KR20130017837A - Polypropylene resin composition for trims of vehicles - Google Patents

Abstract

PURPOSE: A polypropylene resin composition is provided to reduce the size and weight of a product thereof, and to have sufficient scratch resistance and impact resistance for a vehicle door trim. CONSTITUTION: A polypropylene resin composition comprises: 50-99 weight% of highly crystalline polypropylene resin which has a melt index of 5-90 g/10minutes(230 deg. C) and an isotactic index of 98% or more; 0.1-10 weight% of nanoclay master batch; 0.1-20 weight% of thermoplastic elastomer; 0.01-10 weight% of scratch-resisting agent; and 0.01-10 weight% of nucleating agent. The highly crystalline polypropylene resin comprises a propylene mono polymer, a copolymer of the propylene and ethylene, or a mixture thereof.

Description

Polypropylene resin composition for trims of vehicles

The present invention relates to a polypropylene resin composition for automobile door trim, and more particularly, to a light weight of the resin composition by minimizing the amount of the inorganic filler and to a polypropylene resin composition for injection molding having excellent scratch resistance.

Polypropylene resin is a general-purpose plastic that is used as a base material for interior and exterior materials of automobiles due to its excellent price-performance. For automobile parts, composite polypropylene materials reinforced with inorganic fillers and elastomeric rubbers are used to meet mechanical properties such as rigidity, impact strength, and dimensional stability. Among them, the car door trim is the second part that requires the high rigidity and impact resistance after the crash pad among the car interior parts and requires the following characteristics. First, it must be high rigidity because it must maintain shape for assembling parts and there should be no noise caused by vibration when driving the vehicle, and it should have high impact because there should be no sharp edge caused by cracks in the side collision, and to prevent surface damage by scratching Excellent scratch resistance is required.

In order to secure the required performance of the door trim, a large amount of inorganic filler (eg, talc) is used, and elastic rubber is added to compensate for the impact performance deteriorated due to the use of the inorganic filler to finally secure rigidity and impact performance. Done. However, the use of inorganic fillers is advantageous in terms of physical properties but adversely in terms of scratch resistance. This is because the inorganic filler is exposed to the outside when the surface damage caused by the external force occurs, the whitening phenomenon occurs. To improve this, expensive slip agents are sometimes used to impart slip properties to the material surface. As such, the use of inorganic fillers to increase the rigidity is a cause of the increase of the material cost because of the increase of the specific gravity of the material and the addition of a slip agent to increase the rubber content and the scratch resistance.

Recently, research and development on improving scratch resistance and supplementing properties of automotive interior and exterior resin compositions have been steadily progressing, but there are no reports on technologies that satisfy both economical and physical properties.

In order to solve the problems of the prior art, the present inventors provide a composition capable of minimizing the amount of inorganic filler used in a polypropylene material for automobile door trim. Accordingly, to provide a polypropylene-based resin composition that can achieve a low weight and also have properties suitable for use in automobile door trim in terms of physical properties such as scratch resistance and impact resistance.

The present invention for achieving the above object

(a) 50 to 99% by weight of a highly crystalline polypropylene resin having a melt index of 5 to 90 g / 10 min (230 ° C.) and an isotactic index of at least 98%;

(b) 0.1 to 5 weight percent of inorganic filler;

(c) 0.1 to 10% by weight nanoclay master batch;

(d) 0.1 to 20% by weight of thermoplastic elastomer;

(e) 0.01 to 10% by weight of scratch resistant agents; And

(f) 0.01 to 10% by weight of nucleating agent

It provides a polypropylene resin composition for a car door trim.

The polypropylene resin composition according to the present invention can minimize the amount of the inorganic fillers and can be reduced in weight, and the insufficient mechanical properties have been improved by using high crystalline polypropylene, and the stiffness decreases through optimization of the type and content of the elastomer rubber. Minimized and improved impact strength. In addition, it solved by mixing additives such as nucleating agent, nano clay master batch, etc. to secure the dimensional stability, and also to meet the physical properties required for automotive door trim by mixing the scratch resistant agent. Therefore, the polypropylene resin composition according to the present invention can satisfy the physical properties required by the resin for the door trim and at the same time achieve a light weight, thereby ensuring economic efficiency.

