KR100669857B1 - Thermoplastic epoxy-modified acrylic resin composition or polyester resin composition, and heating dry type clear paint composition containing the same - Google Patents

Abstract

The present invention relates to a heat-drying transparent coating composition containing a thermosetting epoxy modified acrylic resin composition, a polyester resin composition or a mixture thereof. More specifically, the heat-drying transparent coating composition of the present invention is an acrylic monomer with respect to 100 parts by weight of the total monomer, 3 to 40 parts by weight of the acrylic monomer represented by the following formula (1) and 5 to 30 parts of the acrylic monomer having a carboxylic acid group Thermosetting epoxy-modified acrylic resin composition consisting of parts; And a copolyester resin composition having a number average molecular weight of 2,000 to 10,000, a glass transition temperature of 20 to 50 ° C., and a hydroxyl group of 10 to 50 mg KOH / g. It shows excellent corrosion resistance and acid resistance and high hardness when applied to the same material. .

(In the formula, R represents alkylene having 8 to 18 carbon atoms.)

Epoxy Modified * Polyester * Transparent Paint * Corrosion Resistance * Acid Resistance

Description

Thermoplastic epoxy-modified acrylic resin composition or polyester resin composition, and heating dry type clear paint composition containing the same}

The present invention relates to a heat-drying transparent coating composition containing a thermosetting epoxy modified acrylic resin composition and a polyester resin composition or a mixture thereof.

Generally, copper materials include bronze, a copper-tin (Cu-Sn) alloy, and brass, a copper-zinc (Cu-Zn) alloy. The bronze has a high copper content and is poor in heat resistance, while brass has moderate strength and malleability and is easy to be molded. However, the brass has a drawback of being easily oxidized or corroded due to its weak chemical resistance such as corrosion resistance and acid resistance. Therefore, a transparent coating is required to compensate for the corrosiveness of these materials.

As a technique related to the resin composition for heat-drying transparent paint applicable to the brass material, there is a method of improving the hardness and corrosion resistance physical properties by adding a small amount of epoxy resin to the acrylic resin. However, when the epoxy resin is added in an excessive amount, there is a problem in that the appearance of the coating film becomes opaque due to incompatibility, and the storage property is inferior. In addition, there is a conventional method for coating the copper material, there is a method for grafting an acrylic monomer to the epoxy resin, while the method improves the appearance and storage, while applying a common acrylic monomer and the content of the acrylic monomer having a carboxylic acid This has shown a limit in improving physical properties, such as corrosion resistance, acid resistance, and flexibility.

Accordingly, the present inventors studied a transparent coating composition having excellent physical properties such as corrosion resistance, acid resistance, and hardness when applied to the same material, results in excellent thermosetting epoxy modified acrylic resin composition having excellent coating film hardness, adhesion, acid resistance, corrosion resistance, and bendability. When preparing a transparent coating composition by using a polyester resin composition to improve the flexibility, impact resistance and the like was found to solve the above problems and completed the present invention.

Accordingly, an object of the present invention is to provide a thermosetting epoxy modified resin composition excellent in coating film hardness, adhesion, acid resistance and corrosion resistance of the transparent coating composition.

In addition, another object of the present invention is to provide a polyester resin composition that complements the flexibility and impact resistance of the transparent coating composition.

In addition, another object of the present invention is to provide a heat-drying transparent coating composition composed of the thermosetting epoxy-modified resin composition or polyester resin composition.

In order to achieve the above object, the thermosetting epoxy modified resin composition of the present invention is obtained by grafting 50 to 90 parts by weight of an acrylic monomer to 10 to 50 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent of 400 to 2000 to a resin solid content. It is characterized by. In particular, the acrylic monomer is composed of 3 to 40 parts by weight of the acrylic monomer represented by the following formula (1) and 5 to 30 parts by weight of the acrylic monomer having a carboxylic acid group based on 100 parts by weight of the total monomers.

[Formula 1]

(In the formula, R represents alkylene having 8 to 18 carbon atoms.)

