KR20180076639A - Resin composition for automobile interior component having improved scratch resistance - Google Patents

Abstract

The present invention relates to a resin composition for automobile interior parts having improved scratch resistance, and more specifically, to a resin composition for the automobile interior parts, the resin composition which is capable of improving scratch resistance compared to an existing resin composition by adding a nucleating agent to a composition prepared by mixing a polyolefin-based resin, rubber, inorganic filler and a slipping agent, thereby increasing crystallinity of the polyolefin-based resin to increase surface hardness. According to the present invention, the resin composition can improve rigidity and miniaturize the size of spherical crystal by adding the nucleating agent, thereby increasing the crystallinity. In general, large spherical crystal parts and amorphous parts are non-uniformly mixed in a polyolefin such as polypropylene or the like. When a crystal nucleating agent is added to the polyolefin, the crystal nucleating agent dispersed in the polyolefin such as the polypropylene or the like becomes a primary nucleus of crystals such that polyolefin crystals are miniaturized, and crystallization rate can be increased at the same time.

Description

TECHNICAL FIELD [0001] The present invention relates to a resin composition for automobile interior parts having improved scratch resistance,

The present invention relates to a resin composition for automotive interior parts having improved scratch resistance, and more particularly, to a resin composition for automobile interior parts having improved scratch resistance, and more particularly, to a composition containing a polyolefin resin, a rubber, an inorganic filler and a slip agent to increase the crystallinity of the polyolefin resin To a resin composition for automobile interior parts which can improve scratch resistance as compared with a conventional resin composition by raising the surface hardness.

There is a problem that scratches are generated in a part of the automobile interior parts which is exposed to a lot of human hands during the transportation or storage after the injection molding. This is the main reason for the decrease in productivity due to the increase of defect rate. A commonly used automobile interior material is a polypropylene composite resin. Polypropylene composite resin is a material which is made by adding polyolefin, rubber and various inorganic fillers to polypropylene. It has excellent properties such as moldability, impact resistance, chemical resistance, low specific gravity and low cost, Such as automobile interior materials such as automobile interior bumpers, instrument panels, door trim panels, and built-in trims, as well as exterior materials. However, the polypropylene resin composition developed so far is excellent in terms of physical properties such as rigidity, scratch resistance and impact resistance, but has a difficulty due to the tendency of the scratch resistance to be inferior as the impact strength increases, There is a disadvantage in maintaining good impact properties when a material having excellent flowability is used for ease of injection molding.

As a result, research on the development of a resin composition for automotive interior parts having excellent scratch resistance has been progressing steadily, but no advanced technology capable of achieving adequate scratch resistance has been reported yet.

Therefore, there is an urgent need to develop a resin composition which can reduce the production cost due to an increase in the defective rate, and which can simultaneously satisfy excellent impact resistance, weather resistance, surface hardness, scratch resistance, and plastic molded articles thereof.

Korean Patent Publication No. 10-2007-0017872 Korean Patent Publication No. 10-2012-0057434

An object of the present invention is to provide a resin composition for automobile interior parts in which the surface hardness is increased by raising the degree of crystallization of the resin due to addition of a nucleating agent and the scratch resistance is improved as compared with the conventional resin composition.

In order to achieve the above object, the present invention provides a polyolefin resin composition comprising 60 to 80% by weight of a polyolefin resin; 2 to 7% by weight rubber; 10 to 20% by weight of an inorganic filler; 1.1 to 8% by weight of slip; And 0.1 to 0.3% by weight of a nucleating agent (crystal nucleating agent).

The resin composition may further comprise 0.3 to 1.5% by weight of a colorant, more specifically 0.6% by weight.

Polyolefin resin

The polyolefin-based resin may be a polypropylene resin, a poly ethylene resin, a polybutene resin, a polypentene resin, a polyhexene resin, a polypropylene resin, propene resin, and poly octene resin, and more preferably, it may include polypropylene.

The polyolefin-based resin may be contained in an amount of 60 to 80% by weight based on the total weight of the composition. More preferably 70% by weight.

Rubber

In the present invention, the rubber is a component used for reinforcing impact resistance and is not limited in its constitution. However, it is preferable to use an ethylene-propylene rubber (EPR), an ethylene-propylene-diene rubber (EPDM), an ethylene- Octene copolymer (EOR) and styrene-butadiene (SBR). The content of the rubber may be 2 to 7 wt%, and more preferably 5 wt%.

