JPS61250024A - Aqueous resin dispersion - Google Patents

Abstract

PURPOSE:The title dispersion that is obtained by dispersing a specific self- emulsible aromatic epoxy resin in an aqueous medium containing amine or the like, then mixing the product with an initial polycondensate of a specific phenolic resin, thus being suitable for use as a paint for metal, because it has good curing properties and give coating films of good physical properties. CONSTITUTION:(A) A partially binding composition of (1) an acrylic resin containing 12-70wt% of monobasic carboxylic acid component and (ii) an aromatic epoxy resin is dispersed in (B) an aqueous medium containing ammonia or an amine in such a amount as the pH of the medium becomes 4-11. Then, an intial concentrate of phenolic resin containing more than 40wt% of compound of formula I (R is H, 1-12C alkyl; X is H, methyl; a, b are 1, 2 where a+b is 3 or 4) such as compound of formula II, is added and dispersed therein to give the objective dispersion. The amount of component B is preferably 2-40wt% based on the total amount of the resins.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to an aqueous resin dispersion, and more specifically, as a coating composition for metals, particularly as a coating composition for the inner surface of a can. This invention relates to useful aqueous resin dispersions.

(Conventional technology) Paints whose main component is aromatic epoxy resin.

Although it is used as a paint for one can because of its excellent processability, content resistance, and physical properties of the coating film, the aromatic epoxy resin itself does not dissolve or disperse in an aqueous medium.

On the other hand, water-based paints for cans are being considered from the viewpoint of resource conservation, energy conservation, and environmental pollution.

Various proposals have also been made regarding paints containing aromatic epoxy resins as a main component.

For example, a method is known in which an aromatic epoxy resin is dispersed in water using a surfactant.

The action of surfactants tends to have an adverse effect on the storage stability and physical properties of the paint film.

Various self-emulsifying aromatic resins and boxy resins, which are aromatic epoxy resins modified with acrylic resins having carboxyl groups, have been proposed.

For example, JP-A No. 53-14963 and JP-A No. 5
5-9433 discloses that a partial reactant containing an excess of carboxyl groups obtained by reacting an acrylic resin and an aromatic epoxy resin can be stably dispersed in an aqueous medium in the presence of ammonia or an amine. There is. JP-A-57-1
No. 05418 and Japanese Unexamined Patent Publication No. 198513/1983.

A low-molecular compound having an epoxy group and an acryloyl group in one molecule, which is obtained by partially reacting an aromatic epoxy resin and (meth)acrylic acid, and a monomer mixture containing acrylic acid or methacrylic acid are polymerized to form a basic Aqueous dispersion compositions obtained by neutralization with compounds are disclosed.

Furthermore, JP-A-53-1228 discloses a grafting method obtained by polymerizing a monomer mixture containing a carboxylic acid monomer using a free radical generator such as benzoyl peroxide in the presence of an aromatic epoxy resin. It has been shown that the prepared epoxy resins can be stably dispersed in aqueous media containing bases.

The self-emulsifying aromatic epoxy resin obtained by the above technology does not contain surfactants in the paint, so it can itself provide a strong coating film, but in order to obtain a faster curing speed for practical use, Contains a highly water-soluble amino resin. By blending an amino resin, the curing speed of the paint can be improved to a certain extent without deteriorating the physical properties of the paint film, but when used in an amount that is practically satisfactory in terms of curing speed, the adhesion, Processability deteriorates, and especially as a paint for the inner surface of a can, low-molecular-weight compounds originating from the amino resin are eluted into the contents of the can during heat sterilization, resulting in hygiene problems.

It is also known to incorporate a phenolic resin into a self-emulsifying aromatic epoxy resin, but it was believed that ordinary phenolic resins have a slow curing speed and cannot contribute to improving fast curing properties.

(Problems to be Solved by the Invention) An object of the present invention is to improve the curing speed of self-emulsifying aromatic epoxy resin paints.

A further object of the present invention is to improve the adhesion and processability of the coating film.

Another object of the present invention is to overcome the sanitary problems associated with the combined use of water-soluble amino resins.

