KR100675422B1 - Coating composition for plastics - Google Patents

Abstract

The present invention relates to a coating composition for plastic material coating, and more particularly, to include a vinyl group copolymer resin, an acrylic copolymer resin solution, a liquid epoxy resin, and various additives into which polar groups are introduced, thereby adhering to various plastic materials with optimized properties. In addition to excellent properties, it is excellent in interlayer adhesion with UV-curable top coat and urethane curable top coat to be subsequently coated, so it can be suitably used for such materials and top coats, and thus has excellent workability compared to conventional coating compositions, appearance and impact resistance. It relates to a room temperature dry coating composition excellent in physical properties such as.

Paint, polar group, vinyl chloride, material adhesion, interlayer adhesion

Description

Coating composition for plastic material coating

The present invention relates to a coating composition for plastic material coating, and more particularly, to include a vinyl group copolymer resin, an acrylic copolymer resin solution, a liquid epoxy resin, and various additives into which polar groups are introduced, thereby adhering to various plastic materials with optimized properties. As well as excellent interlayer adhesion with UV-curable top coat and urethane-curable top coat to be coated subsequently, it can be used suitably for these materials and top coats, so it is excellent in workability compared to conventional coating compositions, appearance and impact resistance, etc. It relates to a room temperature dry coating composition excellent in physical properties.

The use of plastic moldings is gradually increasing in the fields of cosmetic lids, telephones, automobiles and electronic equipment. However, these plastic molded parts have a lower scratch resistance and hardness than glass or metal, resulting in enormous loss in commodity value. Various coating techniques have been developed for surface damage protection, hardness, and gloss improvement of such plastic molded products. The most widely used coating techniques include natural drying method, low temperature baking method of 40 ~ 80 ℃, UV curing method and the like.

The type of paint applied to each material varies depending on the characteristics of the plastic material (difference in glass transition temperature for each material, difference in solvent power due to organic solvent, etc.). However, since the type of the lower coat and the upper coat suitable for each plastic material is limited, it is a situation that greatly affects the productivity and the paintability.

Accordingly, the present inventors are excellent in adhesion to the plastic material in the coating treatment of various plastic materials, and easy to adhere to both the UV-curable top coat and the urethane curable top coat to be subsequently coated, and a coating composition that satisfies physical properties such as durability. Efforts have been made to develop this technology. That is, an object of the present invention is to provide a coating composition for coating a plastic material that satisfies the material adhesion and the interlayer adhesion with the top layer while forming the undercoat of the coating film.

The present invention is a coating composition for plastic material coating,

a) 10 to 30% by weight of a vinyl chloride copolymer resin having a number average molecular weight of 10,000 to 20,000 and a carboxyl group or a hydroxy group substituted; b) an acrylic copolymer resin solution (solid content of 40 to 50%) having a number average molecular weight of 15,000 to 35,000. 50% by weight, c) 1 to 5% by weight of liquid epoxy resin, d) 1 to 10% by weight of wax-based additives, and e) 10 to 60% by weight of a solvent. .

The present invention is characterized by containing a certain amount of polar groups in the vinyl chloride copolymer resin and using a liquid epoxy resin. When the coating composition of the present invention is applied to various plastic materials to form a coating film undercoat, and a UV coating curable or urethane curable paint is applied thereon to form a top coat, appearance, material adhesion, interlayer adhesion and The coating film excellent in thermal shock resistance etc. can be obtained. Here, the plastic material includes a polycarbonate, an acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as ABS), an acrylic material, a polyvinyl chloride material, and the like.

