JPH0645769B2 - Method for producing emulsified water-based paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing an emulsified water-based paint, and more specifically, utilizing the surfactant activity of an acrylic resin compounded in a paint resin melt, The present invention relates to a method for producing an aqueous paint by a phase inversion emulsification method.

(Prior art) Conventionally, in the production of cans for canning, in order to prevent the elution of metal into the contents and to prevent the corrosion of metal, it has been practiced to coat the metal material and the can itself with various paints. It is being appreciated. Not only in the case of squeezing and ironing cans made of unpainted metal material, but also in squeezed cans made of coated metal material and three-piece cans, the paint on the cans that are produced during the can making process is corrected and top coat is applied. In order to form it, various paints are spray-painted and baked on the can body and the can lid.

From the viewpoints of adhesion to metal substrates, corrosion resistance, flavor characteristics, and coating film processability, paints composed of a combination of an epoxy resin and a curing agent resin and vinyl paints are excellent.
When these paints are applied in the form of an organic solvent solution, good performance is exhibited, but during spray coating, the solvent volatilizes into the work environment, causing air pollution and environmental hygiene problems.

In order to eliminate these drawbacks, water-based paints, that is, water-based dispersion paints have already been developed. The first type of such water-based paint is one in which the paint resin is atomized by some means, and a surfactant or a water-soluble or hydrophilic resin is dispersed in water as a dispersant (for example, Japanese Patent Publication No. 44-1
No. 8076). The second type is modified by reacting a coating resin having a functional group such as an epoxy resin with a resin having a carboxyl group such as an acrylic resin, and neutralizing the modified resin with ammonia or amines. By doing so, it is self-emulsified in an aqueous medium (for example, JP-A-59-213718).

(Problems to be Solved by the Invention) However, in the former type of water-based paint, the dispersion particle size of the coating resin component tends to be generally coarse or uneven, and the water-based paint has poor dispersion stability. The performance of the obtained coating film is inferior to that of the solvent type paint.

Further, although the latter type of coating is excellent in dispersibility and the like as compared with the former type of coating, it is greatly restricted by the coating resin composition. Since it is difficult to make the content sufficiently large, it is not possible to sufficiently cure the coating film, so the hardness, denseness, barrier property against corrosive components, etc. are improved to a satisfactory level. There is a problem that it cannot be done.

Therefore, an object of the present invention is to provide a new method capable of producing an aqueous paint in which the above-mentioned problems in conventional aqueous paints are solved.

Another object of the present invention is a method for producing a water-based paint by a phase inversion emulsification method, which can be applied to a paint resin having an arbitrary composition and utilizes the surface active action of an acrylic resin compounded in a melt of the paint resin. To provide.

Another object of the present invention is to provide a method for producing a water-based coating composition in which the resin content is fine and controlled to have a uniform dispersed particle diameter, and which is excellent in dispersion stability.

(Means for Solving Problems) According to the present invention, A. A coating resin containing an epoxy resin and a methylol group-containing thermosetting resin in a weight ratio of 95: 5 to 40:60; 3 to 30% by weight per coating resin
An acrylic resin having an acid value of 35 to 350, or a composition containing a small amount of an organic solvent,
Ammonia or amine and water are mixed and kneaded in this melt to convert the carboxyl group in the acrylic resin into an ammonium salt or an amine salt, and at the same time, the fat content is reduced to O.
There is provided a method for producing an emulsified water-based paint, which comprises self-emulsifying a / W emulsion.

(Function) The present invention is capable of melt-mixing a combination of an epoxy resin and a methylol group-containing thermosetting resin, which are particularly suitable as a can-making coating, with an acrylic resin having an acid value in a specific range, and This molten composition is based on the finding that when it is kneaded with ammonia or amine and water, it self-emulsifies into an O / W type emulsion.

In the present invention, the epoxy resin and the methylol group-containing thermosetting resin are used in a weight ratio of 95: 5 to 40:60 because this combination has excellent adhesion to metal and corrosion resistance. By forming a coating film with excellent workability and the like.

Since the epoxy resin and the methylol group-containing thermosetting resin are thermosetting resins, it is feared that the epoxy resin and the methylol group-containing thermosetting resin will be cured (reticulated) by heating at the time of melting. It has been found that it is possible to form melts which are intimately mixed with one another without gelation.

