JPH06100753A - Propylene polymer composition - Google Patents

Abstract

(57) [Summary] [Problem] The propylene polymer composition of the present invention comprises a specific propylene block copolymer, a specific ethylene / propylene copolymer rubber, and a specific ethylene / propylene /
It contains a diene copolymer rubber, a specific ethylene / butene-1 copolymer rubber, and talc in a specific ratio. [Effect] The propylene polymer composition of the present invention can provide a molded article having an excellent balance between rigidity and impact resistance, high surface hardness, and excellent scratch resistance. The molded product formed from this composition is not only excellent in impact resistance, but also excellent in scratch resistance as compared with the molded product of a conventional propylene polymer composition, so that it is used particularly in automobile bumpers and the like. Useful for.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a propylene polymer composition, and more particularly to a propylene which has improved surface hardness and is particularly provided with scratch resistance and can form a molded article which can be used for automobile bumpers and the like. It relates to a polymer composition.

[0002]

TECHNICAL BACKGROUND OF THE INVENTION Propylene polymers are excellent in strength, heat resistance, molding processability and chemical resistance, and also excellent in economic efficiency, and are widely used in home appliances, automobile parts, building materials and the like. It's being used.

Such a propylene polymer is required to have improved low temperature impact strength in applications such as home electric appliance parts and automobile parts. For example, ethylene / propylene copolymer rubber (EPR) is added to the propylene polymer. The impact resistance is imparted by blending.

Although low-temperature impact strength can be sufficiently imparted to such a propylene polymer by adding a large amount of ethylene / propylene copolymer rubber, the rigidity and surface hardness tend to be lowered. In order to prevent such a decrease in the balance of physical properties, various attempts have been made such as changing the composition of the ethylene / propylene copolymer rubber to be blended with the propylene polymer or adding a filler. For example, in JP-A-62-256856, impact resistance consisting of a block copolymer composed of propylene and ethylene, an ethylene / α-olefin random copolymer rubber, and talc or calcium carbonate ( A propylene polymer composition excellent in low-temperature impact strength), rigidity, paintability, etc. is disclosed.

Further, Japanese Patent Laid-Open No. 2-42852 discloses that
Ethylene / propylene block copolymer
A polypropylene-based resin composition comprising a propylene copolymer rubber, an ethylene / propylene / diene terpolymer rubber, and talc and having excellent rigidity and impact resistance is disclosed.

Further, Japanese Patent Laid-Open No. 4-33814 discloses an ethylene / propylene block copolymer, an ethylene / propylene copolymer rubber, an ethylene / propylene / diene terpolymer rubber, and an inorganic filler such as talc. Disclosed is a polypropylene resin composition comprising an agent and having excellent rigidity, impact resistance, paintability, and molding fluidity.

By the way, a molded article formed from such a propylene polymer composition, for example, an automobile bumper has a high impact resistance, but has a low surface hardness, and the bumper surface is scratched during molding or transportation. There is a demand for a propylene polymer composition which may be a defective product and has a high surface hardness, that is, which can provide a molded product excellent in scratch resistance.

The inventors of the present invention have made earnest studies on a propylene polymer composition capable of forming a molded article excellent in impact resistance and scratch resistance without deteriorating the excellent characteristics originally possessed by the propylene polymer, and specified. Propylene-based block copolymer, specific ethylene / propylene copolymer rubber, specific ethylene / propylene / diene copolymer rubber, specific ethylene / butene-1 copolymer rubber and talc are blended in specific proportions. The propylene polymer composition was found to be capable of forming a molded product having excellent low-temperature impact strength and excellent scratch resistance without impairing the excellent properties inherent to the propylene polymer, and to complete the present invention. I arrived.

[0009]

OBJECT OF THE INVENTION As described above, the present invention can provide a molded product which is excellent in impact resistance and scratch resistance without impairing the excellent properties originally possessed by a propylene polymer. It is intended to provide a propylene polymer composition.

