KR100475870B1 - A polyolefin resin composition for an automobile outerior - Google Patents

Abstract

The present invention relates to a polyolefin-based composite resin composition for automobile exterior materials, more specifically, 40 to 70% by weight of a crystalline ethylene-propylene copolymer, ethylene-propylene-diene rubber 5 to produced using a metallocene catalyst 15 wt%, 10-30 wt% of ethylene-α-olefin copolymer, 10-20 wt% of inorganic reinforcing material having an average particle size of 1-5 μm, 0.1-2.0 wt% of aluminum flakes having an average particle size of 10-100 μm It is characterized in that it comprises a high stiffness, impact resistance, heat resistance, it is possible to reduce the weight of the molded product, and to produce a colorful molded molded molded appearance, especially polyolefin-based composite resin suitable as a material for automotive exterior parts It relates to a composition.

Description

A polyolefin resin composition for an automobile outerior

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin composite resin composition, and more particularly, to a composite resin composition which is excellent in rigidity and fluidity, which can reduce the weight of a molded article and produce a colorful mold-in-color molded article, which is suitable as a material for automotive exterior parts. .

Generally, the resin composition for automobile bumpers includes ethylene-propylene rubber or ethylene-α-olefin copolymer, which is an impact reinforcing material based on a crystalline ethylene-propylene copolymer, and includes an inorganic filler to reinforce rigidity. do. Therefore, rubber and inorganic fillers are basically dispersed using polypropylene as a matrix, and various additives may be added to improve processability and compatibility. Related patents include USP 5484824, USP 5045589, USP 4439573, EP 476926, and the like.

However, these conventional composite resin compositions are difficult to fill the molded article due to the lack of fluidity, and also because the lack of rigidity can easily deform the molded article to meet the needs of automotive exterior goods, such as bumper is getting thinner In particular, the surface hardness was low and was not satisfactory to be applied to the mold in collar bumper.

Recently, bumper of the automobile exterior material is a polypropylene-based composite resin composition is increasingly diversified in design and larger in size, while the thickness is gradually becoming thinner in accordance with the light weight of the vehicle. Therefore, the characteristics required for the resin composition for automobile bumpers are also required to have excellent fluidity (molding), mechanical rigidity, heat resistance, and impact resistance.

In addition, in the case of a mold-in collar bumper used in the related art, since a solid color is used, the appearance of the molded article seems to be monotonous, and surface hardness and moldability are not satisfactory, and development of a new product is required.

An object of the present invention is to use an ethylene-propylene copolymer to have excellent stiffness, heat resistance, impact resistance characteristics and excellent fluidity to reduce the thickness of the injection molded product, in particular, the surface hardness and molded article using aluminum flakes The present invention provides a polyolefin composite resin composition which can be applied to molded articles of mold in color while greatly improving the appearance.

The present invention is 40 to 70% by weight crystalline ethylene-propylene copolymer, 5 to 15% by weight ethylene-propylene-diene rubber prepared using a metallocene catalyst, 10 to 30% by weight ethylene-α-olefin copolymer And a polyolefin-based composite resin composition comprising 10 to 20% by weight of an inorganic reinforcing material having an average particle size of 1 to 5 µm and 0.1 to 2.0% by weight of an aluminum flake having an average particle size of 10 to 100 µm.

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

Polyolefin-based composite resin composition of the present invention (A) crystalline ethylene-propylene having a melt flow index of 40 to 120 g / 10 minutes (230 ℃, 2.16 kg), the content of ethylene-propylene rubber 0.5 to 15% by weight 40 to 70 wt% of the copolymer, (B) 5 to 15 wt% of the ethylene-propylene-diene rubber having a Mooney viscosity at 125 ° C of 10 to 50 ML 1 + 4, and (C) a Mooney viscosity at 121 ° C of 1 10 to 30% by weight of an ethylene-α-olefin copolymer rubber (octene: 20 to 50% by weight) of 35 ML 1 + 4, (D) 10 to 20% by weight of an inorganic reinforcing material having an average particle size of 1 to 5 μm, (E) 0.1 to 2.0% by weight of aluminum flakes having an average particle size of 10 to 100 µm, and in addition, antioxidants, ultraviolet absorbers, light stabilizers, pigments, dispersants, nucleating agents, Additives such as processing lubricants and coupling agents may be included.

The crystalline ethylene-propylene copolymer as component (A) has an ethylene monomer content of 1 to 10% by weight, preferably 4 to 7% by weight, a weight average molecular weight of 100,000 to 250,000 g / mol, and propylene in the copolymer. The isotactic index of is at least 96%, preferably at least 97% by C13-NMR measurement, with a melt flow index of 40 to 120 g / 10 min, preferably 60 to 100 at a temperature of 2.16 kg and a temperature of 230 ° C. Use g / 10 min.

In the present invention, when the isotactic index of the crystalline ethylene-propylene copolymer is less than 96%, the rigidity and surface hardness of the molded article are not satisfactory, and when the melt flow index is less than 60 g / 10 minutes, the fluidity and formability are If it falls, and it is 100 g / 10min or more, the impact resistance of a molded article will fall remarkably.

Ethylene-propylene-diene rubber as component (B) is a ternary copolymerized hydrocarbon rubber under a metallocene catalyst, having a propylene content of 20 to 40% by weight and a Mooney viscosity of 10 to 50 ML1 + 4 at 125 ° C. And 5-ethyldiene-2-norborene content is used with 0.1-2.0 weight%. The ethylene-propylene-diene rubber copolymerized with the metallocene catalyst has a more uniform physical property unlike the conventional ethylene-propylene-diene rubber, thereby maintaining the final physical properties of the composite resin composition.

