KR0174809B1 - Epoxy acrylate resin compositon and a paint composition containing the same for an automobile - Google Patents

Abstract

Disclosed are acrylate resin compositions for preparing unsaturated polyester resin compositions suitable for use in automotive repair paints. The paint composition for automobile repair includes 40 to 55% by weight of an oxirane group-containing epoxy resin, 15 to 30% by weight of an organic acid group-containing monomer having a vinyl group, 0.04 to 0.50% by weight of an oxirane group ring-opening catalyst and an aromatic non-functional unsaturated monomer 20-. An epoxy acrylate resin composition obtained from a monomer mixture composed of 40% by weight, and 10 to 30 parts by weight of the epoxy acrylate resin composition and 90 to 70 parts by weight of an unsaturated polyester resin. In the thin film, air curability is remarkably improved, and polishing property is remarkably improved.

Description

Epoxy acrylate resin composition and automobile repair coating composition containing same

The present invention relates to an epoxy acrylate resin composition and a vehicle repair paint composition containing the same. More specifically, the present invention relates to an epoxy acrylate resin composition and an automobile repair coating composition containing the same, which improves the quality of the thin film and the thick film, thereby improving the quality of the thin film and the thick film.

Generally, resins used in automotive repair paints are unsaturated polyester resins. In the past, waxes were added to form a wax thin film on the resin surface to prevent defects caused by incomplete curing of the surface in contact with the air when the resin was dried in the air, thereby preventing the influence of oxygen. That is, in the reaction between the resin surface and oxygen, first, radicals generated by decomposition of the peroxide curing agent in the curing process of the resin become reactive monomer radicals and participate in the growth reaction of the resin. However, the reaction rate at which a large amount of oxygen reacts on the surface of the coating film in contact with air is one million times faster than the reaction rate at which radicals and monomers react. Therefore, growth radicals are mostly combined with oxygen to become peroxide radicals. The peroxide radicals thus produced no longer have the ability to polymerize and are finally decomposed, so that the chains produced by the polymerization reaction are stopped and low molecular weight polymers remain, resulting in slow surface drying. Besides, it is conceivable that defects on the surface of the coating film may result in incomplete development of the crosslinked structure due to volatilization of the reactive monomer and insufficient monomer.

Therefore, it was very effective to add about 0.05 to 0.5% by weight of wax to prevent this disadvantage. However, in the case where waxes are added, most of the non-wax type resins, which are fast in surface drying, are currently used because of the inconvenience of removing the wax layer formed on the surface during the polishing process after the coating film is dried.

On the other hand, the properties of the resin required for automotive refinish paint is a two-component type that is hardened by the addition of a curing agent, the faster the gel is dried and polished as soon as the coating film becomes gel, the final step should be a resin having a high hardness. In addition, it should be excellent in adhesion with the base material.

Unsaturated polyester resins are actually divided into resin production and molding when used as automotive repair paints.

The preparation of unsaturated polyester resins is synthesized by esterifying glycols, unsaturated acids and saturated acids and finally diluted with reactive monomers.

Glycols used herein include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, dipropylene glycol, 1,5-pentane diol, 1,6-hexanediol, neopentyl glycol, pentaerythritol allyl Ethers, allyl glycidyl ethers, and the like.

As the unsaturated acids, maleic anhydride, fumaric acid, citraconic acid, itaconic acid, and the like are used. As the saturated acids, tetrachlorophthalic anhydride, het acid, phthalic anhydride, isophthalic acid, terephthalic acid, phthalic acid, adipic acid, sebacic acid, and the like are used. . The reactive monomers used as diluents include styrene, vinyl toluene, chlorostyrene, alpha-methyl styrene, and the like, but are not limited to any one type.

In the above raw materials, the unsaturated acid reacts with the reactive monomer by a radical reaction when the unsaturated acid is cured and unsaturated in the polyester resin. When curing the resin thus made, peroxides are used as hardeners, such as benzoyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, cumene peroxide, t-butyl perbenzoate and t-butyl peroxide. Octoate and the like. As the curing accelerator, amines such as cobalt naphthenate, aniline naphthenate, triethanolamine, N, N-dimethyl aniline, and metatoluidine are generally used. The former is used together with a ketone peroxide curing agent, and the latter is acyl peroxide ( For example, benzoyl peroxide) hardener.

