KR100866370B1 - Paint composition for a glass and method of manufacturing a paint for a glass using the same - Google Patents

Abstract

 Disclosed are a high functional ceramic paint composition and a method of manufacturing the ceramic paint using the same. The coating composition for porcelain is 20 to 50 parts by weight of acrylic resin, 30 to 60 parts by weight of urea-formaldehyde resin, 4 to 10 parts by weight of bisphenol-A type epoxy resin having an epoxy equivalent of 180 to 240 g / eq, and an amine 0.2-1.0 weight part of system silanes, 0.2-1.0 weight part of aromatic sulfonic acids which are reaction catalysts, and 3-15 weight part of organic solvents are included. Thus, using the composition consisting of acrylic resin, urea-formaldehyde, epoxy resin as the main resin, using a coating material composition for the introduction of the aromatic sulfonic acid and the amine silane which are selected reaction catalysts, It is possible to produce a high-performance ceramic coating material having extrudability, water resistance, adhesion, solvent resistance, and chemical resistance.

Description

Paint composition for a glass and method of manufacturing a paint for a glass using the same

The present invention relates to a ceramic coating composition and a method for producing a ceramic coating using the same, and more specifically, a coating composition for ceramics having excellent coating properties such as high hardness, chemical resistance, adhesion, etc. which are coated on industrial ceramics It relates to a method for producing a paint for ceramics.

Industrial chogar means packaging containers for cosmetics and alcoholic beverages. Conventionally, the resin composition used for the paint for ceramics uses a mixed resin composition of acrylic resin and melamine-formaldehyde resin (hereinafter referred to as "melamine resin"), but the sensibility, adhesion and solvent resistance are deteriorated, In particular, there is a problem in that dissolution of the dye used by mixing in the paint occurs.

Elution of the dye is one of the most important physical properties of the paint for ceramics, in order to give a color to the industrial porcelain paint is mixed with about 5% of the dye in the paint, the resin composition used in the paint is completely dried, the dye component in the coating film A coating film must be formed to prevent this from eluting. For this reason, when the container is left for a long time, it is possible to prevent a defect due to dye dissolution generated during use by the consumer.

In general, when looking at the coating process of the industrial ultra-high flow, first, the glass body is treated with hydrofluoric acid (the glass is changed from a smooth and transparent state to a rough and opaque state), and then washed with water and dried to use a silane primer. . Subsequently, it is left to stand for 10 minutes and then coated with a paint for coating, dried at 180 ° C. for 15 minutes, cooled, and obtained through a printing process. In the case of a coating using an existing acrylic / melamine-based resin (melamine-formaldehyde) composition, drying conditions of about 200 ° C. or more are generally required. Under the drying conditions of about 200 ° C. or less, adhesion and the solvent resistance of the dye are poor due to undried or incomplete chemical reaction.

As described above, in order to improve the performance of dye solvent resistance, solvent resistance, sunscreen, adhesion, and chemical resistance of industrial ceramic paints currently used in general, a high functional ceramic paint composition is required.

Accordingly, it is an object of the present invention to provide a coating composition for ceramics that is capable of producing a coating for ceramics excellent in sensibility, adhesion, dye solvent resistance, solvent resistance, chemical resistance, and the like for industrial ceramic materials.

In addition, another object of the present invention is to provide a method for producing a high-performance ceramic paint using the ceramic paint composition.

For the purpose of achieving the above object, the coating composition for porcelain of the present invention has 20 to 50 parts by weight of acrylic resin, 30 to 60 parts by weight of urea-formaldehyde resin, and epoxy equivalent of 180 to 240 g / eq in the entire coating composition for porcelain. 4-10 weight part of bisphenol-A type epoxy resins, 0.2-1.0 weight part of amine silanes, 0.2-1.0 weight part of aromatic sulfonic acids which are reaction catalysts, and 3-15 weight part of organic solvents.

For example, the acrylic resin has an acid value of 3 to 10 mgKOH / g, a hydroxyl value of 80 to 140 mgKOH / g, a glass transition temperature of 15 to 40 ° C, a nonvolatile content of 40 to 70% by weight, and a weight average molecular weight of Have a property of 15,000 to 30,000.

In addition, the acrylic resin is prepared by reacting an acrylic monomer with a benzoyl peroxide or t-butyl peroxide as an aromatic monomer in an aromatic solvent, and then adding the organic peroxide initiator to react.

