JPH02124983A - Water-based resin composition for coating - Google Patents

Abstract

PURPOSE:To prepare a water-based resin compsn. for coating with excellent food hygienic and flavor maintaining properties and with little dissolution of the resin during heat sterilization after applied as an inside coating of a metal container by dispersing a carboxylated self-emulsifiable epoxy resin and a polyvinyl chloride resin in an aq. medium. CONSTITUTION:A carboxylated self-emulsifiable epoxy resin obtd. by copolymerizing a vinyl monomer mixture contg. a carboxylated vinyl monomer in the presence of an arom. epoxy resin (contg. 1.1-2.0 epoxy rings in the molecule on the average) and a polyvinyl chloride resin with a mean degree of polymerization of 1000-2000 and a mean particle diameter of 20nm or less are mixed in a wt. ratio of said epoxy resin to said polyvinyl chloride resin of (90:10)-(20:80). The resulting mixture is dispersed in an aq. medium to give a water-based resin compsn. for coating.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an aqueous coating resin composition, and more specifically, to a metal coating composition, particularly as a paint for the inner surface of a can, with good processability, adhesion, etc. The present invention relates to an aqueous coating resin composition containing a vinyl chloride resin dispersed therein, which is capable of forming an excellent coating film that does not require repair after processing.

[Conventional technology]

Traditionally, metal can materials include aluminum, tinplate,
Metals such as Tin 7 Lee Steel are used. These metals are used to prevent corrosion, and usually a coating film is formed on the inside and outside of the can.As a paint for the inside of a can, it has excellent adhesion and anti-corrosion properties. usually,
Paints such as epoxy/phenol resin, epoxy/acrylic resin, and epoxy/amino resin are used.

However, the above-mentioned paints do not have sufficient workability, and the base metal may be exposed during the can manufacturing process. Therefore, after the can manufacturing process, the exposed metal parts are repaired, but such repairs complicate the can manufacturing process and are disadvantageous in terms of cost. is requested. Vinyl chloride resin-based organosol paints have been developed as paints that meet these requirements.

[The problem that the invention attempts to solve]

However, the organosol paint has excellent adhesion to metal materials and processability, and is useful as a paint that does not require repair, but since it uses an organic solvent as a dispersion medium,
Not only does the solvent volatilize into the working atmosphere, worsening the working environment and impairing human safety such as solvent poisoning for workers, but it also pollutes the entire atmosphere and, since organic solvents are flammable, can cause fires. There is always a risk of explosion.

Furthermore, when used as an inner surface coating for metal cans, the epoxidized oil component, which is a plasticizer or stabilizer, is eluted into the contents, especially during the heat sterilization process, which is unfavorable from a food hygiene perspective. This may cause problems such as changing the flavor of the product, whitening of the paint film, or poor opening of the easy-open lid (exempted from opening by pulling the opening tongue on the can lid body). This indicates the degree of remaining coating film on the inner surface of the opening, and the less coating film remaining, the better the opening property.

In order to avoid these problems, especially air pollution, deterioration of the working environment, and the risk of fire and explosion,
Publication No. 72 proposes an aqueous coating resin composition obtained by polymerizing a vinyl monomer containing vinyl chloride in an aqueous medium of a carboxyl group-containing self-emulsifying epoxy resin. However, this aqueous coating resin composition
In order to stably polymerize vinyl chloride, the proportion of the epoxy resin component in the carboxyl group-containing self-emulsifying epoxy resin is 50% by weight or less, resulting in poor adhesion and opening properties of the coating film, and the polymerization initiator. Since ammonium persulfate was used as the coating material, the water resistance and whitening properties of the coating film were poor.

The problem to be solved by the present invention is to solve various problems of conventional vinyl chloride resin-based organosol paints, and to solve the problems on the inner surface of metal containers that are widely used as containers for foods, cosmetics, pharmaceuticals, etc. As a paint, even after heat sterilization, the elution amount of the water-soluble resin component present in the paint film is extremely small, and it has excellent food hygiene and flavor retention, as well as opening properties, processability, adhesion, and aging properties. It is an object of the present invention to provide a resin composition for aqueous waxing which has excellent dispersion stability.

