JPH1060197A - Polypropylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition, which has not only excellent moldability, but also high rigidity and excellent thermal stability, and further, exhibits excellent impact resistance at a low temperature. SOLUTION: This composition comprises 50 to 90wt.% of (A) component which is a polypropylene component; 1 to 25wt.% of (B) component which is an ethylene saturated triblock-copolymer having, in a molecule thereof, polyethylene chains at both terminals and an ethylene-α-olefin copolymer chain at the central portion; 1 to 25wt.% of (C) component which is an ethylene unsaturated triblock-copolymer having, in a molecule thereof, polyethylene chains at both terminals and a polymer chain containing carbon-carbon double bonds at the central portion; 1 to 20wt.% of (D) component which is a polyorganosiloxane having silicon atoms bonded with a hydrogen atom and silicon atoms bonded with a group containing a carbon-carbon double bond; and 7 to 25wt.% of a talc having an average particle size of 2.5μm or less, the sum of the amount of the rubber ingredient contained in component (A) and the amounts of components (B) to (D) being 5 to 30wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polypropylene resin composition having high rigidity and heat resistance, as well as excellent low-temperature impact resistance, and suitable as a material for automobile bumpers, automobile interior and exterior parts, and the like.

[0002]

2. Description of the Related Art Since automobiles are used in cold regions, low-temperature impact-resistant materials are required for automobiles. Further, in the in-line coating process during the production of the vehicle body, the coating may be locally exposed to a high temperature of 60 to 120 ° C., and thus high heat resistance is also required. Also, automobiles are provided with bumpers for reducing impact, and iron bumpers have been used for the bumpers. However, iron bumpers are heavy and have poor impact relaxation. Therefore, in recent years, polyurethane-based or polypropylene-based bumpers have been used in order to reduce the weight and improve the impact relaxation property. Similarly, resin parts are often used for interior and exterior parts.
Particularly recently, inexpensive and lightweight polypropylene-based resin compositions that can be injection-molded have been widely used. Conventionally, polypropylene resin compositions for automotive bumpers and interior / exterior components include blends of polypropylene and ethylene-propylene copolymer (such as propylene homopolymer, propylene block copolymer, and propylene random copolymer). Kosho 60-
No. 3420) and a blend polymer of polypropylene, an ethylene-propylene copolymer and an ethylene-butene copolymer (JP-A-4-372637).

[0003]

However, a material composed of a blend polymer of polypropylene and an ethylene-propylene copolymer or a resin composition composed of a polypropylene, an ethylene-propylene copolymer and an ethylene-butene copolymer has a high rigidity. Although the impact resistance at room temperature and room temperature is good, it has a disadvantage that the impact resistance at a low temperature of about −30 ° C. required as an industrial material is insufficient.

The present invention provides a polypropylene-based resin composition having good moldability, high rigidity and heat resistance, and excellent low-temperature impact resistance, which is suitable as a material for automobile bumpers and automobile interior / exterior parts. Is what you do.

[0005]

The object of the present invention is to solve the above problems by (A) component: 50 to 90% by weight of polypropylene, (B) component: polyethylene at both ends of the molecule, and a central portion of ethylene and α-olefin. 1 to 25% by weight of an ethylene-based saturated triblock copolymer, which is a copolymer, and component (C): a polymer in which both ends of a molecule are polyethylene and a central portion contains a carbon-carbon double bond. 1 to 25% by weight of a certain ethylenically unsaturated triblock copolymer and a component (D) having a silicon atom bonded to a hydrogen atom and a silicon atom bonded to a group having a carbon-carbon double bond. (E) component: 7 to 25 talc having an average particle size of 2.5 μm or less.
% By weight, and the total amount of the rubber component and the components (B), (C) and (D) in the component (A) is 5 to 30% by weight. Solved by things.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. (A) Component: Polypropylene The polypropylene used in the present invention may be any of a propylene homopolymer, a block copolymer, and a random copolymer, and a combination of two or more of these may be used. it can. As the comonomer of the block copolymer and the random copolymer, α-olefins other than propylene such as ethylene, butene-1, pentene-1, and hexene-1 are used, and among them, ethylene is preferable. The propylene content in these copolymers is preferably at least 60% by weight, more preferably at least 80% by weight. In the case of a block copolymer using ethylene as the α-olefin, the ethylene-
The propylene block is dispersed in the homopolypropylene block, exhibits rubber elasticity, and functions as a rubber component. The content of the rubber component is 10 to 10 of the block copolymer.
25% by weight is preferred.