(Means for Solving the Problems) That is, two aspects of the present invention are an acrylic resin (A) portion containing 12 to 70% by weight of monobasic carboxylic acid monomer units as an essential component in one molecule, and an aromatic epoxy resin (
B) acrylic resin with an excess of carboxyl groups-aromatic epoxy resin partial bond (D) having a pH of 4
After dispersing in an aqueous medium in the presence of ammonia or amine in an amount of ~11, the phenolic resin precondensate (C) containing 40% by weight or more of a compound whose general formula is represented by the following formula <1) is prepared. It is an aqueous resin dispersion made by blending and uniformly dispersing.

(However, in formula 9, R is a hydrogen atom or a carbon number of 1 to 1
2 alkyl group, X is a hydrogen atom or methyl group, a, b
are both 1 or 2, and a+b-3 or a+
It is b-4. ) [Structure of the Invention] (Means for Solving the Problems) The acrylic resin-aromatic epoxy resin moiety/bond (D) in the present invention contains at least the acrylic resin (A) moiety in one molecule. and an epoxy resin (B).

The first method for producing the acrylic resin-aromatic epoxy resin partial bond @ (D) in the present invention is to copolymerize a copolymerizable monomer mixture containing 12 to 70% monobasic carboxylic acid monomer. Acrylic resin (A
) and an aromatic epoxy resin (B) having an average of 1.1 to 2.0 epoxy groups in one molecule, preferably in the presence of an amine-based esterification catalyst or in the absence of a catalyst. do.

The acrylic resin (A) is prepared by mixing a monomer mixture consisting of a monobasic carboxylic acid monomer such as acrylic acid or methacrylic acid with other copolymerizable monomers in an organic solvent with azobisisobutyronitrile.

It can be obtained by copolymerization using a common radical polymerization initiator such as benzoyl peroxide at a temperature of 80°C to 150°C.

The copolymerizable monomers include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, and 2-acrylate. Acrylic esters such as ethylhexyl, n-octyl acrylate, decyl acrylate, dodecyl acrylate, methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, n- methacrylate
hexyl, n-octyl methacrylate, methacrylic acid 2
．． -Methacrylic acid esters such as ethylhexyl, decyl methacrylate, and dodecyl methacrylate, styrene,
vinyl toluene.

Styrenic monomers such as 2-methylstyrene, t-butylstyrene, and chlorostyrene; hydroxy group-containing monomers such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate; 9N-methylol (meth); N-substituted (meth)acrylic yarns such as acrylamide, N-butoxymethyl (meth)acrylamide,
It can be selected from one or more epoxy group-containing polymers such as glycidyl acrylate and glycidyl methacrylate, and acrylonitrile.

The amount of monobasic carboxylic acid monomer used is 12 to 70% by weight based on the total amount of monomers.

If it is less than 12% by weight, the dispersion stability of the resin in the aqueous medium, the adhesion of the painted film to metal, the solvent resistance, and the flavor permeability are all poor (unfavorable); conversely, the amount of 70M If it exceeds %, the water resistance and boiling resistance of the coating film will deteriorate.

The acrylic resin (A) preferably has a weight average molecular weight of 3,000 to 80,000.

If the weight average molecular weight is less than 3,000, the crosslinking density of the coating film will increase, which will impede processability.

Also, 40,000. In particular, when the molecular weight exceeds 80,000, gelation tends to occur during reaction with the aromatic epoxy resin (B).

The aromatic epoxy resin (B) in the present invention is preferably one obtained by condensing bisphenol A and epihalohydrin in the presence of an alkali catalyst, and has an average of 1.1 to 2.0 epoxy resins in one molecule. having a number average molecular weight of 300 or more, preferably 900 or more. Commercially available products include Epikoat 828° and Epicoat 1001. manufactured by Shell Chemical Co., Ltd. Epicote 1004
．． Epicote 1007. Examples include Epicote 1009.

Furthermore, as the aromatic epoxy resin, a modified epoxy resin is used in which the epoxy group of the bisphenol A type epoxy resin is reacted with a vegetable oil fatty acid such as dehydrated castor oil, soybean oil fatty acid, or coconut oil fatty acid, or a modifier such as bisphenol A. You can also do that.

The partial reaction product of the acrylic resin (A) and the aromatic epoxy resin (B) is in a hydrophilic organic solvent.

Acrylic resin (A) and aromatic epoxy resin (B) are used in a solid content ratio of 2:1 to 1:6.

It can be obtained by reacting at 60° C. to 170° C. for about 10 minutes to 2 hours in the presence of ammonia or amine. The reaction was measured by measuring oxirane%;
It can be controlled by measuring viscosity or measuring molecular weight distribution by gel verminion chromatography (GPC).