Moreover, the polyester resin composition of this invention shows the number average molecular weight 2000-10000, the glass transition temperature 20-50 degreeC, and a hydroxyl value 10-50 mgKOH / g, and improves flexibility and impact resistance.

Hereinafter, the present invention will be described in more detail.

The thermosetting epoxy modified resin composition of the present invention is obtained by grafting 50 to 90 parts by weight of an acrylic monomer to 10 to 50 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent of 400 to 2000 relative to the resin solid content.

The bisphenol A type epoxy uses an epoxy equivalent of a resin in the range of 400 to 2000, and in the present invention, a commercial product (Kukdo Chemical, Kumho P & B, Bakelite) is used. The content of the epoxy resin is used in 10 to 50 parts by weight relative to the resin solids. In the case of less than 10 parts by weight, the physical properties such as adhesion, corrosion resistance, acid resistance, etc. are lowered, and when it exceeds 50 parts by weight, the impact resistance is generally worsened, the viscosity of the resin is high, the workability is lowered, the adhesion of the dry coating film The problem of deterioration occurs.

In addition, when the epoxy equivalent is less than 400, adhesion, corrosion resistance, and the like is inferior, and when it exceeds 2000, the graft efficiency is poor, the appearance of the resin becomes cloudy, and the viscosity of the resin is high, making it difficult to control the viscosity.

In addition, as said acryl-type monomer, the alkyl acrylate monomer, the hydroxyl-containing alkylacryl monomer, and the acryl monomer which has a carboxylic acid group are used.

 The alkyl acrylate monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, normal butyl (meth) acrylate, isobutyl (meth) acrylate, and tertiary butyl (meth). At least one selected from acrylate, 2-ethyl hexyl (meth) acrylate, isodecyl (meth) acrylate, normal-lauryl (meth) acrylate, tridecyl methacrylate, normal-stearyl methacrylate, and the like Compounds can be used.

2-ethyl hexyl (meth) acrylate, isodecyl (meth) acrylate, and normal-lauryl (meth) acrylate represented by the following general formula (1) to improve the bendability when the thermosetting epoxy-modified acrylic resin composition is applied to the paint It is preferable to select 1 or more types of monomers, such as a tridecyl methacrylate and a normal- stearyl methacrylate, and to contain 3-40 weight part with respect to 100 weight part of all monomers. If the added amount is less than 3 parts by weight, but the possession and adhesion and hardness is good but the flexibility and impact resistance is poor, if the addition amount exceeds 40 parts by weight, the flexibility and impact resistance is good but hardness is significantly lowered There is a disadvantage, so it is preferable to use within the above range.

[Formula 1]

(In the formula, R represents alkylene having 8 to 18 carbon atoms.)

In addition, the acrylic monomer having the carboxylic acid group includes acrylic acid, methacrylic acid, and the like, which is included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the total monomer composition. When the addition amount is less than 5 parts by weight can not exhibit sufficient corrosion resistance and acid resistance, when the addition amount exceeds 30 parts by weight, the corrosion resistance and acid resistance is good but the alkali resistance is remarkably inferior to use within the above range desirable.

In addition, at least one compound selected from 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, etc. may be used as the hydroxyl group-containing alkylacryl monomer. It may be included, 10 to 30 parts by weight based on 100 parts by weight of the total monomers.

On the other hand, the initiator used in the preparation of the epoxy-modified acrylic resin composition of the present invention is selected from peroxide-based benzoyl peroxide, tertiary butyl peroxy benzoate, tertiary butyl peroxy 2-ethyl hexanate and the like. When the azo bisbutylnitrile other than the initiator is used, the graft efficiency of the acrylic monomer may be lowered, and only a mixture of acrylic homopolymers may be produced, and the resin appearance becomes cloudy due to poor compatibility between epoxy and acrylic homopolymers. There is a problem. Therefore, in the present invention, it is preferable to use a peroxide-based initiator having good graft efficiency, and use the content in an amount of 1 to 10 parts by weight based on the acrylic monomer. At this time, when the amount of the initiator is less than 1 part by weight, the amount of the initiator is too small compared to the acrylic monomer, the graft efficiency is lowered, the viscosity of the resin is too high, the workability may be lowered, and when it exceeds 10 parts by weight, the initiator remains in the resin This may adversely affect the cured coating film.

