KR101439140B1 - Polypropylene resin composition and outer parts of vehicle using the same - Google Patents

Abstract

The present invention relates to a polypropylene resin composition and an automobile exterior material using the same, and more particularly, to a polypropylene resin composition comprising 40 to 55 parts by weight of a base resin mixed with an ethylene-propylene-butene copolymer and an ethylene-propylene copolymer; 20-25 parts by weight of glass fiber; 10 to 20 parts by weight of an ethylene-butene elastomer; And 1 to 5 parts by weight of a surfactant; A polypropylene resin composition having a low specific gravity and excellent physical properties such as high strength and impact resistance, excellent resistance to breakage, and heat resistance and molding shrinkage which can be remarkably reduced by load, The present invention relates to an exterior material.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition,

More particularly, the present invention relates to a polypropylene resin composition which is used for an automobile exterior material and which has a low specific gravity and is excellent in properties such as high strength and impact resistance and excellent in resistance to breakage, And an automobile exterior material using the polypropylene resin composition.

The spoiler is attached to the trunk of the vehicle and adjusts the lifting force at the time of high speed driving to improve the running stability. Many automobile exterior materials including the spoiler are manufactured by blow molding using acrylonitrile-butadiene-styrene (ABS) ) Technology.

At this time, the blow molding is a step of manufacturing a hollow plastic. The blow molding is a step of manufacturing a parison, inserting the parison into a metal mold, injecting (blowing) air into the parison, As mentioned above, since the parison has to be manufactured, it has disadvantages such as relatively long process time, high process cost and low production amount compared with injection molding.

The ABS resin has excellent moldability, rigidity, impact resistance, chemical resistance and scratch resistance, and is widely used as an automobile exterior material. However, since the basic chemical resistance of the amorphous resin is deteriorated, There is a problem that cracks and cracks are likely to occur.

In contrast, polypropylene resins are widely used as automotive parts together with ABS resins because they have excellent moldability, impact resistance, chemical resistance, low specific gravity and low cost. However, since they have a large shrinkage rate There is a problem that mold production is necessary separately.

It is an object of the present invention to solve the above-mentioned problems, and an object of the present invention is to provide a polypropylene resin composition which can be applied to an injection molding process instead of a blow molding process, has a mechanical property equivalent to that of ABS resin, .

In order to achieve the above object, the polypropylene resin composition according to the present invention comprises 40 to 55 parts by weight of a base resin obtained by mixing an ethylene-propylene-butene copolymer and an ethylene-propylene copolymer; 20-25 parts by weight of glass fiber; 10 to 20 parts by weight of an ethylene-butene elastomer; And 1 to 5 parts by weight of a surfactant; And a control unit.

At this time, the mixing weight ratio of the ethylene-propylene-butene copolymer and the ethylene-propylene copolymer of the base resin is preferably 1: 2 to 9: 8.

In an embodiment of the present invention, it is preferable that the ethylene-propylene copolymer is a high-crystallinity polypropylene having an isotactic index of 97 or more.

In an embodiment of the present invention, the ethylene-propylene copolymer preferably has a melt index of 10 to 60 g / 10 min (230 ° C).

In an embodiment of the present invention, ethylene of the ethylene-propylene-butene copolymer is preferably 2 to 14% by weight based on the weight of the ethylene-propylene-butene copolymer.

In one embodiment of the present invention, the ethylene-propylene-butene copolymer preferably has a melt index of 1 to 10 g / 10 min (230 ° C).

In one embodiment of the present invention, the glass fibers preferably have an average fiber length of 3 to 10 mm and an average diameter of 4 to 20 μm, and the glass fibers may be surface-treated with a silane-based surface treatment agent.

In one embodiment of the present invention, the melt index of the ethylene-butene elastomer is preferably 0.5 to 20 g / 10 min (190 ° C).

In one embodiment of the present invention, the surfactant is a polypropylene-graft-maleic anhydride (PP-g-MA) surfactant, and the maleic anhydride is a polypropylene-graft- And it is preferably 1 to 3% by weight based on the weight of maleic acid (MA).

In order to accomplish another object, the automobile exterior material according to the present invention is characterized by being manufactured by an injection molding process using the polypropylene resin composition.

The effect of the present invention having the above-described structure not only has a molding shrinkage rate equivalent to that of the ABS resin as a thermoplastic resin, but also exhibits excellent heat resistance and other physical properties.

Further, the polypropylene resin composition according to the present invention can be applied to an injection molding process, thereby reducing the cost and improving the production amount.

In addition, the automobile exterior material manufactured by using the polypropylene resin composition according to the present invention is excellent in resistance to breakage because it has a low specific gravity and excellent performance balance such as high rigidity and impact resistance, .

