| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | December 5, 2000 |
| PATENT TITLE |
Propylene polymer compositions containing a propylene homo- or co-polymer obtained using a bridged metallocene catalyst and another propylene homo- or co-polymer |
| PATENT ABSTRACT | A propylene polymer composition is prepared by mixing a first propylene polymer prepared using an olefin polymerization catalyst containing a specific metallocene catalyst component of formula (I), e.g., rac-dimethylsilylene-bis{1-(2-ethyl-4-phenylindenyl)} zirconium dichloride, and an organoaluminum-oxy cocatalyst, with a second propylene polymer component. The compositions are excellent in heat resistance, mechanical strength, tensile elongation at break, and other properties and can be used to produce various structural materials, sheets and films |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | September 8, 1994 |
| PATENT CT FILE DATE | January 11, 1994 |
| PATENT CT NUMBER | This data is not available for free |
| PATENT CT PUB NUMBER | This data is not available for free |
| PATENT CT PUB DATE | July 21, 1994 |
| PATENT FOREIGN APPLICATION PRIORITY DATA | This data is not available for free |
| PATENT CLAIMS |
What is claimed is: 1. A propylene polymer composition which is the product obtained by the steps comprising: polymerizing propylene or copolymerizing propylene and at least one olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising (i) (h) a transition metal compound represented by the following formula: ##STR12## wherein M is zirconium; R.sup.1 is an alkyl group of 2 to 6 carbon atoms; R.sup.2 is an aryl group selected from the group consisting of phenyl, naphthyl, anthracenyl and phenanthryl which may be substituted with a halogen atom or a hydrocarbon group of 1 to 20 carbon atoms; X.sup.1 and X.sup.2 are each a hydrogen atom, a halogen atom, a hydrocarbon group of 1 to 20 carbon atoms, a halogenated hydrocarbon group of 1 to 20 carbon atoms, an oxygen-containing group or a sulfur-containing group; and Y is a divalent silicon-containing group selected from the group consisting of dialkylsilylene, alkylarylsilylene and diarylsilylene; and (ii) at least one organoaluminum oxy-compound, to prepare a propylene homo- or co-polymer (A); polymerizing propylene or copolymerizing propylene and not more than 10% by mol of at least one .alpha.-olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising a metallocene compound or an olefin polymerization catalyst comprising (d) a solid titanium catalyst component and (e) an organometallic compound catalyst component to prepare a propylene homo- or co-polymer (A') which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene homo- or co-polymer (A), wherein, the ratio of the intrinsic viscosity (.eta..sub.A) of the propylene homo or co-polymer (A) and the intrinsic viscosity (.eta..sub.A') of the propylene homo- or co-polymer (A'), (.eta..sub.A /.eta..sub.A') or (.eta..sub.A' /.eta..sub.A) is in the range of 3 to 30; and mixing 5 to 95% by weight of the propylene homo- or co-polymer (A) and 5 to 95% by weight of the propylene homo- or co-polymer (A'). 2. A propylene polymer composition prepared by a multi-stage polymerization method comprising the steps of: polymerizing propylene or copolymerizing propylene and at least one olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising (i) (h) a transition metal compound represented by the following formula: ##STR13## wherein M is zirconium; R.sup.1 is an alkyl group of 2 to 6 carbon atoms; R.sup.2 is an aryl group selected from the group consisting of phenyl, naphthyl, anthracenyl and phenanthryl which may be substituted with a halogen atom or a hydrocarbon group of 1 to 20 carbon atoms; X.sup.1 and X.sup.2 are each a hydrogen atom, a halogen atom, a hydrocarbon group of 1 to 20 carbon atoms, a halogenated hydrocarbon group of 1 to 20 carbon atoms, an oxygen-containing group or a sulfur-containing group; and Y is a divalent silicon-containing group selected from the group consisting of dialkylsilylene, alkylarylsilylene and diarylsilylene; and (ii) at least one organoaluminum oxy-compound, to prepare a propylene homo- or co-polymer (A); polymerizing propylene or copolymerizing propylene and not more than 10% by mol of at least one .alpha.-olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising a metallocene compound or an olefin polymerization catalyst comprising (d) a solid titanium catalyst component and (e) an organometallic compound catalyst component to prepare a propylene homo- or co-polymer (A') which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene homo- or co-polymer (A), wherein, the ratio of the intrinsic viscosity (.eta..sub.A) of the propylene homo or co-polymer (A) and the intrinsic viscosity (.eta..sub.A') of the propylene homo- or co-polymer (A'), (.eta..sub.A /.eta..sub.A') or (.eta..sub.A' /.eta..sub.A) is in the range of 3 to 30; wherein the steps of preparing the propylene homo- or co-polymers (A) and (A') are conducted in an arbitrary order; and the amount of the propylene homo- or co-polymer (A) is 5 to 95% by weight, and the amount of the propylene homo- or co-polymer (A') is 5 to 95% by weight. 3. The propylene polymer composition of claim 1 wherein the homo- or co-polymer (A) is a propylene homopolymer (A5) characterized by: melt flow rate (MFR), as measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg, in the range of 0.5 to 200 g/10 min, molecular weight distribution, Mw/Mn, in the range of 2.0 to 3.0, intrinsic viscosity (.eta..sub.A5), measured in decalin at 135.degree. C., in the range of 0.5 to 10 dl/g, weight average molecular weight in the range of 1.times.10.sup.4 to 1.times.10.sup.6, crystallinity measured by X-ray diffractometry of not less than 50%, boiling heptane extraction residue proportion (I.I.) of not less than 93%, triad tacticity (mm fraction) as measured by the .sup.13 C-NMR method of not less than 99.2%, proportion of irregularly positioned units (inversely inserted units), based on the 2,1-insertion, of the propylene monomer of not more than 0.18%, and proportion of irregularly positioned units, based on the 1,3-insertion of not more than 0.18%; and propylene homo- or co-polymer (A') is a propylene polymer (A6) characterized by: MFR, measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg in the range of 0.5 to 200 g/10 min, Mw/Mn in the range of 2.0 to 8.0, crystallinity, measured by X-ray diffractometry, of not less than 50%, intrinsic viscosity (.eta..sub.A6) measured in decalin at 135.degree. C. in the range of 0.5 to 10 dl/g, and weight average molecular weight in the range of 1.times.10.sup.4 to 1.times.10.sup.6. 4. The propylene polymer composition of claim 3 which comprises from 30 to 70 percent by weight of propylene homopolymer (A5) and 30 to 70 percent by weight of propylene polymer (A6). 5. The propylene polymer composition of claim 4 wherein the intrinsic viscosity of propylene homopolymer (A5) (.eta..sub.A5) is in the range of 2 to 5 dl/g and intrinsic viscosity of propylene polymer (A6) (.eta..sub.A6) is in the range of 0.3 to 1.0 dl/g. 6. The propylene polymer composition of claim 4 wherein the intrinsic viscosity (.eta..sub.A5) is in the range of 0.3 to 1.0 dl/g and intrinsic viscosity (.eta..sub.A6) is in the range of 2 to 5 dl/g. 7. The propylene polymer composition of claim 1 wherein the resulting mixture of propylene polymer (A) and propylene polymer (A') is characterized by: melt flow rate, MFR, measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg in the range of 0.5 to 200 g/10 min, Mw/Mn of the mixture of propylene polymer components in the range of 4 to 15, and density in the range of 0.89 to 0.92 g/cm.sup.3. 8. The propylene polymer composition of claim 7 wherein the mixture of propylene polymer (A) and propylene polymer (A') is further characterized by: flexural modulus (FM) measured in accordance with ASTM D790 under the following conditions: specimen size of 12.7.times.6.4.times.127; span of 100 mm and flexure rate of 2 mm/min in the range of 12,000 to 21,000 kg/cm.sup.2, Izod impact strength (IZ) measured in accordance with ASTM D256 at 23.degree. C. in the range of 2 to 10 kg.multidot.cm/cm, tensile elongation at break (EL) measured at 23.degree. C. in accordance with ASTM D638 in the range of 100 to 500%, and heat distortion temperature (HDT) measured in accordance with ASTM D648 with a specimen measuring 12.7.times.6.4.times.127 not lower than 95.degree. C. 9. The propylene polymer composition of claim 1 wherein the propylene homo- or co-polymer (A) is a propylene copolymer (A7) which contains from 90 to 98% by mol of propylene units, and units of .alpha.