Inorganic filler

In the present invention, the inorganic filler is a component used for heat resistance and reinforcement of rigidity, and it is preferable that the rigidity and hardness of the resin composition increase markedly as the content of the inorganic filler used increases. The average particle diameter of the inorganic filler is preferably 1 to 30 占 퐉, more preferably 5 to 10 占 퐉. If the average particle diameter of the inorganic filler is less than 1 μm, there may be a problem that the heat resistance and rigidity reinforcing effect are not sufficiently exhibited. If the average particle diameter exceeds 30 μm, there is a problem that the polyolefin resin composition is not easy to handle and work in extrusion molding Can be.

The inorganic filler may be selected from the group consisting of talc, calcium carbonate, wollastonite, calcium sulfate, magnesium oxide, calcium stearate, mica, calcium silicate, clay and carbon black.

The content of the inorganic filler may be 10 to 20% by weight.

When the content of the inorganic filler is less than 10% by weight, the heat resistance and rigidity are insufficient. When the content of the inorganic filler is more than 20% by weight, the flowability is low and the workability may be deteriorated.

Slip agent

In the present invention, the slip agent can reduce the frictional and frictional heat during the processing of the synthetic resin, increase the fluidity of the polymerization agent, and smooth the processing.

The slip agent may include at least one of a silicone slip agent and an amide slip agent.

The silicone-based slip agent may be silicone acrylate or polydimethylsiloxane, and is preferably, but not limited to, polydimethylsiloxane.

The amide-based slipping agent is selected from the group consisting of palmitamide, stearyl arachidamide, stearamidoethyl stearamide, stearamidoethylpalmitamide, erucamide, And oleamide. The term " oleamide "

The content of the silicone slip agent in the slip agent may be 1 to 3 wt%, and more preferably 2 wt%.

When the content of the silicon-based slip agent is less than 1% by weight, scratch resistance is insufficient and the scratch resistance is poor. When the content of the silicone-based slip agent exceeds 3% by weight, peeling or stain may occur on the surface of the injection-molded article.

The content of the amide slip agent in the slip agent may be 0.1 to 0.3 wt%. If the amount is more than 0.3% by weight, there is a possibility of causing a problem of transferring to the surface of the injection molding.

Crystal nucleating agent

In the present invention, the nucleating agent becomes the primary nucleus of the crystal, and the crystal of the polyolefin-based resin used as the composition can be made finer and the crystallization rate can be increased. In general, polyolefins such as polypropylene and the like have a large spherical portion and a non-crystalline portion in a non-uniform manner. According to the present invention, since the above-mentioned micronized crystals are homogeneously dispersed uniformly in the non-crystalline portion of the resin, The optical properties and the mechanical properties can be improved. As the crystallization temperature rises (the crystallization speed is improved), the molding efficiency increases, thereby improving transparency and gloss and shortening the molding cooling time.

The nucleating agent may include at least one selected from the group consisting of an aryl carboxylic acid metal salt, benzylidene sorbitol, and sodium benzoate.

The content of the nucleating agent may be 0.1 to 0.3 wt%, more preferably 0.3 wt%. The crystallization rate increases as the content of the nucleating agent increases from 0.1 wt% to 0.3 wt%. However, when the content of the nucleating agent exceeds 0.3% by weight, problems such as tensile strength and flexural modulus may occur.

coloring agent

The resin composition of the present invention may further contain a coloring agent. Examples of the coloring agent that can be added additionally include aluminum flakes, aluminum powder, aluminum foil, zinc powder, bronze powder, mica powder, titanium white, zinc oxide, zinc sulfide, chromium yellow, barium yellow, Cobalt green or carbon black, or an inorganic pigment such as exemplified by Watchung Red, Permanant Red, Palladium Red, Benzidine Yellow or Phthalocyanine Green. Organic pigments can be applied. The colorant may be added as it is or in the form of a colorant master batch preliminarily mixed with the polyolefin resin in an appropriate ratio. In order to obtain an expected coloring effect, it is preferable to add 0.3 to 1.5% by weight of a coloring agent.

Further, the present invention can provide a plastic molded article for automobile interior parts made of the resin composition for automobile interior parts.

According to the present invention, by adding a nucleating agent to a resin composition for automobile interior parts to improve the degree of crystallization, the surface hardness of a molded article can be increased, and scratch resistance can be improved. More specifically, according to the present invention, the degree of crystallization is increased by the addition of a nucleating agent, thereby improving the rigidity and miniaturizing the lining size. In general, polyolefins such as polypropylene are mixed heterogeneously with large spheres. When such a crystal nucleus agent is added to the polyolefin, a nucleating agent dispersed in a polyolefin such as polypropylene becomes a primary nucleus of the crystal, and the polyolefin crystal is refined And the crystallization rate can be increased at the same time. In particular, as the micronized crystals are uniformly dispersed and homogenized in the non-crystalline region, optical properties (such as transparency) and mechanical properties (scratch resistance, etc.) can be improved. Further, as the crystallization temperature of the resin increases (the crystallization speed increases), the molding efficiency increases and the molding cooling time can be shortened.