In order to improve the air curability of such unsaturated polyester resin, the method of adjusting the content of the glycol component contained in resin may be used.

This method uses the glycol which has an allyl ether group as one component, or uses together with another glycol, or is used independently. The glycols used herein include, but are not limited to, trimethylol propane diallyl ether, allyl glycidyl ether, allyl acetal, methylol glyoxal urein, and the like.

The reason why the resin containing these allyl ether bonds exhibits air curability is presumably due to the crosslinking formed by the production and decomposition of peroxides by oxidation of the methylene bond between the ether bond and the double bond.

In addition, as a method for improving air curability, various methods such as a change in an acid component of an unsaturated polyester resin, a change in a reactive monomer, addition of a thermoplastic polymer, addition of dry oil or epoxidized oil, and the like are used.

The present inventors continued the research effort to improve the air curability of the unsaturated polyester resin, and in particular, to develop a coating composition suitable for use in automobile repair paints, etc., to complete the present invention.

Accordingly, it is an object of the present invention to provide an acrylate resin composition for producing an unsaturated polyester resin composition suitable for use in automotive repair paints.

Another object of the present invention is to provide an unsaturated polyester composition which is a coating composition for automobile repair comprising the acrylate resin composition.

In order to achieve the above object, according to the present invention, 40 to 55% by weight of an oxirane group-containing epoxy resin, 15 to 30% by weight of an organic acid group-containing monomer having a vinyl group, 0.04 to 0.50% by weight of an oxirane group-opening catalyst and an aromatic An epoxy acrylate resin composition obtained from a monomer mixture consisting of 20-40% by weight of a system nonfunctional unsaturated monomer is provided.

The present invention also comprises 10 to 30 parts by weight of the epoxy acrylate resin composition; And 90 to 70 parts by weight of an unsaturated polyester resin.

Hereinafter, the present invention will be described in detail.

The epoxy acrylate resin composition according to the present invention comprises an oxirane group-containing epoxy resin. If the content of the epoxy resin is less than 40% by weight, it is not preferable that the air curability is poor in the thin film (60 μm), and if it exceeds 55% by weight, the air curability is poor when the thick film (180 μm) is applied. Therefore, content of an oxirane group containing epoxy resin is 40-55 weight%, Preferably it is 45-50 weight%. It is preferable to use an epoxy equivalent of 50-300 as said epoxy resin. If the epoxy equivalent is less than 50, the curing density is high and the polishing property is poor, and if the epoxy equivalent is more than 300, the air curing property is poor and the polishing property is not preferable because of the decrease in the polishing property.

The epoxy acrylate resin composition which concerns on this invention contains the organic acid group containing monomer which has a vinyl group. If the content of the organic acid group-containing monomer is less than 15% by weight, the curing density is low and the coating film is soft, which is not preferable. If the content exceeds 30% by weight, the curing density is high and the coating film is too hard, which is not preferable. Therefore, content of an organic acid group containing monomer is 15-30 weight%, Preferably it is 18-24 weight%. Examples of the organic acid having a vinyl group include acrylic acid, methacrylic acid, maleic acid, and itaconic acid, but are not limited thereto. In particular, it is preferable to use methacrylic acid.

The epoxy acrylate resin composition includes a catalyst for opening an oxirane group at both ends of the epoxy resin. Examples of such a catalyst include sodium carbonate, lithium carbonate, triethyl amine, triphenyl phosphine, zirconium octoate, stanus octoate, 2-ethyl-4-methyl imidazole, 2-methyl imidazole, and the like. 0.1 to 1.0 wt% with respect to the epoxy resin (0.04-0.50 wt% with respect to the resin composition), preferably 0.3 to 0.8 wt%. If the content of the catalyst is less than 0.1% by weight relative to the epoxy resin, it is not preferable because the reactivity is high and the acid value is high, and when the content of the catalyst exceeds 1.0% by weight, it is difficult to control the reaction according to the reaction and the storage stability is lowered. In particular, preference is given to using 2-methyl imidazole.