-olefin of from 2 to 10% by mol; said propylene copolymer being characterized by: melt flow rate, MFR, measured according to ASTM D1238 at 23.degree. C. and a load of 2.16 kg, in the range of 0.5 to 200 g/10 min, molecular weight distribution, Mw/Mn, in the range of 2.0 to 3.0, intrinsic viscosity (.eta..sub.A7), measured in decalin at 135.degree. C., in the range of 0.5 to 10 dl/g, weight average molecular weight in the range of 1.times.10.sup.4 to 1.times.10.sup.6, crystallinity measured by X-ray diffractometry of not less than 20%, triad tacticity (mm fraction) as determined by the .sup.13 C-NMR method of not less than 98.2%, and proportion of irregularity positioned units, based on the 2,1-insertion, of not more than 0.18%, and, proportion of irregularly positioned units, based on the 1,3-insertion, of not more than 0.03%; and, wherein the propylene homo- or co-polymer (A') is a propylene polymer (A6) characterized by: MFR measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg in the range of 0.5 to 200 g/10 min, Mw/Mn in the range of 2.0 to 8.0, crystallinity measured by X-ray diffractometry of not less than 50%, intrinsic viscosity (.eta..sub.A6), measured in decalin at 135.degree. C., in the range of 0.5 to 10 dl/g, and weight average molecular weight in the range of 1.times.10.sup.4 to 1.times.10.sup.6. 10. The propylene polymer composition of claim 9 which comprises mixing from 15 to 85 percent by weight of propylene copolymer (A7) and from 15 to 85 percent by weight of propylene polymer (A6). 11. The propylene polymer composition of claim 9 wherein the intrinsic viscosity (.eta..sub.A7) of copolymer (A7) is in the range of 2 to 5 dl/g and intrinsic viscosity of propylene polymer (A6) (.eta..sub.A6) is in the range of 0.3 to 1.0 dl/g. 12. The propylene polymer composition of claim 9 wherein the intrinsic viscosity (.eta..sub.A7) is in the range of 0.3 to 1.0 dl/g and intrinsic viscosity (.eta..sub.A6) is in the range of 2 to 5 dl/g. 13. The propylene polymer composition of claim 9 wherein the mixture of propylene copolymer (A7) and propylene polymer (A6) is characterized by: a melt flow rate, MFR, measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg in the range of 0.5 to 200 g/10 min, Mw/Mn of the mixture of propylene polymer components in the range of 4 to 15, and density in the range of 0.89 to 0.92 g/cm.sup.3. 14. The propylene polymer composition of claim 13 wherein the mixture of copolymer (A7) and polymer (A6) is further characterized by: flexural modulus (FM) measured in accordance with ASTM D790 under the following conditions: specimen size of 12.7.times.6.4.times.127; span of 100 mm and flexure rate of 2 mm/min in the range of 2,000 to 20,000 kg/cm.sup.2, Izod impact strength (IZ) measured in accordance with ASTM D256 at 23.degree. C. in the range of 5 to 20 kg.multidot.cm/cm, tensile elongation at break (EL) measured at 23.degree. C. in accordance with ASTM D638 in the range of 200 to 1000%, and heat distortion temperature (HDT) measured in accordance with ASTM D648 with a specimen measuring 12.7.times.6.4.times.127 in the range of 90.degree. C. to 140.degree. C. 15. The propylene polymer composition of claim 1 wherein the ratio of intrinsic viscosity (.eta..sub.A) of the propylene homo or co-polymer (A) and the intrinsic viscosity (.eta..sub.A') of the propylene homo- or co-polymer (A'), (.eta..sub.A /.eta..sub.A') or (.eta..sub.A' /.eta..sub.A) is in the range of 4 to 20. 16. The propylene polymer composition of claim 2 wherein the ratio of intrinsic viscosity (.eta..sub.A) of the propylene homo or co-polymer (A) and the intrinsic viscosity (.eta..sub.A') of the propylene homo- or co-polymer (A'), (.eta..sub.A /.eta..sub.A') or (.eta..sub.A' /.eta..sub.A) is in the range of 4 to 20. 17. A propylene polymer composition comprising a mixture of: (A) 5 to 95% by weight of propylene homopolymer or copolymer of propylene and at least one olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 20 carbon atoms; and (A') 5 to 95% by weight of propylene homopolymer or copolymer of not less than 90 mol % propylene and not more than 10% by mol of at least one .alpha.-olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 20 carbon atoms and which is different from the propylene homo- or co-polymer (A), wherein the ratio of the intrinsic viscosity (.eta..sub.A) of the propylene homo or co-polymer (A) and the intrinsic viscosity (.eta..sub.A') of the propylene homo- or co-polymer (A'), (.eta..sub.A /.eta..sub.A') or (.eta..sub.A' /.eta..sub.A) is in the range of 3 to 30; and wherein the homo- or co-polymer (A) is characterized by: melt flow rate (MFR), as measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg, in the range of 0.5 to 200 g/10 min, molecular weight distribution, Mw/Mn, in the range of 2.0 to 3.0, intrinsic viscosity (.eta..sub.A), measured in decalin at 135.degree. C., in the range of 0.5 to 10 dl/g, weight average molecular weight in the range of 1.times.10.sup.4 to 1.times.10.sup.6, crystallinity measured by X-ray diffractometry of not less than 50%, boiling heptane extraction residue proportion (I.I.) of not less than 93%, triad tacticity (mm fraction) as measured by the .sup.13 C-NMR method of not less than 99.2%, proportion of irregularly positioned units (inversely inserted units), based on the 2,1-insertion, of the propylene monomer of not more than 0.18%, and proportion of irregularly positioned units, based on the 1,3-insertion of not more than 0.18%; wherein propylene homo- or co-polymer (A') is a propylene polymer (A6) characterized by: MFR, measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg in the range of 0.5 to 200 g/10 min, Mw/Mn in the range of 2.0 to 8.0, crystallinity, measured by X-ray diffractometry, of not less than 50%, intrinsic viscosity (.eta..sub.A') measured in decalin at 135.degree. C. in the range of 0.5 to 10 dl/g, and weight average molecular weight in the range of 1.times.10.sup.4 to 1.times.10.sup.6 ; and wherein the mixture of propylene polymer (A) and propylene polymer (A') is characterized by: melt flow rate, MFR, measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg in the range of 0.5 to 200 g/10 min, Mw/Mn of the mixture of propylene polymer components in the range of 4 to 15, flexural modulus (FM) measured in accordance with ASTM D790 under the following conditions: specimen size of 12.7.times.6.4.times.127; span of 100 mm and flexure rate of 2 mm/min in the range of 12,000 to 21,000 kg/cm.sup.2, Izod impact strength (IZ) measured in accordance with ASTM D256 at 23.degree. C. in the range of 2 to 10 kg.multidot.cm/cm, tensile elongation at break (EL) measured at 23.degree. C. in accordance with ASTM D638 in the range of 100 to 500%, and heat distortion temperature (HDT) measured in accordance with ASTM D648 with a specimen measuring 12.7.times.6.4.times.127 not lower than 95.degree. C. 18. The propylene polymer composition of claim 17 which comprises from 30 to 70 percent by weight of propylene polymer (A) having an intrinsic viscosity (.eta..sub.A) in the range of 2 to 5 dl/g and 30 to 70 percent by weight of propylene polymer (A') having an intrinsic viscosity (.eta..sub.A') in the range of 0.3 to 1.0 dl/g. 19. The propylene polymer composition of claim 17 which comprises from 30 to 70 percent by weight of propylene polymer (A) having an intrinsic viscosity (.eta..sub.A) in the range of 0.3 to 1 dl/g and 30 to 70 percent by weight of propylene polymer (A') having an intrinsic viscosity (.eta..sub.A') in the range of 2 to 5 dl/g. 20. A propylene polymer composition comprising a mixture of: (A) 5 to 95% by weight of copolymer of from 90 to 98 mole percent propylene and from 2 to 10 mole percent of at least one olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 20 carbon atoms; and (A') 5 to 95% by weight of propylene homopolymer or copolymer of not less than 90 mol % propylene and not more than 10% by mol of at least one .alpha.-olefin selected from the group consisting of ethylene and .alpha.-olefins of 4 to 20 carbon atoms and which is different from the propylene homo- or co-polymer (A), wherein the ratio of the intrinsic viscosity (.eta..sub.A) of the propylene copolymer (A) and the intrinsic viscosity (.eta..sub.A') of the propylene homo- or co-polymer (A'), (.eta..sub.A /.eta..sub.A') or (.eta..sub.A' /.eta..sub.A) is in the range of 3 to 30; and wherein the copolymer (A) is characterized by: melt flow rate (MFR), as measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg, in the range of 0.5 to 200 g/10 min, molecular weight distribution, Mw/Mn, in the range of 2.0 to 3.0, intrinsic viscosity (.eta..sub.A), measured in decalin at 135.degree. C., in the range of 0.5 to 10 dl/g, weight average molecular weight in the range of 1.times.10.sup.4 to 1.times.10.sup.6, crystallinity measured by X-ray diffractometry of not less than 20%, triad tacticity (mm fraction) as measured