The thermosetting epoxy modified acrylic resin composition obtained by grafting and polymerizing 50-90 weight part of acrylic monomers to 10-50 weight part of said epoxy equivalent 400-2000 bisphenol-A epoxy resins has a hydroxyl value of 50-150 mg KOH / g, and 20 It has an acid value of ˜150 mg KOH / g and a glass transition temperature of 0 to 100 ° C.

The hydroxyl value of the epoxy modified acrylic resin composition of this invention is 50-150 mg KOH / g, Preferably it is 70-120 mg KOH / g. If the hydroxyl value is less than 50 mg KOH / g, the crosslinking density of the cured film is low, and thus hardness, impact resistance, and bendability are poor. If the hydroxyl value is more than 150 mg KOH / g, the crosslinking density is high and the cured film is too hard, resulting in poor impact resistance. There is this.

The acid value of the epoxy-modified acrylic resin composition of the present invention is 20 to 150 mg KOH / g, preferably 50 to 120 mg KOH / g. If the acid value is less than 20mg KOH / g, the polarity of the resin is small, so that the adhesion to the substrate is poor and the curing reactivity is poor.If the acid value exceeds 150mg KOH / g, excess carboxylic acid groups remain in the cured coating film. There is a problem in that chemical properties such as water resistance and alkali resistance are poor.

In addition, the glass transition temperature of the epoxy-modified acrylic resin composition of the present invention is in the range of 0 ~ 100 ℃, preferably 30 ~ 70 ℃. If the glass transition temperature is less than 0 ℃ the hardness of the cured coating film is lowered, if it exceeds 100 ℃ there is a disadvantage that the physical properties such as adhesion, impact resistance, flexibility of the cured coating film is lowered.

On the other hand, the polyester resin composition of the present invention has the physical properties of the number average molecular weight 2000 ~ 10000, glass transition temperature 20 ~ 50 ℃, hydroxyl group 10 ~ 50mg KOH / g, when contained in the transparent paint flexibility and impact resistance To improve.

The polyester resin composition of the present invention comprises a polyhydric acid component and a polyhydric alcohol component. Examples of the polyvalent acid component used in the present invention include adipic acid, aromatic polyacid, or derivatives thereof such as terephthalic acid, isophthalic acid, or phthalic anhydride, and cycloaliphatic and aliphatic polyacids include cyclohexanedicarboxylic acid, hexa At least one compound selected from hydrophthalic hydride, tetrahydrophthalic hydride, azelaic acid, sebacic acid, fumaric acid and the like can be used. At this time, it is preferable to use 5 to 70 parts by weight of adipic acid or isophthalic acid based on the total weight of polyacid. Less than 5 parts by weight relative to the total weight of the polyvalent acid, the adhesion and corrosion resistance with the material is good, but the flexibility is inferior. If it exceeds 70 parts by weight, the flexibility and weather resistance is good, but corrosion resistance and adhesion to the material is poor There is this.

In addition, as the polyhydric alcohols used in the present invention, ethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol, 1,4-butanediol, mpdiol, pentaerythritol, trimethanol propane, 1,6-hexanediol , At least one compound selected from bisphenol A and the like can be used. In particular, it is preferable to use 5 to 20 parts by weight of bisphenol A or bisphenol A-based ethylene (propylene) adduct relative to the total solids in order to improve adhesion to the material, corrosion resistance, and bendability. This is because when less than 5 parts by weight relative to the total solids, the corrosion resistance and adhesion to the body is poor, if it exceeds 20 parts by weight because the corrosion resistance and adhesion to the base is good but there is a problem that the flexibility is poor.

In the present invention, the epoxy-modified acrylic resin composition and the polyester resin composition prepared as described above can be applied to the transparent coating composition. At this time, the heat-drying transparent coating composition is 30 to 50 parts by weight, 5 to 30 parts by weight of a curing agent, 0.1 to 0.5 parts by weight of an antifoaming agent, alone or mixed with the thermosetting epoxy-modified acrylic resin composition and the polyester resin composition prepared above, and It consists of 10-60 weight part of solvents. At this time, when using the epoxy-modified acrylic resin and polyester resin is mixed 5 ~ 30 parts by weight of the polyester resin to the total weight of the resin.

