KR20010109421A - A polypropylene resin composition having excellent metallic luster - Google Patents

Abstract

The present invention relates to a polypropylene resin composition having excellent metal texture and glossiness after molding the product, and having a low appearance of weld lines in the product, having an excellent appearance, and having excellent rigidity, impact resistance and heat resistance. The polypropylene resin composition of the present invention is a modified resin obtained by grafting 30 to 70% by weight of ultra high crystalline olefin resin having an isotactic peptide content of 96% or more, 10 to 25% by weight of polyolefin elastomer, unsaturated carboxylic acid or anhydride thereof. 3 to 10% by weight, 15 to 30% by weight of talc with an average particle diameter of 5 µm or less, and 2 to 8% by weight of a pigment pigment containing aluminum flakes coated with an organic material such as silane.

Description

Polypropylene resin composition excellent in metallic luster {A POLYPROPYLENE RESIN COMPOSITION HAVING EXCELLENT METALLIC LUSTER}

The present invention relates to a polypropylene composition, and in detail, has excellent impact resistance, heat resistance and rigidity, and there is no molding defect during injection molding of a molded article, and has gloss and metal texture, so that it is directly used without a separate coating process after molding. It is possible, and particularly relates to a polypropylene resin composition for automobile wheel covers with less generation of weld lines and excellent heat resistance.

Polypropylene has been widely used in various fields due to its relatively stable price, excellent weight and mechanical strength, but its impact resistance and rigidity are poor. In order to compensate for this, a polypropylene resin composition in which an inorganic filler such as ethylene-propylene copolymer rubber (EPM) and talc is added has been proposed. However, this molded product has a disadvantage in that the final product has a poor appearance and needs to be coated after molding. have. However, since polypropylene has a nonpolar group in the molecule and is chemically inert, the paintability is extremely low, other methods for improving the paintability are required, but these methods are a factor of the cost increase for the resin composition. .

In addition, although the wheel cover of a conventional automobile was produced by press forming of steel sheets, it uses nylon or polyphenylene oxide having excellent heat resistance for light weight and cost reduction, and recently, polyolefin reinforced resin such as polypropylene in terms of cost reduction The use of the composition has been introduced and many other methods have been proposed. For example, a resin composition characterized by containing a highly crystalline polypropylene resin, a polyolefin elastomer, a resin modified with an unsaturated carboxylic acid or a derivative thereof and talc having an average particle diameter of 10 µm or less is proposed.

Japanese Patent Laid-Open No. 5-20561 discloses a wheel cover made of glass fiber surface-treated with a polypropylene resin and an organosilane compound. The polypropylene-based resin may include a component such as talc or maleic anhydride-modified polypropylene.

In addition, Japanese Patent Application Laid-Open No. Hei 6-80839 discloses a wheel cover produced by injection molding a fiber-reinforced polypropylene resin composition containing polypropylene with polypropylene and carboxyl groups, silane-treated glass fibers and polyethylene wax.

In addition, Japanese Patent Application Laid-open No. Hei 10-44701 discloses a wheel cover resin, 40 to 90 parts by weight of a crystalline propylene ethylene block copolymer, an ethylene-propylene copolymer rubber, a polypropylene resin modified with an unsaturated carbonic acid or a derivative thereof, and an average particle diameter of 10 The glass fiber reinforced resin composition which contains the talc and glass fiber of micrometer or less is proposed.

However, there is a problem that the polypropylene resin compositions for wheel covers must be subjected to a painting process in order to be applied as a final product, and when used directly without a painting process, the gloss and metallic texture of the product are degraded and the external impact is prevented. There is a disadvantage that the surface is easily damaged. In addition, in the case of a paint product there is a problem that is not easy to recycle and recycle.

In order to improve the above problems, Japanese Patent Application Laid-Open No. Hei 8-239527 discloses a resin composition comprising aluminum flakes, metal powder pigments and pearl pigments in a resin composition comprising a highly crystalline polypropylene resin, a polyolefin elastomer, a modified resin, and talc. It is starting. However, when the resin composition is applied to side molds, side garnishes and bumper corners of automobiles, the metal texture and gloss of the products are improved, but when the resin composition is applied to many weld lines such as automobile wheel covers and chairs, Lines have a problem.

The present invention is to solve the above problems, an object of the present invention is to improve the metallic texture and gloss is excellent in appearance, the weld line when applied to the automobile wheel cover and chair products in which a large number of weld lines are generated It is to provide a polypropylene resin composition with low generation and excellent rigidity, impact resistance and heat resistance.