by the .sup.13 C-NMR method of not less than 98.2%, proportion of irregularly positioned units (inversely inserted units), based on the 2,1-insertion, of not more than 0.18%, and proportion of irregularly positioned units, based on the 1,3-insertion, of not more than 0.03%; wherein propylene homo- or co-polymer (A') is characterized by: MFR, measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg in the range of 0.5 to 200 g/10 min, Mw/Mn in the range of 2.0 to 8.0, crystallinity, measured by X-ray diffractometry, of not less than 50%, intrinsic viscosity (.eta..sub.A') measured in decalin at 135.degree. C. in the range of 0.5 to 10 dl/g, and weight average molecular weight in the range of 1.times.10.sup.4 to 1.times.10.sup.6 ; and wherein the mixture of propylene polymer (A) and propylene polymer (A') is characterized by: melt flow rate, MFR, measured according to ASTM D1238 at 230.degree. C. under a load of 2.16 kg in the range of 0.5 to 200 g/10 min, Mw/Mn of the mixture of propylene polymer components in the range of 4 to 15, density in the range of 0.89 to 0.92 g/cm.sup.3 ; flexural modulus (FM) measured in accordance with ASTM D790 under the following conditions: specimen size of 12.7.times.6.4.times.127; span of 100 mm and flexure rate of 2 mm/min in the range of 2,000 to 20,000 kg/cm.sup.2, Izod impact strength (IZ) measured in accordance with ASTM D256 at 23.degree. C. in the range of 5 to 20 kg.multidot.cm/cm, tensile elongation at break (EL) measured at 23.degree. C. in accordance with ASTM D638 in the range of 200 to 1000%, and heat distortion temperature (HDT) measured in accordance with ASTM D648 with a specimen measuring 12.7.times.6.4.times.127 in the range of 90.degree. C. to 140.degree. C. 21. The propylene polymer composition of claim 20 which comprises from 30 to 70 percent by weight of propylene copolymer (A) having an intrinsic viscosity (.eta..sub.A) in the range of 2 to 5 dl/g and 30 to 70 percent by weight of propylene polymer (A') having an intrinsic viscosity (.eta..sub.A') in the range of 0.3 to 1.0 dl/g. 22. The propylene polymer composition of claim 20 which comprises from 30 to 70 percent by weight of propylene copolymer (A) having an intrinsic viscosity (.eta..sub.A) in the range of 0.3 to 1 dl/g and 30 to 70 percent by weight of propylene polymer (A') having an intrinsic viscosity (.eta..sub.A') in the range of 2 to 5 dl/g. |
| PATENT DESCRIPTION |
FIELD OF THE INVENTION The present invention relates to propylene polymer compositions each comprising two kinds of propylene polymers and to propylene polymer compositions each comprising a propylene polymer and other olefin (co) polymer. BACKGROUND OF THE INVENTION Propylene polymers have been conventionally molded by various molding methods and the molded articles are applied to extensive uses. The propylene polymers are generally prepared using a catalyst comprising a transition metal compound and an organoaluminum compound, i.e., so-called Ziegler catalyst. Propylene polymers prepared by the use of a titanium catalyst containing a halogen-containing titanium catalyst component among the Ziegler catalysts are excellent in moldability and rigidity, but they have such problems that they are poor in tensile elongation at break. Moreover, the titanium catalyst causes a large amount of a catalyst residue in the resulting polymer because of low polymerization activities, and hence the molded article is sometimes colored or deteriorated in sanitariness. On the other hand, propylene polymers prepared by the use of a metallocene catalyst containing a transition metal compound catalyst component such as zirconocene are excellent in tensile elongation at break, but they have such problems that they are poor in moldability and rigidity (flexural modulus). As for the metallocene catalyst, however, the amount of the catalyst residue is small because of high polymerization activities, and the molded article is never colored and is good in sanitariness. Though the characteristics required for the propylene polymers vary depending on the molding methods or uses, generally required are moldability, heat resistance, mechanical strength, high tensile elongation at break, impact resistance, etc. For satisfying these requirements, researches on various compositions such as a composition obtained by blending two or more kinds of propylene polymers and a composition obtained