KR100356392B1 - Thermosetting acryl modified epoxy resin composition and method for preparing the same - Google Patents

Abstract

Disclosed is a thermosetting acrylic modified epoxy resin composition having excellent coating properties even in chemical performance such as acid resistance, corrosion resistance, alkali resistance, and physical performance such as hardness and scratch resistance. The resin composition of the present invention is formed by grafting 30 to 90% by weight of an acrylic monomer to 10 to 70% by weight of a bisphenol A epoxy resin having an epoxy equivalent of 400 to 3000. Compared with conventional acrylic resins, physical properties such as hardness and impact resistance, and chemical properties such as water resistance, acid resistance, alkali resistance, and corrosion resistance are very excellent, and thus they are easily used for cree coating of nonferrous metals, which require high corrosion resistance and high hardness. Can be.

Description

Thermosetting acrylic modified epoxy resin composition and its manufacturing method {THERMOSETTING ACRYL MODIFIED EPOXY RESIN COMPOSITION AND METHOD FOR PREPARING THE SAME}

The present invention relates to a highly corrosion-resistant acrylic modified epoxy resin composition for non-ferrous metals, and more particularly, compared to the conventional thermosetting acrylic resin, not only has excellent chemical resistance such as corrosion resistance, acid resistance and water resistance, but also has excellent hardness and gloss. The present invention also relates to an acrylic modified epoxy resin composition having excellent adhesion to nonferrous materials.

Today, with increasing incomes, consumer demands are gradually becoming more sophisticated and diversified, and materials such as industrial products and decorative products are also becoming more sophisticated and diversified. In particular, door locks have been replaced by stainless steel and nonferrous metals for many years. Nonferrous metals are more expensive than stainless steels. Although there are many advantages such as workability, the chemical resistance properties such as corrosion resistance are very weak, thereby reinforcing various properties by coating finishing for the purpose of increasing the durability of the appearance. The door locks include copper (Cu-Sn) alloy bronze (Bronz) and copper-zinc (Cu-Zn) alloy brass (Brass). In general, brass is used a lot. Brass is easy to process, inexpensive and beautiful in color, but the processed brass material is easily oxidized or corroded to reduce the value of the product.

In addition, conventionally, a small amount of epoxy resin is added to the acrylic resin to satisfy physical properties such as hardness and gloss, and to improve vulnerable corrosion resistance. However, in the above-described method, the epoxy resin is added to the acrylic resin. Excessive addition beyond the limit resulted in poor coating appearance and poor shelf life due to poor compatibility, which could not satisfy the needs of consumers.

Accordingly, one object of the present invention is to provide a thermosetting acrylic modified epoxy resin composition capable of improving high appearance, high hardness, chemical resistance, and storage stability by grafting an acrylic resin to an epoxy resin.

In addition, another object of the present invention is to provide a method for producing a thermosetting acrylic modified epoxy resin composition that can improve the appearance, high hardness, chemical resistance and storage stability by grafting an acrylic resin to the epoxy resin.

In order to achieve the above object, the present invention is obtained by grafting and polymerizing 30 to 90% by weight of an acrylic monomer to 10 to 70% by weight of a bisphenol A type epoxy resin having an epoxy equivalent of 400 to 3000 having the following structural formula, It provides a thermosetting acrylic modified epoxy resin composition having an acid value of 5 to 50 mg KOH / g.

N is from 0.5 to 12.

In addition, in order to achieve the above-mentioned other object, the present invention is to form an epoxy resin solution by mixing 10 to 70% by weight of a bisphenol A type epoxy resin with an epoxy equivalent of 400 to 3000 and a solvent, 30 to 90% by weight of an acrylic monomer And mixing a solvent to form an acrylic monomer solution, dropping the acrylic monomer solution into the epoxy resin solution at a temperature of 100 to 130 ° C., and adding benzoyl peroxide to the resulting reactant. It provides a method for producing a modified epoxy resin composition.

