexahydrobisphenol A, diglycidyl ether of polypropylene glycol, diglycidyl ether of neopentyl glycol, diglycidyl phthalate Diglycidyl ester of dimer acid, diglycidyl ether of tetrabromobisphenol A, glycidyl ether of bisphenol hexafluoroacetone, etc., and three or more glycidyl in one molecule. Examples of the polyglycidyl compound having a ether group include, for example, triglycidyl isocyanurate, tetraglycidyl diaminodiphenyl methane, tetraglycidyl metaquinimine diamine, cresol novolak polyglycidyl ether, phenol novolak polyglycidyl ether, epoxidized polybutadiene, and the like. No.

The polyhydric phenol of the component (3) is a compound having two or more phenolic hydroxyl groups in one molecule, for example, bisphenol A, bisphenol F, 2,2-bis (4 ′).
-Hydroxyphenyl) butane, bisphenol S, resorcinol, tetrabromobisphenol A, bisphenolhexafluoroacetone, cresol novolak, resol novolak and the like.

The addition polymerization reaction of the above components (1) to (3)
The compound (3) is blended so that the total phenolic hydroxyl group of the component (3) is 0.5 to 1.5 mol, preferably 0.8 to 1.2 mol, based on 1 mol of the total epoxy group of the component (1) and the component (2). The reaction is preferably carried out at a temperature of about 50 ° C. to about 200 ° C. in the presence, and the addition polymerization reaction is continued until the molecular weight of the reaction product (A-1) finally falls within the range of 1500 to 29,000. Further, when the component (2) is used, it is preferably used in an amount of 90% by weight or less, particularly 70% by weight or less, based on the total amount of the component (1).

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 both groups substantially equimolarly is obtained. The amount of the component (A-1) increases, and it is difficult to increase the molecular weight. If the amount is less than 1.0, the amount of the component (A-1) having a phenolic hydroxyl group increases, and it becomes difficult to increase the molecular weight.

When the molecular weight of the component (A-1) is less than 1500, the resulting composition forms a coating film having poor corrosion resistance and workability. On the other hand, when the molecular weight is more than 29,000, a coating film having extremely high internal stress is formed. It is not preferable because it is easy to do. Also, (A
If the epoxy value of the component -1) is less than 0.006, unreacted components which do not chemically react with the component (B) in the course of the reaction with the component (B) are increased, which is not preferable.

Examples of the catalyst that can be used in the addition polymerization reaction include alkali metal and alkaline earth metal salts such as sodium hydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide, calcium hydroxide, sodium carbonate, and calcium carbonate. ; n-butylamine, tri-n-butylamine,
Amines such as triethanolamine and pyridine, or quaternary ammonium salts such as tetraethylammonium bromide; 1-methylimidazole, 2-methylimidazole, 2-ethyl-4-methyl-imidazole, 1,2-
Imidazole compounds such as dimethyl-imidazole;
And phosphonium compounds. The amount of the catalyst used varies depending on the type of the catalyst, the types and combinations of the components (1) to (3), but is generally preferably 10% by weight or less based on the total solid content of the components (1) to (3). .

In addition, in this addition polymerization reaction, the reactivity of the product [A-1 component] is increased, the thickening gelation during the reaction is prevented, and the reaction is carried out uniformly in an organic solvent, if necessary. Can do it. As an organic solvent that can be used,
Those which can dissolve the components (1) to (3), the catalyst, and the reaction product are preferable. Specifically, for example, aromatic hydrocarbons such as toluene and xylene; and hydroxyl groups such as ethylene glycol dimethyl ether and diethyl glycol dimethyl ether can be used. Ethers not containing; esters such as ethyl acetate and butyl acetate; ketones such as acetone and methyl ethyl ketone.