Hereinafter, the present invention will be described in more detail.

Polypropylene resin composition for automobile door trim according to the present invention

(a) 50 to 99% by weight of a highly crystalline polypropylene resin having a melt index of 5 to 90 g / 10 min (230 ° C.) and an isotactic index of at least 98%;

(b) 0.1 to 5 weight percent of inorganic filler;

(c) 0.1 to 10% by weight nanoclay master batch;

(d) 0.1 to 20% by weight of thermoplastic elastomer;

(e) 0.01 to 10% by weight of scratch resistant agents; And

(f) 0.01 to 10% by weight of nucleating agent

.

In the present invention, the high crystalline polypropylene resin may be a propylene homopolymer or a copolymer of propylene and ethylene or a mixture thereof.

Unlike the conventional polypropylene resin, the high crystalline polypropylene resin used in the present invention is a high crystalline polypropylene (High Crystallinity PolyPropylene), also called HIPP (High Isotacticity PolyPropylene), HSPP (High Stiffness PolyPropylene) In order to improve impact resistance, high hardness and scratch resistance, it is a compound formulated in place of the existing polypropylene. It has high isotacticity compared to the existing isotacticity of polypropylene which is commercially available, and has high crystallinity and 20 to 40% higher stiffness due to high hardness and excellent heat resistance and scratch resistance. Impact resistance has similar strengths.

In other words, the isotactic index of stereopropylene of polypropylene, which is widely used at present, is 94-97%, and the isotactic index of high-crystalline polypropylene is at least 98%. If the isotactic index is increased, the crystallinity of polypropylene is increased to improve mechanical properties and heat resistance.

Highly crystalline polypropylene can be used for the overall parts of the interior and exterior of automobiles. Among them, stiffness and heat resistance are superior to those of the existing polypropylene, so that these properties are used to reduce the specific gravity by reducing the amount of parts or inorganic fillers that require these properties.

In the present invention, the inorganic filler has an average particle diameter of 1 to 30 ㎛, 1 selected from talc, wollastonite, silica, kaolin, titanium dioxide, calcium carbonate, barium sulfate, manganese sulfate, nano clay and carbon black Species or mixtures of two or more kinds can be used.

In addition, in the present invention, the nanoclay master batch may use a master batch prepared by kneading 40% by weight of bentonite clay substituted with alkali ammonium ions and 60% by weight of polypropylene resin grafted with maleic anhydride. .

In the present invention, the thermoplastic elastomer may be a rubber which is a copolymer of ethylene and C3-C10 alpha olefin, and specific examples thereof include ethylene-propylene rubber (EPR) and ethylene-butene copolymer (EBR) ethylene-octene air. Any one or more selected from the group consisting of coalescing (EOR) and styrene-butadiene (SBR) can be used.

In the present invention, a minimum content that can satisfy the impact strength and stiffness required in the automotive industry is added to the high crystalline polypropylene. (See Table 2). Compared with ethylene-propylene rubber (EPR), ethylene-butylene rubber (EBR), ethylene-octene rubber (EOR) and styrene-butadiene rubber (SBR), the impact strength is improved for ethylene-octene copolymer (EOR). The best balance between the effects and the overall physical properties, and can be preferably selected because it can reduce the stiffness relatively lowered as much as possible.

In addition, in the present invention, the scratch resistant agent is a siloxane-based, polyorganosiloxane-based, metal stearate-based, saturated fatty acid amide-based, unsaturated fatty acid amide-based, maleic alpha olefin having an amine functional group and primary or secondary fatty acid amide One or two or more selected from the group consisting of these may be used.

In addition, in the present invention, the nucleating agent may be used one or a mixture of two or more selected from inorganic substances such as sorbitol-based, phosphate-based metal salts, quinacridone, calcium carboxylate and amide-based organic compounds and talc. Since the present invention minimizes the inorganic filler added to polypropylene, problems of shrinkage of the product after injection may occur. To minimize this shrinkage problem, nucleating agents were added to the highly crystalline polypropylene. Highly crystalline polypropylene used in the present invention can be added to the nucleating agent to minimize the occurrence of shrinkage of the product after injection.