What is the final oxirane group content of the partial reactants?

The reduction rate relative to the oxirane content of the aromatic epoxy resin is 5 to 95%, more preferably 30 to 7%.
It is 0%. If the reduction rate of oxirane groups is less than 5%, the acrylic resin-aromatic epoxy resin partial reaction product cannot be sufficiently self-emulsified in the aqueous medium and tends to separate during storage, and if it is greater than 95%, the acrylic resin-aromatic epoxy resin partial reaction product tends to separate during storage. The processability of the film tends to deteriorate.

The second method for producing the acrylic resin-aromatic epoxy resin partially bonded product (D) in the present invention is as follows.

A low molecular weight compound having a (meth)acryloyl group and an epoxy group in one molecule obtained by partially reacting an aromatic epoxy resin (B) with a monobasic carboxylic acid monomer such as (meth)acrylic acid. , a monomer mixture containing a monobasic carboxylic acid monomer and the above-mentioned copolymerizable monomer is subjected to radical polymerization.

The third method for producing the acrylic resin-aromatic epoxy resin partially bonded product (D) in the present invention is as follows.

Polymerization of a copolymerizable monomer mixture containing 12 to 70% by weight of a monobasic carboxylic acid heptamer in the presence of an aromatic epoxy resin (B) using a relatively large amount of an organic peroxide such as benzoyl peroxide. urge In this case, an aromatic epoxy resin grafted with an acrylic resin is obtained.

In the present invention, the preliminary aqueous dispersion is prepared by adding ammonia or amine to the acrylic resin-aromatic epoxy resin partial bond (D) in an amount such that the final composition has a pH of 4 to 11. It may be dispersed in an aqueous medium.

The above amine is, for example, trimethylamine.

Alkylamines such as triethylamine and butylamine, alcohol amines such as 2-dimethylaminoethanol, jetanolamine, triethanolamine, and aminomethylpropanol, 2-morpholine, and the like are used. Also ethylenediamine.

Polyvalent amines such as diethylenetriamine can also be used.

In the present invention, the aqueous medium is water containing at least 10% by weight of water alone or in a mixture with a hydrophilic organic solvent.

Hydrophilic organic solvents include methanol, ethanol, n-
Alkyl alcohols such as propatool, isoproptool, n-butanol, 5ec-butanol, tert-butanol, and isobutanol.

Ether alcohols such as methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, methyl calpitol, ethyl carpitol, ether esters such as methyl cellosolve acetate, ethyl cellosolve acetate, and other dioxane, dimethyl formamide, diaheptone alcohol, etc. are used. be done.

The aqueous resin dispersion in the present invention is an aqueous dispersion of the above-mentioned acrylic resin-aromatic epoxy resin partial bond (D), and a phenolic resin initial condensation containing a compound represented by the following general formula (■). It can be obtained by blending product (C).

(However, in formula 1, R is a hydrogen atom or has 1 to 1 carbon atoms.
2 alkyl group, X is a hydrogen atom or methyl group, a,
Both b are 1 or 2, and a+b=3 or a
+b=4. ) At this time, the phenolic resin initial condensate (C) is.

Add the aqueous dispersion of partially bound product (D) with stirring. By this operation, the phenolic resin initial condensate (C), which itself has no solubility or dispersibility in water, was
It is thought that the partially bound product (D) enters into the dispersed fine particles and becomes associated with the two partially bound products (D), resulting in a stable resin dispersion.

The phenol resin initial condensate (C) containing the compound represented by the general formula (I) is a mixture of bisphenols such as bisphenol A or bisphenol F and formaldehyde, and 5 to 10 moles of formaldehyde per mole of bisphenol A. Using 1.5 to 4 moles of alkali catalyst, relatively mild reaction conditions, i.e. 9
It can be obtained by reacting at a reaction temperature of 30 to 70°C for 30 minutes to 4 hours, more preferably at 45 to 55°C for 2 to 3 hours.

Further, the phenolic resin initial condensate (C) containing the compound represented by the general formula (I) is 2m-ethylphenol carbonate, which is a trifunctional mononuclear phenol.

It can be obtained using 3.5-xylenol and m-methoxyphenol as raw material phenol.