A method of modifying an acrylic resin to an epoxy resin includes a method of radical polymerization by grafting an acrylic monomer to a secondary alcohol functional group of an epoxy resin skeleton, and a primary reaction of a hydroxyl group of an epoxy skeleton with an anhydride group of maleic acid, followed by maleic acid. And a method of radically polymerizing an acrylic monomer to a double bond. The resin composition of this invention was synthesize | combined by grafting an acrylic monomer to the secondary alcohol functional group of an epoxy resin frame | skeleton.

The resin composition of the present invention is a non-ferrous metal which is a material of an industrial product in which mechanical properties such as hardness and scratch resistance of the cured coating film and chemical properties such as corrosion resistance, acid resistance and alkali resistance are important due to heat curing reaction with an amino resin and the like as a crosslinking agent resin. It is an acrylic modified epoxy resin composition for highly corrosion-resistant CREE which can be applied to.

Hereinafter, the present invention will be described in detail.

The acrylic modified epoxy resin composition of this invention contains the bisphenol-A epoxy resin known to be excellent in chemical performance. Such bisphenol A epoxy resin is represented by the following structural formula.

N is from 0.5 to 12. Specific examples of the epoxy resins include YD-128, YD-011, YD-014, YD-019 (trade name of Kukdo Chemical), etc., and products of other companies (LG Chemical, Shell Chemical, etc.) having similar characteristics. Can also be used and can be easily purchased on the market. As the epoxy resin used in the present invention, YD-series products of Kukdo Chemical were used.

At this time, if the content of the epoxy resin is less than 10% relative to the resin solid content, the chemical performance of adhesion, corrosion resistance, acid resistance, alkali resistance, etc. is not sufficient, if the content of the epoxy resin exceeds 70% of the epoxy resin is weak It exhibits bad results in weather resistance, which is physical property, and increases the viscosity of the resin solution, resulting in poor workability. Also, the dry coating is poor in adhesion to the base and easily breaks. Therefore, the content of the epoxy resin is preferably 10 to 70% by weight, preferably 20 to 60% by weight relative to the resin solids.

In addition, the acrylic modified epoxy resin composition includes an acrylic monomer. As the acrylic monomer, an acrylic monomer having a non-functional acrylic monomer and a hydroxyl group and an acrylic monomer having a small amount of carboxylic acid groups are used. Non-functional acrylic monomers include methyl acrylate, ethyl acrylate, normal-butyl acrylate, 2-ethyl hexyl acrylate, methyl methacrylate, normal-butyl methacrylate, and the like. Ethyl methacrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and the like, and acrylic monomers having carboxylic acid groups include acrylic acid, methacrylic acid, and the like. Used. In addition, as an initiator used in the present invention, initiators such as peroxide-based benzoyl peroxide, tertiary butyl peroxy benzoate, tertiary butyl peroxy 2-ethyl hexanate and azo azobisisobutyronitrile and the like are used. Can be.

In general, the desired graft copolymer can be easily obtained by using a peroxide-based benzoyl peroxide as an initiator. On the other hand, when azobisisobutyronitrile is used, the graft efficiency of the acrylic monomer is reduced, and only a mixture of acrylic homopolymer is produced, and the compatibility of the epoxy and acrylic homopolymer becomes poor, and the resin may be turbid. This initiator influence is because 2-cyano-2-propyl radicals generated from azobisisobutyronitrile inhibit the radicals from participating in the graft reaction by resonance stabilization. For this reason, in the present invention, a graft copolymer having a relatively high yield can be obtained using benzoyl peroxide as a graft reaction initiator of an acrylic monomer. In the present invention, in order to graf the acrylic monomer to the epoxy secondary alcohol functional group, it is preferable to use a peroxide-based benzoyl peroxide, and the amount is preferably 1 to 10% by weight relative to the acrylic monomer. At this time, when the amount of the initiator is less than 1%, the amount of the initiator is too small compared to the acrylic monomer, the graft efficiency is lowered, and when the amount of the initiator is more than 10%, the initiator remains in the resin solution prepared, thereby cured coating film May adversely affect

The resin composition according to the present invention has a glass transition temperature in the range of 0 ° C to 60 ° C. When the glass transition temperature of the resin composition is less than 0 ° C., physical properties such as hardness and scratch resistance of the cured coating film may not be exhibited, and when the glass transition temperature is higher than 60 ° C., the adhesion of the cured coating film may be poor and water resistance, acid resistance, corrosion resistance, and the like. It is not preferable because the chemical performance cannot be sufficiently exhibited.