by blending a propylene polymer and other synthetic resin have been made. For example, blending of two kinds of propylene polymers which are different in the molecular weight has been carried out in order to improve physical properties of the propylene polymers prepared by the use of a titanium catalyst. However, when two kinds of propylene polymers produced by the use of a titanium catalyst are blended to prepare a propylene polymer composition, the tensile elongation at break of the resulting composition is markedly lowered, though the moldability thereof is improved. Further, adding of a soft polymer to a propylene polymer which is prepared by the use of a titanium catalyst has been carried out in order to improve the tensile elongation at break and the impact resistance of the propylene polymer. The soft polymer used therefor is, for example, an ethylene/propylene random copolymer prepared by the use of a titanium catalyst or a vanadium catalyst. However, even if the propylene polymer prepared by the use of a titanium catalyst is blended with the ethylene/propylene random copolymer prepared by the use of a titanium catalyst or the like, the resulting composition is not sufficiently improved in the tensile elongation at break and the impact resistance. As described above, the conventional propylene polymer compositions are not always satisfactory in the properties such as heat resistance, mechanical strength and tensile elongation at break. OBJECT OF THE INVENTION The present invention has been accomplished in the light of the foregoing prior art technique, and an object of the present invention is to provide propylene polymer compositions which are excellent in heat resistance, mechanical strength, tensile elongation at break, etc. as compared with the conventional propylene polymers or propylene polymer compositions. SUMMARY OF THE INVENTION The first propylene polymer composition of the invention comprises: (A1) a propylene polymer, in an amount of 10 to 90% by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (a) a compound of a Group IVB transition metal in the periodic table containing a ligand having a cyclopentadienyl skeleton, and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (c) a compound which reacts with the transition metal compound (a) to form an ion pair, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 0.01 to 30 g/10 min, and (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 2 to 3; and (A2) a propylene polymer, in an amount of 10 to 90% by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (a) a compound of a Group IVB transition metal in the periodic table containing a ligand having a cyclopentadienyl skeleton, and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (c) a compound which reacts with the transition metal compound (a) to form an ion pair, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 30 to 1,000 g/10 min, and (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 2 to 4; a ratio ((A2)/(A1)) of the MFR of said propylene polymer (A2) to the MFR of said propylene polymer (A1) being not less than 30. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability. The second propylene polymer composition of the invention comprises: (A1) a propylene polymer, in an amount of 10 to 90 parts by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (a) a compound of a Group IVB transition metal in the periodic table containing a ligand having a cyclopentadienyl skeleton, and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (c) a compound which reacts with the transition metal compound (a) to form an ion pair, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 0.01 to 30 g/10 min, and (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 2 to 3; (A2) a propylene polymer, in an amount of 10 to 90 parts by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (a) a compound of a Group IVB transition metal in the periodic table containing a ligand having a cyclopentadienyl skeleton, and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (c) a compound which reacts with the transition metal compound (a) to form an ion pair, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 30 to 1,000 g/10 min, and (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 2 to 4; and (B) a soft polymer in an amount of 3 to 30 parts by weight; a ratio ((A2)/(A1)) of the MFR of said propylene polymer (A2) to the MFR of said propylene polymer (A1) being not less than 30. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability and impact resistance. The third propylene polymer composition of the invention comprises: (A3) a propylene polymer, in an amount of 10 to 90% by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (d) a solid titanium catalyst component, and (e) an organometallic compound catalyst component, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 0.01 to 30 g/10 min, and (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 4 to 15; and (A2) a propylene polymer, in an amount of 90 to 10% by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (a) a compound of a Group IVB transition metal in the periodic table containing a ligand having a cyclopentadienyl skeleton, and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (c) a compound which reacts with the transition metal compound (a) to form an ion pair, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 30 to 1,000 g/10 min, and (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 2 to 4. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability. The fourth propylene polymer composition of the invention comprises: (A3) a propylene polymer, in an amount of 10 to 90 parts by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (d) a solid titanium catalyst component, and (e) an organometallic compound catalyst component, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 0.01 to 30 g/10 min, and (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 4 to 15; (A2) a propylene polymer, in an amount of 90 to 10 parts by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (a) a compound of a Group IVB transition metal in the periodic table containing a ligand having a cyclopentadienyl skeleton, and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (c) a compound which reacts with the transition metal compound (a) to form an ion pair, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 30 to 1,000 g/10 min, and (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 2 to 4; and (B) a soft polymer in an amount of 3 to 30 parts by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability and impact resistance. The fifth propylene polymer composition of the invention comprises: (A4) a propylene polymer, in an amount of 50 to 97% by weight, which is characterized in that: (1) the propylene polymer is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (d) a solid titanium catalyst component, and (e) an organometallic compound catalyst component, (2) the propylene polymer has a melt flow rate (MFR), as measured at 230.degree. C. under a load of 2.16 kg, of 0.01 to 50 g/10 min, (3) the propylene polymer has a molecular weight distribution (Mw/Mn), as measured by gel permeation chromatography (GPC), of 4 to 15, and (4) the propylene polymer has a crystallinity, as measured by X-ray diffractometry, of not less than 50%; and (C) an ethylene/olefin random copolymer, in an amount of 3 to 50% by weight, which is characterized in that: (1) the copolymer is obtained by copolymerizing ethylene and at least one monomer selected from .alpha.-olefins of 3 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising: (i) (f) a compound of a Group IVB transition metal in the periodic table containing a ligand having a cyclopentadienyl skeleton, (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (g) a compound which reacts with the transition metal compound (f) to form an ion pair, (2) the copolymer contains constituent units derived from ethylene in an amount of 20 to 80% by mol, and (3) the copolymer has an intrinsic viscosity [.eta.], as measured in decalin at 135.degree. C., of 1.5 to 5 dl/g. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also impact resistance, particularly low-temperature impact resistance. The sixth propylene polymer composition of the invention comprises: (A5) a propylene homopolymer, in an amount of 5 to 95% by weight, which is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the following formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair; and (A6) a propylene polymer, in an amount of 5 to 95% by weight, which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene homopolymer (A5); ##STR1## wherein M is a transition metal of Group IVa, Group Va or Group VIa of the periodic table; R.sup.1 is a hydrocarbon group of 2 to 6 carbon