([Means to solve Zhao] The present invention aims to solve the above problems.

Provided is an aqueous coating resin composition (hereinafter referred to as the coating composition of the present invention) comprising a resin mixture comprising a carboxyl group-containing self-emulsifying epoxy resin and a vinyl chloride resin dispersed in an aqueous medium.

The carboxyl group-containing self-emulsifying epoxy resin used in the present invention can be produced, for example, by the following production method.

That is, (a) a method of copolymerizing (a) a vinyl monomer mixture containing a carboxyl group-containing vinyl monomer in the presence of an aromatic epoxy resin and (b) a large amount of a polymerization initiator; (2) (a) An aromatic epoxy resin and (b) a carboxyl group-containing vinyl polymer obtained by copolymerizing a vinyl monomer mixture containing a carboxyl group-containing vinyl monomer, with the carboxyl group being the same as the epoxy group. (3) A method of carrying out an esterification reaction in an alcoholic medium at an excessive concentration of reactive groups; (b) A method of copolymerizing a vinyl monomer mixture containing a carboxyl group-containing vinyl monomer in the presence of a polymerization initiator. can also be used.

Examples of the aromatic epoxy resin include bisphenol Afi epoxy resin, bisphenol F type epoxy resin, Nogelac type epoxy resin, fatty acid modified epoxy resin, and phenol compound modified epoxy resin. Among these aromatic epoxy resins, those having an average of 1 to 2.0 epoxy groups in one molecule and having an epoxy equivalent of 170 or more are preferred. Commercial products such as those manufactured by Shell Chemical Co., Ltd. [Epicor] 152J manufactured by
"Epicor) 154J, [Epicor) 828J, [Epicor] 100IJ, "Epicor) 1004J, [Epicor] 1007J, "x Piquat 1009J,"
Epicort 1010J, "Epicort l100LJ", "Epicron 840" manufactured by Dainippon Ink and Chemicals Co., Ltd.
, "Epicron 1050J, [Epicron 4050J,
Examples include "Epiclon 7050J" and "Epiclon 9050J. One or more kinds of aromatic epoxy resins mentioned above can be selected and used.

Examples of carmexyl group-containing vinyl monomers include:
Acrylic acid, methacrylic acid, crotonic acid, itaconic acid,
Examples include maleic acid and fumaric acid.

Examples of polymerizable vinyl monomers other than carboxyl group-containing vinyl monomers include styrene monomers such as styrene, vinyltoluene, 2-methylstyrene, t-butylstyrene, and chlorostyrene; methyl acrylate, ethyl acrylate, and inglovir acrylate. , n-butyl acrylate, isobutyl acrylate, lower acrylic acid, acrylic isoal ξyl, h-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate, dodecyl acrylate, etc. Acrylic esters; methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, rhoamyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-methacrylate
Methacrylic acid esters such as ethylhexyl, decyl methacrylate, dodecyl methacrylate; Hydroxyethyl acrylate, hydroxyglobyl acrylate, hydroxyethyl methacrylate, hydroxyglobyl methacrylate, etc. Hydroxyl group-containing monomer; N-methylol (meth) Examples include N-substituted (meth)acrylic yarns such as acrylamide% N-butoxymethyl (meth)acrylamide.

Examples of the polymerization initiator used in the copolymerization reaction of a vinyl monomer mixture and the copolymerization reaction of a vinyl group-containing reactant and a vinyl monomer mixture include azobisisobutyronitrile, benzoyl peroxide, t-butylperoxy 2
- Common radical polymerization initiators such as ethylhexanate can be mentioned.

The proportion of these polymerization initiators used is preferably in the range of 0.65 to 20% by weight based on the vinyl mono'7-mixture.

Alcoholic vehicles include, for example, ethanol, h-
Glo/f-nol, isopronof-nol, n-butanol, 8@e-butanol, imbutanol, t@rt-
Alcohols having 2 to 6 carbon atoms such as butanol, amyl alcohol, in-amyl alcohol, l@e-amyl alcohol, n-hexanol, cyclohexanol;
Glycol ethers such as methyl cellosolve, ethyl cellosolve, provir selon, butyl cellosolve, methyl calpitol, ethyl carpitol, etc. Glycol ether acetates such as methyl cellosolve acetate, ethyl cellosolve acetate; dioxane, dimethylformamide, diaheptone alcohol, etc. can be mentioned.