In addition, the polypropylene resin composition according to the present invention may further include additives such as lubricants, oxidative stabilizers, weather stabilizers, pigments, the content is preferably in the range of 0.1 to 5% by weight.

The injection conditions for forming the product are not particularly limited, but may be prepared by injection molding or injection blow molding, and more specifically, using a twin extruder at a temperature of 180 to 250 ° C. to heat melt and pelletize the polypropylene resin composition. After the chip is obtained, it can be molded by injection molding the cavity of the mold by using an injection molding machine and then contacting the mold to cool and solidify the mold. The final form of the plastic molded article according to the method of the embodiment of the present invention is a resin containing a thermoplastic elastomer in a highly crystalline polypropylene resin, the melt index (Melt Index) at 230 ℃, 2.16Kg 20 ~ 35 g / 10 The thermoplastic elastomeric rubber having a powder may be provided in the form of a mixed polypropylene resin composition.

Plastic molded article according to the embodiment of the present invention is not limited to the field used, but is preferably used for the purpose of application to interior trim door trim.

Hereinafter, the present invention will be described in more detail with reference to specific examples, but the scope of the present invention is not limited thereto.

Required Properties of Resin for Car Door Trim division Target Evaluation item unit Inorganic Filler Non-Reinforced Polypropylene Melt Index g / 10min
(230 ℃, 2.16Kg) More than 20 Flexural modulus Kgf / cm ² More than 17,000 IZOD impact strength (23 ℃) Kgf cm / cm 9 or more Scratch resistance class Level 3 or higher

Example  And Comparative example

To prepare a polypropylene resin composition with the composition and content shown in Table 2 below and the results are shown in Table 4.

division Example 1 Example 2 Example 3 Example 4 Comparative example Comparative example Highly crystalline polypropylene resin ^{1 )} 93 93 93 95 - - Ethylene-propylene copolymers ^{2 )} - - - - 93 - Propylene Homopolymer ^{3 )} - - - - - 93 Talc ^{4 )} 2 One 0.1 0.1 2 2 Nano Clay Masterbatch ^{5 )} One One 0.2 0.2 - - Thermoplastic elastomers ^{6 )} 2 3 6 4 4 4 Scratch Resistant ^{7 )} One One 0.5 0.5 One One Nuclear agent ^{8 )} One One 0.2 0.2 - - total 100 100 100 100 100 100 1) Highly crystalline ethylene propylene copolymer with a melt index of 30 g / 10 min (230 ° C.) and an isotactic index of 98.5%
2) General ethylene propylene copolymer with a melt index of 25 g / 10 min (230 ° C.) and an isotactic index of 95%
3) General polypropylene homopolymer with a melt index of 35 g / 10 min (230 ° C.) and an isotactic index of 95%.
4) Talc with an average particle of 1 μm
5) Masterbatch prepared by kneading 40% by weight of bentonite clay substituted with alkali ammonium ions and 60% by weight of polypropylene resin grafted with maleic anhydride
6) Ethylene-Octene Copolymer Rubber (EOR)
7) Master batch of 50% by weight of polyorganosiloxane and 50% by weight of propylene polymer having a melt index of 2 g / 10 min.
8) Sodium Phosphate

Property measurement

(1) Melt index (MI): measured at 230 ° C., 2.16 kgf according to ASTM D-1238.

(2) Density (g / cm3): Measured according to ASTM D-792 method.

(3) Flexural modulus and flexural strength: measured by ASTM D-790 method, the specimen size was 12.7 × 127 × 6.4mm, the crosshead speed was 28mm / min under the test conditions. Door trims in the automotive industry require flexural modulus of more than 17,000 Kg / cm2.

(4) IZOD impact strength: measured at room temperature (+23 ℃) by ASTM D-256 method, the specimen size was 63.5 × 12.7 × 3mm.

(5) Scratch resistance determination: The scratch resistance of the product was determined by scratching the flat sheet specimen once under the scratch experimental conditions of Table 3.

