JPH0681817B2 - Emulsified water-based paint - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an emulsion-type water-based coating material, and more particularly, to preventing the formation of spots on the coating film surface, smoothness of the coating film surface and other coating materials. The present invention relates to an emulsion type water-based paint having improved film characteristics.

(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.
These paints exhibit good performance of being applied in the form of an organic solvent solution, but during spray painting, the solvent volatilizes into the working 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. 44-1807
No. 6). The second type is modified by reacting a coating having a functional group such as an epoxy resin with a resin having a carboxy group such as an acrylic resin,
This modified resin is self-emulsified in an aqueous medium by neutralizing with ammonia or amines (for example, JP-A-59-213718).

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

Further, although the latter type of coating is superior 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, and therefore, the adhesion of the coating film, the hardness of the coating film, the denseness, the barrier property against corrosive components, etc. are satisfied. The problem arises that it cannot be upgraded to the level that it should be.

The present inventors previously carried out phase conversion emulsification of a thermosetting resin containing an epoxy resin component and a curing agent resin component such as a resole phenolic resin by utilizing the surface-active action of an acrylic resin to prepare an aqueous paint. It has been found that a thermosetting paint having excellent curing performance and excellent adhesion of the coating film, hardness of the coating film, denseness, barrier property against corrosive components, etc. can be obtained when producing Pending).

However, the coating film formed using this paint,
It has been found that there are still problems with the smoothness of the coating and the integrity of the coating. That is, the coating film formed by this paint tends to form pits on its surface, which reduces the smoothness of the surface and makes the substrate incompletely coated. Such a phenomenon was first found in the above-mentioned water-based paint containing the three-component resin, and was not observed at all in the conventional organic solvent-based paint.

Therefore, the object of the present invention is to prevent the generation of the above-mentioned spots during coating in an emulsion-type water-based paint containing a carboxyl group-containing acrylic resin component, an epoxy resin component and a resol-type phenol resin component as essential components, It is to improve the smoothness of the film and the completeness of the coating.

(Means for Solving Problems) According to the present invention, a carboxyl group-containing acrylic resin component, an epoxy resin component and a resol-type phenol resin component are contained as coating film forming components, and the carboxyl group of the acrylic resin component is An emulsion type water-based paint which is present in the form of an ammonium salt or an amine salt, and the film-forming component is present in the form of O / W type emulsion particles, and is 30 mol% or more of all the methylol groups of the resol type phenol resin component. There is provided an emulsified water-based coating characterized by being alkyl etherified.

The ether compound of the resol-type phenol resin component is preferably a butyl ether compound, and the present invention provides the resol-type phenol resin component having a low molecular weight of 10 to 98% by weight, particularly 20 to 95% by weight of a dinuclear and mononuclear compound. It is particularly useful when it is contained in a weight percentage.

(Operation) The present invention relates to an emulsion-type water-based paint containing three components, a carboxyl group-containing acrylic resin component, an epoxy resin component, and a resol-type phenol resin, as film-forming components,
As the resol type phenolic resin component, 30 mol% or more of all methylol groups, particularly when 45 to 90 mol% is an alkyl etherified resol type phenolic resin component is used, the occurrence of spots on the coating film surface is eliminated and formed. It is based on the finding that the smoothness of the coating film and the completeness of the coating are significantly improved.

According to the study by the present inventors, the reason why the three-component emulsified water-based coating composition has spots on the coating film surface is considered to be that the coating resin component is deposited by salting out. That is, the resol-type phenol resin for paint always contains a low molecular weight component such as a mononuclear or dinuclear. These low molecular weight components such as mononuclear and dinuclear substances are essential components for the resole type phenol resin, which have a high curing rate for the epoxy resin component and are involved in improving the adhesion of the substrate. It is believed that these low molecular weight components are soluble in water containing ammonia or amines added during emulsification and therefore exist in solution form in aqueous paints. When this water-based paint is applied to a substrate to form a wet coating film, water evaporates on the surface immediately after the coating film is formed, but at this stage the low molecular weight component dissolved in water causes the coating film forming resin to salt. It is considered that this is the cause of the generation of spots on the surface of the coating film.