In addition, when the amount of the curing agent exceeds 30 parts by weight, the hardness is excellent, but the adhesion, impact resistance, etc. are poor, and less than 5 parts by weight, the hardness and corrosion resistance of the coating film is poor.

In addition, as the solvent, in order to adjust the viscosity and smoothness of the paint, aromatic hydrocarbon solvents, esters and ether solvents can be used in various ratios. Specifically, when adjusted to 5 to 30 parts by weight of aromatic hydrocarbon solvent, 5 to 30 parts by weight of ester and ether solvent, and 0.1 to 0.5 parts by weight of isopropyl alcohol, in terms of smoothness of the coating film, spray workability and storage stability of the mixed paint Good.

In addition, silicone additives such as polyether siloxane and polyester siloxane may be used as additives for imparting smoothness and defoaming performance of the coating film in the heat-drying transparent coating composition of the present invention, and have a form having both leveling performance and defoaming performance. It is preferable to select and use.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is provided only to assist in understanding the present invention, but the present invention is not limited thereto.

Example 1 Preparation of Epoxy Modified Acrylic Resin Composition

Into a four-necked flask equipped with a stirrer, a thermometer, and a condenser, 420 parts by weight of YD-014 (Kukdo Chemical Co., Ltd.), 420 parts by weight of butyl cellulsolve, and 350 parts by weight of propylene glycol methyl ether acetate were placed in the flask. After substitution with nitrogen gas, the temperature was raised to 120 ° C. while stirring to completely dissolve the epoxy resin. Next, after confirming that the epoxy resin was dissolved, at this temperature, 250 parts by weight of styrene, 250 parts by weight of methyl methacrylate, 80 parts by weight of butyl acrylate, 100 parts by weight of 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate The mixture of 170 parts by weight of rate, 150 parts by weight of acrylic acid, 58 parts by weight of benzoyl peroxide and 140 parts by weight of xylene was added dropwise and uniformly over 3 hours, followed by stirring for 1 hour. After adding 10 parts by weight of benzoyl peroxide and 140 parts by weight of xylene again, the reaction was further maintained for 2 hours. Then, 160 parts by weight of normal butanol was added thereto, followed by dilution. An epoxy-modified acrylic resin having a characteristic value of 75 mg KOH / g, Gardner viscosity (25 ° C.) Z 4 and a solid content of 55% was obtained.

Example 2 Preparation of Epoxy Modified Acrylic Resin Composition

Into the flask of the same device as in Example 1, 260 parts by weight of YD-017 (Kukdo Chemical Co., Ltd.), 300 parts by weight of butyl cellulsolve, and 300 parts by weight of propylene glycol methyl ether acetate were substituted with nitrogen gas. Then, the mixture was heated to 120 ° C. while stirring to completely dissolve the epoxy resin. Next, after confirming that the epoxy resin dissolved, 523 parts by weight of methyl methacrylate, 100 parts by weight of butyl acrylate, 100 parts by weight of isodecyl methacrylate, 120 parts by weight of 2-hydroxyethyl methacrylate, A mixture of 40 parts by weight of 2-hydroxyethyl acrylate, 117 parts by weight of acrylic acid, 50 parts by weight of benzoyl peroxide and 140 parts by weight of xylene was added dropwise and uniformly over 3 hours and stirred for 1 hour. After adding 10 parts by weight of benzoyl peroxide and 140 parts by weight of xylene again, the reaction was further maintained for 2 hours. Then, 160 parts by weight of normal butanol was added thereto, followed by dilution. Acid value 70 mg KOH / g relative to the resin solid content, hydroxyl group An epoxy-modified acrylic resin having a characteristic value of 71 mg KOH / g, Gardner viscosity (25 ° C.) Z 2, and a solid content of 55% was obtained.