The present invention will be described in more detail for each component as follows.

a) vinyl chloride copolymer resin

The vinyl chloride copolymer resin used in the present invention has a number average molecular weight of 10,000 to 20,000, a glass transition temperature of 30 to 80 ° C, and a carboxyl group or a hydroxyl group is substituted by 1 to 2% by weight with respect to the resin. If the resin having a number average molecular weight of less than 10,000 is used, the hardness is lowered, the curing speed is lowered, and the chemical resistance is lowered. On the other hand, when the number average molecular weight exceeds 20,000, there is a problem in the paintability. In addition, when the glass transition temperature is less than 30 ° C, the hardness is lowered, the curing rate is lowered, and when it exceeds 80 ° C, flexibility and crack resistance are inferior. In addition, the carboxyl group or hydroxy group substituted in the resin serves to give adhesion to the urethane curable top coat which is subsequently coated, and the chlorine (Cl) having high electronegativity introduced into the vinyl main chain has It gives an adhesive force with a UV curable top coat which is subsequently coated. The vinyl chloride copolymer resin may be used in an amount of 10 to 30% by weight based on the total coating composition. When the amount is less than 10% by weight, the adhesion between the material and the top is lowered, the flexibility is reduced, and the amount is greater than 30% by weight. At the time of addition, the hardness of the coating film is lowered, which is not preferable.

Commercially available vinyl chloride copolymer resins satisfying the above conditions include VMCC, VMCH, VROH, VAGC (above, UNION CARBIDE), E15 / 45M, E15 / 48A, H15 / 45M (above, WACKER, etc.). Although it can be mentioned, 1 type or 2 types of these can be selected and used suitably.

b) acrylic copolymer resin solution

The acrylic copolymer resin solution is a resin copolymerized using methyl acrylate, methyl methacrylate, butyl methacrylate, and the like, and has a solid content of 40 to 50%, a number average molecular weight of 15,000 to 35,000, and a glass transition temperature of 60 to 105. What is C is suitably used. At this time, if the number average molecular weight is less than 15,000, the coating film hardness and chemical resistance is lowered, whereas if the number average molecular weight is more than 35,000, there is a problem of lowering the flexibility and poor adhesion of the material and the top. The acrylic copolymer resin solution as described above improves the coating film strength and helps to speed the drying of the coating film. When the acrylic copolymer resin is used in an amount of 10 to 50% by weight based on the total coating composition, when less than 10% by weight is used, the hardness of the coating film is lowered. There is a problem of becoming poor.

Commercial products of the acrylic copolymer resin solution as described above include ACRYDIC CL-408 (DIC), R5566, R5582, R5592 (above, KCC Co., Ltd.), etc., one or two of these can be selected and used suitably. have.

c) liquid epoxy resin

The liquid epoxy resin serves as a heat stabilizer of the vinyl chloride resin. Chlorine groups introduced into the vinyl backbone are unstable and are detached even at room temperature, and in the presence of the detached chlorine atoms, continuous chlorine detachment occurs in the main chain, resulting in severe physical property deterioration such as backbone cutting, double bond formation, and color change. . The epoxy group of the liquid epoxy resin prevents continuous chlorine detachment by reacting with dechlorinated chlorine. The present epoxy resin has an epoxy resin equivalent (EEW) of 70 to 210 and all resins having an epoxy group can be used. However, the smaller the epoxy equivalent (EEW), the greater the effect. Therefore, a liquid epoxy resin solution is used. Such an epoxy resin may be used in an amount of 1 to 5% by weight based on the total coating composition. If the epoxy resin is less than 1% by weight, the paint stability is lowered. When the epoxy resin is more than 5% by weight, the drying speed is lowered and hardness and scratchability are lowered.

Commercially available products of the above-mentioned liquid epoxy resins include ERL 4221, ERL 4206, ERL 4299 (above, UNION CARBIDE, LER 850, LG CHEM, R8828, KCC, etc.). It can select and use suitably.

d) wax-based additives

The wax-based additive is used as a rheology control agent of the paint to prevent sedimentation and agglomeration of the pigment and to assist the orientation of the aluminum flake, and is used in an amount of 1 to 10% by weight.

Commercially available products of such wax-based subscripts include CERATIX 8461, CERATIX 8463 (above, BYK Co., Ltd.), SED AD FX2050 (SERVO Co., Ltd.), and the like.

e) solvent

The solvent may be generally selected and used as necessary in consideration of the solvent's dissolving power, and 10 to 60 wt% of toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, and methyl isobutyl ketone is used. And a pigment etc. can also be selectively added as needed.