It is considered that this is because the epoxy resin and the methylol group-containing thermosetting resin have a relatively low molecular weight and are excellent in compatibility with the acrylic resin.

At this time, the acid value of the acrylic resin used is 35 to 35
0, particularly in the range of 70 to 330, and using this acrylic resin in an amount of 3 to 30% by weight, particularly 5 to 25% by weight, based on the resin for coating (epoxy resin or thermosetting resin containing methylol group). is important.

That is, when the acid value of the acrylic resin is lower than the above range, in the neutralization step and phase conversion emulsification step described below, the coating resin component is dispersed in a fine and uniform O / W (oil-in-water) type. It becomes difficult to emulsify the particles, and the emulsion stability of the dispersed particles tends to decrease. Further, when the acid value of the acrylic resin is higher than the above range, the acrylic resin tends to separate from the coating resin component and migrate to the aqueous phase in a later step, which results in a fine and uniform particle size. It becomes difficult to emulsify into and the stability of the dispersion becomes rather deteriorated,
Further, the formed coating film also has a drawback that it tends to be sensitive to humidity. According to the present invention, by selecting the acid value of the acrylic resin within the above range, it is possible to emulsify the coating resin component into a uniform and fine particle size and improve the dispersion stability of the emulsion resin, and The coating film having excellent moisture resistance and water resistance can be obtained.

Further, when the amount of the acrylic resin compounded is less than the above range, a sufficient carboxylate group is formed at the interface between the water phase and the oil phase (resin phase) in the neutralization step and the phase conversion step. However, it becomes difficult to emulsify the coating resin component into a uniform and fine particle size, and the dispersion stability of the aqueous dispersion also decreases. On the other hand, increasing the amount of the acrylic resin component in the above range also has an effect on the physical properties of the coating film due to the incorporation of a large amount of the acrylic resin in the coating resin component. It should be in the above range.

According to the present invention, the melt containing the coating resin and the acrylic resin is made into an oil-in-water type, that is, an O / W type emulsion. In the dispersed resin particles of the O / W type emulsion, the coating resin and the acrylic resin are in a blended or compatible state, but the group of ammonium salt or amine salt of carboxylic acid formed in the acrylic resin is used. Is considered to exist toward the surface of the dispersed resin particles, that is, the interface with water.

Such an emulsion is formed by adding ammonia or amine and water to a melt containing a coating resin and an acrylic resin and kneading the mixture to convert the carboxyl group in the acrylic resin into an ammonium salt or an amine salt. It is formed by a phase inversion method in which the resin component in the melt is self-emulsified into an O / W type emulsion while being converted. In this case, it is needless to say that the ammonia or amine can be supplied to the system separately from water, but in general, the ammonia or amine is preferably supplied to the system together with water in the form of an aqueous solution.

When kneading is continued while adding ammonia water or amine water to the melt of the coating resin and the acrylic resin, the resin melt is in the continuous phase and the water phase is in the dispersed phase at the initial stage of addition or the initial stage of kneading. Although it exists in the form, as the amount of water added increases or the kneading continues, the resin melt undergoes phase conversion into an O / W type emulsion in which a dispersed particle phase and water become a continuous phase.
This phase inversion is surprisingly as low as 10 parts per resin.
It was found that the addition of a small amount of water, such as wt%, also occurs. Thus, the addition of a small amount of water causes the phase inversion to the O / W type emulsion because the melt of the coating resin and the acrylic resin is used, and the ammonia water or the amine water is blended under melt kneading. This is a novel feature that was made possible for the first time by the method of the present invention, which is not recognized in conventional methods.

This is because when ammonia water or amine water is added to the resin melt, ammonium salt or amine salt groups of acrylic resin carboxylic acid are generated at the contact interface with the water phase of the melt, but melt kneading Under the conditions, the surface tension of water is considerably lowered, and the shearing force at the time of kneading stretches the water in the form of a thin layer, and the resin melt contains the above-mentioned ammonium salt or amine salt groups at the interface side. It is thought that this is due to atomization by the surface tension in the state.

