JPH10139948A - Polypropylene resin composition for automotive exterior parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene resin composition which has high flowability and can give a molding having high surface hardness and excellent heat distortion resistance and low-temperature impact-resistant strength and good appearance, by mixing a specified crystalline ethylene/propylene block copolymer with a specified ethylene/α-olefin copolymer and talc. SOLUTION: This composition comprises 35-74wt.% crystalline ethylene/ propylene block copolymer having an ethylene content of 0.5-15wt.%, the isotactic pentad fraction (mmmm) of the polypropylene component of 96% or above and a melt flow rate (at 230 deg.C under a load of 2160g) of 40-80g/10min, 21-40wt.% ethylene/α-olefin copolymer prepared by polymerization in the presence of a single-site catalyst and having an Mw/Mn of 2.5 or below, a melt flow ratio (MI10 /MI2.16 ) of 6-15 and an α-olefin content of 80mol% or below and 5-25wt.% talc having a means particle diameter of 3-7μm as measured by the laser diffractometry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition for automobile exteriors which has excellent surface hardness, heat deformation resistance, low-temperature impact resistance and moldability and can provide a molded article having a very good appearance. . The composition of the present invention can be suitably used for exterior parts for automobiles, particularly for large and thin bumpers requiring high fluidity.

[0002]

2. Description of the Related Art As materials for automobile bumpers, polypropylene resin-based materials are often used from the viewpoint of weight reduction and design freedom. Conventional bumper resin compositions are disclosed in JP-A-57-55952 and JP-A-58-1118.
Nos. 46, 59-98157, 58-17
139, 57-1777038, 57-
As disclosed in JP-A-207630, JP-A-57-195134, JP-A-57-159841 and JP-A-55-21494, a polypropylene resin is filled with an inorganic filler such as an ethylene-propylene-based copolymer or talc. Has been tried, but such a,
The resin composition has low surface hardness and poor fluidity.
Further, Japanese Patent Application Laid-Open No. 60-13838,
In JP-A-59251, JP-A-05-98093 and JP-A-05-98098, the surface hardness and moldability are improved by improving the polypropylene resin and limiting the type of ethylene / α-olefin copolymer. ing. These compositions do improve surface hardness and moldability, but are still unsatisfactory.

[0003]

[Problems to be Solved by the Invention] In recent years, polypropylene resins for automobile exterior parts, mainly bumpers, include:
Good appearance quality is required in addition to high rigidity, high impact, and easy moldability. In particular, there is a strong demand for high fluidity and improvement in scratch resistance of the surface of the molded product, that is, high surface hardness, which can cope with an increase in the size and thickness of the bumper molded product and diversification of designs.
In order to achieve the above object, the present inventor has proposed a method for optimizing the type of an ethylene / α-olefin copolymer which is an impact resistance improving component added in a large amount to a crystalline ethylene / propylene block copolymer. Diligently studied. As a result, by polymerizing the ethylene / α-olefin copolymer having specific properties with a crystalline ethylene / propylene block copolymer or talc, it is polymerized by a specific catalyst, and has a high fluidity and a high surface hardness, The present inventors have also found that a polypropylene resin composition which is excellent in heat deformation resistance and low-temperature impact resistance and can provide a molded article having no flow mark in appearance can be obtained, and completed the present invention.

[0004]

The polypropylene resin composition for automotive exterior of the present invention comprises the following components: Component (A) Ethylene content of 0.5 to 15% by weight, isotactic pentad fraction of polypropylene component (Mmmm) is 96% or more and the melt flow rate (230 ° C., 2160
g) is 40 to 80 g / 10 minutes, 35 to 74% by weight of a crystalline ethylene / propylene block copolymer, and the component (B) has a molecular weight distribution (Mw / Mn) of 2.5 or less and a melt flow ratio ( MI ₁₀ / MI _2.16 ) in the range of 6 to 15 (where MI ₁₀ represents a melt index at 190 ° C. and a load of 10 kg, MI _2.16 represents a melt index at 190 ° C. and a load of 2.16 kg), The copolymerization ratio of α-olefin is 70 mol% or less, 21 to 40% by weight of ethylene / α-olefin copolymer polymerized using a single-site catalyst, and component (C) average measured by laser diffraction method Particle size 3-7μm
5 to 25% by weight of talc.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. (A) Component The crystalline ethylene / propylene block copolymer (A) used in the present invention refers to a crystalline propylene homopolymer polymerized in the first step and an ethylene / propylene copolymer copolymerized in the second step. It is a mixture with a coalescing compound, and is polymerized in the presence of a combined catalyst of titanium trichloride and an alkylaluminum compound, which is usually called a Ziegler-Natta type catalyst, or a composite catalyst of a magnesium compound and a titanium compound.