In addition, the coating composition for a glass for porcelain may further comprise 3 to 15 parts by weight of a dye.

In order to achieve the above another object, the method for preparing a paint for paint using the paint composition for paints of the present invention has an acid value of 3 to 10 mgKOH / g, a hydroxyl value of 80 to 140 mgKOH / g, and a glass transition temperature of 15 to 40. An acrylic resin having a characteristic of having a temperature of 0 ° C., a nonvolatile content of 40 to 70% by weight, and a weight average molecular weight of 15,000 to 30,000 is prepared. 20 to 50 parts by weight of the acrylic resin, 30 to 60 parts by weight of urea-formaldehyde resin, 4 to 10 parts by weight of bisphenol-A epoxy resin having an epoxy equivalent of 180 to 240 g / eq, 0.2-1.0 weight part of amine silanes, 0.2-1.0 weight part of aromatic sulfonic acids which are reaction catalysts, and 3-15 weight part of organic solvents are stirred. As a result, the porcelain paint is completed.

Industrial vitreous paint prepared using the vitreous coating composition having the composition as described above is excellent in coating properties such as sunscreen, dye solvent resistance, high hardness, solvent resistance, adhesion, chemical resistance.

Hereinafter, although the paint composition for paints according to the preferred embodiments of the present invention and a method for producing a paint for paints using the same in detail, the present invention is not limited to the following embodiments may be implemented in other forms. In addition, the above weight parts and weight percentages may be used interchangeably and the embodiments introduced herein are provided to make the disclosure more complete and to fully convey the spirit and features of the present invention to those skilled in the art.

Paint Coating Composition

It will be described below in detail with respect to the coating composition for a candle according to the invention.

The initial coating composition of the present invention can be produced to have a composition containing an acrylic resin, a urea resin, a bisphenol-A type epoxy resin, an amine silane, and an aromatic sulfonic acid and an organic solvent as a reaction catalyst.

First, an acrylic resin, which is the main body of the resin composition for porcelain, is prepared to have an acrylic backbone structure containing a carboxyl group and a hydroxyl group. When the content of the acrylic resin is less than 20 parts by weight based on the total weight of the paint composition for porcelain, it is not preferable to adjust the solid content of the paint and the solvent selection, and when the content of the acrylic resin exceeds 50 parts by weight, the proper resin viscosity and the molecular weight are difficult to control. Therefore, it is preferable that the usage-amount of the said acrylic resin has 20-50 weight part with respect to the total weight of the coating composition for porcelain.

In general, a hydroxyl value is 80 to 140 mgKOH / g, an acid value is 3 to 10 mgKOH / g, a weight average molecular weight of 15,000 to 30,000, and a nonvolatile content is 40 using an acrylic monomer commonly used. An acrylic resin having a characteristic value of from 70% to 70% and a glass transition temperature of 15 to 40 ° C may be synthesized.

When the hydroxyl value is 80 mgKOH / g or less, dulling occurs in the dried coating due to lack of compatibility with the urea-formaldehyde resin, and the solvent resistance is poor. When the hydroxyl value exceeds 140 mgKOH / g, the amount of the curing agent is large. This is a problem for storage and economics. Therefore, the hydroxyl value is preferably 80 to 140 mgKOH / g.

When the acid value is 3 mgKOH / g or less, the dispersibility of the dye is weakened, and when the acid value is always 10 mgKOH / g, boiling water resistance may be weak. Therefore, the acid value is preferably 3 to 10 mg KOH / g.

When the weight average molecular weight is 15,000 or less, the molecular weight decreases, so that there is a limit in weakening of the overall physical properties of the coating film and viscosity control when the paint is applied, and when the weight average molecular weight exceeds 30,000, the limit of proper viscosity control of the paint and paint workability are weak. Become. Therefore, the weight average molecular weight is preferably 15,000 to 30,000.

If the nonvolatile content exceeds the appropriate range, it causes problems such as weight average molecular weight. If the glass transition temperature is 15 ° C. or less, the coating film hardness is weak and the scratchability becomes weak. If the glass transition temperature exceeds 40 ° C., excessive hardness rises. This results in cracking of the coating film. Therefore, the glass transition temperature is preferably 15 ℃ to 40 ℃.