The coating composition for coating a plastic material according to the present invention prepared as described above has an effect that can be applied to both an ultraviolet curable top coat and a urethane curable top coat as the room temperature drying type, in particular, having excellent interlayer adhesion between the top coat and the top coat.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Example 1

First, 13.2% by weight of methyl ethyl ketone, 13.2% by weight of toluene, and 5% by weight of ethyl acetate were added to a suitable container, and 17.7% by weight of vinyl chloride copolymer resin (VMCC, Union Carbide) was slowly added while stirring. Stirring conditions were room temperature 30 minutes at agitator rotation speed (RPM) 1000. Then, 1.5 wt% of the epoxy resin (LER 850, LG CHEM) was added to the mixture, followed by stirring. Here, 19.7 wt% of the acrylic copolymer resin solution (R5592, KCC), 5.6 wt% of methyl isobutyl ketone, and butyl acetate 3.0 were added. Wt%, 1.6 wt% xylene was added.

5.0 wt% of a wax additive (CERATIX 8461, BYK) was added and stirred in a separate container and then added to the mixture.

Then, 6.5 wt% of aluminum flakes (SSP 554, SILVER LINE) and 8.5 wt% of toluene were added and mixed in a separate container, followed by stirring while slowly adding to the mixture. After sufficient stirring, it was filtered using a 150 mesh filter net, and then adjusted to a viscosity [FORD CUP # 4,25 ° C.] 60 to 65 seconds (viscosity of the paint) with butyl acetate to complete the coating composition. Each composition and content is shown in Table 1 below.

Example 2

The vinyl chloride copolymer resin VMCC of Example 1 was prepared in the same manner as in Example 1 except that the vinyl chloride copolymer resin E15 / 45M (WACKER) was replaced with 17.7% by weight.

Example 3

Except for adjusting the content of the vinyl chloride copolymer resin VMCC of Example 1 from 17.7 wt% to 15.4 wt% and replacing the acrylic copolymer resin R5592 with 22.0 wt% of the acrylic copolymer resin ACRYDIC CL-408 (DIC) Was prepared in the same manner as in Example 1.

Comparative Example 1

In Comparative Example 1, a coating composition for undercoat commonly used in urethane curable top coat was prepared.

First, the main material was manufactured as follows. 52.5 wt% of the acrylic polyol resin solution (R5630, KCC), 10.0 wt% of the acrylic polyol resin solution (R5640, KCC), 4.0 wt% of ethyl acetate, and 2.0 wt% of butyl acetate were added to a titration vessel, followed by sufficient stirring.

Into a separate vessel was added 0.1% by weight of the surface modifier (GLIDE B1484, TEGO) and 19.0% by weight of xylene and mixed in the mixture. Then, 10% by weight of cellulose solution (CAB551-0.2SEC, 20% by weight of solids, EASTMAN), 4.5% by weight of a curing catalyst solution (dibutyltindilaurate, 0.5% by weight of solids, Kolon Emulsification) was added and stirred.

6.5 wt% aluminum flakes (SSP 554, SILVER LINE) and 4.5 wt% toluene were added and mixed in a separate container, followed by stirring while slowly adding to the mixture. After sufficiently stirring, the resultant was filtered using a 150 mesh filter net and adjusted to a viscosity (FORD CUP # 4,25 ° C) 60 to 65 seconds with butyl acetate to obtain a coating composition.

Then, 68% by weight of isocyanate resin (Coronate HX, Nippon Polyurethane), 20% by weight of Cocosol # 100 and 12% by weight of butyl acetate were added and stirred as a curing agent, and then filtered by using a 200 mesh filter net. .

At this time, the mixing ratio of the main material and the curing agent was 9: 1 (volume ratio).

Comparative Example 2

In Comparative Example 2, a coating composition for undercoat commonly used in UV curing top coat was prepared.