Further formula (i) ~ (v) HO -R 1 ··· (i) HO-CmH 2 m-O-R 2 ··· (ii) HO-CmH 2 m-O-CmH 2 m-O- during _{R 2 ··· (iii) HOCmH 2} mOH ··· (iv) HOCmH 2 mO n R 1 ··· (iv) above formulas, R ₁ represents a 1 to 12 alkyl group carbon atoms, R ₂ represents an alkyl group having 1 to 6 carbon atoms, m and n are each an integer of 1 to 6, such as alcohol solvents, cellosolve solvents, carbitol solvents, ether solvents, etc. It is also possible to use a solvent having a hydroxyl group, but only with these (A-
These solvents are desirably used in combination with the above-mentioned organic solvents, since the increase in the molecular weight of the component 1) may be hindered.

Vinyl resin-modified epoxy resin composition (X): Vinyl resin-modified epoxy resin composition (X) of the present invention
Is obtained by graft-polymerizing the component (A-1) and an addition-polymerizable monomer (B) containing a monoethylenically unsaturated carboxylic acid (4).

Specifically, it can be carried out, for example, by graft-polymerizing the component (B) in an organic solvent solution or dispersion of the component (A-1) in the presence of a free radical generator. This grafting is presumed to be caused by extraction of protons on the (A-1) component skeleton by free radicals, and proceeds efficiently by increasing the concentration of radical initiator, the concentration of reaction components, the reaction temperature, and the like. However, it seems that unreacted polymer of the component (A-1) and the component (B) are also present.

The addition-polymerizable monomer (B) contains a monoethylenically unsaturated carboxylic acid (4), and the component ratio of the component (B) is 5 to 100% by weight, particularly 30% by weight.
It is preferable that the content of the polymerizable monomer be at least one of other polymerizable monomers.

The monoethylenically unsaturated carboxylic acid of the component (4) is
A compound having one or more carboxyl groups and one or more polymerizable unsaturated bonds in one molecule, such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid. Alternatively, two or more kinds can be used in combination.

In the component (B), examples of other polymerizable monomers that can be used together with the component (4) include those exemplified in the following (a) to (d).

I Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, i-butyl acrylate, i-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate,
Alkyl or cycloalkyl esters of acrylic acid or methacrylic acid having 1 to 24 carbon atoms, such as 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, decyl acrylate, etc .; Acrylamide, methacrylamide, N-methylacrylamide, N-ethyl methacrylamide, diacetone acrylamide, N-methylol acrylamide, N
Functional acryl or methacrylamide such as methylol methacrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide; c-styrene, vinyltoluene, vinyl propionate,
α-methylstyrene, vinyl acetate, acrylonitrile,
Vinyl monomers such as methacrylonitrile, vinyl propionate, vinyl pivalate, and veroba monomer (Ciel Chemical Products); acrylic acid or methacrylic acid such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate A hydroxyalkyl ester having 1 to 8 carbon atoms in the acid; and the like.

The use ratio of the component (A-1) and the component (B) is not particularly limited, but generally, based on the total solid content of the two components,
The component (A-1) preferably has a content of 10 to 95% by weight, particularly 50 to 90% by weight, and the component (B) has a content of 90 to 5% by weight, particularly preferably 50 to 10% by weight.

The above graft polymerization reaction can be usually performed in an organic solvent in the presence of a free radical generator. Examples of the organic solvent used include component (A-1), component (B) and its polymer and component (X). Are preferable, for example, solvents represented by the above formulas (i) to (v), aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; acetone; And ketones such as methyl ethyl ketone. Examples of the free radical generator include benzoyl peroxide, perbutyl octate, t-butyl hydroperoxide, azobisisobutyronitrile, azobisvaleronitrile, 2,2′-azobis (2-aminopropane ) Hydrochloride and the like can be used, and the amount used varies depending on monomers, solvents, types of catalysts, combinations thereof, reaction temperature, reaction concentration, grafting efficiency, etc., and is generally based on 100 parts by weight of the component (B). It is preferable to use 0.5 to 5 parts by weight.