[0007] The melt flow rate of polypropylene (JI
S K7210, Table 1, condition 14, test temperature: 230 ° C, test load: 2.16 kgf. Hereinafter, it is abbreviated as MFR. ) Is 5-1
00 g / 10 min is preferred, and 10 to 50 g / 10 min is particularly preferred. When the MFR is less than 5 g / 10 min or more than 100 g / 10 min, the low-temperature impact resistance of the obtained resin composition decreases.

Component (B): Ethylene-based saturated triblock copolymer The ethylene-based saturated triblock copolymer used in the present invention has a random or alternating copolymer block of ethylene and α-olefin (C) at the center of the molecule. Hereinafter, it may be referred to as an ethylene-α-olefin block), and a polymer alone or a mixture thereof having a polyethylene block on both sides thereof. The α-olefin referred to herein means propylene, butene-1, pentene-1,
Hexene-1, heptene-1, octene-1, 4-methyl-1-pentene and the like. Generally, it can be produced by hydrogenating a butadiene polymer or a butadiene-isoprene-butadiene polymer. The term "polyethylene block" used herein includes not only a polyethylene block but also a polybutadiene block whose main bonding mode is 1,4-bond hydrogenated by 90% by weight or more. In the binding portion between the polyethylene block located at both ends and the ethylene-α-olefin block located at the center in the ethylene-based saturated triblock copolymer molecule, each component may not be clearly separated, and each component may not be separated. A so-called tapered type in which the density gradually changes from one block component to the other block component may be used.

The content of the polyethylene block in the ethylene-based saturated triblock copolymer is 10 to 70% by weight.
Is particularly preferable, and 15 to 40% by weight is particularly preferable.
When the content of the polyethylene block is less than 10% by weight, the obtained resin composition has reduced rigidity and heat resistance,
When it exceeds 70% by weight, the low-temperature impact resistance of the obtained resin composition decreases. Further, the content of α-olefin in the random or alternating copolymer block of ethylene and α-olefin located in the central portion of the ethylene-based saturated triblock copolymer is preferably from 5 to 60% by weight. When the content of the α-olefin is less than 5% by weight, the low-temperature impact resistance of the obtained resin composition is lowered, and when it exceeds 60% by weight, the low-temperature impact resistance and heat resistance of the obtained resin composition are low. descend.

[0010] The MFR of the ethylene-based saturated triblock copolymer is preferably 0.5 to 100 g / 10 min.
0 g / 10 min is particularly preferred. If the MFR is less than 0.5 g / 10 minutes, the fluidity of the obtained resin composition is poor, and the moldability is reduced. When the MFR exceeds 100 g / 10 minutes, the low-temperature impact resistance of the obtained resin composition decreases.

Component (C): ethylenically unsaturated triblock copolymer The ethylenically unsaturated triblock copolymer used in the present invention is a polymer containing a carbon-carbon double bond in the center of the molecule. The block is located and the polyethylene block is located on both sides. In the central portion, a homo- or copolymer of a conjugated double bond compound such as butadiene, isoprene, and 1,3-pentadiene can be used. In general, it can be produced by partially hydrogenating a butadiene polymer and / or a butadiene-isoprene-butadiene polymer. The polyethylene block referred to here includes not only a polyethylene block but also a polybutadiene block whose main bonding mode is 1,4 bonds which is hydrogenated by 90% by weight or more. In the ethylenically unsaturated triblock copolymer molecule, each component of the polyethylene block located at both ends and the polymer containing a carbon-carbon double bond located at the center, even if there is a portion where the components are mixed with each other A so-called tapered type in which the concentration of each component gradually changes from the component of one block to the component of the other block may be used.

The number of ethyl branches in the polyethylene block in the ethylenically unsaturated triblock copolymer is preferably 1 or less for every 10 carbon atoms in the main chain.
The content of the polyethylene block in the ethylenically unsaturated triblock copolymer is preferably from 10 to 80% by weight. When the content of the polyethylene block is less than 10% by weight or the number of ethyl branches exceeds one for every 10 carbon atoms in the main chain, the ethylene-based saturated triblock copolymer of component (B) and (C) The low-temperature impact resistance of the obtained resin composition is deteriorated due to deterioration of the compatibility with the ethylenically unsaturated triblock copolymer as the component, and also when the content of the polyethylene block exceeds 80% by weight. The low-temperature impact resistance of the obtained resin composition decreases. The poly (butadiene and / or isoprene) block located at the center of the ethylenically unsaturated triblock copolymer may be partially hydrogenated, but the hydrogenation amount is 5%.
It is desirably 0% by weight or less.