According to the present invention, when at least 30 mol% of all methylol groups in the resol type phenolic resin are alkyl etherified, the solubility of the low molecular weight component such as the above-mentioned mononuclear or binuclear body in water is suppressed, or It is believed that the amount dissolved in water is suppressed, salting out of the coating film-forming resin component is prevented, and as a result, the generation of seeds is suppressed.

(Preferred Aspects of the Invention) Coating-Forming Resin Component i) Acrylic Resin The acrylic resin in the present invention has a carboxyl group, and it has a function as a coating-film forming resin component and a function as a polymer dispersant. Have both.

The acrylic resin itself used preferably has an acid value of 35 to 350, particularly 70 to 330.

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 that gives a carboxyl group having the above-mentioned acid value to the resin, an acrylic acid ester or a methacrylic acid ester, and other ethylene-based copolymerizable with them. 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 and itaconic anhydride.

Examples of the esters of acrylic acid and methacrylic acid include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate,
N-Amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, (meth)
2-ethylhexyl acrylate, (meth) acrylic acid n
-For example, octyl. 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, generally 10,000 to 200,000, especially 2
It is desirable to have a molecular weight in the range of 0,000 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 / ethyl acrylate / methacrylic acid, (4) Methyl methacrylate / Ethyl acrylate / acrylic acid, etc.,
Of course, it is not limited to these.

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

ii) Epoxy resin As the epoxy resin, a bisphenol A type epoxy resin obtained by polycondensation of bisphenols such as bisphenol A and epihalohydrin is suitable, and the epoxy equivalent thereof is generally 400 to 20,000, particularly 1,000 to 5,000.
The range of 0 and number average molecular weight are 1,000 to 20,000, especially 2,
Those in the range of 000 to 13,000 are preferred.

iii) Resol-type phenol resin In the present invention, as the resol-type phenol resin, 30 mol% or more, particularly 45 mol% or more, of all methylol groups is alkyl etherified. When the degree of etherification is a resin smaller than the above range, it becomes difficult to reduce the solubility of the low molecular weight component in the resol type resin in water, and the occurrence of spots on the coating film surface is eliminated. Becomes difficult.

Examples of the resol-type phenol resin include carboxylic acid, p-cresol, m-cresol, o-cresol, p-tert-
Butylphenol, p-tert-amylphenol, p-
Phenylphenol, xylenol, o-, p- or m-
Ethylphenol, resorcin, hydroquinone, o-, p
An initial condensate obtained by condensing a bifunctional, trifunctional or tetrafunctional phenol such as-, m-methoxyphenol or bisphenol A with formaldehyde in the presence of an alkali catalyst is generally used. Average molecular weight is
Those of 150 to 1000 are preferably used.

In the resol type phenolic resin obtained, for example, the formula In the formula, R is an alkyl group, It has already been pointed out that these binuclear compounds are contained in a certain distribution amount, and that these low molecular weight components play an important role in the curing rate of the coating film and the adhesion of the coating film to the metal substrate. In the present invention, it is preferable to use a resol-type phenol resin containing the low molecular weight component consisting of mononuclear and dinuclear as exemplified above in an amount of 10 to 98% by weight, particularly 20 to 95% by weight.

Alkyl etherification of the methylol group of the resol type phenolic resin is carried out by changing the methylol group in the resin as shown by the formula --CH ₂ OH + CnH ₂ n ₊₁ OH → --CH ₂ OCnH ₂ n ₊₁ + H ₂ O (3). It is carried out by reacting with an alcohol in the presence of an etherification catalyst, particularly an acid catalyst.

As alcohols, methanol, ethanol, n-
Alternatively, iso-propanol, n-, iso-, tert-butanol or the like can be used, but alcohol having 3 to 6 carbon atoms, particularly butanol is preferable.