The crystalline ethylene / propylene block copolymer has an ethylene content of 0.5 to 15% by weight, preferably 1.0 to 10% by weight, and an isotactic pentad fraction of a polypropylene component (mmmm ) Is 96%
Above, preferably 97% or more, melt flow rate (MFR: 230 ° C., 2160 g) is 40 to 80 g / 1.
0 minutes, preferably 50 to 70 g / 10 minutes.

Here, the ethylene content means a methyl group (-CH ₃ ) and a methylene group (-CH ₂ ) in an infrared absorption spectrum obtained by subjecting a press film specimen to an infrared spectrophotometer.
It was determined by the calibration curve method using the absorbance of the characteristic absorption of-).

[0008] The isotactic pentad fraction is an isotactic chain in a pentad unit in a crystalline polypropylene molecular chain measured by 13C-NMR, and 5 propylene monomer units. It is the fraction of propylene monomer units at the center of successive meso-linked chains. Specifically, it is obtained as a mmmm peak fraction in all absorption peaks in the methyl carbon region of the 13C-NMR spectrum.

If the ethylene content is less than 0.5% by weight,
If the impact resistance of the composition is insufficient, and if it exceeds 15% by weight, the heat deformation resistance and the surface hardness are significantly reduced. When mmmm is less than 96%, the rigidity of the composition is insufficient, and the effect of improving the surface hardness is poor. Further, when the MFR is less than 40 g / 10 min, the flowability is inferior, so that the moldability cannot be improved, and when it exceeds 80 g / 10 min, the effect of improving the impact resistance becomes poor. The content of the crystalline ethylene / propylene block copolymer (A) is 35 to 74% by weight, preferably 40% by weight.
~ 65% by weight. When the amount is less than 35% by weight, the flexural modulus and the surface hardness become insufficient, and when it is more than 75% by weight, the impact strength becomes insufficient.

Component (B) The ethylene / α-olefin copolymer of the component (B) used in the present invention is preferably produced by using a single-site catalyst. Examples of the single-site catalyst used in the present invention include a metallocene compound of a transition metal of Group IV or V of the periodic table and an organoaluminum compound and / or
Alternatively, a combination of ionic compounds is used. As the transition metal of Group IV or V of the periodic table, titanium (T
i), zirconium (Zr), hafnium (Hf), vanadium (V) and the like are preferable.

The metallocene compound is a compound in which at least one cyclopentadienyl group or substituted cyclopentadienyl group (eg, alkyl-substituted cyclopentadienyl group such as methyl, dimethyl, pentamethyl, indenyl group, fluorenyl group) is coordinated. Or a cyclopentadienyl group having a hydrocarbyl group (eg, an alkylene group or a substituted alkylene group), a hydrocarbyl silicon (eg, a silanylene group, a substituted silanylene group, a silaalkylene group, or a substituted silaalkylene group) Cross-linked, and further those in which a cyclopentadienyl group is cross-linked to oxygen, nitrogen, and phosphorus atoms (for example, oxasilanylene group, substituted oxasilanylene group, oxasilaalkylene group, aminosilyl group, monosubstituted aminosilyl group, phosphinosilyl group, The conversion Hosufinoshiriru group) as a ligand, a so-called well-known metallocene compound either can be used.

[0012] Specific examples thereof are disclosed in
Nos. 9309, 60-35006 and 61-
Nos. 130341, 61-264010, 61-296008, 63-222177, 63-251405, and JP-A-1-6621
No. 4, No. 1-74202, No. 1-27560
No. 9, No. 1-301704, No. 1-3194
Nos. 89, 2-41303 and 2-1314
Nos. 88, 3-12406, 3-1395
Nos. 04, 3-179006 and 3-185
005, 3-188092, 3-19
Nos. 7514, 3-207703, 5-2
No. 09013, Japanese Patent Publication No. 1-501950,
JP-A-1-502036 and JP-A-5-50559
No. 3 can be mentioned.