N-butanol is particularly preferred since it is easily removed from the aqueous medium.

The amount of carboxyl group-containing vinyl monomer used is 20% of the vinyl monomer mixture! % or more is preferable. When the amount of carboxyl group-containing vinyl monomer used is less than 20%, the dispersion stability of the resin in the aqueous medium
When used as a painted tiger coating film for gold IIi adhesion, solvent resistance, and for the inside of cans, flavor suitability, etc., tend to deteriorate, which is not preferable.

Aromatic epoxy resin and vinyl monomer mixture or carboxyl group-containing vinylpolymer) -r -(') M
The ratio is preferably in the range of 40:60 to 90:100 by weight.
L<, a reactive group concentration range in which the carboxyl group is in excess with respect to the niboxy group is preferred. If the proportion of aromatic epoxy resin used is as low as 40% by weight, the adhesion of the coating film to metal tends to decrease;
If it exceeds J11%, it is not preferable because the dispersion stability tends to decrease.

Examples of the vinyl chloride resin used in the present invention include vinyl chloride resins, vinylidene chloride resins, and vinyl chloride-vinyl acetate copolymer resins having an average degree of integration in the range of 1,000 to 2,000. For the purpose of modifying vinyl chloride resin, a vinyl monomer copolymerizable with vinyl chloride may be copolymerized in the presence of vinyl chloride resin.

The vinyl chloride resin used in the present invention is called -1-stresin, and its average particle diameter is preferably 20 μm or less, more preferably 5 μm or less, and particularly preferably 2 μm or less.

As a commercially available vinyl chloride resin that can be used in the present invention, for example, [Viniriki P 440J manufactured by Mitsubishi Kasei Vinyl Co., Ltd.
, "Viniki P540J," Zeon 38 from Nippon Zeon Co., Ltd.
Examples include "J", "Zeon 61", and "Zeon 121".

The coating composition of the present invention is prepared by neutralizing at least -s of carboxyl groups contained in a carboxyl group-containing self-emulsifying epoxy resin with a basic compound, and then dispersing the neutralized product in water. It is obtained by dispersing a vinyl chloride resin in an aqueous dispersion of a group-containing self-emulsifying epoxy resin using a dispersion means such as a Gale mill, a sand mill, or an ultrasonic wave. In this case, the amount of the basic compound used is preferably such that the - of the dispersion is 5 or more. After mixing a carboxyl group-containing self-emulsifying epoxy resin and a vinyl chloride resin, the mixture is obtained by dispersing it in an aqueous medium according to the method for obtaining an aqueous dispersion of a carboxyl group-containing self-emulsifying epoxy resin. It will be done.

The ratio of carboxyl group-containing self-emulsifying epoxy resin to vinyl chloride resin is 90:10 to 90:10 by weight of solid content.
A range of 20:80 is preferred. If the proportion of the carboxyl group-containing self-emulsifying epoxy resin used is more than 90% by weight, the easy-open ring lid tends to have poor opening properties, particularly poor flavor suitability for alcoholic beverages; If it is less than %, it is not preferable because the water resistance, processability, adhesion to mm of metals, etc. of the coating film tend to be poor.

The base used to neutralize the carboxyl group is preferably ammonia or a volatile amine, and inorganic bases are not preferred because they tend to remain in the membrane and impair water resistance.

Examples of the amine that can be used include alkyl amines such as trimethylamine, triethylamine, and butylamine; alcohol amines such as dimethylamine ethanol, jetanolamine, and aminomethylglodnol; and morpholine. Polyvalent amines such as ethylene/cyamine and diethylenetriamine can also be used.