As the etherification catalyst, phosphoric acid, sulfuric acid, hydrochloric acid, aromatic sulfonic acid (for example, p-toluenesulfonic acid), oxalic acid, acetic acid or the like can be used. In the synthesis of this resin, the dissolved methylol group-containing thermosetting resin and alcohol are reacted in a suitable solvent in the presence of the catalyst. The amount of the catalyst used is such that the pH of the reaction system becomes 4 to 6, and the reaction temperature is preferably in the range of 70 to 90 ° C.
As the solvent, excess alcohol, toluene, xylene and the like are used alone or in combination. It is advantageous to carry out the reaction while removing by-product water in the above-mentioned reaction,
For this purpose, it is desirable to carry out the reaction while taking out water in the reaction system from the system in the form of azeotropic distillation with a solvent. Of course, if the amount of alcohol in the system is insufficient, it may be added to the reaction system.

The production of the phenolic resin and the alkyl etherification can be carried out in the same step or in separate steps. For example, the reaction between phenols and formaldehyde is carried out in the presence of an alkali catalyst in a medium containing alcohol to obtain a desired methylolated resin, and then an acid catalyst is added to the system to adjust the pH to the above. The alkyl etherification reaction can be carried out while maintaining. Alternatively, the methylolated resin to be formed may be separated by a means known per se, and this may be alkyletherified in another system.

The obtained alkyl etherified resin may be neutralized, washed with water and dried to be used as a film-forming resin component, or may be used as it is in the form of a resin solution after removing salts produced by the neutralization by any means. Good.

iv) Composition The present invention has a remarkable feature that the coating resin can be emulsified and dispersed in a fine dispersion particle size even when the composition ratio of the epoxy resin and the phenol resin is in an arbitrary range. The ratio of epoxy resin to phenol resin is 95: 5 to 40: 6.
It is generally in the range of 0 weight ratio, in particular 90:10 to 50:50 weight ratio.

Acrylic resin as a polymer dispersant has an acid value of 2 to 30 based on the coating resin component, especially 5 to 20 and 3 to 30% by weight, especially 5 to 25% by weight based on the total coating film forming components.
It is important to be present in an amount such that If the acid value is below the above range, it will be difficult to disperse the resin component in the form of an O / W emulsion, and even if it is forcibly dispersed, the dispersion stability will be poor. On the other hand, when the acid value exceeds the above range, the hot water resistance of the coating film for a can coating composition is lowered, and the corrosion resistance after retort sterilization is reduced.

In the present invention, between the resin components, there is no problem even if the reaction is previously carried out by copolymerization, graft polymerization or block polymerization, and for example, the epoxy resin component and the phenol resin component are pre-condensed. You can
Alternatively, the acrylic resin component and the epoxy resin component may be cooked and used as an acrylic resin-epoxy resin copolymer having excess carboxyl groups.

Emulsified water-based paint The emulsified water-based paint of the present invention, that is, O / W emulsion,
The organic solvent solution containing the three-component resin may be mixed with water containing ammonia or amine, or a melt containing the three-component resin may be mixed with water containing ammonia or amine to form a so-called phase inversion method. it can.

When ammonia or amine water is added to an organic solvent solution or a melt containing an epoxy-phenolic resin and an acrylic resin, the viscosity of the system increases at the initial stage of addition, but the viscosity of the system gradually increases as the addition continues. Begins to fall. At this stage, the addition is interrupted to homogenize the whole system by stirring, and if the ammonia or amine water is continued to be added again, the viscosity of the system sharply drops by the addition of a predetermined amount of ammonia or amine water. At the initial stage of adding ammonia or amine water to the resin solution, the water phase exists in the form of a dispersed phase, but at the stage where the viscosity of the system is drastically decreased, the aqueous phase is a continuous (dispersion medium) phase and a resin component. Becomes the disperse phase and O /
The W-type emulsion is stably generated.