First, 32.0 wt% acrylic copolymer resin solution (R5593, KCC), 35.0 wt% acrylic copolymer resin solution (R5566, KCC), 0.5 wt% methyl ethyl ketone, 1.5 wt% ethyl acetate, and 12.0 wt% toluene were added in this order. Stirred. While stirring, chlorine rubber resin solution (SUPERCHLON 822S, 5 wt% solids, SANYO-KOKUSAKU PULP) 2.0 wt%, cellulose solution (CAB551-0.2SEC, 20 wt% solids, EASTMAN) was added in this order and then again. Stirred.

6.5 wt% of aluminum flakes (SSP 554, SILVER LINE) and 3.5 wt% of toluene were added and mixed in a separate container, followed by stirring into the mixture slowly. After sufficiently stirring, the resultant was filtered using a 150 mesh filter net and adjusted to a viscosity (FORD CUP # 4,25 ° C) 60 to 65 seconds with butyl acetate to complete the coating composition.                     

Test Examples 1-4: Coating film forming and physical property measurement

The paint compositions prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were used as the paint for the undercoat, and the two plastic materials were coated with the UV curable paint and the urethane curing paint as the top coat. Is shown in Table 2 below.

In this case, polycarbonate and ABS materials were used as the plastic materials, and each plastic material and the top coat were painted while changing, and these are shown in Table 3 below.

The physical property test was done about the coating film comprised as said Test Examples 1-4, The evaluation method is as follows.

(1) Appearance of coating

The completely dried or cured coating film was visually observed to determine whether the coating film was defective.

(2) Material adhesion of coating film and interlayer adhesion with top layer

100 lines were drawn at intervals of 1 mm in width and length, respectively, and then the tape was measured to determine whether the coating film was peeled off.

(3) Thermal shock of coating film

After leaving the completely dried specimen at 20 ° C. for 2 hours, the sample was left to stand at 80 ° C. for 2 hours in 4 minutes, and then left for 1 hour at room temperature to evaluate adhesion and appearance of the coating.                     

(4) Water resistance of coating

The specimen was immersed in warm water at 40 ° C. for 48 hours and then left for 1 hour at room temperature to evaluate its appearance and adhesion.

(5) impact resistance of coating film

It was measured whether cracking of the coating film occurred when dropping a weight of 500 g at a height of 40 cm.

Then, the measurement result of the physical property about each of said Test Examples 1-4 is shown in Table 4.                     

As described above, the coating composition for plastic material coating according to the present invention is excellent in adhesion to polycarbonate material and ABS material, and can be applied together to UV-curable top coat and urethane curable top coat to be subsequently coated, thereby improving painting workability and There is an effect that can contribute to improved productivity.

Claims (5)

In the coating composition for plastic material coating, a) 10 to 30% by weight of a vinyl chloride copolymer resin having a number average molecular weight of 10,000 to 20,000 and a carboxyl group or a hydroxy group substituted; b) an acrylic copolymer resin solution (solid content of 40 to 50%) having a number average molecular weight of 15,000 to 35,000. 50% by weight, c) 1 to 5% by weight of liquid epoxy resin, d) 1 to 10% by weight of wax-based additive, and 10) 60% by weight of e) solvent. The coating composition for coating a plastic material according to claim 1, wherein the glass transition temperature of the a) vinyl chloride copolymer resin is 30 to 80 ° C, and the glass transition temperature of the acrylic copolymer resin is 60 to 105 ° C. The coating composition for coating a plastic material according to claim 1, wherein the carboxyl group and the hydroxyl group substituted in the a) vinyl chloride copolymer resin are contained in an amount of 1 to 2% by weight based on the resin. The coating film which contains the undercoat obtained by apply | coating the coating composition of the said Claim 1 to a plastic material, and the top coat obtained by apply | coating an ultraviolet curable paint or a urethane curable paint on it. The coating film according to claim 4, wherein the plastic material is selected from polycarbonate, acrylonitrile-butadiene-styrene copolymer (ABS), acryl and polyvinyl chloride.