Preferred examples of the acrylic monomers are methyl methacrylate, methyl acrylate, ethyl acrylate, styrene, 2-ethylhexyl acrylate, normal-butyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylic Elate, methacrylic acid, acrylic acid, fumaric acid, etc. are mentioned.

In addition, the urea-formaldehyde resin preferably contains 30 to 60 parts by weight based on the total weight of the paint composition for porcelain. If the urea-formaldehyde resin is 30 parts by weight or less relative to the total weight of the coating composition for porcelain, the lack of chemical bonds causes a decrease in overall coating properties, and when it exceeds 60 parts by weight, cracking of the coating film and deterioration of storage properties appear. Because. Therefore, the urea-formaldehyde resin preferably contains 30 to 60 parts by weight based on the total weight of the paint composition for porcelain. Specific examples of the urea-formaldehyde resin used in the present invention include Beckamine P-138 and Beckamine P-196M (product name) of Aekyung Chemical Co., Ltd. The mixing ratio of the acrylic resin prepared above and the urea-formaldehyde resin was applied in 7/3, 8/2, and 9/1 ratios (acrylic resin / urea-formaldehyde resin) relative to the nonvolatile content. In the case of the coating using only the acrylic resin or the urea-formaldehyde resin, the coating film exhibits poor physical properties in adhesion and boiling resistance.

In order to supplement the adhesive properties, it is preferable to use a bisphenol-A type epoxy resin having an epoxy equivalent of 180 to 240 g / eq within a range of 3 to 10 relative to the nonvolatile content of the acrylic resin and the urea-formaldehyde resin. When the bisphenol-A type epoxy resin is used at 3 or less than the nonvolatile content of the acrylic resin and the urea-formaldehyde resin, the adhesion improvement effect is insufficient, and the bisphenol-A type epoxy resin is used as the acrylic resin and the urea-formaldehyde resin. If the ratio exceeds 10, the storage stability and the coating viscosity are limited. As a specific example of the epoxy resin used for the said invention, YD-127 and 128 (product name) of Kukdo Chemical Co., Ltd. can be mentioned.

Then, another factor affecting the adhesion is a reaction catalyst, which depends on the application of a strongly acidic aromatic sulfonic acid. It is preferable that the usage-amount of the acid catalyst which is the said reaction catalyst contains 0.2-1.0 weight part with respect to the total weight of a paint composition for a glass. If the content of the aromatic sulfonic acid contained in the coating composition for porcelain is 0.2 parts by weight or less, the adhesiveness is inferior, and when the content exceeds 1.0 parts by weight, the problem of not easy storage of the paint occurs. Therefore, the aromatic sulfonic acid preferably contains 0.2 to 1.0 parts by weight, more preferably 0.3 to 0.5 parts by weight based on the total weight of the porcelain coating composition. As an example of the aromatic sulfonic acid which is the said acid catalyst, Cycat-4040, 500, and 600 (product name) of Cyanamid company can be mentioned.

In addition, it is preferable to have an amine-based silane (δ-aminopropyltrimethoxysilane) in the range of 0.2 to 1.0 parts by weight based on the weight of the coating composition for solvents in order to complement the solvent resistance properties. This is because when the content of the amine silane exceeds the above range, a problem arises in the compatibility of the coating material, thereby lowering the transparency of the coating film formed. As an example of an amine silane applied to a present Example, APS-E (SS-330) of CHISSO company is mentioned.

Subsequently, the organic solvent applied to form the porcelain paint should be selected in consideration of the solubility parameter of the resin, and the solvent used in the porcelain paint composition improves workability in the spray coating process and is dried. It is preferable to use butyl cellosolve or ethyl cellosolve, which is an ethylene glycol-based solvent that sets the viscosity so that a uniform surface is formed on the surface. The organic solvent preferably contains 3 to 15 parts by weight, and more preferably 4 to 14 parts by weight based on the total weight of the initial paint composition.

Generally, organic solvents are alcohols such as ethyl alcohol, propyl alcohol, butyl alcohol, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, ethyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone and ketones, and methyl acetate. Ester solvents such as ethyl acetate, normal propyl acetate, isopropyl acetate, butyl acetate, methyl cellosolve acetate, cellosolve acetate, butyl cellosolve acetate, and carbitol acetate.