Resin for coating-When the melting point or softening point of the melt of the acrylic resin is high, or when its melt viscosity is high, when melting the resin for the purpose of lowering its melting point or softening point and lowering its melt viscosity. An organic solvent can be added. However, since the solvent used in this case is also used for the above purpose, it may be used in a small amount as compared with the case of an ordinary solution, and the phase inversion to the aqueous dispersion also uses the resin solution as a raw material. It should be understood that the phase inversion itself occurs with the addition of a small amount of water as compared to the case. As described above, according to the present invention, a self-emulsifying water-based paint having a fine and uniform particle size of a dispersed resin and excellent dispersion stability can be obtained by a phase inversion emulsification method of a melt. Of course, the addition of the ammonia water or the amine water may be terminated at the stage where the phase inversion occurs, or the ammonia water or the amine water may be further added to homogenize the whole system and dilute it to a predetermined concentration. Of course, it is okay.

(Preferred Embodiment of the Invention) In the present invention, as the acrylic resin, any acrylic resin can be used as long as the acid value is within the above range. This acrylic resin is an ethylenically unsaturated carboxylic acid or an anhydride thereof which gives the resin a carboxyl group having the above-mentioned acid value, an acrylic acid ester or a methacrylic acid ester, and other ethylene copolymerizable therewith. It is composed of a copolymer with an unsaturated monomer. Examples of the ethylenically unsaturated carboxylic acid or its anhydride include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride and itaconic anhydride.

Examples of esters of acrylic acid and methacrylic acid include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and (meth ) N-amyl acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate and the like. However, the above-mentioned (meth) acrylic acid means acrylic acid or methacrylic acid.

Examples of other comonomers copolymerized with these monomers include styrene, vinyltoluene, acrylonitrile, methacrylonitrile and the like.

The acrylic resin used should have a molecular weight sufficient to form a film, and preferably has a molecular weight in the range of 10,000 to 200,000, particularly 20,000 to 150,000.

Examples of suitable combinations of acrylic copolymers are (1) methyl methacrylate / 2-ethylhexyl acrylate / acrylic acid, (2) styrene / methyl methacrylate / ethyl acrylate / methacrylic acid, (3) styrene / acrylic. Ethyl acid / methacrylic acid, and (4) methyl methacrylate / ethyl acrylate / acrylic acid.

These acrylic resins can be easily obtained by polymerizing these monomers in an organic solvent in the presence of azobisisobutyronitriles and peroxides.

In the present invention, a combination of an epoxy resin and a methylol group-containing thermosetting resin is used as a can-making coating material. As the epoxy resin, a bisphenol type epoxy resin obtained by polycondensation of bisphenols such as bisphenol A and epihalohydrin is suitable, and the epoxy equivalent thereof is generally in the range of 400 to 20,000, preferably 1,000 to 5,000. .

Examples of the methylol group-containing resin include resol type and / or novolac type phenol / formaldehyde resins, urea-formaldehyde resins, and melamine / formaldehyde resins. Among these, the resol type phenol resin is preferable.

The present invention is characterized in that even when the composition ratio of the epoxy resin and the methylol group-containing resin is within an arbitrary range, the coating resin can be emulsified and dispersed in a fine dispersed particle size. The epoxy resin and the methylol group-containing resin have a weight ratio of 95: 5 to 40:60, particularly 90:10.
It is preferable that the weight ratio is within the range of 50 to 50:50.

When the amount of the epoxy resin component is less than the above range, the coating film has low curability and its corrosion resistance and hot water resistance are poor. If the amount of the methylol group-containing resin is larger than the above range, the workability of the coating film tends to be poor.

In the present invention, a melt containing a coating resin and an acrylic resin is prepared. The melt viscosity of this melt is generally from 10 to 100,000 centipoise, especially from 100 to 30,00.
It is suitable to be in the range of 0 centipoise, and if the viscosity is higher than the above range, it may be difficult to uniformly and uniformly knead both. The temperature of the melt is 10 to 150.
C., particularly 20 to 120.degree. C. is suitable. If it is higher than the above temperature range, partial gelation or premature gelation of the coating resin component is likely to occur, which is not preferable. An organic solvent can be used for the purpose of lowering the kneading temperature and lowering the melt viscosity. In this case, the organic solvent is an aromatic hydrocarbon solvent such as toluene or xylene; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone or the like. Ketone-based solvent; alcohol-based solvent such as ethanol, propanol, butanol;
One or two or more kinds of cellosolve-based solvents such as ethyl cellosolve and butyl cellosolve; ester-based solvents such as ethyl acetate and butyl acetate can be used. The amount of the organic solvent used is suitably 30% by weight or less, particularly 15% by weight or less, based on the resin content. Of course, one or both resin components may be supplied to the kneading in the form of an organic solvent solution.