[0010]

SUMMARY OF THE INVENTION The propylene polymer composition according to the present invention comprises [A] propylene block copolymer;
% By weight, [B] ethylene / propylene copolymer rubber; 5
15% by weight, [C] ethylene / propylene / diene copolymer rubber; 5 to 15% by weight, [D] ethylene / butene-1
Copolymer rubber; 8-20% by weight, and [E] talc; 5
The propylene-based block copolymer [A] is composed of 2 to 15% by weight, and the structural unit derived from ethylene is 2
The amount of the n-decane-soluble component at room temperature is 5 to 15% by weight, the melt flow rate is 15 to 60 g / 10 min, and the [B] ethylene-propylene copolymer rubber is , A constituent unit derived from ethylene in an amount of 70 to 90 mol%, a melt flow rate of 0.1 to 2.0 g / 10 minutes, and [C] ethylene / propylene / diene copolymer rubber is Containing structural units derived from ethylene in an amount of 70 to 90 mol%, containing structural units derived from a diene in an amount of 8 to 13 mol%,
The melt flow rate is 0.1 to 0.4 g / 10 minutes, and the [D] ethylene / butene-1 copolymer rubber contains a constitutional unit derived from ethylene in an amount of 85 to 95 mol%, Flow rate is 1.0 to 10.0 g / 10
It is characterized by being minutes.

The propylene polymer composition according to the present invention is
It is possible to form a molded product with excellent impact resistance, high surface hardness and scratch resistance without deteriorating the excellent properties of propylene polymer, which is useful for applications such as automobile bumpers. can do.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The propylene polymer composition according to the present invention will be specifically described below. The propylene polymer composition according to the present invention comprises a propylene block copolymer [A] and an ethylene / propylene copolymer rubber [B].
And ethylene / propylene / diene copolymer rubber [C]
And ethylene / butene-1 copolymer rubber [D] and talc [E].

Propylene Block Copolymer [A] The propylene block copolymer [A] used in the present invention has 2 to 15 structural units derived from ethylene.
It is contained at a ratio of mol%, preferably at a ratio of 4 to 10 mol%, and contains a room temperature n-decane-soluble component at a ratio of 5 to 15% by weight, preferably 7 to 10% by weight. .
This room temperature n-decane soluble component has an intrinsic viscosity [η] of 4.5 to
It is 9 dl / g, preferably 5.5 to 7.5 dl / g. The intrinsic viscosity is measured by setting a decalin solution in which the n-decane-soluble component concentration at room temperature is adjusted to 0.08 to 0.1 g / 100 ml at 135 ° C.

The ethylene content in the n-decane-soluble matter at room temperature is 35 to 45 mol%, preferably 38.
Is about 42 mol%. When a propylene-based block copolymer having a content of constituent units derived from ethylene and a room temperature n-decane-soluble component in the above range is used,
A propylene polymer composition which can provide a molded article excellent in impact resistance and rigidity can be obtained.

The content of the structural unit derived from ethylene as described above is a value measured by infrared spectroscopy, and the room temperature n-decane soluble component is obtained by boiling 2 g of the sample and 500 g of n-decane. It is a value obtained by back-calculating from the measured solid phase weight after immersing in the solution for 5 hours to dissolve and then cooling to room temperature, filtering the precipitated solid phase with a G4 type glass filter, and drying.

Further, the propylene block copolymer [A] used in the present invention has a melt flow rate (MFR; 230) measured according to ASTM D-1238.
C., measured with 2.16 kg load) is 15 to 60 g / 10
Min, preferably 30 to 50 g / 10 min. When a propylene block copolymer having a melt flow rate in the above range is used, a propylene polymer composition having excellent moldability can be obtained.