The ethylene-α-olefin copolymer as component (C) is a rubber component copolymerized under a metallocene catalyst, having an octene content of 20 to 50% by weight, a Mooney viscosity of 1 to 35 ML1 + 4 at 121 ° C, and a glass transition temperature. Uses the thing of -50-65 degreeC. If the glass transition temperature exceeds -50 ℃ low temperature impact resistance is lowered, if less than -65 ℃ the rigidity is lowered.

The inorganic reinforcing material as component (D) was used as added for rigid reinforcement, and 10 to 20% by weight of talc having an average particle size of 1 to 5 μm was used.

Component (E) uses aluminum flakes to make the appearance of the molded article brilliant even without a separate coating process. In this case, the aluminum flakes used are those having an average particle size of 10 to 100 µm and an aluminum pigment having a purity of 99.7% or more, in order to improve compatibility with the components (A), (B) and (C). Use an aluminum pigment made from a polypropylene or polyethylene carrier as the master batch.

In the present invention, if the average particle size of the aluminum flakes is less than 10 μm, the surface area of the aluminum pigment is too low to transfer to the surface of the molded article, and if the average particle size exceeds 100 μm, the appearance of the molded article is gorgeous but the weld line And when the impact resistance is lowered and the master batch is not made of polypropylene or polyethylene as a carrier, a phenomenon in which aluminum pigment is collected in a molded article during injection molding occurs.

The resin composition of the present invention, in addition to the above five main components, additives such as primary and secondary antioxidants, ultraviolet absorbers, light stabilizers, pigments, dispersants, nucleating agents, processing lubricants, coupling agents, etc. in order to improve the performance and processing characteristics of the molded article. May be preferably added.

In addition, the resin composition of the present invention may be prepared under a condition of the rotation speed 100 ~ 300 RPM at 180 ~ 220 ℃ temperature using a twin screw extruder after uniformly mixing the above components in a super mixer.

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

Example

Next, a composite resin composition was prepared according to the composition ratio of Table 5 using the raw materials shown in Tables 1 to 4, and the resin composition was prepared by using an injection molding machine (Model: SPF-150, Hyundai Hole) at a cylinder temperature of 220 ° C. And injection molding at a mold temperature of 50 ℃ to prepare a test piece.

Physical properties of the test specimens prepared according to Examples 1 to 9 were measured as follows, and the results are listed in Table 5 below.

Test methods for the physical properties shown in Table 5 are as follows.

<Test method>

(1) Melt Flow Index (MFR): Measured according to ASTM D1238 (230 ° C, 2160g).

(2) Tensile strength: measured according to ASTM D638 (TYPE I, speed: 50mm / min).

(3) Flexural modulus: measured according to ASTM D790 (Speed: 10mm / min).

(4) Izod impact strength was measured according to ASTM D256 (23 ° C, -30 ° C).

(5) Heat deflection temperature was measured according to ASTM D648 (load: 4.16kg).

(6) Rockwe hardness: measured according to ASTM D785.

(7) Flowability (mouldability): In order to measure the flowability of the resin, the flow distance of the resin was measured by injection molding at a temperature of 220 ° C. with a mold having a spiral shape having a thickness of 4 mm, a width of 10 mm, and a length of 1500 mm.

(8) Appearance:

◎ The aluminum pigment is distributed evenly on the surface of the molded product, the aluminum pigment is transferred to the surface well and the surface is gorgeous, and there are few weld lines.

○ The aluminum pigment is distributed evenly on the surface of the molded product, the aluminum pigment is well transferred to the surface, the surface is gorgeous, and the weld line is severely generated.

△ The aluminum pigment is not evenly distributed on the surface of the molded product, or the aluminum pigment is not well transferred to the surface, the weld line is less generated.

× Aluminum pigment is not evenly distributed on the surface of molded part, or aluminum pigment is not well transferred to the surface.

The polyolefin composite resin composition of the present invention improves the rigidity and flowability (molding) of the molded article, reduces the thickness to reduce the weight of the product, and can be applied to the molded article of the mold in color by using aluminum flakes to enhance the appearance of the molded article. It is possible to obtain the effect of reducing the cost of the coating process. Therefore, it is expected to contribute greatly to the weight reduction and cost reduction of automobile exterior materials, especially bumpers.

Claims (6)

40 to 70% by weight of crystalline ethylene-propylene copolymer, 5 to 15% by weight of ethylene-propylene-diene rubber prepared using metallocene catalyst, 10 to 30% by weight of ethylene-α-olefin copolymer, average particle 10 to 20% by weight of an inorganic reinforcing material having a size of 1 to 5 μm, and 0.1 to 2.0% by weight of an aluminum flake having an average particle size of 10 to 100 μm. The crystalline ethylene-propylene copolymer has a melt flow index of 60 to 100 g / 10 minutes (230 ° C., 2.16 kg), and the content of ethylene-propylene rubber is 0.5 to 15% by weight. Composite resin composition. The ethylene-propylene-diene rubber according to claim 1, wherein the ethylene-propylene-diene rubber has a propylene content of 20 to 40% by weight, a Mooney viscosity of 10 to 50 ML 1 + 4 at 125 ° C, Composite resin composition, characterized in that the content is 0.1 to 2.0% by weight. The ethylene-α-olefin copolymer according to claim 1, wherein the ethylene-α-olefin copolymer has an octene content of 20 to 50% by weight, a Mooney viscosity of 1 to 35 ML 1 + 4 at 121 ° C, and a glass transition temperature of -50 to -65 ° C. Composite resin composition, characterized in that. The composite resin composition of claim 1, wherein the aluminum flakes have a purity of at least 99.7%. Automobile exterior parts manufactured in a mold in color using the polyolefin composite resin composition of claim 1.