The melt-kneading can be performed using a kneader, Banbury mixer, single-screw or twin-screw extrusion-type kneader. Upon kneading, the melt may optionally contain known compounding agents for paints such as plasticizers, lubricants, pigments, fillers and stabilizers. Examples of amines used for neutralization include alkylamines such as trimethylamine, triethylamine and butylamine, alcohol amines such as 2-dimethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol, dimethylaminomethylpropanol and morpholine. To be done. Also, polyamines such as ethylenediamine and diethylenetriamine can be used. Ammonia and amines are preferably used in an amount of at least 0.3 chemical equivalents, particularly 0.7 to 1.3 chemical equivalents with respect to the carboxyl groups of the acrylic resin. The amount of water used for phase conversion varies depending on the type of resin and the concentration of the raw material solution, but is generally 0.5 to 5 per raw material resin melt.
It is recommended to use 2.0 times water, especially 0.7 to 1.5 times water.

Ammonia water or amine water is added in the above-mentioned melt-kneading device. Needless to say, the melt-kneading after adding water can be performed by a device different from the kneading of resins.

When an organic solvent is used in combination, the aqueous dispersion produced by the phase conversion contains both water and the organic solvent. By subjecting this aqueous dispersion to azeotropic vacuum distillation, the organic solvent can be removed azeotropically with water, and the aqueous dispersion can be concentrated. It should be understood that the azeotropic distillation of the organic solvent can be performed while supplementing water from the outside.

The concentration of the coating resin solids in the final water-based paint is preferably 10 to 70% by weight, particularly 20 to 60% by weight, and the content of the organic solvent in the water-based paint is 15%.
It is preferably not more than 5% by weight, especially not more than 5% by weight.
Further, for the purpose of improving the dispersion stability of the resin component in the paint, it is acceptable to add a slight amount of a surfactant or a polymer dispersant to the system at any stage.

(Effects of the Invention) According to the present invention, a epoxy resin and a methylol group-containing thermosetting resin are melt-kneaded, and a phase-change emulsification method in which ammonia water or amine water is added thereto is applied to obtain a can-making paint. A combination of useful epoxy resin and methylol group-containing thermosetting resin could be made into a self-emulsifying water-based paint by using a small amount of water. In this water-based paint, the resin content is fine and dispersed in a uniform dispersed particle size, and the dispersion stability and coatability are good, and the curability of the coating film is equivalent to that of organic solvent type paints. It also has excellent adhesion to, corrosion resistance, hot water resistance, workability, etc.

Further, the ammonia or amine used for neutralizing the carboxyl group is volatilized when the coating film is cured, so that the acrylic resin component is also insoluble in water, and the coating film is whitened even when retort sterilization is performed. Does not occur.

(Examples) In the examples, parts are by weight unless otherwise specified.

Example 1 20 parts ethyl acrylate, 20 methyl methacrylate
Parts, methacrylic acid 40 parts, styrene 20 parts and tert-butyl hydroperoxide 1 part were prepared, and ethyl cellosolve 50 was added to a flask equipped with a stirrer, a thermometer, a dropping funnel, a reflux condenser and an inert gas inlet. And 25 parts of the above mixture were charged and stirred under a nitrogen stream while stirring 9 parts.
After the temperature was raised to 0 ° C., the remaining amount of the above-mentioned monomer mixture was dropped into the flask kept at the same temperature for 3 hours for copolymerization, and 0.1 part of tert-butyl hydroperoxide was further added to the flask for 3 hours. After continuously stirring for 50 hours, 50 parts of ethyl cellosolve was added and cooled to complete the reaction. The resulting acrylic resin (acrylic resin 1) had a weight average molecular weight of about 120,000, an acid value of 124, and a solid content of the resin solution of 5
It was 0%. This acrylic resin solution was gradually added to 500 parts of deionized water under vigorous stirring to precipitate a solid content, and the obtained solid acrylic resin was further vacuum dried.