In the case of the solution phase conversion method, an organic solvent solution (I) of an epoxy-phenolic coating resin and an organic solvent solution (II) of an acrylic resin are prepared, and these solutions (I) and (II) are uniformly mixed. To prepare a raw material solution. As the organic solvent for this solution, aromatic hydrocarbon solvents such as toluene and xylene; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohol solvents such as ethanol, propanol, butanol;
One or more of cellosolve solvents such as ethyl cellosolve and butyl cellosolve; ester solvents such as ethyl acetate and butyl acetate can be used. The resin content concentration in the raw material solution is generally 5 to 80% by weight, particularly 20 to 70% by weight.
It should be in the range of weight percent. If desired, the raw material solution may contain known compounding agents for paints such as plasticizers, lubricants, pigments, fillers and stabilizers.

As amines used for neutralization, trimethylamine,
Alkylamines such as triethylamine and butylamine, alcohol amines such as 2-dimethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol and dimethylaminomethylpropanol, and morpholine are used. 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 2.5 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 generally 0.5 to 2.0 times by weight, particularly 0.7 to 1.5 times by weight of water is recommended for the raw material solution. Mixing the resin solution with ammonia or amine water is sufficient at room temperature, but may be heated to a temperature of about 100 ° C. if desired. The addition and mixing can be carried out in a reaction vessel equipped with an ordinary stirrer, but if desired, a high shear stirrer such as a homomixer or irradiation of ultrasonic vibration can be used.

Due to the phase inversion, the aqueous dispersion contains both water and an organic solvent. By subjecting this aqueous dispersion to azeotropic distillation under reduced pressure, 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.

Concentration of paint resin solids in final water-based paint is 10 to 70
The content is preferably in the range of 20% to 60% by weight, and the content of the organic solvent in the water-based paint is preferably 15% by weight or less, more preferably 5% by weight or less. 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.

In the case of the melt phase conversion method, a melt containing a coating resin and an acrylic resin is prepared. The melt viscosity of this melt is generally in the range of 10 to 100,000 centipoise, particularly 100 to 30,000 centipoise, and when the viscosity is higher than the above range, it becomes difficult to uniformly and uniformly knead both. There is. The temperature of the melt is 10 to 150 ° C, especially 20
It is suitable to be in the range of from 120 to 120 ° C., and 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. The organic solvent described above can be used for the purpose of lowering the kneading temperature and lowering the melt viscosity.

The amount of organic solvent used is 30% by weight or less, especially 15% by weight of resin.
It is suitable that the content is less than or equal to weight%. 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, or a single-screw or twin-screw extrusion-type kneader.

The amount of water added and the removal of the organic solvent are the same as in the solution phase conversion method.

The water-based paint according to the present invention has a viscosity suitable for coating and can be used for coating various metal materials, can bodies, can lids or other members. This water-based paint is not only used for ordinary spray coating and electrostatic coating, but also roller coating,
Brush application, doctor coater, air knife coater,
It can be used for coating work with various coaters such as a reverse coater.

(Effect of the invention) According to the present invention, in an emulsion type water-based coating composition containing three components of a carboxyl group-containing acrylic resin component, an epoxy resin component and a resol type phenol resin as a coating film forming component, the resol type phenol resin is By using the alkyl etherified product, it is possible to eliminate the generation of spots on the surface of the coating film, and to significantly improve the smoothness of the coating film and the degree of coating perfection.

Example 1 Example 1 Resol-type phenol resin derived from bisphenol A, p-cresol, and formaldehyde using an ammonia catalyst (bisphenol A / p-cresol = 80 /
20, number average molecular weight 650) 20 parts by weight to 40 parts by weight of a mixed solvent of xylene, methyl isobutyl ketone, cyclohexanone and n-butanol (xylene / methyl isobutyl ketone / cyclohexanone / n-butanol = 1/1/1/1) A dissolved solution was prepared. Analysis by gel permeation chromatography (hereinafter abbreviated as GPC) shows that this phenolic resin contains 26% of 1 to 2 benzene ring components.
It was confirmed that it was contained. The phenol resin solution was stirred at 115 ° C. for 2 hours under reflux to convert some of the methylol groups in the phenol resin into butyl ether. When analyzed by a nuclear magnetic resonance method (hereinafter abbreviated as NMR), 68% of all methylol groups were butyl etherified.