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In one aspect, the present invention relates to a polypropylene resin composition.

More specifically, the polypropylene resin composition according to the present invention comprises 40 to 55 parts by weight of a base resin obtained by mixing an ethylene-propylene-butene copolymer and an ethylene-propylene copolymer; 20-25 parts by weight of glass fiber; 10 to 20 parts by weight of an ethylene-butene elastomer; And 1 to 5 parts by weight of a surfactant; And each component will be discussed in detail below.

On the other hand, the term "ethylene-propylene-butene copolymer" as used in the present invention may refer to low-shrinkage polypropylene, and the "ethylene-propylene copolymer" may refer to high crystalline polypropylene.

(1) Base resin

Firstly, the base resin means the basic raw material of the polypropylene resin composition of the present invention, and is characterized by mixing an ethylene-propylene-butene copolymer and an ethylene-propylene copolymer, and the polypropylene resin composition according to the present invention The amount of the base resin is preferably 40 to 55 parts by weight, and if it is less than 40 parts by weight, stiffness and the like are insufficient. When the amount is more than 55 parts by weight, the impact resistance is decreased and used as a material for automobile exterior materials It is preferable to satisfy the above range.

As the ethylene-propylene copolymer, it is preferable to use a high crystallinity high crystallinity ethylene-propylene copolymer unlike the conventional polypropylene. Specifically, the isotactic index of the stereoregularity of polypropylene which is currently widely used is in the range of 94 to 97, and the ethylene-propylene copolymer according to the present invention is a high crystalline polypropylene having an isotactic index of 97 or more . The resin composition containing a highly crystalline ethylenepropylene copolymer having an isotactic index of 97 or more can be used for general components such as automobile interior and exterior materials, Heat resistance and the like, it is preferable to satisfy the above range.

The mixing weight ratio of the ethylene-propylene-butene copolymer and the ethylene-propylene copolymer in the base resin is preferably 1 to 2: 9 to 8, and if the mixing weight ratio is less than 1: more than 9, When the ratio is more than 2 but less than 8, the deviation of the molding shrinkage ratio is reduced, but the physical properties such as rigidity are lowered, so that it is preferable to satisfy the above range.

It is preferable that the ethylene-propylene copolymer has a melt index of 10 to 60 g / 10 min (230 ° C). If the melt index of the ethylene-propylene copolymer is less than 10 g / 10 min (230 ° C) If it is more than 60 g / 10 min (230 DEG C), the mechanical strength such as impact strength and rigidity is reduced and it is difficult to use as an automotive exterior material.

Herein, the weight of the ethylene is preferably 2 to 14% by weight based on the weight of the ethylene-propylene copolymer. If the weight of the ethylene-propylene copolymer is less than 2% by weight, the impact strength of the polypropylene resin is decreased. But it is preferable that the above range is satisfied as the rigidity is reduced.

The ethylene-propylene-butene copolymer preferably has a melt index of 1 to 10 g / 10 min (230 ° C) because the ethylene-propylene-butene copolymer has a melt index of 1 g / , The moldability is not good. If it is more than 10 g / 10 min (230 DEG C), the mechanical strength such as the impact strength of the polypropylene resin is lowered.

(2) Fiberglass

The glass fiber is used as a reinforcing agent for a polypropylene resin composition and is dispersed in a highly crystalline polypropylene resin in the form of a fiber filament. The content of the glass fiber in the polypropylene resin composition according to the present invention is 20 to 25 parts by weight When the amount is less than 20 parts by weight, there is a problem that rigidity and impact resistance are reduced. When the amount is more than 25 parts by weight, the surface of the product becomes unstable.

The glass fiber preferably has an average fiber length of 3 to 10 mm and an average diameter of 4 to 20 μm. When the average fiber length is less than 3 mm, the rigidity is deteriorated. When the average fiber length is more than 10 mm, When the average diameter of the glass fibers is less than 4 탆, the rigidity is decreased. When the average diameter is more than 20 탆, the glass fiber aspect ratio is increased to increase the rigidity, but it is difficult to disperse in the polypropylene resin It is preferable to satisfy the above range.

The glass fiber is preferably surface-treated with a silane-based surface treatment agent to improve the affinity with the polypropylene resin.

(3) Ethylene-butene elastomer

The content of the ethylene-butene elastomer in the polypropylene resin composition according to the present invention is in the range of 10 to 30 parts by weight, If the amount is less than 10 parts by weight, the impact property and the molding shrinkage rate deviation are hardly affected. If the amount is more than 20 parts by weight, the molding shrinkage rate deviation is improved, desirable.