The hydroxyl value of the said resin composition has a hydroxyl value of about 50-150 mg KOH / g, Preferably it has a hydroxyl value of about 60-140 mg KOH / g. When the resin value of the resin composition is less than 50 mg KOH / g, the crosslinking density of the hardened wood is low, the physical properties such as hardness, impact resistance and chemical resistance of corrosion resistance can not be sufficiently exhibited, the hydroxyl value of the resin composition is 150 mg KOH / g If it exceeds, crosslinking agent resin will be required excessively, acid resistance will become bad, crosslinking density will be too high, a coating film will be too hard, and impact resistance will become bad, and it is unpreferable.

Furthermore, the resin composition of this invention has an acid value of 5-50 mg KOH / g. In this case, when the acid value of the resin composition is less than 5 mg KOH / g, since the polarity of the resin is relatively small, sufficient performance cannot be exhibited in the holding force of the resin, and also the curing reactivity of the epoxy resin with the oxirane ring and the curing with the crosslinking agent resin. It may not exhibit sufficient performance due to poor reactivity, and if the acid value of the resin composition exceeds 50 mg KOH / g, excessive carboxylic acid groups will be present in the cured coating film, resulting in poor chemical performance such as water resistance, acid resistance and alkali resistance. Not preferred.

The number average molecular weight of the said resin composition is about 2,000-8,000. If the number average molecular weight of the resin composition is less than 2,000, the chemical performance such as acid resistance, alkali resistance, corrosion resistance, etc. of the cured coating film cannot be sufficiently exhibited. If the number average molecular weight of the resin composition is 8,000 or more, the cured coating film may have a gloss lowering or decrease in contrast. It is not preferable because the appearance of the phenomenon is poor and the paintability is also poor.

Accordingly, the resin composition according to the present invention has such a resin characteristic value, that is, the acid value is 5-50 mg KOH / g, the hydroxyl value is 50-150 mg KOH / g, the glass transition temperature is 0-60 ° C., and the number average molecular weight is 2,000-. It is an epoxy-modified acrylic resin composition of 8,000, and thus has excellent hardness and physical properties such as scratch resistance, and has excellent chemical performance such as corrosion resistance, acid resistance and alkali resistance.

Although the resin composition of this invention is demonstrated concretely as an Example below, the scope of the present invention is not restrict | limited by these Examples.

Example 1

Into a flask equipped with a thermometer, a condenser and a stirrer, 400 g of YD-019 (Kukdo Chemical Co., Ltd.) and 400 g of cellosolve acetate were added as an epoxy resin, and then heated to 120 ° C. while stirring to completely dissolve the epoxy resin. Next, the following mixture was added dropwise to the epoxy resin mixture at a uniform rate over 3 hours.

261 g of styrene

150 g methyl methacrylate

Methacrylic acid 18 g

101 g of 2-hydroxyethyl methacrylate

70 g of 2-ethylhexyl acrylate

40 g of benzoyl peroxide

Butyl Cellosolve 120g

760 g in total

After completion of the dropwise addition, 10 g of benzoyl peroxide was added to the flask, and further maintained for 2 hours. Then, 250 g of butyl cellosolve and 250 g of xylene were added to the flask in that order and diluted.

In this way, the thermosetting acrylic modified epoxy resin solution which has the characteristic value of acid value 12 mg KOH / g with respect to resin solid content, Gardner viscosity (25 degreeC) Z, a number average molecular weight 2600, a weight average molecular weight 15000, and resin solid content 50% was obtained.