Here, the paint coating composition for porcelain further comprises a dye to impart color. The dye preferably contains 3 to 10 parts by weight, and more preferably 4 to 9 parts by weight based on the total weight of the paint composition for a candle.

In addition, the initial paint composition may be additionally used for additives used in the conventional paint composition. That is, in general, the use of additives is not limited because the additives are added in a very small amount in order to optimize the elements that have a slight influence on the manufacturability and the workability in the paint. As an example of the said additive, an antifoamer, a dispersing agent, a flow inhibitor, a plasticizer, etc. are mentioned. Since the amount of the additive varies depending on the type of the additive, the amount of the additive in the present embodiment is not a limiting factor of the present invention.

Manufacturing method of ceramic paint

Hereinafter, the manufacturing method of the ceramic paint using the ceramic paint composition of the present invention will be described in detail.

First, it has physical properties such as lightness, high hardness, solvent resistance, acid value of 3 to 10, hydroxyl value of 80 to 140, glass transition temperature of 15 to 40 ° C, nonvolatile content of 40 to 70% by weight. To prepare an acrylic resin having a weight average molecular weight of 15,000 to 30,000.

Specifically, the acrylic resin is reacted by adding an acrylic monomer and an organic peroxide initiator to the aromatic solvent, and then additionally added an organic peroxide initiator. More specifically, after heating 30-40 weight part of xylene and normal butanol as an aromatic solvent, it heats up. Subsequently, a mixture containing 40 to 60 parts by weight of at least one acryl monomer and 0.5 to 2.0 parts by weight of benzoyl peroxide or t-butyl peroxide as an organic peroxide radical initiator is added to the aromatic solvent. Subsequently, 0.1-0.4 weight part of organic peroxide initiators are re-injected. Subsequently, a small amount of solvent is added and then cooled to prepare an acrylic resin.

Next, 20 to 50 parts by weight of the acrylic resin, 30 to 60 parts by weight of the urea-formaldehyde resin, and 4 to 10 parts by weight of the bisphenol-A type epoxy resin having an epoxy equivalent of 180 to 240 g / eq. And 0.2 to 1.0 part by weight of the amine silane and 0.2 to 1.0 part by weight of the aromatic sulfonic acid serving as the reaction catalyst are stirred until a uniform solution is obtained. As a result, a paint for ceramics is formed. In this case, the paint for paint and the elements constituting it are described in detail in the paint for paint composition for the first time will be omitted to avoid duplication.

The porcelain paint prepared from the materials having the above-described composition and properties will be described in more detail by the following synthesis examples and examples, and the scope of the present invention is not limited to these examples. In the following Synthesis Examples and Examples, the content means parts by weight.

Acrylic resin composite

Synthesis Example 1

30 parts by weight of xylene, which is an aromatic solvent, and 5 parts by weight of normal butanol were added to the synthetic flask, and the temperature was raised to about 110 to 130 ° C. Subsequently, 10 parts by weight of styrene, 7.6 parts by weight of methyl methacrylate, 21.6 parts by weight of butyl acrylate, 10.5 parts by weight of 2-hydroxyethyl acrylate, 0.5 parts by weight of acrylic acid, and 1.0 parts by weight of benzoyl peroxide as an organic peroxide radical initiator The mixture was added dropwise into the synthetic flask at a uniform rate over about 2 to 5 hours. After dropping, the reaction was carried out for 30 to 60 minutes, and then 0.5 parts by weight of benzoyl peroxide (75%) and 5.0 parts by weight of organic peroxide initiator were added thereto, and the reaction was carried out for 1 to 2 hours. Thereafter, 8.5 parts by weight of xylene was added to the resultant, followed by cooling to obtain an acrylic resin shown in Table 1 below.

Synthesis Example 2

28 parts by weight of xylene, which is an aromatic solvent, and 7 parts by weight of normal butanol were added to the synthetic flask, and the temperature was raised to about 110 to 130 ° C. Then, 12 parts by weight of styrene, 5 parts by weight of methyl methacrylate, 14 parts by weight of butyl acrylate, 5.5 parts by weight of isobutyl methacrylate, 13 parts by weight of 2-hydroxyethyl acrylate, 0.5 parts by weight of acrylic acid, organic peroxide radical A mixture of 1.0 parts by weight of benzoyl peroxide as an initiator was added dropwise at a uniform rate to the synthetic flask over 2 to 5 hours. After the dropwise addition, the reaction was carried out for 30 to 60 minutes, and then 0.5 parts by weight of benzoyl peroxide (75%), which is an organic peroxide initiator, and 5.0 parts by weight of xylene were added and then reacted for 1 to 2 hours. Thereafter, 8.5 parts by weight of xylene was added to the resultant, followed by cooling to obtain an acrylic resin shown in Table 1 below.