The propylene-based block copolymer [A] as described above can be produced by using an ordinary stereoregular catalyst. For example, in the presence of a catalyst comprising a halogen-containing titanium compound catalyst component or a transition metal compound catalyst component supported on a carrier, and an organoaluminum compound catalyst component, propylene and ethylene are polymerized, for example, in two stages to produce a propylene-based block copolymer. The polymer [A] can be obtained. Specifically, a propylene-based block copolymer can be produced by first polymerizing propylene alone and then copolymerizing propylene and ethylene. Such a catalyst may further contain an electron donor, if necessary, and may be activated by a technique such as co-milling. A specific method for producing a propylene block copolymer is described in, for example, JP-A-52-98,045 and JP-B-57-26,61.
It is described in detail in Japanese Patent Publication No.

The propylene block copolymer [A] used in the present invention is such that the content of the constituent units derived from ethylene, the n-decane-soluble component at room temperature and the melt flow rate are within the above ranges. May be a propylene block copolymer as a whole, or may be a mixture of a propylene block copolymer and another polypropylene.

Further, the propylene block copolymer [A] used in the present invention may contain a structural unit derived from another polymerizable monomer as long as the object of the present invention is not impaired. .

Specific examples of such a polymerizable monomer include butene-1, hexene-1, octene-1, 4,
Examples include α-olefins such as methyl-1-pentene, vinyl esters such as vinyl acetate, unsaturated organic acids such as maleic anhydride, and derivatives thereof.

When the other polymerizable monomer as described above is contained, the propylene block copolymer [A]
May be a ternary copolymer of ethylene, propylene and another polymerizable monomer, and the terpolymer and a propylene block copolymer containing no other polymerizable monomer. It may be a mixture.

The propylene polymer composition according to the present invention is
The propylene block copolymer [A] as described above is added to
The content is 5 to 85% by weight, preferably 57 to 70% by weight.

In the present invention, by using the above-mentioned propylene block copolymer [A] as the propylene polymer, the balance of mechanical strength such as impact resistance and rigidity is excellent, and the heat resistance and processing size are excellent. A propylene polymer composition having excellent moldability capable of forming a molded article having excellent stability can be obtained.

Ethylene / Propylene Copolymer Rubber [B] The ethylene / propylene copolymer rubber [B] used in the present invention comprises 70 to 9 constitutional units derived from ethylene.
It is contained in a proportion of 0 mol%, preferably 75 to 85 mol%. When the ethylene / propylene copolymer rubber in which the content of the constitutional unit derived from ethylene is in the above range is used, it is possible to provide a molded product having excellent low temperature impact strength as well as excellent physical property balance and scratch resistance. A propylene polymer composition can be obtained.

The content of the structural unit derived from ethylene is a value measured by infrared spectroscopy. The ethylene / propylene copolymer rubber [B] used in the present invention has a melt flow rate (MFR; 230) measured according to ASTM D-1238.
C., measured with 2.16 kg load) is 0.1 to 2.0 g / 1
It is 0 minutes, preferably 0.1 to 1.0 g / 10 minutes.

The ethylene / propylene copolymer rubber [B] may be provided in any shape such as pellets, crumbs or veils, as long as it does not interfere with the kneading operation performed when forming the propylene polymer composition. Good.

The propylene polymer composition according to the present invention is
The ethylene / propylene copolymer rubber [B] as described above is contained in an amount of 5 to 15% by weight, preferably 7 to 12% by weight.

Ethylene / propylene / diene copolymer rubber
[C] The ethylene / propylene / diene copolymer rubber [C] used in the present invention has a constitutional unit derived from ethylene of 7
It contains 0 to 90 mol%, preferably 75 to 85 mol%, and 8 to 13 mol%, preferably 9 to 11 mol% of a structural unit derived from a diene. There is.

The content of the structural unit derived from ethylene or diene is a value measured by infrared spectroscopy. Further, the ethylene / propylene / diene copolymer rubber [C] used in the present invention is ASTM
The melt flow rate (MFR; measured at 230 ° C., 2.16 kg load) measured according to D-1238 was 0.
1 to 0.4 g / 10 minutes, preferably 0.1 to 0.3 g /
10 minutes.