On the other hand, bisphenol A type epoxy resin (epoxy resin 1) 8 having a number average molecular weight of about 3,750 and an epoxy equivalent of about 3,000 8
0 part by weight, 20 parts by weight of a resol type phenol resin (phenol resin 1: bisphenol A / paracresol = 80/20, number average molecular weight 650) derived from bisphenol A, paracresol, and formaldehyde using an ammonia catalyst, Hexyl cellosolve 12 parts and deionized water 150 parts with dimethylaminoethanol 1
An amine water having 0 parts dissolved therein was prepared.

The total amount of the above-mentioned epoxy resin and phenol resin and the above solid acrylic resin 10 were placed in a kneader kept at 80 ° C.
80 parts after adding all the parts of hexyl cellosolve and mixing to form a uniform thick solution.
The above-mentioned amine water kept at a temperature of ° C was gradually added dropwise. The system became white cream-like by the addition of amine water, and the viscosity of the system drastically decreased as the addition of amine water proceeded. When the dropping of the amine water was continued, a safe O / W type emulsion was formed after the dropping of the entire amount was completed. The average particle size of the resin particles in this emulsion (emulsified water-based paint 1) is
It is 0.60 μm and contains 4.3% of organic solvent per paint.

100 m of this emulsified water-based paint was put in a glass wide-mouthed bottle with an internal volume of 100 m, and the bottle was tightly stoppered.
After storing for 6 months and opening the bag for inspection, no skin was found on the liquid surface. In addition, the viscosity of the emulsion type water-based paint,
The average particle size of the resin particles did not change compared with that before storage.

This emulsion type water-based paint is applied to electrolytic chromic acid treated steel sheet (hereinafter referred to as TFS) using a reverse type roll coater. 2
It was baked by curing at 10 ° C. for 10 minutes.

The coated plate was bonded by using a nylon adhesive and pressing it for 2 minutes with a hot press heated to 200 ° C. When the peel strength was measured by T-peel, the initial peel strength immediately after bonding was about 7 kg / 5 mm width, 90 ° C.
After being soaked in warm water for 1 week, the peel strength with time is 4.5 kg /
It kept a value of 5 mm width or more. When this adhesive test piece was subjected to retort treatment at 125 ° C. for 30 minutes and then evaluated, no whitening of the coating film was observed and the adhesive strength of 4.5 kg / 5 mm width or more was retained.

Also, use a roll coater to coat one side of TFS at 210 ° C.
After baking and drying for 10 minutes, the other one side is similarly painted and baked to prepare a double-sided coated plate, and using this coated plate and a nylon adhesive, a 202 diamond adhesive can body (both ends are neck-in processed It was made into 200 diamonds), the bottom lid was double-wound, the coffee beverage was filled, and the canopy was double-wound to make a canned coffee beverage. The canned coffee beverage was subjected to retort sterilization treatment at 125 ° C. for 30 minutes, dried with cooling air, and stored in a warehouse. When the cans were opened and evaluated after storage for 6 months, no abnormalities such as whitening of the coating film and internal corrosion were observed.

Example 2 The same epoxy resin as shown in Example 1, a phenol resin, and an acrylic resin were prepared, and the epoxy resin 8
To 0 parts and 20 parts of phenolic resin, the amount of acrylic resin and 12 parts of hexyl cellosolve shown in Table 1 were added, and the mixture was put into a kneader kept at 80 ° C. and mixed to prepare 6 kinds of coating resin. It was a concentrated solution.

On the other hand, an ammonia water prepared by dissolving 20 m of concentrated ammonia water in 150 parts of deionized water was prepared and phase-converted into an O / W type emulsion according to the method shown in Example 1 to prepare 6 types of emulsion-type aqueous paints. did. Table 1 also shows the average particle size of the resin particles of the obtained emulsified water-based paint. Further, the evaluation of the performance of the obtained emulsion-type water-based paint according to the method shown in Example 1 is also shown in Table 1.

Example 3 300 parts by weight of a resole-type phenol resin (phenol resin 2: number average molecular weight 500) derived from bisphenol A and formaldehyde using an ammonia catalyst and 300 parts of the epoxy resin 1 of Example 1 were prepared.

Also, eight kinds of acrylic resins having the second composition were prepared by the suspension polymerization method. In the table, the monomer composition is shown as the mixing ratio of the mixed monomer of ethyl acrylate / methyl methacrylate / styrene = 1/1/2 and methacrylic acid. Benzoyl peroxide was used as the polymerization initiator, and polyvinyl alcohol was used as the suspension stabilizer. The acid value and molecular weight of the resulting acrylic resin are shown in Table 2.