Separately, 80 parts by weight of a bisphenol A type epoxy resin having a number average molecular weight of about 3750 and an epoxy equivalent of about 3000 is added to butyl cellosolve.
A solution dissolved in 160 parts by weight was prepared and mixed with the above-mentioned phenol resin solution.

On the other hand, a mixture of 20 parts by weight of ethyl acrylate, 20 parts by weight of methyl methacrylate, 40 parts by weight of methacrylic acid, 20 parts by weight of styrene and 1 part by weight of tert-butyl hydroperoxide was prepared, and a stirrer, a thermometer, a dropping funnel, and a reflux were prepared. A flask equipped with a cooling tube and an inert gas inlet was charged with 50 parts by weight of ethyl cellosolve and 25 parts by weight of the above mixture, heated to 90 ° C. with stirring under a nitrogen stream, and then held at the same temperature. The remaining amount of the above-mentioned monomer mixture was dropped thereinto for 3 hours for copolymerization, and 0.1 part by weight of tert-butyl hydroperoxide was further added to the mixture for 3 hours at the same temperature.
After continuing the stirring for 50 hours, 50 parts by weight of ethyl cellosolve was added and cooled to complete the reaction. The acrylic resin thus obtained had a weight average molecular weight of about 120,000, an acid value of 124, and a solid content of the resin solution of 50%.

Then, after pre-condensing 300 parts by weight of the mixed solution of the epoxy resin solution and the phenol resin solution at 115 ° C. for 4 hours,
20 parts by weight of the acrylic resin solution was added and stirred until uniform.

Further, ammonia water prepared by dissolving 6 parts by weight of 28% concentration ammonia water in 450 parts by weight of deionized water was prepared, and the whole amount of the mixed solution of the epoxy resin, the phenol resin and the acrylic resin was vigorously stirred. Was gradually added dropwise to. At the beginning of the addition of aqueous ammonia, the viscosity of the system rises to a white cream, but as the addition of aqueous ammonia progresses, the viscosity of the system begins to gradually decrease. At this stage, the addition of the ammonia water was interrupted, the stirring was continued, and when the whole was uniformly dispersed, the addition of the ammonia water was restarted, and the viscosity of the system dropped sharply. When the dropwise addition of ammonia water was continued under stirring, it was stable after the dropping of the entire amount.
An O / W type emulsion was formed.

This emulsion was concentrated by a rotary evaporator to recover about 300 parts by weight of water and about 200 parts by weight of an organic solvent to a solid content of 40%, which was further filtered through a # 1 glass filter to obtain an emulsified water-based paint (water-based paint). 1). This emulsified water-based paint has an average particle size of resin particles of 0.61 μm and contains 3.6% of organic solvent per paint.

100 ml of this emulsified water-based paint was placed in a glass wide-mouthed bottle with an internal volume of 100 ml, tightly stoppered, stored in a constant temperature bath at 50 ° C for 1 month and then opened and investigated. No skinning occurred on the liquid surface. It was In addition, neither the viscosity of the emulsified water-based paint nor the average particle size of the resin particles changed as compared with those before storage.

On the other hand, the emulsified water-based paint was applied to an electrolytic chromic acid treated steel sheet (hereinafter referred to as TFS) using a roll coater,
It was baked for 10 minutes to cure. When the coated surface was visually observed, no spots were found.

The coated plate was adhered by using a nylon adhesive by 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 7.1 kg / 5 mm width, and the time-dependent peel strength after immersion in warm water at 90 ° C for 1 week was 4.5 kg / 5 mm width or more. It held the value. In addition, this adhesion test piece
When the film was evaluated after being subjected to a retort treatment at 30 ° C. for 30 minutes, no whitening of the coating film was observed and the adhesive strength of 4.5 Kg / 5 mm width or more was retained.