As a single-site catalyst other than the above,
JP-A-61-180314, 61-26401
0, 63-142004, JP-A-1-1-1
No. 29004, No. 1-301704, No. 2-
75605, 3-12406, 3-1
Nos. 2407 and 4-227708 and 4-2
Nos. 68308, 4-300887, 6-
Metallocene compounds as described in, for example, Japanese Patent No. 25343 can be mentioned.

These metallocene compounds have a bridged type capable of forming a complex having a C ₂ symmetry element by themselves and / or a polysubstituted ligand. As a specific example,
Dimethylsilyl (2,4-dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) zirconium dichloride, dimethylsilyl (2.4-dimethylcyclopentadienyl) (3 ′, 5′-dimethyl Silicon-bridged metallocene compounds such as cyclopentadienyl) hafnium dichloride, ethylenebisindenyl zirconium dichloride, ethylenebisindenylhafnium dichloride, ethylenebis (methylindenyl) zirconium dichloride, and ethylenebis (methylindenyl) hafnium dichloride An indenyl crosslinked metallocene compound can be mentioned.

In the present invention, as the organoaluminum compound used in combination with the metallocene compound, a linear or cyclic polymer represented by the general formula (-Al (R) O-) _N (R is 1 to 10 hydrocarbon groups, including those partially substituted with halogen atoms and / or RO groups. N is the degree of polymerization and is 5 or more, preferably 10 or more. , And R are methyl, ethyl, and isobutyl groups, such as methylalumoxane, ethylalumoxane, and isobutylethylalumoxane.

Further, other organic aluminum compounds include trialkylaluminum, dialkylhalogenoaluminum, sesquialkylhalogenoaluminum, alkenylaluminum, dialkylhydroaluminum, sesquialkylhydroaluminum and the like.

Specific examples thereof include trialkylaluminums such as trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, dialkylhalogenoaluminums such as dimethylaluminum chloride and diethylaluminum chloride, sesquimethylaluminum chloride, Examples thereof include sesquialkylhalogenoaluminums such as sesquiethylaluminum chloride, ethylaluminum dichloride, diethylaluminum hydride, and sesquiethylaluminum hydride. These organic aluminum compounds can be used in combination with the aforementioned organic alnium oxy compounds.

The ionic compound is represented by the general formula: C ⁺ A
^And C ⁺ is an oxidizing cation of an organic compound, an organometallic compound, or an inorganic compound, or a Bronsted acid composed of a Lewis base and a proton, and reacts with an anion of a metallocene ligand to form a metallocene cation. Can be generated.

A ^- is a bulky, non-coordinating anion capable of stabilizing the metallocene cation without coordinating to the metallocene. Specific examples thereof are disclosed in JP-A-4-253711 and JP-A-4-30558.
No. 5, JP-A-5-507756, JP-A-5-5
What was described in 02906 can be used.

In particular, an ionic compound of a tetrakis (pentafluorophenyl) borate anion and a triphenylcarbonium cation or a dialkylanilinium cation is preferred. These ionic compounds can be used in combination with the aforementioned organic aluminum compounds.

As a method for copolymerizing ethylene and an α-olefin using a single-site catalyst, various well-known methods can be employed, such as fluidized-bed gas-phase polymerization in an inert gas or stirring gas-phase polymerization. Examples include phase polymerization, slurry polymerization in an inert solvent, and bulk polymerization using a monomer as a solvent.

The polymerization temperature is usually from 10 to 150 ° C., preferably from 20 to 90 ° C., and the polymerization time is usually from 0.1 to 150 ° C.
10 hours.

When a metallocene compound and an organoaluminum compound are used as the single-site polymerization catalyst of the present invention, the molar ratio of the aluminum atom of the organoaluminum compound to the transition metal atom of the metallocene compound is usually 1
It is 0 to 100,000, preferably 10 to 1,000.

As the single-site polymerization catalyst of the present invention, an ionic compound may be used alone or in combination with an organic aluminum compound instead of the organic aluminum compound. The molar ratio between the ionic compound and the transition metal atom is
Usually, it is 0.1 to 50, preferably 0.5 to 5.