In addition, the epoxy acrylate resin composition contains an aromatic nonfunctional unsaturated monomer as a reactive monomer. Examples of such aromatic nonfunctional unsaturated monomers include styrene, vinyl toluene, chlorostyrene, alpha-methyl styrene, and the like. If the content of the monomer is less than 20% by weight, the curing density is low and the coating film is soft, which is not preferable. If the content of the monomer exceeds 40% by weight, the curing density is high and the coating film is too hard, which is not preferable. Thus, the content of monomers is 20-40% by weight, preferably 25-30% by weight.

The epoxy acrylate resin used in the present invention for improving air curability is also called a vinyl ester resin. The said epoxy acrylate resin is ester resin which carried out addition polymerization of the epoxy resin and the organic acid which has a vinyl group between 100-130 degreeC.

The epoxy acrylate resin composition of the present invention is prepared by addition polymerization of the above-mentioned epoxy resin and organic acid having a vinyl group in the presence of a catalyst to synthesize an epoxy acrylate resin, followed by addition of a reactive monomer.

The weight average molecular weight of the epoxy acrylate resin thus prepared is 700-1000, molecular weight distribution is less than 1.5, the acid value 10-0.1 mg KOH / g, at 25 ℃ Gardner viscosity of the range of G-J, non-volatile content 60% It is preferable that it is above.

10-30 weight part of said epoxy acrylate resin compositions and 90-70 weight part of unsaturated polyester resins are mixed, and the automotive repair coating composition is manufactured. Air curability and abrasiveness in a thin film of a coating film when the epoxy acrylate resin is mixed with an unsaturated polyester resin at a constant ratio, that is, at a ratio of 10:90 to 30:70, more preferably at a ratio of about 20:80. This can be improved.

Such an effect is considered to be because an appropriate mixing ratio of a properly prepared epoxy acrylate resin and an unsaturated polyester resin shortens the curing time.

According to the present invention, the epoxy acrylate resin thus synthesized by reacting with methacrylic acid using an epoxy having an epoxy equivalent of 50 to 300 is prepared by mixing an unsaturated polyester resin with a predetermined ratio, that is, 10: 90-30: 70. In the thin film, the air curability is remarkably improved, and the polishing property is remarkably improved.

Although the Example regarding the synthesis | combination and application of an epoxy acrylate resin as mentioned above is described, the scope of the present invention is not limited to these Examples.

Example 1

A four-necked flask equipped with a thermometer, condenser, dropping funnel and stirrer was used as the reactor.

In Example 1, 47.55 g of epoxy resin having an epoxy equivalent of 50 to 300, 0.20 g of reaction catalyst 2-ethyl-4-methyl imidazole, and 0.01 g of hydroquinone as a reaction inhibitor were added to a 2 L flask, and stirred slowly at 92 ± 2 ° C. The temperature was raised to.

Then, the solution which mixed 21.80 g of methacrylic acid and 0.20 g of reaction catalyst 2-methyl imidazole was dripped at 0.18 g / min, and it heated up at 115 degreeC.

At this temperature, the reaction was carried out at an acid value of 0.5 mg KOH / g or less and at 25 ° C. until the Gardner viscosity became G to J, followed by cooling to 100 ° C. or less. 30.00 g of a styrene monomer as a reactive monomer and 0.04 g of hydroquinone as a reaction inhibitor were added thereto, followed by stirring for 1 hour. The solid content of the resin thus obtained was obtained by collecting 1.00 to 1.50 g of a resin sample, volatilizing the reactive monomer at 105 ° C. for 3 hours, and quantifying the amount of solid content as a percentage to express 69.80% and an acid value of 0.30 mg KOH /. and at 25 ° C. Gardner viscosity was H. The weight average molecular weight was 700-1000 and the molecular weight distribution was 1.15.

Example 2

20 wt% of the resin prepared in Example 1 and 80 wt% of an unsaturated polyester resin were mixed, and 0.57 g of cobalt organic acid salt was added as a curing accelerator, and 0.03 g of acetyl acetone was added as a curing aid.

Example 3

30% by weight of the resin prepared in Example 1 and 70% by weight of an unsaturated polyester resin were mixed and prepared by adding 0.47 g of cobalt organic acid salt as a curing accelerator and 0.03 g of acetyl acetone as a curing aid.

Example 4

10 wt% of the resin prepared in Example 1 and 90 wt% of an unsaturated polyester resin were mixed, and 0.47 g of cobalt organic acid salt was added as a curing accelerator, and 0.03 g of acetyl acetone was added as a curing aid accelerator to prepare a resin.

