KR100344892B1 - Polypropylene resin composition having improved coating property - Google Patents

Abstract

PURPOSE: Provided is a polypropylene resin composition having improved coating property, which is used for car accessories like bumpers or electric home appliances and has excellent coating adhesion, impact strength, and flexural modulus without the treatment by 1,1,1-trichloroethane. CONSTITUTION: The polypropylene resin composition comprises: 100pts.wt. of a propylene polymer, which is an isotactic ethylene/propylene block copolymer having crystallinity and a melt index of 10-70g/10min(230deg.C); 30-80pts.wt. of an ethylene propylene copolymer rubber having Mooney viscosity(ML1+4, 100deg.C) of 40-60 and produced by mixing an ethylene propylene copolymer rubber having Mooney viscosity(ML1+4, 100deg.C) of 10-30 and an ethylene propylene copolymer rubber having Mooney viscosity(ML1+4, 100deg.C) of 60-90; 0.2-15pts.wt. of a modified polyolefin modified by an unsaturated carboxylic acid or derivatives thereof; 3-20pts.wt of a high density polyolefin; and 3-30pts.wt. of an inorganic filler.

Description

Polypropylene resin composition with improved paintability

Field of invention

The present invention relates to a polypropylene resin composition with improved paintability. More specifically, the present invention is a resin composition containing a polypropylene resin, an ethylene / propylene copolymer rubber, a modified propylene polymer, a high density polyethylene, and an inorganic filler, and is not subjected to 1, 1, 1-trichloroethane treatment. It is related with the polypropylene resin composition which is excellent in the adhesiveness of a coating film, and has high rigidity and impact strength even if it coats after coating of a primer.

Background of the Invention

Polypropylene resins are known to be chemically inert and particularly poor in paintability because they do not have polar groups in their molecules. Therefore, in the case of coating an automobile bumper or the like made of polypropylene resin, a method of performing a pretreatment step for enhancing the coating film adhesion of the coating material before undercoating the primer is used.

One such pretreatment process is the method by corona treatment disclosed in EP 0 589 660 A1 and EP 0 578 368 A1. However, this method has disadvantages such as poor process flow and uneven corona treatment. In addition, the most widely practiced, and the method disclosed in Japanese Patent Publication No. Hei 3-22895, there is a process of applying a primer after the 1, 1, 1-trichloroethane intermediate treatment, 1, 1, 1-trichloroethane Recently, there is a problem in that its use is regulated as an ozone depleting substance.

In order to solve the above problems, Japanese Patent Laid-Open No. 7-26044 discloses a method of adding modified polyolefin. However, this method has a problem in that the coating film adhesive strength is improved but the water resistance is poor and bubbles are generated. In addition, Japanese Patent Application Laid-Open No. 5-179097 describes a method of mixing and using a modified polyolefin and styrene / butadiene block copolymer. However, this method is difficult to commercialize due to its excellent film adhesion but poor heat resistance and high price. There are disadvantages.

Therefore, the present inventors have been made to develop a polypropylene resin composition that can be applied to products requiring painting of automobile parts or home appliances as a result of repeated studies to solve the above problems.

Purpose of the Invention

It is an object of the present invention to provide a polypropylene resin composition which can be coated without steaming with 1, 1, 1-trichloroethane when applied to a product to be coated.

Another object of the present invention is to provide a novel polypropylene resin composition having excellent coating film adhesion and excellent impact strength and flexural modulus compared to conventional materials even when washed with water without heavy treatment with 1, 1, 1-trichloroethane. will be.

Summary of the Invention

The present invention is a resin composition for use in automobile parts, home appliances, and the like, such as automobile bumpers, the ethylene propylene copolymer copolymer rubber and pattern having a pattern viscosity (ML _{1 +4} , 100 ℃) 10 to 30 parts by weight of polypropylene viscosity _{(ML 1 + 4, 100 ℃} ) are 60 to 90 ethylene propylene copolymer viscosity by mixing a rubber pattern _{(ML 1 + 4, 100 ℃} ) is 40 to 60 of ethylene-propylene copolymer rubber 30 to 80 wt. The present invention relates to a polypropylene resin composition comprising 0.2 to 15 parts by weight of polyolefin modified with an unsaturated carboxylic acid or derivative thereof, 3 to 20 parts by weight of high density polyethylene, and 3 to 30 parts by weight of an inorganic filter.