Also, coat it on one side of TFS with a roll coater and apply 10
After baking and drying for a minute, the other side is also painted and baked in the same way 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 Of 200 diamonds), the bottom lid was double-wound, the coffee beverage was filled, and the canopy was double-wound to make a can of coffee beverage. The canned coffee beverage was retort-sterilized at 125 ° C. for 30 minutes, cooled, air-dried, and stored in a warehouse. After storage for 6 months, the cans were opened and evaluated, and no abnormalities such as whitening of the coating film and internal corrosion were observed.

Comparative Example 1 An emulsified water-based paint (Comparative Paint 1) was prepared in the same manner as in Example 1 except that the resol-type phenol resin used in Example 1 was used without butyl etherification. This water-based paint was applied to TFS using a roll coater, and when visually observed after baking, spot-like irregularities were conspicuous on the coating surface,
The coating appearance was inferior to the coated plate produced in Example 1.

Example 2 A solution having 80 parts by weight of a bisphenol A type epoxy resin having a number average molecular weight of about 3400 and an epoxy equivalent of about 1100 dissolved in 80 parts by weight of butyl cellosolve was prepared and mixed with 80 parts by weight of the acrylic resin solution of Example 1. This mixed solution was placed in a 4-necked flask and stirred with diethylaminoethanol.
16 parts by weight was added to neutralize the carboxyl groups in the acrylic resin, and the liquid temperature was raised to 80 ° C. After continuing stirring at the same temperature for 30 minutes, the mixture was cooled to room temperature. It was confirmed by GPC measurement that the epoxy resin and the acrylic resin were copolymerized to increase the molecular weight. Furthermore, the presence of amine salts of epoxy groups and carboxyl groups was confirmed by an infrared spectrophotometer.

240 parts by weight of the above copolymer resin solution and 60 parts by weight of the butyl etherified resol-type phenol resin solution of Example 1 were mixed to prepare an emulsified water-based paint (water-based paint 2) according to Example 1 below. . The resin particles of this emulsion type water-based paint had an average particle size of 0.58 μm, a solid content of about 49%, and an organic solvent content of 4.6% per paint.

This emulsion type water-based paint was applied to TFS using a roll coater, and baked at 210 ° C. for 10 minutes to cure. When the coated surface was visually observed, no spots were found.

Comparative Example 2 An emulsified water-based paint (Comparative Paint 2) was prepared in the same manner as in Example 2 except that the resol-type phenol resin used in Example 1 was used without butyl etherification. When this water-based paint was applied to TFS using a roll coater and visually observed after baking, spot-like irregularities were conspicuous on the surface of the paint film, and the paint appearance was inferior to that of the paint plate prepared in Example 2. .

Example 3 A resol-type phenol resin was synthesized using p-cresol and formaldehyde as raw materials and using a magnesium hydroxide catalyst. The number average molecular weight of the obtained phenol resin is
At 350, it was confirmed that 56% of the component having 1 or 2 benzene rings was contained. This phenol resin solution was dissolved in the same solvent as in Example 1, and part of the methylol groups in the phenol resin was butyl etherified by stirring under reflux at 115 ° C. for a predetermined time. A solution of the butyl etherified phenolic resin was obtained. The ratio of butyl etherified methylol groups to all original methylol groups (degree of butyl etherification) was determined by NMR, and the results are shown in Table 1.

Using these butyl etherified phenol resin solutions and non-butyl etherified phenol resin solutions and the epoxy resin and acrylic resin solutions of Example 1, six types of emulsion-type aqueous solutions were prepared according to the method shown in Example 1. Paints (water-based paints 3 to 8) were prepared.

These emulsion type water-based paints were applied to TFS using a roll coater.
It was painted on and baked at 210 ° C. for 10 minutes to cure. The results of visual observation of the coated surface are also shown in Table 1.