In the present invention, the aqueous medium refers to at least 10 fl.
% or more of water alone or a mixture with a hydrophilic organic solvent. Examples of the hydrophilic organic solvent include methanol, ethanol, n-gulo-f-nol, inguron-9-nol, n-7"tanol, zen-C-butanol,
Alkyl alcohols such as t@rt-butanol and inbutanol; methylcellonulp, ethylcellosolve,
Glycol ethers such as globil cellosolve, butyl cellosolve, hexyl cellosolve, methyl carpitol, ethyl carpitol; methyl cellosolve acetate,
Glycol ether esters such as ethyl cellosolve acetate; in addition, dioxane, dimethylformamide, tetrahydrofuran, methyl ethyl ketone, dia-7ton alcohol, etc. can be used.

When it is necessary to reduce the organic solvent contained in the coating composition of the present invention, when producing KVi, a carboxyl group-containing self-emulsifying epoxy resin, the boiling point of acetatone, methyl ethyl ketone, n-butanol, butyl cellosolve, etc. After dispersion in an aqueous medium using a solvent that has a low azeotrope with water,
By distilling at normal pressure or reduced pressure, a coating composition with a low organic solvent content can be obtained stably and easily.

It is also possible to add a solvent, a surfactant, and an antifoaming agent to the coating composition of the present invention, if necessary, in order to improve the coating properties. It is also possible to add an amine resin or a phenolic resin to the coating composition of the present invention as a curing agent, but if a large amount of hexagonal is added, the amount of unreacted low molecular weight compounds remaining in the coating film increases and the coating composition becomes difficult to coat. Although it is undesirable because it increases the amount of elution from the membrane into the contents of the can, moderate addition is effective in improving adhesion and opening properties. When adding these hardening agents, 5
% or less, preferably 3% or less.

(91) It is possible to add wax, which is a lubricant, to the am-acid product of the present invention for the purpose of preventing scratches on the coating film during processing.

The features of the coating composition of the present invention are as follows.

(a) Kume, which is a water-based vinyl chloride resin-based sol paint that replaces the conventional vinyl chloride resin-based organosol paint;
It has excellent workability and low pollution.

(2) Since it contains a vinyl chloride resin with high barrier properties, it has excellent flavor suitability for the contents, and exhibits particularly excellent performance for alcoholic beverages.

(3) There is very little water extractable from the coating film, and it has excellent food hygiene properties.

(4) By mixing a vinyl chloride resin, which is a different type of resin, with a carboxyl group-containing self-emulsifying epoxy resin, the opening property is significantly improved.

(5) By mixing a different type of vinyl chloride resin powder with a carboxyl group-containing self-emulsifying acrylic resin), there is less foaming during baking of the paint, and it is possible to bake at high temperatures for short periods of time and in thick films.

(6) Vinyl chloride resin is obtained by emulsion polymerization method or suspension polymerization method, called paste resin, with an average particle size of 1 μm.
The dispersion stability of the coating composition over time is very good due to the use of fine powder of around m and the high dispersion effect of the carboxyl group-containing self-emulsifying epoxy resin.

Due to these characteristics, the coating composition of the present invention is useful as a coating material for aluminum, tin-plated steel sheets, pretreated metals, steel, and the like. The coating composition of the present invention is also useful as a coating material for nonmetallic substrates such as wood. The most preferred use of the coating composition of the present invention is to coat the inner surface of metal containers used for food and drink, etc. ! ! The membrane is water resistant, does not elute low-molecular compounds from the coating into the contents of the can, and has extremely high mM impermeability, so it will not alter the natural taste or aroma of the food or drink stored inside the can. It also has excellent workability and opening properties.

Further, the coating composition of the present invention does not foam even under high temperature and short baking conditions, allows thick film coating, and has good workability and contact resistance, so it is suitable for welding cans. It is also useful as a paint for color correction.

Painting methods include air spray, airless spray,
Spray coating such as electrostatic spraying is preferred, but dip coating, roll coater coating, electrodeposition coating, etc. are also possible.

In addition, the baking conditions are 120 to 280℃ for 10 seconds to
A range of 30 minutes is preferred.