Furthermore, the above trifunctional mononuclear phenol, p-cresol, 0-cresol, p-tert-butylphenol, p-ethylphenol, 2.3-xylenol, m-
A difunctional phenol such as methoxyphenol can also be used in combination. The preparation of the phenol resin condensate (C) using these mononuclear phenols may be performed under the same reaction conditions as those using bisphenols.

The alkali catalyst used in the synthesis of the phenol resin initial condensate (C) is preferably a strong base such as sodium hydroxide or potassium hydroxide, but sodium carbonate and the like can also be used alone or in combination.

Formaldehyde can also be used as formalin and paraformaldehyde.

The important point in this synthesis is to suppress the condensation reaction and allow only the addition reaction of formaldehyde to the phenols to occur.To this end, the reaction temperature is as low as possible, an alkaline catalyst is used in excess of the number of moles of the phenols, and formaldehyde is also added to the phenols. Use more than the equivalent number of the class.

For example, when 1 mole of bisphenol A is used as the phenol, it is suitable to use the alkali catalyst in an amount of about 2 moles and the amount of formaldehyde in an amount of about 8 moles.

The end point of the reaction is determined by GPC measurement.

For reactions such as carbolic acid, the color changes from pale yellow to dark red depending on the degree of condensation.

It can also be determined by managing hue. Furthermore, if the reaction conditions can be controlled sufficiently, it can also be determined by the reaction time.

To separate the phenolic resin initial condensate (C) containing the compound of general formula (I) from the reaction product.

It can be obtained by making the solution of the reaction mixture acidic with hydrochloric acid, sulfuric acid, etc., filtering the precipitate, and washing with water. In the case of reaction products with high solubility in organic solvents, such as bisphenols, the organic solvent and acid can be added simultaneously and extracted into the solvent.

The extracted reaction product is treated with acid or alkali as necessary.

It can be purified by washing with water etc.

The amount of the compound represented by the general formula (■) produced in the phenol resin initial condensate (C) can be confirmed by GPC measurement. Furthermore, the methylol concentration can be confirmed from nuclear magnetic resonance spectroscopy.

The content of the compound represented by the general formula (■) in the phenol resin initial condensate (C) is 40% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more. The more the compound represented by the general formula (I), the faster the curing property and the hot water resistance.

Improves workability and adhesion.

Further, the phenol resin initial condensate (C) is used in an amount of 2 to 40% by weight based on the total amount of the resin including the acrylic resin (A) and the aromatic epoxy resin (B). 2% by weight
If it is smaller than this, the contribution to the curing speed of the coating film will not be sufficient, and if it exceeds 40% by weight, the physical properties such as processability of the coating film will tend to deteriorate.

The aqueous resin dispersion according to the present invention can be used as a paint by adding a surfactant, an antifoaming agent, etc. to improve coating properties, if necessary.

The applicable substrates include metal plates such as untreated steel plates, treated steel plates, galvanized iron plates, and tin plates, and the preferred coating method is air spray, airless spray, electrostatic spray, etc. , dip coating, roll coater coating, electrodeposition coating, etc. are also possible. Further, the baking conditions can be selected from the range of 2 to 30 minutes at a temperature of 150° C. to 230° C. for 2 hours.

The aqueous resin dispersion of the present invention can also be used in rust-preventing primers, printing, inks, anti-corrosion paints, etc. by adding appropriate rust preventive agents, pigments, fillers, etc., depending on the purpose.

The aqueous resin dispersion according to the present invention can be used as a paint by adding a surfactant, an antifoaming agent, etc. to improve coating properties, if necessary.

Commonly used substrates include metal plates such as untreated steel plates, treated steel plates, galvanized iron plates, and tin plates.As for the coating method, spray painting such as air spray, airless spray, and electrostatic spray is preferred. Dip coating, roll coater coating, electrodeposition coating, etc. are also possible. The baking conditions can be selected from a temperature range of 150°C to 230°C for 2 to 30 minutes per hour.

The aqueous resin dispersion of the present invention can also be used in rust-preventing primers, printing inks, anti-corrosive paints, etc. by adding appropriate rust preventive agents, pigments, fillers, etc., depending on the purpose.

The present invention will be explained below using two examples. In addition.

In the examples, "parts" and "%" are "parts by weight" and "% by weight," respectively.
” is shown.

(Example) The present invention will be explained below using two examples. In addition.

In the examples, "r part" and "%" are "part by weight" and "% by weight," respectively.
” is shown.