Example 3 Preparation of Epoxy Modified Acrylic Resin Composition

260 parts by weight of YD-014 (Kukdo Chemical Co., Ltd.), 350 parts by weight of butyl cellulose, 300 parts by weight of propylene glycol methyl ether acetate as an epoxy resin was added to the flask of the same apparatus as Example 1, and the inside of the flask was replaced with nitrogen gas. Then, the mixture was heated to 120 ° C. while stirring to completely dissolve the epoxy resin. Next, after confirming that the epoxy resin was dissolved, at this temperature, 300 parts by weight of styrene, 150 parts by weight of methyl methacrylate, 100 parts by weight of butyl acrylate, 140 parts by weight of 2-ethylhexyl acrylate, 2-hydroxyethyl meta A mixture of 190 parts by weight of acrylate, 120 parts by weight of methacrylic acid, 65 parts by weight of benzoyl peroxide and 140 parts by weight of xylene was uniformly added dropwise over 3 hours and stirred for 1 hour. After adding 10 parts by weight of benzoyl peroxide and 140 parts by weight of xylene again, the reaction was further maintained for 2 hours, and then diluted by adding 120 parts by weight of normal butanol to 60 mg KOH / g of acid value to the resin solids and hydroxyl groups. An epoxy-modified acrylic resin having a characteristic value of 82 mg KOH / g, Gardner viscosity (25 ° C.) Z 2, and a solid content of 55% was obtained.

Example 4 Preparation of Polyester Resin Composition

In a four-necked flask equipped with a stirrer, a thermometer, a condenser and a water separator, 120 parts by weight of isophthalic acid, 78 parts by weight of terephthalic acid, 52 parts by weight of adipic acid, 100 parts by weight of trimethylol propane, 90 parts by weight of bisphenol A, and 100 parts by weight of dipiol Add 50 parts by weight of ton polyol (molecular weight: 830, manufactured by Dow), add 0.4 parts by weight of dibutyltin dioxide as a catalyst, and then esterify at 230 ± 10 ° C. Propylene glycol methylether acetate and butyl cellulsolve Was diluted with a solvent mixed at 5: 5 to obtain a polyester resin composition having a Gardner viscosity (25 占 폚) Z, an acid value of 2.5 mg KOH / g, a number average molecular weight of 7100, and a solid content of 50%.

Comparative Example 1 Preparation of Acrylic Resin

550 parts by weight of xylene and 300 parts by weight of normal butanol were added to the flask of the same device as in Example 1, and the temperature was raised to 110 ° C., 275 parts by weight of styrene, 500 parts by weight of methyl methacrylate, and 210 parts by weight of 2-hydroxyethyl methacrylate. A mixture of 15 parts by weight of methacrylic acid and 27 parts by weight of tertiary butylperoxy 2-ethyl hexanate was uniformly added dropwise over 4 hours and stirred for 1 hour. After adding 3 parts by weight of tertiary butylperoxy 2-ethyl hexanate and 60 parts by weight of xylene, the reaction was further maintained for 2 hours, followed by diluting by adding 120 parts by weight of xylene to acid value of 7 to the resin solids. An acrylic resin having a characteristic value of mg KOH / g, hydroxyl value of 90 mg KOH / g, Gardner viscosity (25 ° C.) Z, and solid content of 50% was obtained.

Comparative Example 2 Preparation of Epoxy Modified Acrylic Resin

450 parts by weight of YD-014 (Kukdo Chemical Co., Ltd.), 420 parts by weight of propylene glycol methyl ether acetate as an epoxy resin was added to the flask of the same apparatus as in Example 1, the inside of the flask was replaced with nitrogen gas, and stirred at 120 ° C. The temperature was raised to completely dissolve the epoxy resin. Next, after confirming that the epoxy resin was dissolved, 355 parts by weight of styrene, 215 parts by weight of methyl methacrylate, 180 parts by weight of butyl acrylate, 235 parts by weight of 2-hydroxyethyl methacrylate, 15 parts by weight of acrylic acid, A mixture of 40 parts by weight of benzoyl peroxide and 200 parts by weight of xylene in advance was added dropwise uniformly over 3 hours and stirred for 1 hour. After adding 10 parts by weight of benzoyl peroxide and 160 parts by weight of xylene again, the reaction was further maintained for 2 hours. Then, 280 parts by weight of butyl cellulsolve and 136 parts by weight of normal butanol were added to the mixture to dilute the acid value of the resin solids. An epoxy-modified acrylic resin having 8 mg KOH / g, hydroxyl value of 100 mg KOH / g, Gardner viscosity (25 ° C.) Z, and solid content of 55% was obtained.