Vinyl resin-modified epoxy resin composition (X) of the present invention
Preferably has an acid value in the range of 10 to 200, particularly 15 to 80.

The composition (X) can be used as a paint as it is. However, it is preferable that the organic solvent is removed and neutralized as necessary, and then dissolved or dispersed in water to make it water-based and then used for inner can coating.

Vinyl resin-modified epoxy resin composition (Y): Next, vinyl resin-modified epoxy resin composition (Y)
It can be obtained by further copolymerizing the component (B) with the radically reactive advanced epoxy resin (A-2) obtained by reacting the component (4) with the component (A-1).

The component (A-2) is obtained by reacting the carboxyl group of the component (4) with the epoxy group of the component (A-1) to introduce a polymerizable unsaturated bond. Accordingly, the component (A-1) preferably has an average of 0.2 or more, particularly 0.5 or more epoxy groups per molecule. In the reaction between the two components, the epoxy group in the component (A-1) / the carboxyl group in the component (4) is usually 1 / 0.1 to 1 / 5.0, preferably 1 / 0.5 to 1 / 5.0.
/2.0 within the range of 50% in the presence of an esterification catalyst (eg, n-butylamine, tetraethylammonium bromide, dibutylene oxide, etc.).
The reaction can be carried out at a temperature of 200200 ° C. by continuing the reaction to a target reaction point while controlling the epoxy value of the reactant. (A-2) The average number of polymerizable unsaturated bonds to be introduced into the component is preferably in the range of 0.2 to 1.5 per molecule.

The reaction between the two components can be carried out without a solvent or in an organic solvent, and the usable solvent is a reactant (A
Preferred are organic solvents that dissolve or disperse the -1) component, the (4) component, the reaction catalyst, and the product (A-2) component, and are specifically selected from those exemplified for the synthesis of the (X) component. Organic solvents.

The composition (Y) is obtained by radically copolymerizing the component (B) with the component (A-2).

The component ratio of the component (A-2) to the component (B) is such that the component (A-2) is 10 to 90 based on the total weight of the solid components.
%, Preferably 50-90%, and 10-90%, preferably
It is in the range of 10-50%.

Specifically, it is preferable that the component (A-2) and the component (B) are copolymerized in the presence of an organic solvent and a free radical generator. As the component (B), the organic solvent, the free radical generator, and the like, those described above can be used.

The vinyl resin-modified epoxy resin (Y) of the present invention is preferably adjusted to have an acid value of 10 to 200, particularly 15 to 80.

The component (Y) can be used by dissolving or dispersing it in an organic solvent. However, it is particularly preferable that the component is neutralized by an ordinary method, if necessary, and then dissolved or dispersed in water.

When the component (X) and the component (Y) have a high acid value, they can be dissolved or dispersed in water as they are. However, by neutralizing the carboxyl groups in the components with a basic compound, the components are not dispersed in water. Water solubility can be easily achieved. The water-dispersed product or water-soluble product prepared in this manner may be hereinafter collectively referred to as "emulsion" or "aqueous dispersion".

As the basic compound as the neutralizing agent, those known per se can be used, and preferred specific examples are those represented by the general formula R ₃ R ₄
R ₅ N wherein R ₃ and R ₄ are a substituted or unsubstituted monovalent alkyl group containing 1 or 2 carbon atoms in the alkyl moiety, and R ₅ is 1 to 4 carbon atoms A substituted or unsubstituted monovalent alkyl containing], N-methylpyrrolidine, N-methylmorpholine, pyridine, N-methylpyrrole, N-methylpiperidine,
And a mixture thereof. Examples of compounds of the above formula R ₃ R ₄ R ₅ N include trimethylamine, dimethylethanolamine (dimethylaminoethanol), methyldiethanolamine, ethylmethylethanolamine, dimethylethylamine, dimethylpropylamine, dimethyl-3-hydroxy-1- Propylamine, dimethylbenzylamine,
Examples thereof include dimethyl-2-hydroxy-1-propylamine, diethylmethylamine, dimethyl-1-hydroxy-2-propylamine, and mixtures thereof. Most preferably, trimethylamine or dimethylethanolamine is used.