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

The present invention will be explained below using examples. In addition, in the example, 1
Example 1 (Synthesis of carboxyl crystal-containing self-emulsifying epoxy resin) 1) n-butanol 120 parts 2)
"Epicote 10IOJ (epoxy equivalent weight 4380) 15
0 parts 3) Methacrylic 71!25 m 4) Styrene 10 parts 5)
Ethyl acrylate 2 parts 6) Benzoyl peroxide 3 parts (n-butanol 10 parts Nitrogen substituted 4)
The above (a) to (2) were charged into a tube and dissolved by heating and refluxing. A uniform mixture of (3) to (7) above was slowly added dropwise to this solution over 2 hours while stirring and maintaining the temperature of the flask at 100°C. After the dripping is finished,
The mixture was further stirred at the same temperature for 4 hours to obtain a carboxyl group-containing self-emulsifying epoxy resin solution with a solid content of 58%.

(Water dispersion of carxyl group-containing self-emulsifying epoxy resin) (8) The above carxyl group-containing self-emulsifying epoxy resin solution Ioo part (9) Dimethylethanolamine 4 parts OI ion exchange water 260 parts Nitrogen gas substitution Pour the above (81) into 4 Lof flasks, and add this to 100
The mixture was heated to .degree. C., and the mixture of (9) and ao was gradually added dropwise over 30 minutes with stirring to obtain an aqueous dispersion of a carboxyl group-containing self-emulsifying epoxy resin. Further, 130 parts of n-butanol and water were removed by azeotropic distillation under reduced pressure to obtain a solvent-free aqueous dispersion of a carboxyl group-containing self-emulsifying epoxy resin with a non-volatile content of 25%.

(Manufacture of aqueous resin composition for coating) Aqueous dispersion of carkyl group-containing self-emulsifying epoxy resin on Uυ 100 parts oz "Zeon 121"
J (vinyl chloride resin manufactured by Nippon Zeon)
When 15 parts of the above (a1) and part a were mixed and thoroughly dispersed in a sand mill, an aqueous coating resin composition with very good dispersibility that passed through all 420 mesh door cloths could be obtained. Ta. This composition remained in the same state even after 20 days, and no change in viscosity was observed.

The nonvolatile content of this composition was 35%.

(Painting) 0 100 parts of the above water-based coating resin composition (A4)
rEP-560J (phenol resin manufactured by Monfon Ht) 1 part (L-tuptylselonrup 5 parts above u3,
Oa and U! A paint was obtained by mixing 9 and stirring thoroughly.

Examples 2 to 4 and Comparative Examples 1 to 3 Using the systems shown in Table 1, each hydrophobic resin composition for coating was obtained in the same manner as in Example 1, and then each glaze paint was obtained in the same manner.

However, in Example 4, when making a paint in Example 1,
A coating material was obtained in the same manner as in Example 1 except that the phenol resin was not used.

Comparative Example 1 is a paint that does not use vinyl chloride resin. In Comparative Example 2, the vinyl chloride thread resin accounted for 90% of the solid content of the dye.
It is a paint that contains ion exchange water and is carefully adjusted using ion-exchanged water so that the nonvolatile content after paint is 35%. Comparative Example 3 is a paint obtained in the same manner as Example 1 except that a vinyl chloride resin having an average particle size of 50 μm was used.

In addition, in Table 1, "Zeon 38J" refers to Nippon Zeon (
Ltd.), It! It is a vinyl chloride-vinyl acetate copolymer.

Comparative Example 4 (Synthesis of carboxyl group-containing acrylic resin) Compensation) n-butanol 670 parts (b) Styrene 180 parts (e) Ethyl acrylate 45 parts (dl methacrylic acid
225 parts (8) 9 parts of benzoyl peroxide (&) 4 with total nitrogen substitution
Pour into a double flask and keep at 100℃ while stirring.
In this, lli!ll of the mixture and solution of the above (b) to (@l') was added over 120 minutes. After the dropwise addition, the mixture was further stirred at the same temperature for 3 hours, and the solid content was 40%. A containing acrylic resin solution was obtained.

(Synthesis of carboxyl group-containing self-emulsifying epoxy resin) (f) [Epicote i 010J
5 parts (gll the above carboxyl-containing acrylic resin solution)
238 parts (h) dimethylethanolamine
20 parts of the above (f) and (gl) were replaced with nitrogen, and the above (h) was added to the bath liquid after being completely dissolved by stirring at 100°C for 2 hours. and stirred for 1 hour to reduce the solid content to 3.
A self-emulsifying epoxy resin containing 8% carboxyl groups was obtained.