The MFR of the ethylenically unsaturated triblock copolymer is preferably from 0.5 to 100 g / 10 minutes, more preferably from 1 to 50 g / 10 minutes. If the MFR is less than 0.5 g / 10 minutes, the flowability of the obtained resin composition is poor, and the moldability is deteriorated. When the MFR exceeds 100 g / 10 minutes, the low-temperature impact resistance of the obtained resin composition decreases.

Component (D): Polyorganosiloxane The polyorganosiloxane used in the present invention has a silicon atom bonded to a hydrogen atom and a silicon atom bonded to a group having a carbon-carbon double bond. The number of the repeating units (degree of polymerization) is in the range of 10 to 50,000. Specifically, a polyorganosiloxane having one or more silicon atoms bonded to a hydrogen atom and one or more silicon atoms bonded to a group having a carbon-carbon double bond in one molecule. (Hereinafter, also referred to as polysiloxane A) or a polyorganosiloxane having two or more silicon atoms bonded to a hydrogen atom in one molecule and having a carbon-carbon double bond. It may be a mixture of polyorganosiloxanes having two or more silicon atoms bonded to a group (hereinafter sometimes referred to as polysiloxane B) or a mixture of polysiloxane A and polysiloxane B.

The ratio of the silicon atom bonded to the group having a carbon-carbon double bond to the silicon atom bonded to a hydrogen atom in the polyorganosiloxane is preferably 0.1 to 1.3. When the ratio is less than 0.1, foaming is likely to occur during the production of the polypropylene resin composition or during the molding of the obtained resin composition. The heat resistance of the resin composition decreases.

The polyorganosiloxane may be linear or branched, and may be used as a mixture thereof. Examples of the group having a carbon-carbon double bond in this case include a vinyl group, an allyl group,
A 1-butenyl group and the like can be mentioned, but a vinyl group is most preferable because of easiness of synthesis. Further, in the molecule of the polyorganosiloxane, as the organic group bonded to the silicon atom except for the hydrogen atom bonded to the silicon atom and the group having a carbon-carbon double bond, for example, a methyl group, an ethyl group, a propyl group, Butyl group, pentyl group, hexyl group, heptyl group, alkyl group such as octyl group,
An aryl group such as a phenyl group, a β-phenylethyl group,
Examples include an unsubstituted hydrocarbon group such as an aralkyl group such as a β-phenylpropyl group, and a substituted hydrocarbon group such as a chloromethyl group, a cyanoethyl group, and a 3,3,3-trifluoropropyl group. Among these, a methyl group is preferred from the viewpoint of ease of synthesis and good physical properties of the obtained polypropylene resin composition. Furthermore, in order to obtain good low-temperature impact resistance, it is preferable that the phenyl group in these organic groups is 10% by weight or less.

The polyorganosiloxane preferably has a viscosity at 25 ° C. of 1 to 1000 P, and 3 to 5 P.
0P is more preferred. When the viscosity is less than 1P, it is difficult to uniformly mix the composition, and the low-temperature impact resistance of the obtained resin composition is reduced. Also, if the viscosity is 100
Even when it exceeds 0P, the low-temperature impact resistance is reduced.

Further, the polyorganosiloxane used in the present invention includes a group having a hydrogen atom bonded to a silicon atom and a carbon-carbon double bond bonded to a silicon atom in the polyorganosiloxane of the component (D); )) An addition reaction catalyst used for accelerating the reaction with the carbon-carbon double bond in the ethylenically unsaturated triblock copolymer of the component may be added. For example, chloroplatinic acid, alcohol-modified solution of chloroplatinic acid, platinum compounds such as coordination compounds of chloroplatinic acid and olefins or vinylsiloxane, tetrakis (triphenylphosphine) palladium, chlorotris (triphenylphosphine) rhodium, etc. And a platinum-based compound is preferred.

In addition to the above-mentioned addition reaction catalyst, conventionally known reaction inhibitors such as polymethylvinylsiloxane cyclic compounds, acetylene compounds, organic phosphorus compounds, so-called silicone rubber curing accelerators, silicone rubber curing inhibitors, etc. Can be added to control the reaction between the component (C) and the component (D).