(Example) [Preparation of acrylic resin solution] Styrene 300.0 parts Ethyl acrylate 210.0 Methacrylic acid 90.0 Ethylene glycol motupyl ether 288.0 Benzoyl peroxide 12.0 174 of the mixture of the above compositions was replaced with nitrogen Pour into 4 flasks with gas replaced 8
Heat to 0-90°C.

While maintaining the temperature, the remaining 3/4 was gradually added dropwise over 2 hours. After one drop was added, the mixture was stirred at that temperature for another 2 hours, then cooled, and the acid value was 93 (in terms of solid content).

(same below), solid content 59.7%, viscosity 4100 cps (
A carboxyl group-containing resin solution was obtained (all viscosities hereinafter refer to measurement results at 25°C).

[Preparation of epoxy resin solution]

Epicoat 1007 500 parts Ethylene glycol monobutyl ether 333.3 Pour the entire amount into a 4-hole flask purged with nitrogen gas.

The mixture was gradually heated to raise the internal temperature to 100°C, stirred for 1 hour to completely dissolve, and then cooled to 80°C to obtain an epoxy resin solution with a solid content of 60%. , [Preparation of phenolic resin (C1) solution] Bisphenol A 228 g (I mol), 37% formalin 649 g
(8 mol), 302 g (2,6 mol) of 35% sodium hydroxide
4 mol) and reacted at 50°C for 2 hours, then ethyl acetate 2
50 g and 250 g of n-butyl alcohol were added thereto, followed by 401 g (2.2 mol) of 20% hydrochloric acid, and after stirring at 60° C. for 10 minutes, the mixture was allowed to stand and was separated into two layers within a few minutes. The upper layer was an organic compound layer and the yield was 430 g.

Wash the organic layer using water and aqueous ammonia.

Neutralized and 330g of pale purple transparent phenolic resin (C1
)was gotten. Solid content was 30%.

When this solution was analyzed by high performance liquid chromatography and nuclear magnetic resonance absorption spectroscopy, it was confirmed that it contained 75% of a tetramethylol compound of bisphenol A represented by the following chemical formula. The remaining 25% was a mixture of 2Ii bisphenol A condensed at the methylol group and polymethylolated trimer.

[Preparation of phenolic resin (C2) solution] 228 g (1 mol) of bisphenol A, 649 g of 37% formalin (
8 mol), 229 g (2 mol) of 35% sodium hydroxide
was synthesized and purified in the same manner as in the preparation of the phenol resin in Example 1, resulting in a solution with a solid content of 30%.
g was obtained. The content of tetramethylolated bisphenol A in this phenol resin (C2) solution was 63%.

The remaining 37% was a mixture of polymethylolated bisphenol A dimers or more.

[Preparation of phenolic resin (C3) solution] 94 g of carbolic acid (
I mol), 37% formalin 405 g (5 mol), 25
% sodium hydroxide (I, 32 mol) was mixed and reacted at 50°C for 2 hours, and then at 70°C for 2 hours, a red transparent solution was obtained. Add 100 g of ethyl acetate and 100 g of n-butyl alcohol to this solution.

Subsequently, 200 g (I, 1 mol) of 20% hydrochloric acid was added.

When the mixture was stirred at 60° C. for 10 minutes and allowed to stand, it separated into two layers within a few minutes: the upper layer was a golden yellow organic layer and the lower layer was a pale brown aqueous layer. When the organic layer was washed twice with 150 g of water, the lower layer became an organic layer. The pH of the aqueous layer at this time was 4.2. The yield of the organic layer was 303 g, solid content 26.3%. Remove some of the solvent.

The solid content was 30%. This organic layer was a phenol resin (C3) containing 55% of a mixture of dicarboxylic acid polymethylolates and 45% of polynuclear polymethylolates.

[Preparation of phenolic resin (C4) solution] Bisphenol A 22Bg (1 mol), 37% formalin 324g (
4 mol), 114 g (I mol) of 35% sodium hydroxide
After reaction at 70℃ for 4 hours, 200g of ethyl acetate
Add 200g of n-butyl alcohol to 20%
151 g (0.83 mol) of hydrochloric acid was added, stirred at 60° C. for 10 minutes, and then allowed to stand, resulting in separation into two layers within a few minutes.

A light brown color with a solid content of 30% was obtained by the same operation as in Example 1.