(Water dispersion of carboxyl group-containing self-emulsifying epoxy resin) (a) 76 parts of the above solution of the self-emulsifying epoxy resin containing carboxyl groups (94 parts of ion-exchange water ℃, and while stirring, the above ijl was added dropwise over 30 minutes to obtain an aqueous dispersion of carboxyl group-containing self-emulsifying epoxy resin with a solid content of 17.0%.From this aqueous dispersion, n- Butanol and water were removed by azeotropic distillation under reduced pressure to obtain a solvent-free aqueous dispersion of a carboxyl group-containing self-emulsifying epoxy resin with a nonvolatile content of 25%.

(Production of aqueous coating resin composition) (k) Aqueous dispersion of the above carboxyl group-containing self-emulsifying epoxy resin 100 parts (a) Vinyl chloride 15 parts - 10% ammonium peroxide solution 4 parts above (kl is nitrogen gas It was charged into a replaced stainless steel autoclave equipped with a stirring device, and 10 parts of the above (a) was added while stirring.Next, after heating this mixture to -55°C, the above fnl was added to start the polymerization reaction. Next, the remaining 5 parts of the above f1) were gradually added to keep the internal pressure of the reaction Vi constant. After the addition, stirring was continued until the internal pressure became 0 Yu/α2. As a result, the solid content was 33. A 5% aqueous coating resin composition was obtained.

This water-based coating resin composition? A paint fc was obtained in the same manner as in Example 1.

Example 5 (Synthesis of carboxyl group-containing self-emulsifying epoxy resin) 1) "Epicor" 1001j (t450 per epoxy) 1
50 parts 2) Methacrylic anhydride 7
, 7 parts 3) n-butanol 64
Part 4) Methacrylic acid 20 parts 5
) Styrene 13 parts 6) Ethyl acrylate 03 parts
5 parts of Butyl QJ (t-cal 9-oxy 2-ethylhexanate manufactured by Nippon Oil & Fats Co., Ltd.) were placed in a four-hole flask filled with nitrogen gas (a). After preparing and completely melting while heating, prepare the above (2),
Contents t-Heat to 80℃ while stirring, and heat to 60℃ at the same temperature.
By stirring for a period of time, a vinyl group-containing reactant was obtained.

This vinyl group-containing reactant and the above (3), (4), (5)
After uniformly mixing , (6) and (7), 100 parts of the mixed mixture was charged into a Rofranuco, which had been replaced with nitrogen gas, heated to 100°C, and while keeping the same temperature, the remaining mixture was mixed. liquid? The solution was added dropwise over 3 hours and further stirred at the same temperature for 4 hours to obtain a carboxyl group-containing self-emulsifying edexy resin solution.

(Water dispersion of carboxyl group-containing self-emulsifying epoxy resin) (8) 260 parts of the above carboxyl group-containing self-emulsifying epoxy resin solution (9) 9.5 parts of ammonia water (containing 28% ammonia) [1 ion exchange water 600 parts] Pour the above (8) e into a fourth flask that has been purged with nitrogen gas, heat to 100°C, and add 30% of the mixture of the above (9) and Ql while stirring.
The mixture was gradually added dropwise over several minutes to obtain an aqueous dispersion of a carboxyl group-containing self-emulsifying epoxy resin. Further, 105 parts of n-butanol and water were distilled off by azeotropic distillation under reduced pressure.
An aqueous dispersion of carboxyl group-containing self-emulsifying epoxy resin that does not contain solvents and has a non-volatile content of 25%? Obtained.

(Production of aqueous coating resin composition) Uυ 100 parts of the above carkyl group-containing self-emulsifying epoxy resin aqueous dispersion tta 70 parts of ion-exchanged water (a3 [Zeon 121j
When 55 parts μm of former XO Hono R1 was passed through and thoroughly dispersed in a sand mill, 4
An aqueous coating resin composition was obtained which had very good dispersibility and passed through all 20 meshes of furnace cloth. This composition remained in the same state even after 20 days, and no change in viscosity was observed. The nonvolatile content of this composition was 35%.