The diene constituting the ethylene / propylene / diene copolymer rubber [C] is specifically 5
-Ethylidene-2-norbornene is preferably used.
The propylene polymer composition according to the present invention comprises the above-mentioned ethylene / propylene / diene copolymer rubber [C] in an amount of 5 to 5.
The content is 15% by weight, preferably 5 to 10% by weight.

Ethylene / Butene-1 Copolymer Rubber [D] The ethylene / butene-1 copolymer rubber [D] used in the present invention has 85 to 9 constitutional units derived from ethylene.
The content is 5 mol%, preferably 88 to 92 mol%.

The content of the structural unit derived from ethylene is a value measured by infrared spectroscopy. This ethylene-butene-1 copolymer rubber [D]
Has a melt flow rate (MFR; measured at 230 ° C. and 2.16 kg load) of 1.0 to 10.0 g / 10 minutes, preferably 1.
It is 0 to 8.0 g / 10 minutes.

Further, the ethylene / butene-1 copolymer rubber [D] may contain a constitutional unit derived from the following polymerizable comonomers as long as the object of the present invention is not impaired. .

Specific examples of such a polymerizable comonomer include pentene-1, hexene-1,4-methyl-
Examples include α-olefins such as 1-pentene. The propylene polymer composition according to the present invention contains the above-mentioned ethylene / butene-1 copolymer rubber [D] in an amount of 8 to 20% by weight, preferably 10 to 17% by weight.

Talc [E] Talc [E] used in the present invention usually has an average particle size of
It is desirable that the thickness is 0.2 to 10 μm, preferably 0.2 to 5.0 μm. The average particle size of talc is measured by a liquid phase sedimentation method.

In the present invention, among such talcs, talc having an average aspect ratio (indicating the ratio of the length or the length in either the length or the width) of 3 or more, particularly 4 or more is preferably used. .

The talc [E] used in the present invention may be untreated or may be surface-treated in advance. Specific examples of this surface treatment include chemical or physical treatment using a treatment agent such as a silane coupling agent, a higher fatty acid, a fatty acid metal salt, an unsaturated organic acid, an organic titanate, a resin acid, or polyethylene glycol. Can be mentioned. When talc subjected to the above surface treatment is used, it becomes possible to obtain a propylene polymer composition which can provide a molded product excellent in weld strength, paintability, and moldability.

The propylene polymer composition according to the present invention comprises
The talc [E] as described above is contained in an amount of 5 to 15% by weight, preferably 7 to 12% by weight. By using talc as described above, it becomes possible to obtain a propylene polymer composition which is excellent in balance between rigidity and low temperature impact strength, and which can provide a molded article excellent in paintability, dimensional stability and appearance. .

Preparation of Propylene Polymer Composition The propylene polymer composition according to the present invention comprises the above-mentioned propylene block copolymer [A], ethylene / propylene copolymer rubber [B], ethylene / propylene / diene. The copolymer rubber [C], the ethylene / butene-1 copolymer rubber [D], and the talc [E] are used to prepare a generally widely used composition kneading method.

The above-mentioned kneading can be carried out using a kneading device such as a single-screw extruder, a twin-screw extruder, a twin-screw kneader, a Banbury mixer, or a roll. The propylene polymer composition according to the present invention is usually used by kneading the above components with a kneading device such as an extruder, and then molding the kneaded product into pellets.

The order of adding the respective components to the kneading device in the preparation of the propylene polymer composition is not limited, and they may be added simultaneously or separately. In addition, the above-mentioned rubber components (ethylene / propylene copolymer rubber [B], ethylene / propylene / diene copolymer rubber [C] and ethylene / butene are previously prepared.
-1. Obtaining a masterbatch containing 1 copolymer rubber [D]) and talc [E] in high concentrations, and blending the masterbatch while diluting the masterbatch with the propylene block copolymer [A]. Alternatively, the propylene polymer composition according to the present invention may be obtained by molding.