The neutralization is usually preferably performed with a neutralization equivalent of 0.1 to 2.0.

When neutralized in this manner, the component (X) and the component (Y) become self-emulsifying and dissolve or disperse in water.
It is not always necessary to use an emulsifier or a dispersant.

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

The components (X) and (Y) are converted from W / O type to O / W
Since the viscosity of the system is not significantly increased at the time of phase change to the mold, there is also an advantage that an excessive load is not applied to the manufacturing equipment and the like.

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

Epoxy Resin Emulsion (Z): Further, the epoxy resin emulsion (Z) in the present invention is obtained by converting the ethylenically unsaturated monomer (C) in the emulsion (aqueous dispersion) of the component (X) and / or (Y). Obtained by seed polymerization.

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

The aqueous dispersion of the component (X) and the component (Y) can be obtained by appropriately selecting the molecular weight, the acid value, the degree of neutralization, the composition, and the like of the component, and the size of the dispersed particles in water is 1 μm. The following are suitable: When the ethylenically unsaturated monomer (C) is mixed with the aqueous dispersion, the monomer (C) concentrates in the dispersed particles and in the vicinity thereof. This tendency increases as the monomer (C) becomes more lipophilic. Then, when heating is performed, polymerization (seed polymerization) of the monomer (C) is performed in and near the particles.

As the ethylenically unsaturated monomer (C) that can be subjected to seed polymerization, one or more of the monomers described for the addition-polymerizable monomer (B) are used.
Of these, hydrophobic monomers 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 seed polymerization temperature and time vary depending on the type of monomer used, the type of initiator, etc., but usually the reaction temperature is in the range of about 30 to about 100 ° C., and the polymerization time is 30 minutes to 10 minutes. It can be on the order of hours.

The monomer (C) is generally used in an amount of 1 to 300 parts by weight based on 100 parts by weight of the solid component of the component (X) and / or (Y),
Preferably, the amount is in the range of 10 to 150 parts by weight.

The epoxy resin emulsion (Z) obtained by such seed polymerization includes the component (A-1) and the component (A-2).
Since the use ratio of components can be reduced, it is effective for cost reduction.

The vinyl resin-modified epoxy resin (X) in the present invention,
(Y) and the epoxy resin emulsion (Z) obtained by using the same, can be obtained without adding a curing agent, without adding a secondary hydroxyl group in the skeleton of the advanced epoxy resin (A-1) and a monoethylenically unsaturated acid. Although it is possible to form a cured coating film by reaction with a carboxyl group based on (4), a curing agent such as a urea resin, a melamine resin, or a phenol resin (including a methylol compound or an alkyl ether compound) is mixed. This makes it possible to form a coating film having improved curability and corrosion resistance.

Further, the vinyl resin-modified epoxy resin (X),
(Y) and epoxy resin emulsion (Z) include polyester resin, polybutadiene and its modified resin,
Properly mixing vinyl chloride-vinyl acetate copolymer, maleic anhydride-styrene copolymer, maleic anhydride-vinyl methyl ether copolymer, ethylene-acrylic acid copolymer-ethylene-methacrylic acid copolymer, etc. Is also possible.