In this case, the melt index of the ethylene-butene elastomer is preferably 0.5 to 20 g / 10 min (190 ° C). When the melt index is less than 0.5 g / 10 min (190 ° C) ° C), the mechanical strength such as the impact strength of the polypropylene resin is lowered, so that it is preferable to satisfy the above range.

(4) Surfactants

The general polypropylene resin composition contains a surfactant. The content of the surfactant in the polypropylene resin composition according to the present invention is preferably 1 to 5 parts by weight, and when the amount is less than 1 part by weight, the polypropylene resin composition exhibits an effect as a surfactant When the amount is more than 5 parts by weight, impact resistance and the like are lowered. Therefore, it is preferable to satisfy the above range.

As an example of the surfactant, a polypropylene-graft-maleic anhydride (PP-g-MA) surfactant may be used, and the maleic anhydride (MA) If the amount of the surfactant is less than 1% by weight, the effect of the surfactant is not exhibited. If the amount of the surfactant is more than 3% by weight, the rigidity is satisfied but the impact resistance is lowered. It is preferable to satisfy the above range.

In another aspect, the present invention relates to an automobile exterior material using the polypropylene resin composition.

Specifically, the polypropylene resin composition according to the present invention has excellent moldability and shrinkage ratio, which is equivalent to that of ABS resin, as a thermoplastic resin composition, and is excellent in balance of performance such as high rigidity and impact resistance, And the injection molding process can be applied unlike the ABS material to which the conventional blow molding is applied, thereby reducing the cost and improving the productivity.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are merely illustrative of the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

(By weight) as shown in Table 1 below, and the mixture was dry-blended and extruded using a twin-screw extruder set at 220 DEG C (manufacturer: SM, diameter: 45) to prepare pellets for the resin composition . The composition on the pellet was set to 210 DEG C in an injection molding machine (manufacturer: LG-type warrior, mold clamping force: 140 tons), and a test piece for measurement of physical properties and a 300x100x3 mm sheet specimen were injected.

(High crystallinity PP means ethylene-propylene copolymer, low shrinkage PP means ethylene-propylene-butene copolymer, EOR means ethylene-octene-elastomer and EBR means ethylene-butene-elastomer)

division Highly crystalline PP Low shrinkage PP EOR EBR Glass fiber Surfactants additive ABS
room
city
Yes
One 53.8 6 15 23 One 1.2 2 42.8 10 20 25 One 1.2 3 49.8 10 15 23 One 1.2 4 45.8 10 18 24 One 1.2 5 51.8 13 13 20 One 1.2
ratio
School
Yes
One 100 2 59.8 15 23 One 1.2 3 59.8 15 23 One 1.2 4 61.8 13 23 One 1.2 5 49.8 10 15 23 One 1.2 6 50.8 10 15 23 1.2

Examples 1 to 5 in Table 1 are polypropylene resin compositions satisfying the composition ratio according to the present invention, Comparative Example 1 is a conventional ABS resin, Comparative Example 2 is a polypropylene resin composition using only highly crystalline polypropylene, Comparative Example 3 A polypropylene resin composition using only low-shrinkage polypropylene, a polypropylene resin composition except for EBR in Comparative Example 4, a polypropylene resin composition using EOR in place of EBR in Comparative Example 5, and a polypropylene resin composition using polypropylene resin composition except for a surfactant to be.

Test specimens such as specific gravity, tensile strength, flexural modulus, impact strength and shrinkage ratio for applying a polypropylene resin composition having the above composition as a material for automobile exterior materials are shown below, Table 2 shows the results.

(1) Specific gravity

A flexural specimen according to ASTM D790 was cut to prepare a specimen for measuring specific gravity, and the specimen was measured by ASTM D792 method. DENSITY METER (manufacturer: MIRAGE, measuring range: 200 g / 0.0001 g) was used as the measuring equipment.

(2) Tensile strength

ASTM D638 method. The test speed (Crosshead speed) is 50 mm / min. UTM (manufacturer: INSTRON) was used as the measuring equipment.

(3) Flexural strength / flexural modulus

ASTM D790 method. The test speed (Crosshead speed) is 10 mm / min. UTM (manufacturer: INSTRON) was used as the measuring equipment.

(4) Impact strength

ASTM D256 method. At room temperature (23 캜). An impact tester (manufacturer: YASUDA) was used as the measuring equipment.