The above components have good kneadability and can be easily kneaded to form a composition. The propylene polymer composition according to the present invention has rigidity and low-temperature impact strength of a molded product formed from a conventional propylene polymer or a molded product formed from a propylene polymer-ethylene / propylene copolymer rubber composition. It is possible to provide a molded article which is excellent in surface hardness and has excellent scratch resistance, which is not obtained by a conventional propylene polymer or a rubber-blended propylene polymer composition.

The propylene polymer composition according to the present invention comprises
As described above, in the specific propylene block copolymer [A], the specific ethylene / propylene copolymer rubber [B], the specific ethylene / propylene / diene copolymer rubber [C], and the specific ethylene / Butene-1 copolymer rubber [D] and talc [E] are blended in a specific ratio.

The physical properties of the propylene polymer composition according to the present invention and their preferred ranges are as follows. (1) Melt flow rate (ASTM D-1238, 2
30 ° C, 2.16 kg load) is 12 to 25 g / 10 minutes,
It is preferably 15 to 20 g / 10 minutes.

(2) Flexural modulus (ASTM D-790)
Is 10,000 kg / cm ² or more, preferably 11,
It is 000 kg / cm ² or more. (3) Izod impact value at -30 ° C (with notch)
Is 5 kg · cm / cm or more, preferably 6 kg · cm
/ Cm or more.

(4) Rockwell hardness (ASTM D-6
48) is 55 or more, preferably 60 or more. (5) The heat distortion temperature (ASTM D-648) is 100 ° C or higher, preferably 105 ° C or higher.

(6) Low temperature embrittlement temperature (ASTM D-746)
Is −30 ° C. or lower, preferably −35 ° C. or lower.

The propylene polymer composition according to the present invention comprises
Of these rubber components, ethylene / propylene copolymer rubber [B] and ethylene / propylene / diene copolymer rubber [C] usually have a considerably low melt flow rate. As described above, the ethylene / butene-1 copolymer rubber [D] has a relatively large melt flow rate as a rubber. Furthermore, the ethylene / butene-1 copolymer rubber [D] used in the present invention
Has a higher degree of crystallinity than ordinary rubber. In the propylene polymer composition according to the present invention, the surface hardness of the obtained molded article is increased and excellent scratch resistance is imparted by combining such three specific rubbers.

The propylene polymer composition according to the present invention comprises
In addition to the components described above, other components may be contained as long as the object of the present invention is not impaired. Examples of such other components include thermoplastic resins and thermosetting resins. Specifically, polyethylene, polybutene-1
And other α-olefin homopolymers or their α-olefin copolymers, copolymers of α-olefin and vinyl monomers, modified olefin polymers such as maleic anhydride modified polypropylene, nylon, polycarbonate, AB
Examples thereof include S, polystyrene, polyvinyl chloride, polyphenylene oxide, petroleum resin, and phenol resin.

Further, the following rubbers and latexes may be added to the propylene polymer composition. Specific examples of such rubbers and latexes include polybutadiene, polyisobutylene, 1,2-polybutadiene / acrylonitrile / butadiene rubber, polyisobutylene, styrene / butadiene rubber, and styrene / styrene.
Examples include butadiene / styrene block copolymers, styrene / isobutylene / styrene block copolymers; hydrogenated products of styrene / butadiene / styrene block copolymers and hydrogenated products of styrene / isobutylene / styrene block copolymers. .

Further, various additives may be added to the propylene polymer composition. As such additives, specifically, phenol-based, sulfur-based,
Improvement of flowability of phosphorus-based antioxidants, lubricants, antistatic agents, dispersants, copper damage inhibitors, neutralizing agents, foaming agents, plasticizers, antifoam agents, flame retardants, crosslinking agents, peroxides, etc. Agents, ultraviolet absorbers, light resistance stabilizers, weld strength improvers, nucleating agents and the like.