The vinyl resin-modified epoxy resins (X) and (Y) of the present invention are preferably used after being dissolved or dispersed in an organic solvent and / or water. Further, these and the epoxy resin emulsion (Z) are used as a paint. Is preferred. Among them, it is most preferable to apply an aqueous material using water as a solvent or a dispersion medium as the inner coating composition for food cans. As a material for cans, aluminum plate, steel plate or zinc, chromium, tin,
A plated steel sheet plated with aluminum or the like, a treated steel sheet whose surface is chemically converted with chromic acid, iron phosphate, or zinc phosphate, or the like can be used. The inner surface of the can can be applied by, for example, roll coating, spray coating, brush coating, spray coating, dipping, or the like. The coating thickness is usually in the range of 5 to 30 μm based on the cured coating film. The baking of the coating is generally from about 150 to about 220 ° C, preferably from about 180 ° C.
It can be carried out at a temperature of from about 30 to about 600 seconds, preferably from about 60 to about 300 seconds.

The above vinyl resin-modified epoxy resin compositions (X) and (Y) of the present invention and an epoxy resin emulsion (Z)
Since all components are based on the component (A-1) including the component (1), the viscosity is lower than that of a normal bisphenol A type epoxy resin.
The composition (X), the component (A-2) and the composition (Y) have a small increase in viscosity during the production (reaction), and the load on the production (stirring) apparatus is reduced, and the amount of the organic solvent used in the aqueous compound is also reduced. Since only a small amount is required, it is possible to reduce costs and improve production efficiency. Further, the vinyl resin-modified epoxy resin compositions (X) and (Y) and the epoxy resin emulsion (Z) of the present invention have excellent compatibility with the above-mentioned curing agent, and have an increased viscosity when the coating film is cured by heating. Smooth, uniform and efficient coatings with high crosslink density can be formed, resulting in improved flavor, corrosion, hygiene, chemical, boiling water, processability and adhesion .

Next, the present invention will be described more specifically with reference to examples and comparative examples. All parts and percentages in the examples and comparative examples are based on weight unless otherwise specified.

I. Production Example 1. Advanced epoxy resin [component (A-1)] The components shown in Table 1 below were placed in a reaction vessel and placed under a nitrogen stream.
The reaction was performed at 160 ° C. Reaction is epoxy value (solid content 100g
And the solution viscosity (solid content 40% at 25 ° C., Gardner-Holt viscosity of butyl carbitol solution). The reaction took about 6 hours.

In Table 1, ( ^* 1) is the blending amount of 2,2-bis (p- (3-butoxy-2-glycidyloxypropoxy) phenyl) propane, epoxy equivalent is 315, and nonvolatile content is 100%. is there.

( ^* 2): (2-1) is a diglycidyl ether of bisphenol A (epoxy equivalent: 186, nonvolatile content: 100%), (2)
-2) is a diglycidyl ether of bisphenol F (epoxy equivalent 164, nonvolatile content 100%).

( ^* 3): (3-1) is bisphenol A (hydroxyl 11
(4, nonvolatile content 100%), (3-2) is bisphenol F
(Hydroxyl value 100, nonvolatile content 100%).

2. Radical reactive advanced epoxy resin [(A-2)
Components] The component (A-1) is placed in a reaction vessel, heated at 110 ° C. in an air stream to sufficiently dissolve, and then the component (4) and a catalyst are added.
React for 10 hours at 110 ° C under air flow until the acid value becomes 0,
Radical-reactive advanced epoxy resin in which an acryloyl group is partially introduced into the advanced epoxy resin (A-
2) was obtained.

Table 2 below shows the names and amounts of the components (A-1), (4) and the catalyst, and the properties of the obtained component (A-2).

II. Example 1. Vinyl resin-modified epoxy resin composition (X) The component (A-1) and a solvent are put into a reaction vessel and placed under a nitrogen stream.
When the component (A-1) is sufficiently dissolved by heating at 110 ° C., the component (B) is dropped into the reaction system at 110 ° C. over 3 hours, and after completion of the dropping, the mixture is kept at the same temperature for 2 hours to obtain a vinyl resin. A modified epoxy composition (X) solution was obtained.

Table 3 below shows the names and amounts of the components (A-1), (B) and solvents, and the properties of the obtained composition (X).