Example 4 50 parts by weight of the resol-type phenolic resin synthesized in Example 3 was mixed with xylene, methyl isobutyl ketone, cyclohexanone, and alcohols (xylene / methyl isobutyl ketone / cyclohexanone / alcohol = 1/1 /
1/1) Dissolved in 100 parts by weight and stirred under reflux at a predetermined temperature for a predetermined time to partially alkylate-convert the methylol groups in the phenol resin. The types of alcohols (solvents) used for the alkyl etherification are shown in Table 2. Analysis by NMR was performed to obtain the ratio of the alkyl etherified methylol groups to all the original methylol groups (degree of alkyl etherification), and the results are shown in Table 2.

A solution of these alkyl etherified phenolic resins,
Using the epoxy resin and acrylic resin solutions of Example 1, five types of emulsified water-based paints (water-based paints 9 to 13) were produced according to the method shown in Example 1.

These emulsion type water-based paints were applied to TFS using a roll coater.
It was painted on and baked at 210 ° C. for 10 minutes to cure. The results of visual observation of the coated surface are also shown in Table 2.

Example 5 Seven kinds of resole type phenol resins (bisphenol A / p-cresol = 80/20) having different molecular weight distributions were synthesized from bisphenol A, p-cresol and formaldehyde using a magnesium hydroxide catalyst. Table 3 shows the number average molecular weights of these phenolic resins and the contents of components having 1 or 2 benzene rings (low molecular weight component contents). 50 parts by weight of these are dissolved in 100 parts by weight of a mixed solvent of xylene, methyl isobutyl ketone, cyclohexanone and i-butanol (xylene / methyl isobutyl ketone / cyclohexanone / i-butanol = 1/1/1/1),
A portion of the methylol groups in the phenol resin was butyl etherified by stirring under reflux at 0 ° C. for 2 hours. NM
The ratio of butyl etherified methylol groups to all the original methylol groups (degree of butyl etherification) was determined by R, and the results are shown in Table 3.

Using these butyl etherified phenol resin solutions and the epoxy resin and acrylic resin solutions of Example 1, 7 emulsion-type water-based paints (water-based paints 14 to 20) were prepared according to the method shown in Example 1. It was made.

These emulsion type water-based paints were applied to TFS using a roll coater.
It was painted on and baked at 210 ° C. for 10 minutes to cure. The results of visually observing the coated surface and the results of evaluating the initial adhesion and the temporal adhesion according to Example 1 are also shown in Table 3.

Example 6 The resol type phenolic resin solution of Example 1 was used without mixing the phenolic resin with butyl ether, mixed with the epoxy resin solution of Example 1, and then precondensed at 115 ° C. for 4 hours. When confirmed by NMR after precondensation, 85% of the methylol groups in the phenolic resin were butyl etherified.

Using this precondensate and the solution of the acrylic resin of Example 1, an emulsified water-based paint (water-based paint 21) was prepared according to Example 1.

This emulsion type water-based paint was applied to TFS using a roll coater, and baked at 210 ° C. for 10 minutes to cure. When the coated surface was visually observed, no spots were found.

Claims (6)

[Claims] 1. A carboxyl group-containing acrylic resin component, an epoxy resin component and a resol-type phenol resin component are contained as coating film forming components, and the carboxyl group of the acrylic resin component is present in the form of an ammonium salt or an amine salt, The coating film forming component is an emulsion type water-based coating which is present in the form of O / W type emulsion particles, characterized in that 30 mol% or more of all the methylol groups of the resol type phenol resin component are alkyl etherified. Emulsified water-based paint that does. 2. A carboxyl group-containing acrylic resin component and an epoxy resin component are present in the form of a copolymer.
The water-based paint according to the item. 3. The water-based paint according to claim 1, wherein the copolymer contains a free carboxyl group and an epoxy group. 4. The aqueous paint according to claim 1, wherein the carboxyl group-containing acrylic resin component and the epoxy resin component are present in a blended state. 5. The water-based paint according to claim 1, wherein the etherified product of the resol type phenol resin component is a butyl etherified product. 6. The water-based paint according to claim 1, wherein the resol type phenol resin component contains a low molecular weight component consisting of a binuclear body and a mononuclear body in an amount of 10 to 98% by weight.