The propylene polymer composition according to the present invention comprises
By blending the additives as described above, it is possible to further improve the physical property balance, durability, paintability, printability, scratch resistance and molding processability of the obtained molded product.

[0053]

INDUSTRIAL APPLICABILITY The propylene polymer composition according to the present invention comprises a specific propylene block copolymer [A], a specific ethylene / propylene copolymer rubber [B] and a specific ethylene / propylene / diene copolymer. Polymerized rubber [C] and a specific ethylene / butene-1 copolymer rubber [D] are blended in a specific ratio, so that the balance between rigidity and impact resistance (low temperature impact strength) is excellent and high. It is possible to provide a molded product having surface hardness and excellent scratch resistance.

The molded article formed from the propylene polymer composition according to the present invention is excellent not only in impact resistance but also in scratch resistance as compared with conventional molded articles of propylene polymer composition. Therefore, it is particularly useful for applications such as automobile bumpers. The automobile bumper formed from the propylene polymer composition according to the present invention is unlikely to be scratched during molding and transportation, and the defect rate due to scratches can be significantly reduced.

Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples,
Each physical property was measured as follows. (1) Melt Flow Rate (MFR) The melt flow rate was measured under the following conditions according to ASTM D-1238.

Conditions: 230 ° C., 2.16 kg (pellet) (2) Flexural modulus (FM) The flexural modulus was determined by conducting a bending test under the following conditions in accordance with ASTM D-790.

Test piece: 12.7 mm (width) x 6.4 mm
(Thickness) x 127 mm (Length) Span: 100 mm Bending speed: 2 mm / min (3) Izod impact value (IZ) Izod impact value is an impact test under the following conditions according to ASTM D-256. And asked.

Temperature: -30 ° C. Test piece: 12.7 mm (width) × 6.4 mm (thickness) × 6
4mm (length) Notch is machined (4) Rockwell hardness (HR) Rockwell hardness is based on ASTM D648,
The test was conducted under the following conditions.

Scale: R Test piece: 120 mm (length) × 130 mm (width) × 3.
Two 0 mm (thickness) test pieces were overlaid (5) Heat distortion temperature (HDT) The heat distortion temperature was determined by conducting a test under the following conditions in accordance with ASTM D-648.

Test piece: 12.7 mm (thickness) × 6.4
mm (width) × 127 mm (length) Test load: 4.6 kg / cm ² (6) Low temperature embrittlement temperature (BT) The low temperature embrittlement temperature was determined by performing a test according to ASTM D-746.

[0061]

Examples 1 to 5 Propylene block copolymer [A], ethylene / propylene copolymer rubber [B] shown in Table 1,
Ethylene / propylene / diene copolymer rubber [C], ethylene / butene-1 copolymer rubber and talc were mixed with a Henschel mixer at room temperature for 2 minutes.

Then, the mixture obtained as described above was subjected to the conditions of a resin temperature of 210 ° C. and a rotor speed of 900 rpm by using a granulator [NCM-60, manufactured by Kobe Steel, Ltd.]. Then, the mixture was kneaded and granulated to obtain pellets of the propylene polymer composition. Then, the pellet-shaped propylene polymer composition was subjected to an ASTM test piece and a 3 mm thick flat plate (1 by an injection molding machine under the conditions of a resin temperature of 200 ° C. and a mold temperature of 40 ° C.
20 mm × 130 mm) was molded and the above physical properties were measured.