Examples of such polyorganosiloxanes include those commonly referred to as modified silicone oils, addition-reaction silicone adhesives, addition-reaction silicone gels, and addition-reaction silicone RTV rubbers.

Component (E): Talc The talc used in the present invention preferably has an average particle size of 2.5 μm or less, more preferably 0.5 to 2 μm. In general, in a polypropylene resin composition, it is known that the blending of an inorganic filler reduces impact resistance, but in combination with the resin composition of the present invention, without lowering low-temperature impact resistance, rigidity is reduced. As an inorganic filler that significantly improves heat resistance, the average particle size is 2.
It has been found that talc of 5 μm or less is particularly effective and enhances the surface smoothness, dimensional stability and surface hardness of the molded product. When the average particle size of talc is larger than 2.5 μm, low-temperature impact resistance, rigidity and heat resistance are reduced.

(Composition Ratio) The mixing ratio of the component (A) in the polypropylene resin composition of the present invention is 50 to 90% by weight. If the compounding ratio of the component (A) is less than 50% by weight, the rigidity and heat resistance are reduced, and if it is more than 90% by weight, the low-temperature impact resistance becomes insufficient. The blending ratio of the component (B) in the polypropylene resin composition of the present invention is 1 to 25% by weight, and preferably 2 to 10% by weight. If the blending ratio of the component (B) in the resin composition is less than 1% by weight, the low-temperature impact resistance of the obtained polypropylene-based resin composition decreases, and if it exceeds 25% by weight, rigidity and heat resistance decrease. The blending ratio of the component (C) in the polypropylene resin composition of the present invention is 1 to 25% by weight, preferably 2 to 10% by weight. When the blending ratio of the component (C) in the resin composition is less than 1% by weight, the low-temperature impact resistance of the obtained polypropylene-based resin composition is lowered,
If the content is more than 10% by weight, rigidity and heat resistance decrease.

The compounding ratio of the component (D) in the polypropylene resin composition of the present invention is 1 to 20% by weight, preferably 2 to 10% by weight. If the blending ratio of the component (D) in the resin composition is less than 1% by weight, the low-temperature impact resistance of the obtained polypropylene-based resin composition decreases, and if it exceeds 20% by weight, rigidity, heat resistance and low-temperature impact resistance are obtained. Is reduced. The compounding ratio of the component (E) in the polypropylene resin composition of the present invention is 7 to 25% by weight, preferably 10 to 25% by weight. If the blending ratio of the component (E) in the resin composition is less than 7% by weight, the rigidity and heat resistance of the obtained polypropylene-based resin composition will decrease, and if it exceeds 25% by weight, the low-temperature impact resistance will decrease. .

Further, in the present invention, the total amount of the rubber component and the components (B), (C) and (D) in the component (A) (hereinafter also referred to as "all rubber components"). Is 5 to 30% by weight of the whole propylene resin composition. The content of all rubber components in the total propylene resin composition is 5
If the amount is less than 30% by weight, the low-temperature impact resistance of the obtained resin composition is reduced. If the amount is more than 30% by weight, the rigidity and the heat resistance are reduced.

In the polypropylene resin composition of the present invention, heat, oxygen and light stabilizers, crystal nucleating agents, flame retardants, fillers and coloring agents, which are widely used in the field of synthetic resins and synthetic rubbers, are used. Additives such as lubricants, plasticizers and antistatic agents, or high polymers such as polyethylene polymers, poly-4-methyl-1-pentene polymers, styrene graft polymers of polystyrene, polybutadiene or polyisoprene, polyesters, polyamides and polycarbonates. A molecular polymer or the like may be added to the extent that the characteristics of the polypropylene resin composition of the present invention are not substantially impaired, depending on the purpose of use. Further, the resin composition of the present invention is obtained by adding the above-mentioned addition reaction catalyst, reaction inhibitor, silicone rubber curing accelerator, silicone rubber curing inhibitor, etc. separately from the polyorganosiloxane as the component (D); The reaction between the component and the component (D) can also be controlled.