Synthesis Example 3

25 parts by weight of xylene, which is an aromatic solvent, and 10 parts by weight of normal butanol were added to the synthetic flask, and the temperature was raised to about 110 to 130 ° C. Thereafter, 13 parts by weight of styrene, 6.5 parts by weight of methyl methacrylate, 9.0 parts by weight of butyl acrylate, 6.0 parts by weight of isobutyl methacrylate, 15 parts by weight of 2-hydroxyethyl acrylate, 0.6 parts by weight of acrylic acid, organic peroxide A mixture of 1.0 parts by weight of a benzoyl peroxide (or t-butyl peroxide) which is a radical initiator is added dropwise to the synthetic flask at a uniform rate over 2 to 5 hours. After the dropwise addition, the reaction was carried out for 30 to 60 minutes, and then 0.5 parts by weight of benzoyl peroxide (75%), which is an organic peroxide initiator, and 5.0 parts by weight of xylene were added, followed by holding for 1 to 2 hours. Thereafter, 8.5 parts by weight of xylene was added to the resultant, followed by cooling to obtain an acrylic resin shown in Table 1 below.

[Table 1] Acrylic resin synthesis

   Raw material name Synthesis Example 1 Synthesis Example 2 Synthesis Example 3 xylene 30 28 25 Normal butanol  5 7 10 Styrene 10 12 13 Methyl methacrylate  7.6 5 6.5 Butyl acrylate  21.4 14 9 Isobutyl acrylate -  5.5 6 2-hydroxyethyl acrylate  10.5 13 15 Acrylic acid  0.5 0.5 0.5 Benzoyl peroxide  1.0 1.0 1.0 xylene 5 10 10 Benzoyl peroxide (75%)  0.5 0.5 0.5 xylene  8.5 5.5 5.5 Sum 100 100 100 Nonvolatile matter (%) 50 50 50 Viscosity (Gardner) W Y Z1 OH value 90 112 130

Preparation of Paint Composition

The mixing is carried out by stirring the urea-formaldehyde resin, epoxy resin, acid catalyst, amine-based silane, organic solvent and additives in the formulations shown in Table 2 below, to the acrylic resin which is the main resin obtained in Synthesis Examples 1 to 3 as described above. The one-component powder coating compositions for example 1 to 3 and Comparative Examples 1 and 2 were prepared.

TABLE 2 Mixing ratio of paint composition

               Blended raw materials Example 1  Example 2  Example 3  Comparative Example 1  Comparative Example 2  Organic solvents 7.1 7.1 7.1 7.4 13.1  Resin of Synthesis Example 1 Resin of Synthesis Example 2 Resin of Synthesis Example 3 35-- -35- --35 35-- -35- Urea-formaldehyde resin 50 50 50 - - Melamine resin 50 50 Epoxy resin 6 6 6 6 - Acid catalyst 0.4 0.4 0.4 0.1 0.4 Amine-based silane 0.5 0.5 0.5 0.5 0.5 additive One One One One One Sum 100   100    100 100 100

(Representative examples of the composition used in the above paint formulation are as follows: urea-formaldehyde resin: Beckamine P-138, melamine resin: Super Beckamine L-145-60, organic solvent: Xylene, acid catalyst: Cycat-4040, Epoxy Resin: YD-128, Additive (Defoamer: Byk-054, Surface Regulator: Byk-306))

Evaluation of Physical Properties of Ceramic Paints

According to the blending ratio of Examples 1 to 3 and Comparative Examples 1 to 2, by adding and stirring the resin of Synthesis Examples 1 to 3, urea-formaldehyde resin, melamine resin, epoxy resin, acid catalyst, amine silane, etc. A paint composition was obtained. In order to evaluate the elution of dye in the obtained paint composition for the porcelain, 3 parts by weight of the yellow dye and blue dye were separately mixed with respect to the total weight of the paint composition for porcelain and used as a paint for evaluation of physical properties.