The present invention relates to a polypropylene resin composition having a metal texture and glossiness and no weld line in the product after molding the product without a coating process. More specifically, the present invention is 30 to 70% by weight of ultra high crystalline olefin resin, 10 to 25% by weight of polyolefin elastomer, unsaturated carboxylic acid or anhydride thereof having an isotactic peptide content by C-NMR method of 96% or more. 3 to 10% by weight of modified resin grafted, 15 to 30% by weight of talc with an average particle diameter of 5 μm or less, and 2 to 8% by weight of pigment pigment including aluminum flakes coated with organic materials such as silane. It relates to a polypropylene resin composition.

It is preferable that the ultra-high crystalline olefin resin whose isotactic peptide content measured by C-NMR method is 96% or more, 30-70 weight% is used for the composition of this invention. When the ultra high crystalline olefin resin is used at less than 30% by weight, the required mechanical properties are lowered, and when used in excess of 70% by weight, low temperature impact and heat resistance are lowered. For example, copolymers of propylene with small amounts of other alpha olefins such as isotactic polypropylene, propylene ethylene copolymers, propylene 1-butene copolymers, propylene 1-hexene copolymers, propylene 4-methyl-1-pentene copolymers, Random copolymers or mixtures thereof. The melt index of the copolymer is 20 to 80 g / 10 minutes (ASTM D1238, 230 ℃), preferably 30 to 60 g / 10 minutes. If the melt index of the copolymer is less than 30 g / 10 minutes, the melt index for the composition is lowered, and thus unmolding occurs during injection molding. If the melt index of the copolymer is greater than 60 g / 10 minutes, the mechanical properties of the copolymer are lowered. . These ultra-high crystalline olefin resins preferably have an isotactic peptide fraction of at least 96%, and serve to improve the flowability of the olefin elastomer and to improve heat resistance, rigidity and thermal deformation. If the isotactic peptide portion of the propylene homo portion is less than 96%, mechanical properties such as strength, impact resistance, heat resistance, and rigidity of the ultrahigh crystalline olefin resin are lowered, and heat resistance and rigidity of the resulting wheel cover molded article are lowered.

The polyolefin-based elastomer is preferably a thermoplastic elastomer having a pattern viscosity (ML1 + 4, 100 ° C) of 10 to 100 and a melt index of 0.5 to 10 g / 10 minutes. Such polyolefin-based elastomers are, for example, ethylene propylene copolymer rubber, ethylene propylene dicyclo pentadiene rubber, ethylene propylene 1,4-hexadiene rubber, ethylene propylene cyclopentadiene rubber, ethylene propylene methylene norbornene rubber, ethylene propylene ethylidene Novoden rubber, hydrogenated styrene-butadiene block copolymer (SEBS), hydrogenated styrene butadiene rubber (HSBR), styrene-ethylene-butylene block copolymer (SEBC) and crystalline ethylene-butylene block copolymer (CEBC) And the like. It is preferable that the polyolefin elastomer is used in the composition of the present invention 10 to 25% by weight, and gives elasticity and flexibility, and mixes with the ultra high crystalline olefin resin to improve impact properties. When used in less than 10% by weight, the effect of low temperature impact strength is hardly observed, and when used in excess of 25% by weight, the low temperature impact strength is improved but heat resistance is deteriorated. When the rubber having a pattern viscosity (ML1 + 4, 100 ° C.) is less than 10, the flowability is improved, but the mechanical properties are lowered. If the rubber is more than 100, the mechanical properties are improved, but the flowability is reduced, making molding difficult.

The modified resin obtained by grafting the unsaturated carboxylic acid or anhydride thereof used in the present invention is specifically a modified polypropylene resin or modified polyolefin copolymer rubber prepared by melt kneading, and the unsaturated carboxylic acid or its anhydride and catalyst are twin screw extruder. It was prepared by heating to melt at a temperature of 180 ~ 220 ℃ to 3 to 10% by weight to the composition of the present invention. When the modified polypropylene resin is used at less than 3% by weight, the interfacial adhesion to the talc and each resin, which is an inorganic filler, is lowered, and when used at more than 10% by weight, the flowability and mechanical properties are lowered. These modified resins improve the adhesion to the talc interface of the resin composition, thereby improving impact resistance and heat resistance.

The talc used in the present invention has a weight average particle diameter of 5 μm or less, preferably 1 to 4 μm, measured in the laser diffraction scattering method, and is used in the composition of the present invention in an amount of 15 to 30% by weight. To improve. When the average particle diameter of talc exceeds 5 micrometers, a specific surface area cannot be enlarged enough and there exists a disadvantage that the hardness and impact resistance of a composition fall. When talc is mixed with the composition of the present invention at less than 15% by weight, no effect on improving heat resistance is exhibited. When the talc is mixed at more than 30% by weight, the weight and impact resistance of the product are lowered.