The melt index (1) of the ethylene / α-olefin copolymer of the component (B) used in the present invention.
90 ° C., 2.16 kg) is 0.1 to 50 g / 10 minutes,
Preferably it is 0.3 to 30 g / 10 minutes. If the melt index is less than 0.1 g / 10 minutes, the fluidity of the composition will be poor, and the dispersion will be insufficient, resulting in poor impact resistance.
If it exceeds 50 g / 10 minutes, the effect of improving the impact resistance of the composition is poor. The molecular weight distribution ( _Mw / _Mn ) of the component (B) used in the present invention is 2.5 or less, preferably 1.5 or less.
~ 2.2. If the molecular weight distribution (M _w / M _n ) exceeds 2.5, the compatibility between the component (B) and the component (A) is poor,
As a result, the impact resistance of the composition decreases. The melt flow ratio (MI ₁₀ / MI _2.16 ) of the component (B) is 6-1.
5, preferably 6.5 to ₁₀ (however, MI ₁₀ is 1
90 ° C., melt index at 10 kg load, MI _2.16
Represents a melt index at 190 ° C. under a load of 2.16 kg). When the melt flow ratio (M ₁₀ / MI _2.16 ) is less than 6, the impact resistance of the composition is poor, and when it exceeds 15, the fluidity is poor.

The α-olefin of the ethylene / α-olefin copolymer of the component (B) has 1 to 3 carbon atoms.
-Olefin, and the copolymerization ratio of α-olefin is 7
It is 0 mol% or less, preferably 50 mol% or less, more preferably 3 to 30 mol%. If the copolymerization ratio exceeds 70 mol%, the fluidity of the composition will be poor, and the rigidity and heat deformation resistance will decrease.

The content of the component (B) is from 20 to 40% by weight, preferably from 25 to 35% by weight. 20 content
If the amount is less than 40% by weight, there is no effect of improving the impact resistance, and if it exceeds 40% by weight, the rigidity and the thermal deformation resistance are significantly reduced.

Further, within the range not impairing the characteristics of the polypropylene resin composition of the present invention, the component (B) and the ethylene / α-olefin polymerized using a general vanadium catalyst or titanium catalyst are used. Known rubber components such as an elastomer such as a polymer rubber or a hydrogenated product of a styrene-butadiene block copolymer and a hydrogenated polybutadiene-based block polymer may be used in combination.

Component (C) The talc of component (C) used in the present invention has an average particle diameter of 3 to 7 μm, preferably 3 to 7 μm, as measured by a laser diffraction method.
５5 μm.

Fine talc having an average particle diameter of less than 3 μm has a small average aspect ratio and little effect of improving rigidity. If the average particle size exceeds 7 μm, the impact resistance is poor and the effect of improving rigidity is small.

The average particle size of talc is determined by a Microtrac particle size distribution meter (model 7995-40DRA manufactured by Nikkiso Co., Ltd.).
Was determined by the Fraunhofer diffraction equation of the laser light source forward scattered light and the side scattered light intensity diffraction equation of the halogen light source.

The content of the component (C) is 5 to 25% by weight, preferably 7 to 20% by weight. When the content is less than 5% by weight, the effect of improving rigidity is poor. When the content is 25% by weight or more, fluidity and moldability are reduced, flow marks are generated, and the appearance is poor.

The talc of the present invention is obtained by pulverizing raw talc to a predetermined average particle diameter using a known pulverizer such as a roller mill or a crusher, and then using a known dry classifier to remove particles having an average particle diameter other than 3 to 7 μm. It can be manufactured by the following method. Further, classification may be performed while re-grinding with a known grinder.

The talc of the present invention may be surface-treated with various treating agents as long as the purpose is not adversely affected. Examples of the surface treatment agent include chemical or physical treatment with various treatment agents such as a silane coupling agent system, a higher fatty acid system, a fatty acid metal salt system, an unsaturated organic acid or a derivative thereof, an organic titanate system, and a resin acid system. Surface treatment can be given.