In order to evaluate the physical properties of the present invention, the dye-coated paint was coated with a hydrofluoric acid-treated glass bottle at a thickness of 15 to 20 microns and dried at 180 ° C. for 15 minutes to form a coating film. Subsequently, adhesion to the coating film, dye solvent resistance, water resistance, solvent resistance, boiling resistance, chemical resistance, and the like were evaluated by the physical property evaluation test method shown in Table 3 below. Table 3 shows the results of the evaluation of physical properties of the paint for porcelain.

[Table 3] Paint property evaluation test for porcelain

Test Items  Experiment method  Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Sunyoung Sung Coating film degree (visual) Good Good Good Slightly cloudy Slightly cloudy  Dye content  24 hours soak in ethanol Good  Good Good  Elution *  Elution *  Adhesion 1mm cross cut 100/100 100/100 100/100 80/100 90/100 Solvent resistance 24 hours of xylene dipping Good Good Good Peeling Peeling Boiling water resistance  1 hour immersion Good Good Good Swelling Swelling Alkali resistance 5% NaOH, 24 hours (spot test) Good Good Good Swelling Swelling Acid resistance Immersion in acid solution Good Good Good Swelling Swelling Salt spray Salt spray Good Good Good Good Good Water resistance 240 hours immersion in room temperature Good Good Good Good  Good Pencil hardness Mitsubishi pencil 2H 2H 2H + H H +

 (* Yellow dye, blue dye elutes equally)

Referring to Table 3, as can be seen from the physical property evaluation results for Examples 1 to 3, the dye solvent resistance, sunscreen, solvent resistance, boiling resistance, All physical properties such as chemical resistance are excellent or good.

 By using the coating composition for a ceramic according to the present invention it is possible to produce a high-functional ceramic coating having sunscreen, dye solvent resistance, chemical resistance. In addition, the coating material for the porcelain can be coated on a glass bottle to form a high-performance coating film that can solve the problem of the weakness of the dye resistance, adhesion, and chemical resistance, which is a problem of conventional acrylic and melamine-based coating compositions have. That is, the coating film formed of the coating material for porcelain not only has excellent adhesion to the glass bottle but also has excellent coating properties such as solvent resistance, boiling resistance, solvent resistance, chemical resistance, high hardness, and coating film selectivity. Have

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (5)

20 to 50 parts by weight of acrylic resin, 30 to 60 parts by weight of urea-formaldehyde resin, 4 to 10 parts by weight of bisphenol-A type epoxy resin having epoxy equivalent of 180 to 240 g / eq, and amine silane 0.2 To 1.0 part by weight, 0.2 to 1.0 part by weight of an aromatic sulfonic acid as a reaction catalyst, and 3 to 15 parts by weight of an organic solvent, wherein the acrylic resin has an acid value of 3 to 10 mgKOH / g and a glass transition temperature of 15 to 40 ° C. , Non-volatile content 40 to 70% by weight, weight average molecular weight is 15,000 to 30,000, hydroxyl value is 80 to 140mgKOH / g to prevent compatibility with the urea-formaldehyde resin Composition. delete The method of claim 1, wherein the acrylic resin is made by adding an acrylic monomer and a benzoyl peroxide or t-butyl peroxide as an organic peroxide initiator to an aromatic solvent, and then re-adding the organic peroxide initiator to react. Paint compositions. According to claim 1, wherein the coating composition for the ceramic paint composition characterized in that it further comprises 3 to 15 parts by weight of the dye. Acid value is 3-10mgKOH / g, glass transition temperature is 15-40 ° C, non-volatile content 40-70% by weight, weight average molecular weight is 15,000-30,000, and hydroxyl value is compatibility with urea-formaldehyde resin Preparing an acrylic resin having a property of 80 to 140 mgKOH / g to prevent degradation; And 20 to 50 parts by weight of the acrylic resin, 30 to 60 parts by weight of the urea-formaldehyde resin, 4 to 10 parts by weight of a bisphenol-A type epoxy resin having an epoxy equivalent of 180 to 240 g / eq, and an amine in the entire coating composition for porcelain. A method for producing a paint for ceramics comprising the step of stirring 0.2 to 1.0 parts by weight of silane, 0.2 to 1.0 parts by weight of aromatic sulfonic acid as a reaction catalyst and 3 to 15 parts by weight of an organic solvent.