300 g of a clear solution was obtained. This phenolic resin (C4
) The solution contains 4 tetramethylolated products of bisphenol A.
．． 8%, and the rest was a condensed polynuclear mixture.

[Preparation of phenolic resin (C5) solution] 94 g of carbolic acid (
I mol), 324.3 g (4 mol) of 37% formalin,
211 g (I, 32 mol) of 25% sodium hydroxide was mixed and reacted at 50° C. for 2 hours, and then further reacted at 70° C. for 4 hours to obtain a dark red transparent solution. Add 100 g of ethyl acetate and 1 portion of n-7' methylalcohol to this solution.
00 g was added, followed by 200 g (I, 1 mol) of 20% hydrochloric acid. Thereafter, the same operation as in Example 1 was performed to finally obtain a brown transparent organic layer. The yield of the organic layer was 311 g, solid content 35.6%. Add n-butyl alcohol,
The solid content was 30%. Organic layer is mononuclear form of carbolic acid 9.6%
A phenolic resin (C5) solution was obtained, which was a mixture of polymethylol compounds containing 26.7% of dinuclear materials and 63.7% of polynuclear materials.

Comparative Example 1 [Preparation of aqueous resin dispersion] ■ 50 parts of the above acrylic resin solution ■ 100 parts of the above epoxy resin solution ■ 2-dimethylaminoethanol 4.8 ■ Ion exchange water
205.2 ■, ■, ■ were placed in a reaction vessel, and after reacting at 80°C for 70 minutes with stirring, ■ was added dropwise over an hour without stirring, resulting in a milky white predispersion with a solid content of 25% and a viscosity of 6300 cps. body (Dl) was obtained.

This preliminary dispersion (Dl) was diluted with 90 parts of ion-exchanged water to finally obtain a resin dispersion having a solid content of 20% and a viscosity of 125 cps.

Example 1 [Preparation of aqueous resin dispersion] ■ 360 parts of the above predispersion (DI) ■ 60 parts of the above phenol resin (C1) solution ■ 120 parts of ion-exchanged water, without stirring ■
was added dropwise, further diluted with ■, and the final solid content was 20%.
A resin dispersion with a viscosity of 50 cps was obtained.

Example 2 [Preparation of aqueous resin dispersion] ■360 parts of the above preliminary dispersion (Di)■
Stir the above phenol resin (C1) solution 30■ ion-exchanged water 105■■
was added dropwise, further diluted with ■, and the final solid content was 20%.
A resin dispersion with a viscosity of 75 cps was obtained.

Example 3 [Preparation of aqueous resin dispersion] ■ 360 parts of the above preliminary dispersion (D) ■ 10 parts of the above phenol resin (C1) solution 10 ■ ion-exchanged water [While stirring 5 ■, add ■ dropwise, and then add ■ Finally, a resin dispersion having a solid content of 20% and a viscosity of 80 cps was obtained.

Example 4 A resin dispersion was obtained in the same manner as in Example 1 except that phenol resin (C2) was used instead of the phenol resin (C1) solution in Example 1. Solid content 20%, viscosity 62cp
It was s.

Example 5 A resin dispersion was obtained in the same manner as in Example 1 except that phenol resin (C2) was used in place of the phenol resin (C1) solution in Example 2. Solid content 20%, viscosity 83cp
It was s.

Example 6 A resin dispersion was obtained in the same manner as in Example 1 except that phenol resin (C2) was used in place of the phenol resin (C1) solution in Example 3. Solid content 20%, viscosity 90cp
It was s.

Example 7 A resin dispersion was obtained in the same manner as in Example 1 except that phenol resin (C3) was used instead of the phenol resin (C1) solution in Example 1. Solid content 20%, viscosity 45cp
It was s.

Example 8 A resin dispersion was obtained in the same manner as in Example 1 except that phenol resin (C3) was used in place of the phenol resin (C1) solution in Example 2. Solid content 20%, viscosity 66cp
It was s.

Example 9 A resin dispersion was obtained in the same manner as in Example 1 except that phenol resin (C3) was used in place of the phenol resin (C1) solution in Example 3. Solid content 20%, viscosity 73cp
It was s.

Comparative Example 2 A resin dispersion was obtained in the same manner as in Example 1 except that phenol resin (Cf) was used instead of the phenol resin (C1) solution in Example 1. Solid content 20%, viscosity 45cp
It was s.