In order to obtain the polypropylene resin composition of the present invention, the crystalline ethylene / propylene block copolymer (A), the ethylene / α-olefin copolymer (B) and the talc (C) are variously used in the above range. Known methods, for example, blending with a Henschel mixer, V-blender, ribbon blender, etc., and a single-screw extruder, a twin-screw extruder, a twin-screw extruder having a raw material supply port in a cylinder in addition to a usual raw material supply port After melt-mixing with a kneader, a Banbury mixer or the like, a method of pelletizing can be employed.

Further, in order to further enhance the performance of a molded article obtained by molding the resin composition of the present invention, or to generally provide functions necessary for the intended use, the components of the composition of the present invention are mixed. Or after mixing, compounding antioxidants, ultraviolet absorbers, light stabilizers, pigments, dispersants, paintability improvers, moldability improvers, antistatic agents, lubricants, nucleating agents, mold release agents, etc. Can be. In particular, antioxidants, ultraviolet absorbers,
Light stabilizers, pigments and the like are desirably added.

Examples of the antioxidant include 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, and 2,6-di-tert-butylphenol. Butyl-α-dimethylamino-para-cresol, 6
-(4-hydroxy-3,5-di-tert-butylaniline) -2,4-bisoctyl-thio-1,3,5-
Triazine, n-octadecyl-3- (4'-hydroxy-3 ', 5'-ditert-butylphenyl) propionate, tris- (2-methyl-4-hydroxy-
5-tert-butylphenyl) butane, tetrakis- [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6 -Tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, dilaurylthiodipropionate, and the like.

Examples of the ultraviolet absorber and light stabilizer include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone,
Dodecyloxy-2-hydroxyhenzophenone, 2-
(2′-hydroxy-3′-tert-butyl-5 ′
-Methylphenyl) -5-chlorobenzotriazole,
Bis- (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 1,2,3,4-butanetetracarboxylic acid-1,2,2,6,6-pentamethyl-4-piperidinol And tridecyl alcohol condensate.

The physical properties of the resin composition of the present invention are as follows: MFR ≧ 1
0 g / 10 min (230 ° C., 2.16 kg), preferably 15 to 50 g / 10 min. FM ≧ 1560 MPa,
Preferably 1580-2500MPa. TYS ≧ 19M
Pa, preferably 20 to 30 MPa. IZOD ≧ 70J
/ M (−30 ° C.), preferably ≧ 75 J / m. HDT ≧
125 ° C, preferably ≧ 128 ° C. RH ≧ 55, preferably 58-78. BT ≦ −25 ° C., preferably ≦ −28
° C. It is preferred that the flowability is ≧ 100 cm, preferably ≧ 110 cm.

[0040]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. Next, the method of measuring the physical properties in the examples will be described below. For the test pieces of the mechanical properties, a cylinder setting temperature of 230 ° C., a mold temperature of 40 ° C., and a J100SAII type injection molding machine manufactured by Japan Steel Works, Ltd. 1) Melt flow rate (MFR) According to a method specified in ASTM D1238. (2) Tensile yield point strength (TYS) According to the method specified in ASTM D638. (3) Flexural modulus (FM) According to a method specified in ASTM D790. (4) Heat distortion temperature (HDT) According to the method specified in ASTM D648. Fiber stress is measured at 4.6 / cm ² . (5) Surface hardness (RH) According to a method specified in ASTM D685. The steel ball is R
And the value of the evaluation is shown on the R scale. (6) Izod impact strength (IZOD) According to a method specified in ASTM D256. The measurement temperature is -30C. (7) Brittle temperature (BT) According to the method specified in ASTM D746. (8) Fluidity Fluidity was 3 mm thick, 10 mm wide, and 2000 mm long.
Injection molding was performed using a mold for measuring resin flow length having a spiral flow path as described above, and the flow length was measured and determined (230).
° C). (9) Glossiness A flat test piece having a thickness of 3 mm, a length of 75 mm, and a width of 150 mm was formed by injection molding using a mirror-finished mold.
The injection molding was performed using a M100SJ molding machine manufactured by Meiki Seisakusho Co., Ltd. under the conditions of a cylinder set temperature of 210 ° C. and a mold temperature of 40 ° C. The gloss was measured using a digital variable-angle gloss meter VG-1D manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS Z874.
The center of the test piece was measured and determined by Method 1 (light incident angle 60 °, light receiving angle 60 °).