Example 2

In a flask of the same apparatus as in Example 1, 300 g of YD-019, 300 g of cellosolve acetate, and 200 g of toluene were dissolved as an epoxy resin, followed by melting in the same manner as in Example 1, and the following mixture was dissolved in the epoxy resin mixture. Was added dropwise at a uniform rate over 3 hours.

250 g of styrene

150 g methyl methacrylate

10 g of methacrylic acid

167 g of 2-hydroxyethyl methacrylate

Butyl butyl 123g

30 g of benzoyl peroxide

Butyl Cellosolve 113g

843 g

After completion of dropping, 10 g of benzoyl peroxide was added to the flask, and the reaction was maintained for 2 hours. Subsequently, 187 g of butyl cellosolve and 240 g of normal-butyl alcohol were sequentially added to the flask and diluted.

Thus, a thermosetting acrylic modified epoxy resin solution having characteristic values of an acid value of 7 mg KOH / g, a Gardner viscosity (25 ° C.) Y, a number average molecular weight of 2500, a weight average molecular weight of 14000, and a solid content of 50% of the resin was obtained.

Example 3

In a flask of the same device as in Example 1, 400 g of YD-014 (Kukdo Chemical Co., Ltd.), 300 g of cellosolve acetate, and 200 g of toluene were dissolved and dissolved in the same manner as in Example 1, followed by melting. Was added dropwise to the epoxy resin mixture at a uniform rate over 3 hours.

Styrene 220g

130 g of methyl methacrylate

15 g of methacrylic acid

137 g of hydroxyethyl methacrylate

Butyl acrylate 98g

30 g of benzoyl peroxide

Butyl Cellosolve 113g

743 g of total

After completion of dropping, 10 g of benzoyl peroxide was added to the flask, and the reaction was carried out for 2 hours. Subsequently, 187 g of butyl cellosolve and 240 g of normal-butyl alcohol were sequentially added to the flask and diluted.

In this way, the thermosetting acrylic modified epoxy resin solution which has the characteristic value of the acid value 10 mg KOH / g with respect to resin solid content, Gardner viscosity (25 degreeC) X, Receptor bacteria molecular weight 2100, weight average molecular weight 11000, and 50% of solid content of resin was obtained.

Comparative Example 1

Toluene 350g and butyl acetate 150g were thrown into the flask of the same apparatus as Example 1, and it heated up at 110 degreeC. The following mixture was then added dropwise to the solution at a uniform rate over 3 hours.

165 g of styrene

25 g of methyl methacrylate

150 g normal-butyl acrylate

155 g of 2-nuclear ethyl methacrylate

5 g acrylic acid

4 g of benzoyl peroxide

504 g of total

After completion of the dropwise addition, 1 g of benzoyl peroxide was added twice every hour while maintaining the reaction.

Thus, the acid value 8 mg KOH / g, Gardner viscosity (25 degreeC) T, the number average molecular weight 1500, the weight average molecular weight 7000, and the solid content of resin obtained the acrylic resin which has the characteristic value of 50%.

Comparative Example 2

A resin containing 40 wt% of YD-019 and 60 wt% of an acrylic monomer as an epoxy resin, having an acid value of 70 mg KOH / g, a Gardner viscosity (25 ° C) S, a number average molecular weight of 1500, and a weight average molecular weight of 8000 Synthesis was carried out in the same manner as in Example 1.

Comparative Example 3

90 weight% of acrylic resin of the said Comparative Example 1 was put into the flask, and it heated up at 60 degreeC. Subsequently, 10 weight% of YD-011 (Kukdo Chemical Co., Ltd. brand name) was thrown in slowly as an epoxy resin, and the resin which melt | dissolved was obtained.