Comparative Example 3 A resin dispersion was obtained in the same manner as in Example 1. Solid content 20%
, the viscosity was 60 cps.

Example 10 [Preparation of epoxy acrylate resin solution] ■ Epicote 1009 646 parts ■ Ethylene glycol monobutyl ether 349 ■ 10% sodium hydroxide 1 ■ Hydroquinone
0.02■Methacrylic acid
Prepare 4 ■ and ■ and heat 2 at 110℃.
The mixture was stirred for a period of time to ensure dissolution, and then cooled. ■■ was added at 100°C, and after heating, ■ was added. The reaction was carried out at 130°C for 5 hours, and the end point was reached when the acid value decreased to 0.3 mg KOH/g, and the reaction mixture was taken out after cooling.

The number average molecular weight of the product is 3800. Epoxy equivalent is 27
50. The average number of epoxy groups per molecule was 1.3B, solid content was 65%, and the viscosity at 50°C was 80,000 cps. [Preparation of aqueous resin dispersion] ■Methyl ethyl ketone 40 parts■The above epoxy acrylate resin solution 171■ Styrene 16.7 ■ Ethyl acrylate 19.5 [Co.] Methacrylic acid 19.5 ■ Ethylene glycol monobutyl ether 33.40 Azobisisobutyronitrile 2.40 Azobisisobutyronitrile 0.6 [Phase] Methyl ethyl ketone 10 @2-Dimethylaminoethanol 10% aqueous solution 7.0 [Phase] Ion-exchanged water 505.8O Phenol resin (C1) solution 111.1■ is charged into a flask and heated to reflux, and the mixed solution from ■ to @ is placed in it. was added little by little over 3 hours. After the addition was completed, the temperature was raised to 90°C, and (2) was added to continue the reaction. Since the sampled solution reached 55%, add [phase] while cooling.
After 15 minutes, the [phase] was added, and then O was gradually added to the obtained resin dispersion. Solid content 20%, viscosity 15c
An aqueous dispersion of ps was obtained.

Comparative Example 4 In Example 1, 22°5 of Cymel 325 (water-soluble amino resin manufactured by Mitsui Toatsu Co., Ltd., solid content: 80%) was used in place of the phenolic resin (C1).

A resin dispersion was obtained in the same manner as in Example 1. The resulting resin dispersion had a solid content of 20% and a viscosity of 130 cps.

The aqueous resin dispersions obtained in Coating Test Examples 1 to 10 and Comparative Examples 1 to 4 were subjected to solvent substitution to obtain resin dispersions containing 4.6% ethylene glycol, 72.4% water, and 23% solid content. After that, 25% ammonia water was added little by little, and the solid content of all the resin dispersions was 21-22, 5%, and the viscosity was 800-1.
It was adjusted to 200 cps. All resin dispersions after this preparation.

After storage at 50°C for 3 months, there was no change in viscosity and no sedimentation was observed, confirming that it was extremely stable.

Next, the prepared resin dispersion was placed on a tin plate for 8 to 10 minutes.
A test panel was prepared by applying the coating to a thickness of μ and baking and drying at 165° C. and 200° C. for 5 minutes each. Further, the above aqueous dispersion was applied to the inner surface of a 2-piece tin can with a content of 250 ml by spraying.

The cans were baked at 165° C. and 200° C. for 5 minutes each, dried, and coated on the inside of the cans, which were tested for various resistances.

The test method is as follows.

(I) Adhesion: Approximately 1.5 nm using a knife on the coating surface
Make 11 vertical and horizontal cuts in the goban with a width of ＋＋＋＋. Adhere 2401111 width cellophane adhesive tape.

The number of unpeeled parts of the goblin area when strongly peeled is expressed in the numerator.

(2) Retort resistance: After treatment in water at 125°C for 30 minutes.

The coating film was judged visually and by peeling off with cellophane adhesive tape.

(3) Workability: This occurs when a special fold-type DuPont impact tester is used, a sample folded in half is placed at the bottom, and an iron weight with a flat contact surface weighing Ikg is dropped from a height of 50cm. The length of the paint film color crack at the bent part was measured.

(4) Corrosion resistance: A test piece with an X cut made on the coating surface using a knife was treated in 1% saline at 125°C for 30 minutes, and the degree of corrosion near the X mark was determined.