The raw materials used in the examples and comparative examples are as follows. (1) Crystalline ethylene / propylene block copolymer Table 1 summarizes the contents of the crystalline ethylene / propylene block copolymer.

[0042]

[Table 1]

[0043] (2) an ethylene · alpha-olefin copolymer component (B) R-1: obtained by polymerization using a single site catalyst of claim 1, a melt index (190 ° C.) is 5, the molecular weight distribution (M _W / M _n ) is 2.1 and the melt flow ratio (MI ₁₀ /
MI _2.16 ) is 7.2, an octene-1 content is 7.3 mol%. R-2: polymerized using the single-site catalyst of claim 1, having a melt index (190 ° C.) of 3, a molecular weight distribution (M _w / M _n ) of 2.0, and a melt flow ratio (MI ₁₀ /
MI _2.16 ) is 7.1, an hexene-1 copolymer having a hexene-1 content of 11.5 mol%. R-3: polymerized using a normal vanadium catalyst, melt index (190 ° C.) 1.5, molecular weight distribution (M _w / M _n ) 2.1, melt flow ratio (MI ₁₀ / M)
I _2.16 ) is 5.5, butene-1 content is 14.3 mol%
Ethylene-butene copolymer. R-4: Polymerization was performed using a normal vanadium-based catalyst. The melt index (190 ° C.) is 0.5, the molecular weight distribution (M _w / M _n ) is 2.2, and the melt flow ratio (MI ₁₀ / M)
I _2.16 ) is 5.4 and the propylene content is 16.6 mol%
Ethylene-propylene copolymer.

(3) Talc component (C) Classified talc manufactured by CALCEED Co., Ltd. was used. T-1: Talc having an average particle diameter of 4 μm. T-2: Talc having an average particle diameter of 8 μm.

Examples 1 to 3 Comparative Examples 1 to 7 Polypropylene having the compounding formulation shown in Table 2 was mixed with a rubber component, talc, the following additives and a pigment by a tumbler mixer, and then melt-kneaded by a twin-screw kneading extruder. And pelletized. The pellet was formed into a test piece by an injection molding machine, and a physical property test was performed. Additives 2,6-di-tert-butyl-4-methylphenol tetrakis- [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxylphenyl) propionate] methane bis- (2 , 2,6,6-tetramethyl-4-piperidyl) sebacate pigment / iron oxide / titanium oxide The results are shown in Table 2. Compared with Examples of the present invention, Comparative Examples 1, 4 and 5 are inferior in surface hardness, flexural modulus and thermal deformation resistance, and Comparative Examples 2 and 3 are inferior in low-temperature impact resistance. In Comparative Example 6, the fluidity was significantly poor.
Are almost all inferior to the examples.

[0046]

[Table 2]

[0047]

According to the present invention, the polymerization is carried out by a specific catalyst,
By combining an ethylene / α-olefin copolymer with specific properties with a crystalline ethylene / propylene block copolymer or talc, high fluidity and high surface hardness,
Further, the molded article has excellent heat deformation resistance and low-temperature impact resistance, and achieves the appearance of a molded article without generation of flow marks. The composition of the present invention can be suitably used for exterior parts for automobiles, particularly for large and thin bumpers requiring high fluidity.

Claims (1)

[Claims] 1. Component (A) Ethylene content of 0.5 to 15% by weight, isotactic pentad fraction (mmmm) of polypropylene component of 96% or more, melt flow rate (230 ° C., 2160 ° C.)
g) is 40 to 80 g / 10 minutes, 35 to 74% by weight of a crystalline ethylene / propylene block copolymer, and the component (B) has a molecular weight distribution (Mw / Mn) of 2.5 or less and a melt flow ratio ( MI ₁₀ / MI _2.16 ) in the range of 6 to 15 (where MI ₁₀ represents a melt index at 190 ° C. and a load of 10 kg, MI _2.16 represents a melt index at 190 ° C. and a load of 2.16 kg), The copolymerization ratio of α-olefin is 70 mol% or less, 21 to 40% by weight of ethylene / α-olefin copolymer polymerized using a single-site catalyst, and component (C) average measured by laser diffraction method Particle size 3-7μm
5 to 25% by weight of talc.