The polypropylene resin composition of the present invention comprises the components (A), (B), (C), (D),
It is produced by uniformly blending the component (E) and additives. The method of mixing (mixing method) is not particularly limited, and a method generally used in the field of synthetic resins may be applied. As a mixing method, a method of dry blending using a mixer such as a Henschel mixer, a tumbler and a ribbon mixer, which is generally performed, and melting while using a mixer such as an open roll, an extruder, a kneader and a Banbury are used. The method of mixing is mentioned. Of these methods,
In order to obtain a more uniform resin composition, it is preferable to dry blend in advance and then melt-mix the mixture.
Regardless of the case of using a dry blend or the case of using two or more kinds of melt-mixing methods, it is particularly preferable to produce pellets using a pelletizer in advance and use them in producing a molded product. Even when melt mixing,
Even when molding, it must be carried out at a temperature at which the resin used melts. However, if it is carried out at a high temperature, the resin is thermally decomposed or deteriorated.
It is carried out at 50C, preferably at 170-250C.

The polypropylene resin composition of the present invention comprises:
A molding method such as an injection molding method, an extrusion molding method, a compression molding method, and a hollow molding method generally used in the field of synthetic resins may be applied to form a desired shape. Further, after forming into a sheet using an extruder, the sheet may be formed into a desired shape by a secondary processing method such as a vacuum forming method or a pressure forming method.

The use of the polypropylene resin composition for automobile bumpers and interior / exterior parts of automobiles requires that the material is inexpensive, lightweight, has heat resistance that meets ordinary requirements, and has appropriate hardness and rigidity. , And is also a very suitable material because it also has impact relaxation properties. However, the impact resistance at low temperatures is poor, and many methods for improving this property have been proposed. The means adopted to improve this property is a method of blending a rubber component or blending a resin such as polyethylene having excellent low-temperature impact resistance. But,
Since this means reduces the rigidity and heat resistance of the polypropylene resin, an inorganic filler is also added thereto. The compounding of this filler is effective in improving rigidity and heat resistance, but lowers impact strength. The present invention solves this problem by (A) component: 50 to 90% by weight of polypropylene, (B) component: both ends of the molecule are polyethylene,
1 to 25% by weight of an ethylene-based saturated triblock copolymer whose central portion is a copolymer of ethylene and an α-olefin,
Component (C): 1 to 25% by weight of an ethylenically unsaturated triblock copolymer in which both ends of the molecule are polyethylene and a central part is a polymer containing a carbon-carbon double bond;
(D) component: a silicon atom bonded to a hydrogen atom, and
1 to 20% by weight of a polyorganosiloxane having a silicon atom bonded to a group having a carbon-carbon double bond,
Component (E): talc 7 having an average particle size of 2.5 μm or less
-25% by weight, and the total amount of the rubber component and the components (B), (C) and (D) in the component (A) is 5 to
The problem was solved by producing a polypropylene-based resin composition having 30% by weight. As a result, the polypropylene resin composition obtained by the present invention has a flexural modulus (ASTM D-790) of 20,000 kgf / cm ² or more and a heat distortion temperature (ASTM D-648; measured under a load of 66 psi). Above 135 ° C, Izod impact strength (ASTM D-256; -3
(Measured at 0 ° C.) of 4 kgf · cm / cm or more.

[0029]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. Component (A), component (B), component (C), component (D) used in Examples and Comparative Examples,
The type and physical properties of the component (E) are as follows. (A) Component (Polypropylene) PP-1: A homo-type polypropylene having an MFR of 30 g / 10 minutes. PP-2: MFR 40 g / 10 min, rubber component content 18
Weight% block type polypropylene.

Component (B) (ethylene-based saturated triblock copolymer) and component (C) (ethylenically unsaturated triblock copolymer) Each of the two types of ethylene-based saturated triblock copolymer shown in Table 1 ( TBC1) and an ethylenically unsaturated triblock copolymer (TBC2).

[0031]

[Table 1]

Component (D) (polyorganosiloxane) POS-1: Silicone gel KE1055 having a viscosity of 7 P at 25 ° C. in an unreacted state (Shin-Etsu Chemical Co., Ltd.) POS-2: Silicone having a viscosity of 35 P Adhesive KE1842 (manufactured by the company) However, in each case, a group having a carbon-carbon double bond bonded to a silicon atom and a hydrogen atom bonded to a silicon atom react by heating to form a crosslink / gel.

Component (E): Talc Talc 1: an average particle diameter of 1.3 μm. Talc 2: having an average particle size of 5.6 μm. The central particle size of the talc was determined by a light scattering sedimentation method, and the average particle size was determined.

For comparison, an ethylene-propylene copolymer (intrinsic viscosity [η] = 2.5 dl / g, propylene content) was used instead of the components (B), (C) and (D). 25 wt%, hereinafter referred to as EPR), ethylene-butene copolymer (intrinsic viscosity [η] = 3.5 dl / g,
A butene content of 15% by weight, hereinafter referred to as EBR) was used.