2. Vinyl resin-modified epoxy resin composition (Y) Half of the solvent is put in a reaction vessel and heated to 100 ° C. under a nitrogen stream, and then the components (A-2), (B) and the remainder of the solvent are reacted. The solution was added dropwise to the system over 3 hours, and after completion of the addition, the mixture was maintained at the same temperature for 2 hours to obtain a vinyl resin-modified epoxy resin composition (Y) solution.

Table 4 below shows the names and amounts of these components (A-2), (B) and solvents, and the performance of the obtained composition (Y).

3. Aqueous Conversion of Vinyl Resin Modified Epoxy Resin Compositions (X) and (Y) Components The compositions (X-1) to (X-4) and (Y-1) to (Y-4) obtained in the above Examples. ) Was completely neutralized by adding dimethylethanolamine to each 140 parts, and water was further added to obtain an aqueous dispersion having a nonvolatile content of 20%.

4. Epoxy Resin Emulsion (Z) 500 parts of the above hydrated product is heated to 80 ° C., and ethylenically unsaturated monomer (C) and azobisisobutyronitrile are added to 3 parts.
It was added dropwise over time, aged at the same temperature for 3 hours, and subjected to seed polymerization to obtain emulsion (Z).

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

In Table 5, compositions (X) and (Y) are both aqueous dispersions of 20% nonvolatiles, and the ethylenically unsaturated monomer (e) is styrene / n-butyl acrylate = 80/20.
(Part).

5. Compositions (X-1) to (X) obtained in Examples 3 and 4 above
-4) and the aqueous dispersions of (Y-1) to (Y-4) and the emulsion (Z) were applied to the substrate, and the performance of the cured coating film was also examined.

Specifically, these aqueous compositions were applied to a tin plate using a bar coater to a thickness of 15 to 20 μm based on the cured coating film, and heated at 200 ° C. for 10 minutes to cure the coating film. The results of the performance tests of the coating films are shown in Table 6 below.

In Table 6, in Examples and Comparative Examples in which "O" was added in the column of the components, "Hitanol 4010 [trade name, phenolic resin manufactured by Hitachi Chemical Co., Ltd., phenolic resin]" 10 parts by weight based on the solid content per 100 parts by weight per minute. In addition, "-" in the same column indicates that the curing agent was not blended.

(X-1) ', (Y-1)' and (Z-3) 'used in Comparative Examples 1, 3, 5, 7, 9, 11, 13 and 15 are:
Advanced epoxy resin (A-1) in Examples (X-1), (Y-1), (Z-1) and (Z-3)
-1 is the diglycidyl ether of bisphenol A 200
Part, bisphenol A114 part, and an epoxy value 0.026 synthesized from 1 part of tetrabutylammonium bromide,
Except for replacing the advanced epoxy resin with a solution viscosity Z6 and a molecular weight of about 5500, and reacting the acrylic modification reaction of this advanced epoxy resin with 40% in n-butanol solution,
Neutralize in the same manner as in (X-1), (Y-1), (Z-1) and (Z-3), add water and disperse, and remove excess n-butanol if necessary. This is an aqueous dispersion composition removed under reduced pressure.

(X-2) ', (Y-2)', (Z-2) 'and (Z-4)' used in Comparative Examples 2, 4, 6, 8, 10, 12, 14 and 16 were Examples (X-2), (Y-2),
Epoxy value of advanced epoxy resin (A-1) -2 in (Z-2) and (Z-4) synthesized from 175 parts of diglycidyl ether of bisphenol F, 100 parts of bisphenol F, and 1 part of tetrabutylammonium bromide (X-2), (Y-2), except that the advanced epoxy resin is substituted with 0.026, the solution viscosity of Zn is about 5500, and the acrylic modification reaction of this advanced epoxy resin is carried out at 50% in n-butanol solution. This is a water-dispersed composition obtained by neutralizing in the same manner as in (Z-2) and (Z-4), adding water and dispersing, and removing excess n-butanol under reduced pressure as necessary.