Hereinafter, the content of the present invention will be described in detail.

Detailed Description of the Invention

The polypropylene resin composition of the present invention consists of polypropylene, ethylene propylene copolymer rubber, modified polyolefin, high density polyethylene, and inorganic filler.

The polypropylene used in the present invention is preferably an isotactic ethylene / propylene block copolymer having a melt index (MI) of 10 to 70 g / 10 minutes (ASTM D1238, 230 ° C) and crystallinity. When the melt index is 10 g / 10 minutes or less, the moldability is not good and productivity is lowered, whereas when the melt index is 70 g / 10 minutes or more, the impact strength is sharply lowered.

Ethylene propylene copolymer rubber is composed of ethylene propylene copolymer rubber having a pattern viscosity (ML _{1 + 4} , 100 ° C) of 10 to 30 and an ethylene propylene air of 60 to 90 juni viscosity (ML _{1 + 4} , 100 ° C) of Ethylene propylene-based copolymer rubbers in which the copolymer rubber is mixed and the pattern viscosity (ML _{1 + 4} , 100 ° C) is 40 to 60 are preferable. In this case, the ethylene propylene-based copolymer rubber having different pattern viscosities is preferably 50 to 80 parts by weight. When the pattern viscosity of the mixture of ethylene propylene copolymer rubbers having different pattern viscosities is 40 or less, the coating film adhesion of the molded article is lowered, whereas when it is 60 or more, flow marks tend to occur on the molded article. As described above, two ethylene propylene copolymer rubbers having different pattern viscosities are not mixed, and the ethylene propylene copolymer rubbers having a pattern viscosity (ML _{1 + 4} , 100 ° C.) of 40 to 60 are used alone. In this case, coating film adhesion is not good. The mixed ethylene propylene copolymer rubber used in the present invention is used in an amount of 30 to 80 parts by weight based on the polypropylene polymer of the resin composition. If the content of the ethylene propylene-based copolymer rubber is 30 parts by weight or less, sufficient coating film adhesion is hardly obtained. If the content of the ethylene propylene copolymer rubber is 80 parts by weight or more, mechanical properties such as rigidity are lowered, and thus it cannot be used as a bumper material.

The modified polyolefin used in the present invention is a modified polyolefin by unsaturated carboxylic acid or derivatives thereof. Examples of polyolefins include polypropylene, polyethylene, ethylene / α-olefin copolymer rubber, ethylene / α-olefin nonconjugated diene compound copolymer (e.g. EPDM), ethylene / aromatic monovinyl compound conjugated diene compound copolymer rubber, and the like. have. Examples of the α-olefins include propylene, butene-1, heptene-1, hexene-1, and 4-methylpentene, and these may be used alone or in combination of two or more thereof. The unsaturated carboxylic acid for modifying the polyolefin includes acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, ditraconic acid, sorbic acid, metaconic acid, unglycaic acid, and the like. Anhydrides, esters, amides, imides, metal salts, and the like, examples of which are maleic anhydride, itaconic anhydride, ditraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, maleic acid monoethyl ester, and acrylamide , Maleic acid monoamide, maleimide, N-butyl maleimide, sodium acrylate, sodium methacrylate, and the like.

When the polyolefin is modified with the unsaturated carboxylic acid or its derivatives, the above materials may be used alone or in combination of two or more thereof. The method for modifying the polyolefin is not particularly limited, and conventionally known methods can be used, which can be easily carried out by those skilled in the art. For example, polyolefin is dissolved in a suitable organic solvent and kneaded by adding unsaturated carboxylic acid and / or its derivatives and a radical generator, or graft copolymerization is carried out by supplying each of the above components to an extruder. Can be.

As for the modified polyolefin used for this invention, 0.01-10.0 weight% of addition amount of unsaturated carboxylic acid and / or its derivative (s) is preferable with respect to a modified polyolefin. However, in the case where the polyolefin before modification is polypropylene or polyethylene having crystallinity, the addition amount is more preferably 1.0 to 8.0% by weight based on the modified polyolefin, and the styrene / ethylene / butadiene copolymer in which the polyolefin before modification is amorphous. In the case of rubber or the like, the addition amount is more preferably 0.2-8.0% by weight with respect to the modified polyolefin, and most preferably 0.5-5.0% by weight.