Hereinafter, the present invention will be described in more detail with reference to Examples. The objects, features and advantages of the present invention will be readily understood through the following examples. The present invention is not limited to the embodiments described herein, but may be embodied in other forms. The embodiments described herein are provided to enable those skilled in the art to fully understand the spirit of the present invention. Therefore, the present invention should not be limited by the following examples.

Examples and Comparative Examples: Production of Resin Composition for Automobile Interior Parts

Each raw material was mixed with a Henschel mixer for 3 minutes according to the composition ratios described in Table 1 below, extruded in a twin extruder at 190 to 230 ° C, cooled and solidified to obtain a pellet-like composition.

Content of resin composition for automobile interior parts division Comparative Example 1 Example 1 Example 2 Example 3 Content (% by weight) Content (% by weight) Content (% by weight) Content (% by weight) PP 70 70 70 70 RUBBER 5 5 5 5 TALC 20 20 20 20 Slip agent 3.3 3.3 3.3 3.3 additive 1.1 0.8 0.8 0.8 coloring agent 0.6 0.6 0.6 0.6 Nucleating agent - 0.3 0.3 0.3 aryl carboxylic acid metal salt benzylidene sorbitol sodium
benszoate RUBBER: Ethylene-Propylene-Rubber (EPR)
Slip agent: poly dimethyl siloxane, palmitamide,
Colorant: paladium red

Experimental Example: Test of change in scratch resistance due to addition of nucleating agent

In order to confirm that the scratch resistance is improved when a nucleating agent is added to a resin composition for a conventional automobile interior part, a test piece is divided into three types of nucleating agent and no nucleating agent according to the embodiment The physical properties were evaluated. Polypropylene (PP) was used as the olefin resin, and talc was used as the inorganic filler. The composition ratios of the resin compositions constituting the specimen are as follows.

Evaluation of scratch resistance division Comparative Example 1 Example 1 Example 2 Example 3 ΔL average 1.3 1.1 1.1 1.0

The method of testing the scratch was carried out by the Ericsson test. When scratches were generated on the specimen made of the above composition, when the whitening occurred, the part where no whitening occurred and the color difference were measured (? L value). The lower the DELTA L value, the better the scratch resistance.

As a result of the measurement of the ΔL value, the ΔL value of the specimen without nucleating agent was 1.3, the ΔL value of the specimen No. 2 added with the arylcarboxylic acid metal salt as nucleating agent was 1.1, the content of benzylidene sorbitol was 3 The ΔL value of the No. 1 specimen was 1.1 and the ΔL value of the No. 4 specimen containing sodium benzoate as nucleating agent was 1.0. As a result, it was confirmed that the scratch resistance was improved in the case where the nucleating agent was added, and that the sodium benzoate in the nucleating agent was most effective in improving the scratch resistance.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereto will be. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (6)

60 to 80% by weight of a polyolefin-based resin;
2 to 7% by weight rubber;
10 to 20% by weight of an inorganic filler;
1.1 to 8% by weight of slip; And
And 0.1 to 0.3% by weight of a crystal nucleating agent.
The method according to claim 1,
Wherein the resin composition further comprises 0.3 to 1.5% by weight of a colorant.
The method according to claim 1,
The polyolefin-based resin may be a polypropylene resin, a poly ethylene resin, a polybutene resin, a polypentene resin, a polyhexene resin, a polypropylene resin, propene resin, and poly octene resin. The resin composition for automotive interior parts of the present invention is preferably a resin composition for automobile interior parts.
The method according to claim 1,
Wherein the inorganic filler comprises at least one selected from the group consisting of talc, calcium carbonate, wollastonite, calcium sulfate, magnesium oxide, calcium stearate, mica, calcium silicate, clay and carbon black / RTI >
The method according to claim 1,
Wherein the slip agent comprises at least one of a silicone slip agent and an amide slip agent.
The method according to claim 1,
Wherein the crystal nucleating agent comprises at least one member selected from the group consisting of an aryl carboxylic acid metal salt, benzylidene sorbitol and sodium benzoate. Composition.