The results are shown in Table 1. The physical properties of each component used when preparing the propylene polymer composition shown in Table 1 are as follows. [A] Propylene-based block copolymer PP-A Content of structural unit derived from ethylene; 4.7 mol% MFR; 50 g / 10 minutes Normal temperature n-decane soluble content; 7.0 wt% [B] Ethylene / propylene copolymer rubber EPR-A Content of constituent units derived from ethylene; 80 mol% MFR; 0.4 g / 10 minutes EPR-B Content of constituent units derived from ethylene; 80 mol% MFR; 0.7 g / 10 min EPR-C content of constituent units derived from ethylene; 60 mol% MFR; 7.1 g / 10 min [C] ethylene / propylene / diene copolymer rubber EPT-A derived from ethylene Content of constituent units; content of constituent units derived from 80 mol% diene; content of 9 mol% diene; 5-ethylidene-2-norbornene MFR; 0.2 g / 10 minutes [D Ethylene / Butene-1 Copolymer Rubber EBR-A Content of constituent units derived from ethylene; 89 mol% MFR; 1.5 g / 10 minutes Content of constituent units derived from EBR-B ethylene; 89 mol% MFR; 6.7 g / 10 min EBR-C Content of constituent units derived from ethylene; 89 mol% MFR; 28 g / 10 min [E] Talc average particle size; 2.5 μm Particles containing 5 μm or more in particle size Rate: 3% by weight

[0064]

Comparative Examples 1 to 7 The propylene polymer compositions shown in Table 1 were prepared in the same manner as in Example 1, and the physical properties of these propylene polymer compositions were measured in the same manner as in Example 1.

The results are shown in Table 1.

[0066]

[Table 1]

Front page continuation (72) Inventor Takao Nomura 1 Toyota-cho, Toyota-shi, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Takeshi Nishio 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72) Inventor Hisashi Iwai Yukio 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd.

Claims (4)

[Claims] 1. [A] Propylene-based block copolymer; 5
5 to 85% by weight, [B] ethylene / propylene copolymer rubber; 5 to 15% by weight, [C] ethylene / propylene / diene copolymer rubber; 5 to 15% by weight, [D] ethylene / butene-1 copolymerization Rubber; 8 to 20% by weight, and [E] talc; 5 to 15% by weight, and the [A] propylene-based block copolymer contains 2 to 15 mol% of a structural unit derived from ethylene. In addition, the room temperature n-decane soluble content is 5 to 15% by weight, the melt flow rate is 15 to 60 g / 10 minutes, and the [B] ethylene-propylene copolymer rubber is derived from ethylene. Containing structural units in an amount of 70 to 90 mol%, and having a melt flow rate of 0.1 to 2.0 g /
It is 10 minutes, and the [C] ethylene / propylene / diene copolymer rubber contains the constituent unit derived from ethylene in an amount of 70 to 90 mol%, and the constituent unit derived from diene is 8 to 13
It is contained in an amount of mol% and has a melt flow rate of 0.1 to
0.4 g / 10 minutes, [D] ethylene butene-1
The copolymer rubber contains a constitutional unit derived from ethylene in an amount of 85 to 95 mol% and has a melt flow rate of 1.0 to 10.0 g.
/ 10 minutes, The propylene polymer composition characterized by the above-mentioned. 2. A propylene block copolymer 57-70.
% By weight, ethylene / propylene copolymer rubber 7 to 12% by weight, ethylene / propylene / diene copolymer rubber 5 to 10% by weight, ethylene / butene-1 copolymer rubber 10 to 17% by weight, and talc 7 to The propylene polymer composition according to claim 1, wherein the propylene polymer composition comprises 12% by weight. 3. A melt flow rate of 12 to 25 g / 10
The flexural modulus is 10,000 kg / cm ² or more, and the Izod impact value (notched) at −30 ° C. is 5 minutes.
It is at least kg · cm / cm, has a Rockwell hardness of at least 55, has a heat distortion temperature of at least 100 ° C, and has a low temperature embrittlement temperature of at most -30 ° C. The propylene polymer composition described. 4. The talc has an average particle size of 0.2 to 10 μm.
The propylene polymer composition according to claim 1, wherein