The modified polyolefin may be used by itself, but may also contain an appropriate amount of unmodified polyolefin. The modified polyolefin is added in an amount of 0.2 to 15 parts by weight based on 100 parts by weight of the polypropylene-based polymer of the entire resin composition. When the content of the modified polyolefin is 0.2 parts by weight or less, sufficient coating film adhesion is difficult to be obtained. When the content of the modified polyolefin is 15 parts by weight or more, mechanical properties such as rigidity and weather resistance are deteriorated, and thus it cannot be used as a bumper material.

The high density polyethylene used in the present invention has a density of at least 0.94 g / cm 3 (ASTM D 1505), and preferably has a melt index (MI) of 0.6 to 25 g / 10 min (ASTM D 1238, 190 ° C.). If the density is 0.94 g / cm 3 or less, the stiffness of the molded product is lowered. If the melt index is 0.6 g / 10 minutes or less, flow marks are generated on the molded product. Is lowered. High density polyethylene is used in an amount of 3 to 20 parts by weight based on the propylene polymer. If the content of the high-density polyethylene is 3 parts by weight or less, sufficient coating film adhesion is hardly obtained. If the content of the high-density polyethylene is more than 20 parts by weight, flow marks are generated and the appearance is significantly reduced.

3-30 weight part of inorganic fillers are used with respect to the propylene polymer in this invention. A representative example of the inorganic filler is talc, and talc having an average particle diameter of 2.0 mu and a maximum particle diameter of 10 mu or less can be preferably used. If the content of the inorganic filler is 3 parts by weight or less, sufficient rigidity cannot be obtained. If the content of the inorganic filler is 30 parts by weight or more, the low-temperature impact strength is lowered and it cannot be used as a bumper material or the like.

To the resin composition of the present invention, various additives such as reinforcing materials, fillers, heat stabilizers, weather stabilizers, antistatic agents, lubricants, slip agents, nucleating agents, flame retardants, pigments, dyes and the like may be added within a range not departing from the object of the present invention. Specific examples thereof include glass fiber, carbon fiber, calcium carbonate and calcium sulfate.

There is no restriction | limiting in particular in the method of manufacturing the resin composition of this invention, The method of manufacturing the conventional polypropylene resin composition can be used. Each of the above components can be freely selected and mixed in a desired order. In general, a method of training using a kneader such as a kneader, a roll, a short-barrier mixer, and a single screw or twin screw extruder may be used by adding the components and other additives in the required amounts.

The present invention can be understood in more detail by the following examples, which are only intended to illustrate the invention and are not intended to limit the scope of the invention.

Example

Example 1-5 below is an example according to the present invention, Comparative Example 1-5 is an example for comparison with the present invention. Table 1 shows the contents of the components of Examples 1-5 and Comparative Examples 1-5 and the physical properties of the resin compositions prepared according to the examples.

Description of each component used in Example 1-5 and Comparative Example 1-5 of Table I is as follows.

(1) polypropylene: melt index (MI) is 45 g / 10 min (230) and ethylene unit content is 10.5 mol%,

(2) modified polyolefin: maleic anhydride modified polypropylene wax

(3) ethylene propylene copolymer rubber

(i) EPR-1: ethylene-propylene random copolymer, ethylene unit content 74% by weight, pattern viscosity (ML _{1 + 4} , 100 ° C): 24.

(ii) EPR-1: ethylene-propylene random copolymer, ethylene unit content of 73% by weight, pattern viscosity (ML _{1 + 4} , 100 ° C): 70.

(iii) EPR-3: ethylene-propylene-diene random copolymer, ethylene unit content 72% by weight, pattern viscosity (ML _{1 + 4} , 100 ° C): 88

(4) High density polyethylene: Density is 0.954 g / cm 3 and melt index is 0.8 g / 10 min (190 ° C.).