[Manufacture example 1-6]

Using the resin compositions of Examples 1 to 4 and Comparative Examples 1 to 2 to prepare a transparent coating composition of Preparation Examples 1 to 4 and Comparative Preparation Examples 1 to 2 in the composition of Table 1.

First, KM-325-60 (manufactured by Samwha), which is a modified melamine resin, was added to 30 to 50 parts by weight and a curing agent in Examples 1 to 4 and Comparative Examples 1 to 2, respectively, and the solvent was an aromatic hydrocarbon solvent. 5-30 parts by weight of Solveso 100, Solveso 150 or xylene, 5-30 parts by weight of butyl cellulsolve, an ester and ether solvent, 0.1-0.5 parts by weight of isopropyl alcohol, and silicone additives (trade name; BYK 301, BYK Chemie)) to 0.1 to 0.5 parts by weight to prepare a transparent liquid paint.

  Compounding (content; parts by weight) Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Comparative Production Example 1 Comparative Production Example 2 Resin of Example 1 (solid content 55%) 40 - - 32 - - Resin of Example 2 (solid content 55%) - 40 - - - Resin of Example 3 (solid content 55%) - - 40 - - - Resin of Example 4 (50% solids) - - - 10 - - Resin of Comparative Example 1 (50% solids) - - - - 44 - Resin of Comparative Example 2 (solid content 55%) - - - - - 40 KM-325-60 (manufactured by Samwha) 9.2 9.2 9.2 9.2 9.2 9.2 Solvesso 100 10 10 10 10 10 10 xylene 20 20 20 18 16 20 Butyl Cell Solution 16.5 16.5 16.5 16.5 16.5 16.5 Isopropyl Alcohol 4 4 4 4 4 4 BYK 301 (BYK Chemie manufacture) 0.3 0.3 0.3 0.3 0.3 0.3 all 100 100 100 100 100 100

[Test Example 1]

The transparent coating compositions of Preparation Examples 1 to 4 and Comparative Preparation Examples 1 to 2 were coated in brass by an air spray method with a dry coating thickness of 10 to 15 μm, and dried by heating at 150 ° C. for 20 minutes. Next, the adhesion, pencil hardness, impact resistance, acid resistance and corrosion resistance test were carried out by the following method, and the results are shown in Table 2.

-Adhesion-

According to the test method of TEST METHOD B of ASTM D3359, the degree of peeling of the coating film after attaching the cellophane tape on 100 scales formed by crossing 11 horizontal and 11 vertical lines with a 1 mm interval with a sharp knife on the dried coating film Evaluate in six steps according to.

5B: no peeling of film, 4B: less than 5% of peeling film, 3B: 5 to 15% peeling of film, 2B: 15 to 35% peeling of film, 1B: 35 to 65% peeling of film, 0B: 65% or more peeling .

-Pencil hardness-

The maximum number of traces does not appear on the coating film when drawn under a load of 45 degrees by 1 kg according to the type of pencil (B, HB, F, H, 2H, 3H, 4H, etc.) according to the pencil hardness method of JIS K-5400. Express the strength in pencil hardness. At this time, if one sample is tested five times and no trace occurs more than three times, the hardness of the pencil is considered as pass.

Impact resistance

If the coating film is not peeled off by dropping to a height of 30cm with a load of 500g using a dupont type impact tester, it is good. At this time, the impact surface uses a spherical surface 1/2 inch in diameter.

Acid Resistance

5% sulfuric acid aqueous solution was added to the coating film, which was left at room temperature for 24 hours, followed by wiping with water to visually determine the degree of damage to the coating film.