50 parts of the above-mentioned epoxy resin, 50 parts of phenol resin, and 10 parts of acrylic resin were put into a kneader held at 95 ° C. and melt-mixed, and then heated to 95 ° C. according to the method shown in Example 1. A warm aqueous solution of dimethylaminoethanol was added to cause phase conversion into an O / W type emulsion to obtain an emulsion type water-based paint.

The average particle size of the resin particles in the obtained emulsion type water-based paint is shown in Table 2.
Are also shown. However, the emulsified water-based paint 8 could not be emulsified by the method shown in Example 1. Therefore, the following evaluation of coating film performance was not performed.

Apply normal solvent type paint on one side of the tin plate, 180 ℃
After baking in a hot air drier for 10 minutes, the emulsion-type water-based paint was applied to the other surface of the tin plate and baked at 200 ° C. for 10 minutes to dry. This coated plate was formed into a 211 diamond can lid so that the coating surface of the emulsion-type water-based paint would be the inner surface side, and double-wound onto one end of the 211 diamond welded can barrel,
It was filled with tuna oil pickling, and the other end was also double-tightened in vacuum with the above-mentioned can lid. This canned tuna oil pickled at 115 ℃ 10
After being subjected to heat sterilization treatment for 0 minutes, it was stored at room temperature. After the lapse of 6 months, the can was opened and the state of the inner surface of the can lid and the adhesion of the coating film were examined. The results are also shown in Table 2.

Example 4 The emulsified water-based paint 16 was produced in the following manner. Example 1
85 parts of the epoxy resin 1 and 15 parts of the urea-formaldehyde resin, 10 parts of the acrylic resin 1 of Example 1, and 10 parts of ethyl cellosolve were put into a kneader kept at 95 ° C. and melted and mixed. According to the method described in Example 1, an aqueous dimethylaminoethanol solution kept at 95 ° C. was added to cause phase conversion into an O / W type emulsion to obtain an emulsion type aqueous coating material.

The average particle size of the resin particles in the obtained emulsified water-based paint is 0.58
Even when it was stored at 50 ° C. for 1 month, it did not settle, and neither skinning nor remarkable change in viscosity occurred.

Example The emulsified water-based paint 19 was produced in the following manner.

5 parts of the acrylic resin 1 of Example 1, 80 parts of the epoxy resin 1, 20 parts of the phenol resin 1, 5 parts of oleic acid,
20 parts deionized water and 1 dimethylaminoethanol
After pre-mixing 0 parts, the mixture was put into a twin-screw kneading and extruding device maintained at 90 ° C and kneaded to convert into an O / W emulsion, and 80 parts of deionized water was vigorously stirred with a homomixer. The extruded product was added to the emulsion to dilute it to obtain an emulsion type water-based paint.

The average particle size of the resin particles in the obtained emulsified water-based paint is 0.54
Even when it was stored at 50 ° C. for 1 month, it did not settle, and neither skinning nor remarkable change in viscosity occurred.

Example Emulsified water-based paints 20 to 24 were prepared in the following manner.

Using an epoxy resin having an epoxy equivalent as shown in Table 3 and using a phenol resin of Example 3 (phenol resin 2) in an amount ratio as shown in Table 3 with respect to the epoxy resin.
In accordance with the method shown in Example 1 except that
Five types of emulsion type water-based paints were prepared.

The average particle size of the resin particles in the obtained emulsion type water-based paint is shown in Table 3.
Also described in. None of the emulsified water-based paints settled at 50 ° C. for 1 month and did not settle, and neither skinning nor remarkable change in viscosity occurred.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication C09D 163/00 PKH 8830-4J

Claims (1)

[Claims] 1. A. A coating resin containing an epoxy resin and a methylol group-containing thermosetting resin in a weight ratio of 95: 5 to 40:60; and B. An acrylic resin having an acid value of 3 to 30% by weight per coating resin within the range of 35 to 350, or a composition containing a small amount of an organic solvent is melted, and ammonia or amine and water are added to the melt. Is mixed and kneaded to convert the carboxyl group in the acrylic resin into an ammonium salt or an amine salt, and at the same time, the resin component is self-emulsified into an O / W type emulsion.