(5) Inorganic filler: Talc with an average particle diameter of 2.0 μ

The components of Table I were added once into a PCM-30φ biaxial kneading extruder and kneaded to prepare a polypropylene resin composition, which was then injection molded with Samsung Kleckerner FCM-110 (clamping force = 110 tons). A molded article of 100 × 2 mm was produced. Next, after performing a degreasing process with alkaline aqueous solution, the primer was apply | coated to this, the urethane paint was spray-coated, and it was dried for 30 minutes in 80 degreeC oven.

Each of the physical properties measured molar and the measuring method shown in Table I are as follows.

(1) coating film adhesion

It was measured according to the lattice cutting method of ASTM D 3359 and the coating film peel strength measurement method of ASTM D 903.

(2) water resistance

After immersion in a water bath at 50 ° C. for 240 hours, the appearance of bubbles was visually confirmed.

(3) Flexural modulus

Flexural modulus was measured according to ASTM D 790.

(4) impact sugar

Izod impact strength notched at 23 ° C. was measured according to ASTM D 256.

In addition, after coating the brand name R-123 primer of Daehan Bi Chemical Co., Ltd. as a coating material, DR-262 was used as an upper coating material. The measurement results of each physical property are as shown in I, and the most important paint peeling strength of the paint bumper is required to be 700 g / cm when measured by ASTM D 903. In Comparative Example 2, although the coating peeling strength is excellent at 1000 g / cm or more, it is prohibited from being used for pollution, whereas in Example 1, washing with water instead of 1, 1, 1-trichloroethane steam treatment is performed. The degree of peeling strength of paint is excellent as 1000g / cm or more.

Simple modifications or variations of the present invention may be readily made by those skilled in the art, but such modifications or changes will be apparent from the appended claims, all of which fall within the protection scope of the present invention.

Claims (7)

100 parts by weight of a propylene polymer; Mooney viscosity _{(ML 1 + 4, 100 ℃} ) are 10 to 30 ethylene propylene-based copolymer rubber with a viscosity pattern _{(ML 1 + 4, 100 ℃} ) are 60 to 90 ethylene propylene-based Mooney viscosity by mixing the copolymer rubber 30 to 80 parts by weight of ethylene propylene copolymer rubber having (ML _{1 + 4} , 100 ° C) of 40 to 60; 0.2 to 15 parts by weight of modified polyolefin modified with unsaturated carboxylic acid or derivatives thereof; 3-20 parts by weight of high density polyolefin; And 3 to 30 parts by weight of an inorganic filler; Paintability improved polypropylene resin composition, characterized in that consisting of. The polypropylene resin composition of claim 1, wherein the propylene polymer is an isotactic ethylene / propylene block copolymer having a melt index of 10 to 70 g / 10 minutes (230 ° C.) and having crystallinity. . The modified polyolefin of claim 1, wherein the modified polyolefin is made of polypropylene, polyethylene, ethylene / α-olefin copolymer rubber, ethylene / α-olefin nonconjugated diene compound copolymer, and ethylene / aromatic monovinyl compound conjugated diene compound copolymer rubber. A polypropylene resin composition with improved paintability, characterized by modifying one or more polyolefins selected from the group with unsaturated carboxylic acids or derivatives thereof. 4. The unsaturated carboxylic acid according to claim 3, wherein the unsaturated carboxylic acid is unsaturated carboxylic acid, maleic anhydride, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, ditraconic acid, sorbic acid, metaconic acid and unglycaic acid Itaconic acid, ditraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, maleic acid monoethyl ester, acrylamide, maleic acid monoamide, maleimide, N-butyl maleimide, sodium acrylate, sodium methacrylate A polypropylene resin composition having improved paintability, characterized in that one or two or more selected from unsaturated carboxylic acid derivatives such as these are selected and used. The polypropylene resin composition with improved paintability according to claim 1, wherein the amount of unsaturated carboxylic acid and / or derivative thereof added to the modified polyolefin is 0.01 to 10.0 wt% based on the modified polyolefin. The polypropylene resin composition of claim 1, wherein the high density polyolefin has a density of at least 0.94 g / cm 3 and a melt index of 0.6 to 25 g / 10 minutes (190 ° C.). The polypropylene resin composition of claim 1, wherein the inorganic filler is talc having an average particle diameter of 2.0 μ and a maximum particle diameter of 10 μm or less.