These components were blended at the ratios shown in Table 2 and dry-blended for 5 minutes using a Henschel mixer. The resulting mixture was kneaded using a co-rotating twin-screw extruder (diameter 30 mm) set at 210 ° C. to produce pellets. The pellets were subjected to injection molding using an injection molding machine set at 230 ° C. to produce test pieces. Each test piece was evaluated for low-temperature impact resistance, rigidity, and heat resistance.
In addition, each physical property was measured by the following method. As the low-temperature impact resistance evaluation, Izod impact strength (unit kgfcm / cm)
Notched and measured at a temperature of −30 ° C. according to STM D-256. As the rigidity evaluation, the bending elastic modulus (unit: kgf
/ Cm ² ) was measured at a temperature of 23 ° C. according to ASTM D-790. Heat distortion temperature (HDT)
Measured under a load of 66 psi according to ASTM D-648.

[0036]

[Table 2] * 1): The breakdown of 35 wt% is that polypropylene is 35 × 0.82 = 2
8.7wt%, rubber component is 35 × 0.18 = 6.3wt% * 2): 6.3 + 3 + 3 + 9 = 21.3wt%

Example 1 As shown in Table 2, Example 1
Is 65% by weight of homotype PP-1 as the component (A), 5% by weight of TBC1-1 as the component (B), and (C)
5% by weight of TBC2-1 as a component, 10% by weight of POS-1 as a component (D), and 15% by weight of talc 1 having an average particle diameter of 1.3 μm as a component (E). Things. The resin composition obtained in Example 1 has a high rigidity (a flexural modulus of 20,000 kgf / c).
m ² or more), in addition to high heat resistance (HDT is 135 ° C. or higher), having excellent low-temperature impact resistance (Izod impact strength 4 kgf · cm / cm or more at -30 ° C.).

[Examples 2 to 7]
Examples 2 to 4 in which the types and the proportions of the components (A), (B), (C), (D) and (E) were changed.
As for No. 7, the obtained resin composition was not only high in rigidity and heat resistance, but also excellent in low-temperature impact resistance.

[Comparative Examples 1 to 4] Comparative Example 1 is a combination of polypropylene and an ethylene-propylene copolymer known as the prior art.
The only difference is that EPR was used in an amount of 20% by weight instead of the components (C) and (D). Comparative Example 2 is a combination of a polypropylene, an ethylene-propylene copolymer, and an ethylene-butene copolymer known in the prior art. In Example 1, the components (B), (C), and (D)
The only difference is that 10% by weight of EPR and 10% by weight of EBR were used instead of the components. Comparative Example 1 and Comparative Example 2 are Examples 1
Low-temperature impact resistance is lower than that of Comparative Example 3 is different from Example 1 only in that the average particle diameter of the talc of the component (E) is 5.6 μm, which is out of the range of the present invention. Comparative Example 3 has lower low-temperature impact resistance, rigidity, and heat resistance than Example 1. In Comparative Example 4, the content of all rubber components was 45% by weight, which was outside the range of the present invention, and the obtained resin composition had low rigidity and heat resistance.

[0040]

The polypropylene resin composition of the present invention has the following effects. (1) Excellent low-temperature impact resistance. (2) High rigidity. (3) High heat resistance. Since the polypropylene resin composition of the present invention has the above-mentioned physical properties, it is exposed to a high temperature or used as a material for various parts of automobiles used even in cold regions, particularly as a material for automobile bumpers and interior and exterior parts of automobiles. It is suitable.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08L 83:07)

Claims (1)

[Claims] (1) Component (A): 50 to 9 polypropylene
Component (B): 1 to 25% by weight of an ethylene-based saturated triblock copolymer in which both ends of the molecule are polyethylene and the center is a copolymer of ethylene and an α-olefin; Component (C): 1 to 25% by weight of an ethylenically unsaturated triblock copolymer in which both ends of the molecule are polyethylene and the central portion is a polymer containing a carbon-carbon double bond; : A silicon atom bonded to a hydrogen atom, and
1 to 20% by weight of a polyorganosiloxane having a silicon atom bonded to a group having a carbon-carbon double bond; and (E) component: 7 to 25 of talc having an average particle size of 2.5 μm or less. % Of the rubber component in the component (A), the component (B), the component (C),
(D) A total amount of the component and the polypropylene resin composition is 5 to 30% by weight.