Performance evaluation of coating

To 100 g of the respective resin solids of the Examples and Comparative Examples synthesized as described above, 67 g of noluminin-2060 (melamine resin of Daehan Paint & Ink Co., Ltd.), a melamine resin, was added as a crosslinker resin, and then diluted with xylene. Pod cup 4, 25 ° C, the viscosity was adjusted to 15 seconds to be sprayed by air spray. The paint thus prepared was coated with a brass base degreased with a solvent so that the dry coating film had a thickness of 20 to 30 μm, and then left at room temperature for 10 minutes and then cured and dried at 150 ° C. for 30 minutes to evaluate the coating performance. .

The performance of the coating film was evaluated according to the general coating performance evaluation method. In other words, the hardness was tested according to the pencil hardness test method, the impact resistance was tested by the method of 1/2 '× 500g × 30cm with DuPont's impact tester, the water resistance of the coating film after immersing the specimen in 50 ℃ hot water for 10 days. The presence or absence of abnormality was determined by visual observation, and acid resistance was determined by dropping a 5% sulfuric acid aqueous solution onto the coating film, and then left at room temperature for 24 hours, followed by wiping with water to determine the degree of damage to the coating. It tested by the same method as the evaluation method of.

Corrosion resistance was visually determined by peeling and corrosion of the coating after 120 hours test in a salt spray tester with 35 ℃, 5% brine. The above performance test results are shown in Table 1 below.

Coating film performance evaluation test result of an Example and a comparative example Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Hardness 2H 3H 2H 3H 2H 2H Impact resistance ◎ ◎ ○ ○ ○ Ｘ Water resistance ◎ ◎ ◎ ○ △ ○ Acid resistance ◎ ◎ ○ ○ △ ○ Alkali resistance ○ ○ ◎ △ Ｘ ○ Corrosion resistance ○ ◎ ◎ Ｘ ○ △

Evaluation standard ; ◎: Excellent, ○: Good, △: Normal, Ｘ: Poor

As can be seen in Table 1 above, the acrylic modified epoxy resins of Examples 1 and 2 are superior in impact resistance to the acrylic resins of Comparative Example 1 and the epoxy modified acrylic resins of Comparative Examples 2 and 3, and particularly, are excellent in water resistance and acid resistance. The chemical performances such as alkali resistance and corrosion resistance were very good.

As described above, the thermosetting acrylic-modified epoxy resin composition according to the present invention has superior physical properties such as hardness and impact resistance, and has improved chemical performance such as water resistance, acid resistance, alkali resistance, and corrosion resistance, compared to conventional acrylic resins. . Therefore, the acrylic modified epoxy resin composition of the present invention can be easily used for the cree coating of nonferrous metals, which particularly require excellent corrosion resistance and high hardness.

Claims (4)

In the known bisphenol A type epoxy resin obtained from bisphenol A and epichlorohydrin, 10 to 70 wt% of the bisphenol A type epoxy resin having the above structural formula and having an n value of 0.5 to 12, and an epoxy equivalent of 400 to 3000, and 90 to 30 wt% of an acrylic monomer. A thermosetting acrylic modified epoxy resin composition obtained by grafting on a functional group to polymerize and having an acid value of 5 to 50 mg KOH / g. According to claim 1, wherein the acrylic monomer is 40 to 90% by weight of the non-functional monomer, 0.5 to 10% by weight of the monomer having a carboxylic acid group, 10 to 40% by weight of the monomer having a hydroxy group It is contained in the range, The thermosetting acrylic modified epoxy resin composition. The thermosetting acrylic modified epoxy resin composition according to claim 1, wherein the hydroxyl value is 50 to 150 mg KOH / g, the glass transition temperature is 0 to 60 ° C, and the number average molecular weight is 2,000 to 8,000. Mixing 10 to 70% by weight of a bisphenol A epoxy resin having an epoxy equivalent of 400 to 3000 and a solvent to form an epoxy resin solution; Mixing an acrylic monomer with 30 to 90% by weight and a solvent to form an acrylic monomer solution; Adding the acrylic monomer solution to the epoxy resin solution at a temperature of 100 to 130 ° C .; And Method for producing a thermosetting acrylic modified epoxy resin composition comprising the step of adding a benzoyl peroxide to the reaction product obtained.