Scratch resistance test conditions and criteria Experimental conditions Load: 0.5kgf, Sapphire ball 0.5R, Stroke: 100mm, Speed: 100 mm / s Rating Scratch Resistance Criteria Scratch width (㎛) Exterior Grade 5 <20 Almost no surface damage Grade 4 100-200 No obvious surface damage was noticed Level 3 200-300 Minor surface damage is noticed 2nd class 300 to 400 Whitening due to obvious surface damage 1st grade > 400 Very severe surface damage

-It was judged that it is suitable for interior materials application when it is higher than grade 3 of automobile standard.

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 importance 0.92 0.92 0.915 0.915 0.92 0.92 Tensile Strength (Kgf / cm ² ) 320 330 310 315 270 290 Elongation (%) 110 120 130 110 80 50 Flexural Strength (Kgf / cm ² ) 450 460 430 430 320 340 Flexural modulus (Kgf / cm ² ) 19000 19500 18300 18400 13000 15500 Impact Strength (Kgfcm / cm) 11 13 12 10 5 3 Heat deformation temperature (캜) 135 137 133 135 115 120 Scratch resistance 3.5 3.5 3.5 3.5 2.5 2.8

It can be seen from the results of Table 4 that the polypropylene resin compositions of Examples 1 to 4 according to the present invention have excellent physical properties such as impact resistance, rigidity and scratch resistance. However, when talc is mixed with general ethylene-propylene copolymer resin as in Comparative Example 1, scratch resistance and mechanical properties are not satisfactory, and when talc is mixed with general polypropylene homopolymer as in Comparative Example 2, scratch resistance It can be seen that the improvement is better than Comparative Example 1, but not satisfactory, and the elastic properties such as elongation and impact strength are not satisfactory.

It will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention. Accordingly, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (8)

(a) 50 to 99% by weight of a highly crystalline polypropylene resin having a melt index of 5 to 90 g / 10 min (230 ° C.) and an isotactic index of at least 98%;
(b) 0.1 to 5 weight percent of inorganic filler;
(c) 0.1 to 10% by weight nanoclay master batch;
(d) 0.1 to 20% by weight of thermoplastic elastomer;
(e) 0.01 to 10% by weight of scratch resistant agents; And
(f) 0.01 to 10% by weight of nucleating agent
Polypropylene resin composition for a car door trim comprising a.
The polypropylene resin composition of claim 1, wherein the high crystalline polypropylene resin is a propylene homopolymer or a copolymer of propylene and ethylene or a mixture thereof.
The method of claim 1, wherein the inorganic filler has an average particle diameter of 1 to 30 ㎛, 1 selected from talc, wollastonite, silica, kaolin, titanium dioxide, calcium carbonate, barium sulfate, manganese sulfate, nano clay and carbon black A polypropylene resin composition for automobile door trims, characterized in that the species or a mixture of two or more thereof.
The motor vehicle according to claim 1, wherein the nanoclay master batch is a master batch manufactured by kneading 40% by weight of bentonite clay substituted with alkali ammonium ions and 60% by weight of polypropylene resin grafted with maleic anhydride. Polypropylene resin composition for door trim.
The polypropylene resin composition according to claim 1, wherein the thermoplastic elastomer is a copolymer of ethylene and C3-C10 alphaolefin.
The method of claim 1, wherein the scratch resistant agent is a group consisting of siloxane-based, polyorganosiloxane-based, metal stearate-based, saturated fatty acid amide-based, unsaturated fatty acid amide-based, maleic alpha olefin having an amine functional group and primary or secondary fatty acid amide Polypropylene resin composition for a car door trim, characterized in that one or two or more selected from.
The polypropylene for a car door trim of claim 1, wherein the nucleating agent is one or a mixture of sorbitol-based, phosphate-based metal salts, quinacridones, calcium carboxylates, and amide-based organic compounds and inorganic materials. Resin composition.
The polypropylene resin composition for automobile door trim according to claim 1, further comprising 0.1 to 5% by weight of at least one additive selected from the group consisting of lubricants, oxidative stabilizers, weather stabilizers, and pigments.