(paint) A paint was obtained in the same manner as in Example 1.

Next, the paints obtained in each Example and each Comparative Example were evaluated by the following method, and the results are summarized in Table 1.

[Evaluation of dispersion stability over time of coating composition]

Seal various paints in a 200M glass container and store at room temperature for 20 minutes.
The dispersion state M4 of the dispersion liquid after being left for one day was evaluated in the following three grades.

Q: No precipitate Δ: Some precipitate is seen ×: Very large amount of precipitate [Evaluation of foaming properties during baking] 120 rL on an aluminum plate with a thickness of 0.32 ysx
# of T9/dm2 [-1JX & Cloth] Various paints were applied using a percoater and baked for 30 seconds in the open at 260°C, then the surface of the painted board was observed and evaluated in the following three stages. I regret it.

○...No foaming Δ...Small foaming occurs X...Large foaming occurs on the entire surface [Creation of coated board for testing] On an aluminum plate with a thickness of 0.32m Various paints were applied using a percoater so that the weight of the dry coating film was 120 Da/dm 2 , baked in an open air at 260° C. for 30 seconds, and then cooled to room temperature to prepare a coated board for testing.

[Adhesion]

Use a cutter to cut the coating film formed on the test painted board.
1 Create 1 tloo base of VZ, apply adhesive tape to that part, quickly peel off the adhesive tape, and then
Observe the peeling state of the paint film and measure it in the following three stages.

○... No peeling Δ... 1-30% peeling ×... 31-100% peeling [Workability] The test painted board was pressed at a press temperature of 20°C and a painted board temperature of 20°C.
The lid was made with. In order to check the degree of damage to the paint film after processing, test the painted surface of the lid with an enamel tester. Fill the top of the lid with 1% saline, use the lid as an anode, insert the anode into the saline, and measure the current value. It was measured and evaluated in the following three stages.

○... Less than 0.3 mA Δ... 0.3 to 3 mA ×... 3 mA or more [Openability] After processing the round lid and boiling it at 100°C for 30 minutes, open the tongue piece. Make sure to check the extent of the coating remaining on the inner surface of the opening when fully tensioned and opened.

O... Nothing remains at all. Δ...A little paint film remains.

×...A considerable amount of paint remains.

[Elution test]

The above test coated plate of 160 cIIL2 was immersed in 100 g of purified water, and the amount of potassium permanganate consumed in the purified water after boiling at 100°C for 1 hour was measured.
Rated in stages.

○... 5 ppm or less Δ... 10 pprn or less After the water has submerged and the natural drip has stopped,
It was baked for 30 seconds in the open at 260°C. After taking it out and cooling it, it is placed in a container containing purified water with a coating surface area of 100 g and 100 g of distilled water as described above.
1, the coating film was completely immersed in purified water, kept in a sealed state and boiled for 30 minutes, and then cooled to 20°C.

As a control, a similar glass rod was baked for 30 seconds in the open at 260°C without being immersed in the paint, and otherwise treated in the same manner to prepare control water, and the odor and IT of the test water were compared to this. The results were evaluated in the following three stages.

■...Substantially no difference is observed.

△...Suspicious difference is observed.

×...Difference is clearly recognized.

・σ [Effects of the Invention] When the aqueous coating resin composition of the present invention is used as a metal coating composition, particularly as a paint for the inner surface of a can, the amount of water-soluble components eluted from the coating film into the contents of the can is reduced. Therefore, it has excellent food hygiene properties and flavor retention, and also has excellent dispersion stability over time and opening property.

Further, since the aqueous coating resin composition of the present invention has excellent adhesion to metal materials, it is useful as an aqueous coating material for plate materials used for rolling out punched cans, drawn cans, and the like.