[Comparative Example]

Instead of using the resin prepared in Example 1, only unsaturated polyester resin was used.

[Gelation Time and Abrasion Test]

2 g of a peroxide curing agent was mixed with 100 g of the resin prepared in Example 2-4 and the comparative example, a 60 μm coating film was made on a glass plate with a coating machine (manufactured by Yoshimitsu Seiki Co., Ltd.) and naturally dried. The obtained coating film was examined for 25 degreeC Gardner viscosity, gelation time, and polishing property. The results are shown in Table 1 below.

1) The gelation time shows the time taken to add a peroxide curing agent (methyl ethyl ketone peroxide) to the resin until it becomes a gel (near 30 ° C).

2) Abrasiveness was expressed by the amount of the part polished from the surface and the degree of pinching on the abrasive paper when the same strength was applied using # 220 abrasive paper. (Circle) is a very good state.

As shown in Table 1, the gelation time of the acrylate resin according to Example 2 was 5 minutes and 36 seconds, which was faster than the gelation time of 6 minutes and 10 seconds of the unsaturated polyester resin of Comparative Example 1. Also, the polishing property was superior to the resin of the comparative example.

The gelation time of the resin according to Example 3 was 6 minutes and 5 seconds, which was similar to the comparative example, and the viscosity at 25 ° C. was 3 steps lower than the comparative example by Gardner viscosity.

The gelation time of the resin according to Example 4 was 5 minutes and 36 seconds, 24 seconds faster than that of the resin of the comparative example, and the viscosity at 25 ° C. was one step lower as the Gardner viscosity. In Example 2-4, the resin of Example 2 made by mixing 20% by weight of the epoxy acrylate resin of Example 1 and 80% by weight of the unsaturated polyester resin was shown to have the best polishing property.

This is considered to improve the polishing property because the resin of Example 2 had a higher initial hardness within 30 minutes after the coating film was formed compared to the unsaturated polyester resin, thereby reducing the phenomenon of being pinched by the abrasive paper.

The pencil hardness according to the aging change of the resin of Example 2 in which 20 weight% of the resin of Example 1 and 80 weight% of unsaturated polyester resins were mixed was measured. The results are shown in Table 2.

1) Pencil hardness was measured by Mitsubishi's pencil used when measuring the hardness.

2) Tack drying is a measure of the time it takes to make the coating film with a coating machine (made by Yoshimitsu Seiki Co., Ltd.) and not feel sticky when pressed on the surface with a finger.

3) Solidification Drying is a measurement of the time it takes for a fingerprint to not be printed on the surface when the coating film is made by hand after the coating film is made by a film maker.

In Table 2, the measurement standard of pencil hardness is based on 100 g of unsaturated polyester resin and 2.2 g of cobalt organic acid salt as a curing accelerator and 0.21 g of acetyl acetone as a curing aid. And the gelling time of the resin at the time of curing was 9 minutes 20 seconds.

Pencil hardness measurement according to the change over time was made with a coating film maker (manufactured by Yoshimitsu Seiki Co., Ltd.) adjusted to a thickness of 60 μm, and the pencil hardness of the coating film was measured at an interval of 30 minutes. The thick film was measured in the same manner as in the thin film after the coating film was made by adjusting the thickness of the coating machine to 180 μm.

On the other hand, the measurement of the pencil hardness in the thick film is similar to the contact drying time and the solidification drying time of Example 2 and Comparative Example 1, and the initial hardness of 30 minutes after the coating film was formed was that the resin of Example 2 Compared with the comparative example 1, all of them were higher by one step.

Therefore, the reason why the resin of Example 2 is improved in the thin film having a thickness of 60 μm compared with the comparative example is considered to be due to the reduction in the abrasive paper due to the high initial hardness as shown in Table 2 above.

The polishing property of the coating film was evaluated based on the test result of resin of Example 2-4 demonstrated above and the comparative example, and applied to the final automobile repair paint mix.

[Test Example 1-4]

The abrasiveness test of the coating film was generally evaluated according to the coating film physical property evaluation method. Table 3 shows the paint standard formulations in which the resins of Examples 2-4 and the comparative examples were applied to the paint.