Metallic pigmentation pigments used in the present invention include aluminum flakes coated with an organic material such as silane, and are used in the composition of the present invention in an amount of 2 to 8% by weight, so that the same metallic texture and gloss as the coated product after molding the product are Also, weld lines are not generated, which serves to reduce damage due to external impact and improve appearance quality. More specifically, the color pigment is prepared by the melt kneading method, and 7 to 15 weight pieces of aluminum having an average particle diameter of 5 μm or less, which is surface treated with 40 to 70 wt% of crystalline polypropylene, modified silicone, silane compound, or the like. %, 15 to 20% by weight of inorganic materials such as mica and silica, 5 to 10% by weight of dispersant for improving the dispersibility of inorganic materials, 0.1 to 1% by weight of pigment for coloring to form color and beta crystal forming nucleating agent required for beta crystallization It is a coloring pigment for metal textures containing 0.1-0.3 weight%. The generation of the weld line in the product is mainly caused by the aluminum pieces and the metal pigments used to express the metallic texture and gloss. When the aluminum pieces and the metal pigments in the resin composition form a good dispersion phase in the weld line generation site, In order to reduce the occurrence of, the inorganic material treated with modified silicone and silane compound was used in an amount of 7 to 15% by weight in order to uniformly disperse these inorganic materials (a piece of aluminum and metal pigment). In order to minimize the weld line, beta crystals should be formed at the site of generation, so 0.1-0.3% by weight of the nuclear agent for beta crystals was used. The beta nucleating agent which forms these beta crystals is a metal salt of group IIA of the periodic table of the amic acid, and there is a calcium salt of dicarboxylic acid. When using the pigment pigment less than 2% by weight can not produce the effect of the metal texture, when using over 8% by weight the mechanical properties of the composition is lowered.

The composition of the present invention contains various additives, reinforcing agents, fillers, for example, heat stabilizers, weather stabilizers, antistatic agents, lubricants, slip agents (SLIP), nucleating agents, flame retardants, wollastonite, calcium carbonate, mica, kaolin, clay, barium sulfate , Calcium sulfate or the like can be added within a range not inconsistent with the object of the present invention.

The composition of the present invention can be usefully applied to side molds, side garnishes, bumper corners, wheel covers and office chairs of automobile parts obtained by injection molding.

The present invention will be described in more detail through the following examples, but the present invention is not limited to these examples.

Examples and Comparative Examples

In the examples and comparative examples, the symbol means the following contents.

1) polypropylene

PP-1: Melt index 55g / 10min (230 ° C), ethylene unit content 5-25 mol%, isotactic peptide content by NMR method is less than 96%

PP-2: Melt index 60 g / 10 min (230 ° C.), ethylene unit content 5-25 mol%, isotactic peptide content by NMR method of 96% or more

PP-3: Melt index 25g / 10min (230 ° C), ethylene unit content 5 mol% or less, isotactic peptide content by NMR method is 96% or more

2) Polyolefin Elastomer (EPM)

EP-1: Ethylene-propylene copolymer rubber, pattern viscosity (ML1 + 4, 100 ° C) 24, propylene content 26% by weight

EP-2: Ethylene-propylene copolymer rubber, pattern viscosity (ML1 + 4, 100 ° C) 70, propylene content 27% by weight

EP-3: ethylene-butene copolymer rubber, pattern viscosity (ML1 + 4, 100 ° C) 44, butene content 20% by weight

EP-4: polyolefin elastomer, pattern viscosity (ML1 + 4, 100 ° C) 35, octene content 25% by weight

3) Modified polypropylene resin (CP): Modified polypropylene resin grafted with maleic anhydride (modification ratio = 0.4)

4) Talc

TALC-1: Talc with an average particle diameter of 4 μm or less

TALC-2: Talc with an average particle diameter of 8 µm or less

5) Toning Pigment

CPG-1: 55% by weight of crystalline polypropylene, 15% by weight of aluminum flakes having an average particle diameter of 5 μm or less surface treated with a modified silicone or silane compound, 20% by weight of inorganic materials such as mica or silica, 9.4% by weight of dispersant, color A coloring pigment for metal texture comprising 0.23% by weight of a pigment, 0.17% by weight of a calcium salt of dicarboxylic acid, a nucleating agent for forming beta crystals, and 0.2% by weight of a stabilizer such as an antioxidant.

CPG-2: 55% by weight of crystalline polypropylene, 14% by weight of aluminum flakes having an average particle diameter of 5 µm or less, 20.1% by weight of inorganic substances such as mica or silica, 10.4% by weight of dispersant, 0.3% by weight of pigment for coloring and antioxidants Toning pigment for metal texture comprising 0.2% by weight.