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

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

◎ 0 to less than 1 mm ○ less than 1 to 2 mm △ less than 2 to 6 mm × 6 mm or more Water resistance: 100 ° C-6 after cross-cutting as above
After being immersed in water for 0 minutes, the coating film was dried at room temperature, a cellophane adhesive tape was stuck on the coated surface, and the coated surface after strong peeling was evaluated.

◎ No peeling at all ○ Very slight peeling △ Slight peeling × Extremely peeling Adhesiveness: Using a knife on the coating film surface, make 11 cuts each in the vertical and horizontal directions with a width of about 1.5 mm in a gobang shape. twenty four
A cellophane pressure-sensitive adhesive tape having a width of mm was adhered to the tape, and the number of remaining sticking holes when strongly peeled was observed.

◎ 100 pieces ○ 95-99 pieces △ 80-94 pieces × 79 pieces or less Impact resistance: Cut the coated plate into a size of 40 mm x 50 mm, fold the coating film outside, and fold it into two to make the test part 40 mm. , Two pieces of 0.23mm thick taine-free steel are sandwiched between the two folded test pieces, and 3kg of weight is 42cm in height.
After dropping to the bent part, 6.5V
The current was applied for 6 seconds, and a current value (mA) having a width of 2 cm in the processed portion was measured.

◎ Less than 0 to 1 ○ Less than 1 to 3 △ Less than 3 to 10 × 10 or more Tensile workability: Tensileon (“Tensilon UTN II-20”, trade name, manufactured by Toyo Baldwin Co., Ltd.) Measured using The tensile speed was set at 20 ° C. and 5 mm / min, and the workability was evaluated from the average value of the elongation percentage of 10 samples.

Elongation rate 0 to 10%: × 11% to 20%: △ 21 to 30%: ○ 31% or more: ◎ Flavor: Each aqueous coating composition is applied to the inner surface of a can and heated at 200 ° C for 5 minutes. After curing (film thickness 15
~ 20μ), 250ml of tap water treated with activated carbon
After filling and winding, sterilization treatment at 100 ° C for 30 minutes, storage at 37 ° C for 4 months, and then flavor test.

◎ No change ○ Very slight change △ Slight change × Significant change Sanitation: Fill a can made of the painted tin plate with 250 ml of deionized exchanged water, tightly wind, and tighten at 60 ℃ -30 Min and 100 ° C. for 30 minutes, and measured according to the test method described in the Food Sanitation Law. The consumption of potassium permanganate is given in ppm.

 ◎ 0 to less than 2 ○ 2 to less than 5 △ 5 to less than 10 × 10 or more

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kyokawa Symbiosis 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Kansai Paint Co., Ltd. (56) References JP-A-3-179018 (JP, A) JP-A-63 -20311 (JP, A) JP-A-1-158028 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 59/14-59/17 C09D 163/00-163/10 C08F 2/44 C08F 283/10

Claims (4)

(57) [Claims] (1) 2,2-bis (p- (3-butoxy-2-glycidyloxypropyloxy) phenyl) propane (1), if necessary, a polyglycidyl compound (2) other than the component (1), And an advanced epoxy resin (A-) having a molecular weight of 1500-29000 and an epoxy value of 0.006 or more obtained by reacting a polyhydric phenol (3)
A vinyl resin-modified epoxy resin composition obtained by graft-polymerizing 1) and an addition-polymerizable monomer (B) containing a monoethylenically unsaturated carboxylic acid (4). 2. A radically reactive advanced epoxy resin (A-2) obtained by reacting the advanced epoxy resin (A-1) according to claim 1 with a monoethylenically unsaturated carboxylic acid (4). And a vinyl resin-modified epoxy resin composition obtained by copolymerizing an addition polymerizable monomer (B). 3. An epoxy resin emulsion obtained by subjecting an ethylenically unsaturated monomer (C) to seed polymerization 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 inner surface of a can containing 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.