In order to determine the paint properties of the resin of Example 2-4 and the resin of Comparative Example described above, the paint was prepared as follows. Namely, unsaturated polyester resin (trade name (manufactured by Daehan Paint Co., Ltd.): K7-3236) 70 to 100 wt%, epoxy acrylate resin 10 to 30 wt%, white pigment (brand name (Titanium Korea)): KA-100 1 to 5% by weight, sieving pigment (trade name (Ilshin Industries): 35 to 45% by weight), dispersant (brand name (BK-W980): BYK-W980) 0.1-2.0% by weight and styrene monomer 8 to 15% by weight, and cobalt organic acid salt (brand name (Shinil Chemical): cobalt naphthenate) as a curing accelerator, 0.1 to 1.0% by weight, acetyl acetone (trade name (Japan Daicel Chemical)): acetyl acetone ) 0.01 to 0.1% by weight, and then mixed and dispersed, and then an antifoaming agent was used for smoothness of the coating film appearance and prevention of pinholes. The viscosity of the prepared paint was adjusted to 600 poise at 25 ° C. with a viscometer made by Japan Lion. Thereafter, the film was applied to the pretreated 0.5T-tin plate so as to be 60 μm in the case of a thin film and 180 μm in the case of a thick film, and then naturally dried at room temperature.

The abrasiveness test of the coating film obtained above was measured. The results are shown in Table 4 below.

1) The viscosity of the coating material was measured using a viscometer (trade name: VT-04) of Japan Lion.

2) The gelation time is the time taken to add a peroxide curing agent (cyclohexanone peroxide) to the paint and then to a gel (near 30 ° C).

3) Abrasiveness was measured by applying the same force to # 220 abrasive paper, the amount to be polished and the degree of being pinched by the abrasive paper. ◎ is in a very good condition.

The abrasiveness of the paint showed that the resin of Test Example 1, which is the case of using the resin of Example 2 in Table 1 when the coated film was polished with # 220 abrasive paper, showed the best abrasive property in the thin film. The reason is considered to be because the initial hardness of the resin of Example 2 is higher than that of the resin of Comparative Example 1, as shown in Table 2 mentioned above.

When forming a coating film using the epoxy acrylate resin composition which concerns on this invention, compared with the conventional unsaturated polyester resin, the initial hardness within 30 minutes after forming a coating film is high. Therefore, polishing property is improved. In addition, the automotive repair coating composition produced using the epoxy acrylate resin composition described above has improved abrasiveness in a thin film having a thickness of 60 μm compared with a conventional coating composition using an unsaturated polyester resin alone.

Claims (6)

A monomer consisting of 45 to 50% by weight of an oxirane group-containing epoxy resin, 18 to 24% by weight of an organic acid group-containing monomer having a vinyl group, 0.04 to 0.50% by weight of an oxirane group ring-opening catalyst and 25 to 30% by weight of an aromatic non-functional unsaturated monomer. Epoxy acrylate resin composition obtained from the mixture. The epoxy acrylate resin composition according to claim 1, wherein an epoxy equivalent of the oxirane group-containing epoxy resin is in the range of 50 to 300. The organic acid group-containing monomer having a vinyl group is at least one monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, itaconic acid and anhydrides thereof. Is at least one selected from the group consisting of sodium carbonate, lithium carbonate, triethyl amine, triphenyl phosphine, zirconium octoate, stannus octoate, 2-ethyl-4-methyl imidazole and 2-methyl imidazole. Epoxy acrylate resin composition, characterized in that used. The epoxy acrylate resin composition according to claim 1, wherein the acid value is 10 to 0.1 mg KOH / g, the Gardner viscosity is in the range of G to J, and the nonvolatile content is 60% or more at 25 ° C. The epoxy acrylate resin composition according to claim 1, wherein the epoxy acrylate resin has a weight average molecular weight of 700 to 1000 and a molecular weight distribution of 1.5 or less. A monomer consisting of 45 to 50% by weight of an oxirane group-containing epoxy resin, 18 to 24% by weight of an organic acid group-containing monomer having a vinyl group, 0.04 to 0.50% by weight of an oxirane group ring-opening catalyst and 25 to 30% by weight of an aromatic non-functional unsaturated monomer. 10-30 parts by weight of the epoxy acrylate resin composition obtained from the mixture; And 90 to 70 parts by weight of an unsaturated polyester resin.