Each component of the present invention was introduced into a kneading extruder in a batch at the blending ratio shown in Table 1, and kneaded to prepare a resin composition. Both Examples and Comparative Examples were dried in an 80 ° C. oven for 2 hours in consideration of the deterioration of physical properties due to moisture absorption in the composition. Using this composition, Samsung Kleukner FCM-110 (molding force = 110 tons) injection machine, the injection temperature is 30/200/200/200/200 ℃ in order from the feeding hopper to the nozzle, the mold temperature is 60 ℃, injection pressure Was injection molded at 60 to 100 bar to prepare molded articles for measurement of physical properties and test specimens for appearance tests.

Measurement of physical properties of each Example and Comparative Example was carried out by the following test method.

(1) Flexural modulus (MPa): ASTM D790

(2) IZOD impact strength (Kgcm / cm): ASTM D256

(3) Heat Deflection Temperature (℃): ASTM D656

(4) Low-temperature falling impact strength: In the low temperature state (-30 ℃), the weight of 500g falls naturally to determine the cracking phenomenon.

(5) Appearance judgment: Visual judgment on the gloss and metallic texture of products coated after molding.

(6) Weld line: The degree of weld line generation for the molded product was tested, and it was judged to be unsatisfactory when the weld line was observed by visual inspection at a place 1m away from the weld line occurrence area.

(7) Scratch resistance: judged by pencil hardness, and when pencil hardness is B or more, O when pencil hardness is less than 2B, Ｘ, and when pencil hardness is between 2B and B level, it is determined by △.

From the results of Table 2, it can be seen that the polyolefin resin compositions of Examples 1 to 4 had good rigidity, impact resistance, heat resistance, and impact resistance to fall, and exhibited a metallic appearance and less generation of weld lines.

In Comparative Example 1, the rigidity, impact resistance and heat resistance are excellent and the appearance of the metal texture is exhibited, but the weld lines of the product are generated in a large amount. In Comparative Example 2, the rigidity, impact resistance and heat resistance are excellent, but the appearance is metallic. It did not show, there were many weld line occurrences. In the case of Comparative Example 3, the impact resistance and falling impact strength were good, but the heat resistance and the appearance were poor, and there were many weld lines in the product. In Comparative Example 4, the impact resistance was good and the appearance was metallic, but the heat resistance was lowered and the weld was good. There were many line occurrences.

The polypropylene resin composition of the present invention is excellent in wheel cover strength, impact resistance, heat resistance and rigidity, has a glossiness and a metallic feel during injection molding of a molded article, and has a good appearance due to less generation of weld lines.

Claims (7)

30-70% by weight of ultra-high crystalline olefin resin having an isotactic peptide content of 96% or more by C-NMR method, pattern viscosity (ML1 + 4 (100 ° C)) of 10-100, MI (230 ° C, 2.16Kg) 10-25 wt% of polyolefin-based elastomer having 0.5-10 g / 10min), 3-10 wt% of modified polypropylene grafted with unsaturated carboxylic acid or its anhydride and 15-30 wt% of talc having an average particle diameter of 5 μm or less, Polypropylene resin composition comprising 2 to 8% by weight of pigment pigment, including a piece of aluminum coated with an organic material such as modified silicone or silane. The isotactic polypropylene, propylene-ethylene copolymer, propylene 1-butene copolymer, propylene 1-hexene copolymer, and propylene 4- have a melt index of 20 to 80 g / 10 minutes. An alpha olefin such as methyl-1-pentene copolymer and a copolymer of propylene with a copolymer, a random copolymer, or a mixture thereof. The method of claim 1, wherein the polyolefin elastomer is ethylene propylene copolymer rubber, ethylene propylene dicyclo pentadiene rubber, ethylene propylene 1,4-hexadiene rubber, ethylene propylene cyclo pentadiene rubber, ethylene propylene methylene norbornene rubber, ethylene propylene Ethylidene novoden rubber, hydrogenated styrene-butadiene block copolymer (SEBS), hydrogenated styrene butadiene rubber (HSBR), styrene-ethylene-butylene block copolymer (SEBC), crystalline ethylene-butylene block copolymer ( CEBC) or crystalline ethylene-butylene block copolymer (CEBC). The pigment according to claim 1, wherein the pigment is 40 to 55% by weight of crystalline polypropylene, 7 to 15% by weight of aluminum flakes having an average particle diameter of 5 µm or less surface-treated with a modified silicone or silane compound, minerals such as mica or silica A polypropylene resin composition, comprising:-20 wt%, dispersant 5-10 wt%, color pigment 0.1-1 wt%, and beta crystal forming nucleating agent 0.1-0.3 wt%. The polypropylene resin composition according to claim 4, wherein the nucleating agent for forming beta crystals of the pigment is a calcium salt of dicarboxylic acid. An automobile wheel cover molded article manufactured by injection molding the polypropylene resin composition of claim 1. Chair molded article prepared by injection molding the polypropylene resin composition of claim 1.