-Corrosion resistance-

Cross-cut the specimen to be visible on the coating film, and after 200 hours test with a salt spray tester (35 ± 2 ℃, 5% sodium chloride solution), determine the degree of peeling and corrosion of the coating film visually. Evaluate with branches.

(Double-circle): When there is no rust in a crosscut part,

(Circle): When rust is less than 0.5 mm in a cross cut part,

(Triangle | delta): When rust is 0.5-1 mm in a crosscut part,

X: When rust is 1 mm or more in a crosscut part.

Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Comparative Production Example 1 Comparative Production Example 2 Pencil hardness 2H 3H 2H 2H 3H 2H Impact resistance O O  ◎  ◎  × O Flexibility O O  ◎  ◎  × O Acid resistance  ◎  ◎ O  ◎  ×  × Adhesion 4B 4B 3B 5B 4B 3B Corrosion resistance  ◎ O O  ◎  ×  △ * Evaluation criteria ~ ◎: Excellent, O: Good, △: Normal, ×: Poor

As shown in Table 2, the physical properties of Preparation Examples 1 to 4 to which the resins of Examples 1 to 4 manufactured in the preferred range of the present invention were generally obtained, in particular, the resins of Example 4 were mixed. In the case of the applied Preparation Example 4, it was confirmed that physical properties of adhesion, flexibility, and impact resistance were further improved.

In addition, in Comparative Preparation Examples 1 and 2 to which the Comparative Examples 1 to 2 resins prepared without departing from the scope of the present invention without adding the compound represented by Formula 1 were found to have poor corrosion resistance, impact resistance, and acid resistance.

As described above, the thermosetting epoxy-modified acrylic resin composition according to the present invention has excellent physical properties such as coating hardness and adhesion, and chemical properties such as acid resistance and corrosion resistance, compared to conventional acrylic resins. The result which improves the bending property and impact resistance of a resin coating film at the time of mixed use with an epoxy modified acrylic resin is shown. Therefore, the heat-drying transparent coating composition using the epoxy-modified acrylic resin and polyester resin prepared as described above can effectively exhibit physical properties such as corrosion resistance, acid resistance, high hardness when applied to the same material.

Claims (5)

50 to 90 parts by weight of an acrylic monomer is grafted to 10 to 50 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent of 400 to 2000, and a hydroxyl value of 50 to 150 mg KOH / g is 20 to 150 mg KOH / g. A thermosetting epoxy modified acrylic resin composition having an acid value and a glass transition temperature of 0 to 100 ° C, a copolymerized polyester resin composition having a number average molecular weight of 2,000 to 10,000, a glass transition temperature of 20 to 50 ° C, and a hydroxyl group of 10 to 50 mg KOH / g. 30 to 50 parts by weight of one or more resin compositions selected from the group consisting of; 5 to 30 parts by weight of modified melamine resin hardener; Antifoaming agent 0.1-0.5 parts by weight; And 10 to 60 parts by weight of one or more solvents selected from aromatic hydrocarbon, ester, ether and alcohol solvents; Heat-drying transparent coating composition containing a. According to claim 1, wherein the acrylic monomer is an alkyl acrylate monomer represented by the following formula (1) 2-ethyl hexyl (meth) acrylate, isodecyl (meth) acrylate, normal- lauryl (meth) acrylate, tri A heat-drying transparent coating composition comprising a monomer selected from the group consisting of decyl methacrylate and normal-stearyl methacrylate in an amount of 3 to 40 parts by weight based on 100 parts by weight of the total monomer composition. [Formula 1]

(In the formula, R represents alkylene having 8 to 18 carbon atoms.) The heat-drying transparent coating composition according to claim 1, wherein the acrylic monomer contains 5 to 30 parts by weight of the acrylic monomer having a carboxylic acid group based on 100 parts by weight of the total monomer composition. According to claim 1, wherein the acrylic monomer is a hydroxyl group-containing alkyl selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate Heat-drying transparent coating composition, characterized in that the acrylic monomer is contained in 10 to 30 parts by weight based on 100 parts by weight of the total monomer composition. delete