(5) Potassium permanganate consumption: Fill a can with internal coating with 250 ml of ion-exchanged water, tighten twice, and heat at 60°C.
Treatment was performed for 30 minutes and at 100°C for 30 minutes.

It was measured according to the test method described in the Food Sanitation Law.

(6) Salt solution storage test: 25% of 1% salt solution in a can with internal coating
After filling with 0m+1 and tightening 9 times, pack it into a cardboard box (15 cans in a 30-can-sized box), apply vibration with a vibrator for 5 hours, collide with 2 renters, and store at 25℃ for 1 month. Did 0
The above test cans were opened and the amount of iron eluted into the saline solution was measured by atomic absorption spectrometry. (Average of n: 15) (7) Flavor retention: 250 m of ion-exchanged water in a can with internal coating
1 was filled and sealed, and after sterilization at 100°C for 30 minutes, the solution in the can was further stored at 50°C for 6 months, and a flavor test was conducted on the solution in the can.

Test Results (I) Adhesion: All samples of Examples and Comparative Examples baked at 165°C and 200°C were 100/100.

(2) Retort resistance: The judgment results are shown in Table 1. No abnormalities (○): Slight whitening or peeling of the paint film (△): Significant whitening or peeling of the paint film (
×).

(3) Workability: All samples of Examples and Comparative Examples baked at 165°C and 200°C had a crack length of 1
It was 0 mm or less and passed 9.

(4) Corrosion resistance: The judgment results are shown in Table 1.
): Slightly corroded (△): Significantly corroded (x).

(5) Potassium manganate consumption: Table 1 shows the numerical values (p
pm).

(6) Salt solution storage test: Table 1 shows the values (ppm).

(7) Flavor preservability: Some changes were observed in the inner-coated can of Comparative Example 3, but no changes were observed in the inner-coated cans of other Examples and Comparative Examples.

(Kuhaku) Procedural amendment (voluntary) May 9th, 1985

Claims (1)

[Claims] 1. Acrylic resin containing 12 to 70% by weight of monobasic carboxylic acid monomer units in one molecule as an essential component (
The carboxyl-excess acrylic resin-aromatic epoxy resin partial bond (D) having the A) part and the aromatic epoxy resin (B) part is treated with ammonia or amine in an amount such that the pH becomes 4 to 11. A phenolic resin precondensate (C) containing 40% by weight or more of a compound whose general formula is represented by the following formula (I) after being dispersed in an aqueous medium in the presence of
An aqueous resin dispersion made by blending and uniformly dispersing. (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, R is a hydrogen atom or has 1 or 1 carbon atoms.
2 alkyl group, X is a hydrogen atom or methyl group, a, b
are both 1 or 2, and a+b=3 or a+
b=4. ) 2. 60% by weight of a compound whose general formula is represented by formula (I)
The aqueous resin dispersion according to claim 1, which is blended with the phenolic resin precondensate (C) containing the above. 3. 70% by weight of a compound whose general formula is represented by formula (I)
The aqueous resin dispersion according to claim 1, which is blended with the phenolic resin precondensate (C) containing the above. 4. The aqueous resin dispersion according to claim 1, wherein the weight of the phenolic resin (C) is 2 to 40% by weight based on the total weight of the resin. 5. Acrylic resin-aromatic epoxy resin partially bonded with acrylic resin-aromatic epoxy resin (D) is obtained by partially reacting acrylic resin (A) and aromatic epoxy resin (B). Acrylic resin with excess carboxyl groups-aromatic The aqueous resin dispersion according to claim 1, which is a partial reactant of a group-based epoxy resin. 6. The weight average molecular weight of the acrylic resin (A) is 3000
80,000 to 80,000. 7. The aqueous resin dispersion according to claim 5, wherein the aromatic epoxy resin has a number average molecular weight of 900 to 6,000. 8. Acrylic resin (A) and aromatic epoxy resin (B)
) The aqueous resin dispersion according to claim 5, having a solid content ratio of 2:1 to 1:6. 9. The acrylic resin-aromatic epoxy resin partial bond (D) has a (meth)acryloyl group in one molecule obtained by partially reacting the aromatic epoxy resin (B) and (meth)acrylic acid. The aqueous resin dispersion according to claim 1, which is a partially bonded product (D) obtained by radical polymerizing a monomer mixture containing a monobasic carboxylic acid monomer to a low molecular weight compound having an epoxy group.