(5) Mold Shrinkage

ASTM D256 method.

division
importance
Seal
burglar curve
Modulus of elasticity curve
burglar Shock
burglar
HDT
(1.84
MPa) Mold Shrinkage flow
direction Perpendicular
direction MD / TD
Deviation Average unit kgf / cm ² kgf / cm ² kgf / cm ² kgfcm / cm ² ℃ One/
1000 One/
1000 One/
1000 One/
1000 standard 1.06
Below 438
More than Over 19,990 622
More than 10
More than 110
More than - - - 3 to 4 room
city
Yes
One 1.044 461 24020 668 15 147 1.8 5.0 2.8 3.4 2 1.050 450 22150 650 16 141 1.8 4.6 2.6 3.2 3 1.045 492 26870 694 15 143 2.0 5.0 2.5 3.5 4 1.048 500 27830 702 13 140 2.0 5.2 2.6 3.6 5 1.038 512 30210 721 12 138 2.1 5.5 2.7 3.8 ratio
School
Yes

One 1.060 461 22675 652 13 118 3.0 3.6 1.2 3.3 2 1.045 551 32110 728 4 151 3.2 7.2 2.3 5.2 3 1.044 412 20200 588 8 110 1.8 4.4 2.5 3.1 4 1.045 525 31111 719 4 155 4.0 11.2 2.8 7.6 5 1.044 495 26920 692 14 141 3.4 9.8 2.9 6.6 6 1.044 411 19910 572 15 121 2.0 5.2 2.6 3.6

As shown in Table 2, Comparative Example 1 was a conventional ABS material, and both mechanical properties and molding shrinkage ratio were satisfactory as compared with Examples 1 to 5.

In the case of Comparative Example 2, the mechanical stiffness satisfies the standard, but the impact strength is 4 kgfcm / cm ² and the average of the shrinkage rate is 5.2 × 10 ^-3 .

In the case of Comparative Example 3, the formability was satisfactory but the tensile strength was 412 kgf / cm ² , the flexural strength was 588 kgf / cm ^2, and the impact strength was 8 kgfcm / cm ² .

Also, in the case of Comparative Example 4, the mechanical properties meet the specifications, but the impact resistance is 4 kgfcm / cm ² and the molding shrinkage rate is 7.6 × 10 ^-3 .

Also, in the case of Comparative Example 5, the molding shrinkage rate did not satisfy the specification of 6.6 × 10 ^-3 .

In the case of Comparative Example 6, the tensile strength was 411 kgf / cm ² And flexural strength of 572 kgf / cm ² .

On the other hand, it was confirmed that the polypropylene resin compositions of Examples 1 to 5 satisfying the composition ratio according to the present invention satisfied all the criteria required for a vehicle exterior material in terms of specific gravity, rigidity, impact resistance and mold shrinkage.

Although the present invention has been described in connection with the specific embodiments of the present invention, it is to be understood that the present invention is not limited thereto. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. Various modifications and variations are possible.

Claims (11)

40 to 55 parts by weight of a base resin obtained by mixing an ethylene-propylene-butene copolymer and an ethylene-propylene copolymer;
20-25 parts by weight of glass fiber;
10 to 20 parts by weight of an ethylene-butene elastomer; And
1 to 5 parts by weight of a surfactant; Lt; / RTI >
Wherein a mixing weight ratio of the ethylene-propylene-butene copolymer and the ethylene-propylene copolymer in the base resin is 1: 2 to 9: 8.
delete The method according to claim 1,
Wherein the ethylene-propylene copolymer is a highly crystalline polypropylene having an isotactic index of 97 or more.
The method according to claim 1,
Wherein the ethylene-propylene copolymer has a melt index of 10 to 60 g / 10 min (230 DEG C).
The method according to claim 1,
Wherein the ethylene of the ethylene-propylene-butene copolymer is 2 to 14% by weight based on the weight of the ethylene-propylene-butene copolymer.
The method according to claim 1,
Wherein the ethylene-propylene-butene copolymer has a melt index of 1 to 10 g / 10 min (230 ° C).
The method according to claim 1,
Wherein the glass fiber has an average fiber length of 3 to 10 mm and an average diameter of 4 to 20 占 퐉.
The method according to claim 1,
Wherein the glass fiber is surface-treated with a silane-based surface treating agent.
The method according to claim 1,
Wherein the ethylene-butene elastomer has a melt index of 0.5 to 20 g / 10 min (190 DEG C).
The method according to claim 1,
Wherein the surfactant is a polypropylene-graft-maleic anhydride (PP-g-MA) surfactant and the maleic anhydride (MA) is a surfactant selected from the group consisting of polypropylene-graft- maleic anhydride To 3% by weight of the polypropylene resin composition.
An automobile exterior member manufactured by an injection molding process using the polypropylene resin composition of any one of claims 1 to 10.