Agent Patent Attorney Katsutoshi Takahashi 1゜2゜3゜4゜Indication of the case 1999 Patent Application No. 156723 Name of the invention Person who amends resin composition for aqueous coating Relationship with the case Patent applicant address: 35-58 Sakashita, Itabashi-ku, Tokyo 174 (28B)
) Representative of Dainippon Ink and Chemicals Co., Ltd.
Kuni Shigeru

Claims (1)

[Scope of Claims] 1. An aqueous coating resin composition comprising a resin mixture comprising a carboxyl group-containing self-emulsifying epoxy resin and a vinyl chloride resin dispersed in an aqueous medium. 2. Claim 1 comprising a vinyl chloride resin dispersed in an aqueous dispersion of a carboxyl group-containing self-emulsifying epoxy resin.
The aqueous coating resin composition described above. 3. The carboxyl group-containing self-emulsifying epoxy resin is obtained by copolymerizing (a) a vinyl monomer mixture containing a carboxyl group-containing vinyl monomer in the presence of (a) an aromatic epoxy resin. The aqueous coating resin composition according to claim 1 or 2, which is a resin composition. 4. The aqueous coating resin composition according to claim 3, wherein the ratio of the aromatic epoxy resin to the vinyl monomer mixture is in the range of 40:60 to 90:100 by weight. 5. The carboxyl group-containing self-emulsifying epoxy resin is a carboxyl group-containing vinyl polymer obtained by copolymerizing (a) an aromatic epoxy resin and (b) a vinyl monomer mixture containing a carboxyl group-containing vinyl monomer. The aqueous resin composition for coating according to claim 1 or 2, which is a carboxyl group-containing resin reactant obtained by esterifying in an organic solvent. 6. The ratio of aromatic epoxy resin to carboxyl group-containing vinyl polymer used is 40:60 to 90:1 by weight.
6. The aqueous coating resin composition according to claim 5, having a range of 0.00 to 0.00. 7. The carboxyl group-containing self-emulsifying epoxy resin comprises (a) aromatic epoxy resin, acrylic anhydride and/or
or a carboxyl group-containing product obtained by copolymerizing a vinyl group-containing reactant obtained by reacting methacrylic anhydride with (b) a vinyl monomer mixture containing a carboxyl group-containing vinyl monomer in the presence of a polymerization initiator. The aqueous coating resin composition according to claim 1 or 2, which is a modified polymer. 8. The aqueous coating resin composition according to claim 7, wherein the ratio of the aromatic epoxy resin to the vinyl monomer mixture is in the range of 40:60 to 90:10 by weight. 9. The ratio of carboxyl group-containing self-emulsifying epoxy resin to vinyl chloride resin is 90:1 in solid weight ratio.
The aqueous coating resin composition according to claim 1, 2, 3, 5 or 7, which has a ratio of 0 to 20:80. 10. The average degree of polymerization of the vinyl chloride resin is 1,000~
The aqueous coating resin composition according to claim 1, 2, 3, 5 or 7, which has a molecular weight of 2,000. 11. The aqueous coating resin composition according to claim 1, 2, 3, 5 or 7, wherein the vinyl chloride resin has an average particle size of 20 nm or less. 12. The content of carboxyl group-containing vinyl monomer is
Claim 3: 20% by weight or more of the vinyl monomer mixture
, 5 or 7. The aqueous coating resin composition according to . 13. The aqueous coating resin composition according to claim 3, 5 or 7, wherein the carboxyl group-containing vinyl monomer is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid. 14. Aromatic epoxy resin has an average content of 1.1 per molecule
Claim 3, which has ~2.0 epoxy groups;
8. The aqueous coating resin composition according to 5 or 7. 15. The aromatic epoxy resin according to claim 3 or 5, wherein the aromatic epoxy resin is selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, novolak epoxy resin, fatty acid modified epoxy resin, and phenolic compound modified epoxy resin. Resin composition for aqueous coating. 16. A paint comprising the aqueous coating resin composition according to claim 1, 2, 3, 5 or 7. 17. A paint for metal plates comprising the aqueous coating resin composition according to claim 1, 2, 3, 5 or 7. 18. A paint for correcting a welded part of a welded can, comprising the aqueous coating resin composition according to claim 1, 2, 3, 5 or 7. 19. A paint for the inner surface of a can, comprising the aqueous coating resin composition according to claim 1, 2, 3, 5 or 7.