atoms; R.sup.2 is an aryl group of 6 to 16 carbon atoms which may be substituted with a halogen atom or a hydrocarbon group of 1 to 20 carbon atoms; X.sup.1 and X.sup.2 are each a hydrogen atom, a halogen atom, a hydrocarbon group of 1 to 20 carbon atoms, a halogenated hydrocarbon group of 1 to 20 carbon atoms, an oxygen-containing group or a sulfur-containing group; Y is a divalent hydrocarbon group of 1 to 20 carbon atoms, a divalent halogenated hydrocarbon group of 1 to 20 carbon atoms, a divalent silicon-containing group, a divalent germanium-containing group, a divalent tin-containing group, --O--, --CO--, --S--, --SO--, --SO.sub.2 --, --NR.sup.3 --, --P(R.sup.3)--, --P(O) (R.sup.3)--, --BR.sup.3 -- or --AlR.sup.3 -- (R.sup.3 is a hydrogen atom, a halogen atom, a hydrocarbon group of 1 to 20 carbon atoms or a halogenated hydrocarbon group of 1 to 20 carbon atoms). Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability. The seventh propylene polymer composition of the invention comprises: (A5) a propylene homopolymer, in an amount of 5 to 95% by weight, which is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair; and (D) an olefin elastomer, in an amount of 5 to 95% by weight, which is characterized in that: (1) the elastomer is a polymer or copolymer of at least one monomer selected from olefins of 2 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms, (2) the elastomer contains constituent units derived from ethylene, propylene, butene or 4-methyl-1-pentene in an amount of less than 90% by mol, and (3) the elastomer has a glass transition temperature (Tg) of not higher than 10.degree. C. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also impact resistance. The eighth propylene polymer composition of the invention comprises: (A5) a propylene homopolymer, in an amount of 5 to 95% by weight, which is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair; and (E) an olefin polymer, in an amount of 5 to 95% by weight, which contains constituent units derived from one monomer selected from the group consisting of ethylene, butene and 4-methyl-1-pentene in an amount of not less than 90% by mol. Such propylene polymer composition is excellent in heat resistance, rigidity and tensile elongation at break. The ninth propylene polymer composition of the invention comprises: (A5) a propylene homopolymer which is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair; (A6) a propylene polymer which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene homopolymer (A5); and (D) an olefin elastomer which is characterized in that: (1) the elastomer is a polymer or copolymer of at least one monomer selected from olefins of 2 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms, (2) the elastomer contains constituent units derived from ethylene, propylene, butene or 4-methyl-1-pentene in an amount of less than 90% by mol, and (3) the elastomer has a glass transition temperature (Tg) of not higher than 10.degree. C.; said propylene polymer composition containing the propylene homopolymer (A5) in an amount of 5 to 95% by weight, the propylene polymer (A6) in an amount of not more than 95% by weight and the olefin elastomer (D) in an amount of not more than 95% by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability and impact resistance. The tenth propylene polymer composition of the invention comprises: (A5) a propylene homopolymer which is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair; (A6) a propylene polymer which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene homopolymer (A5); and (E) an olefin polymer which contains constituent units derived from one monomer selected from the group consisting of ethylene, butene and 4-methyl-1-pentene in an amount of not less than 90% by mol; said propylene polymer composition containing the propylene homopolymer (A5) in an amount of 5 to 95% by weight, the propylene polymer (A6) in an amount of not more than 95% by weight and the olefin polymer (E) in an amount of not more than 95% by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability. The eleventh propylene polymer composition of the invention comprises: (A5) a propylene homopolymer which is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair; (D) an olefin elastomer which is characterized in that: (1) the elastomer is a polymer or copolymer of at least one monomer selected from olefins of 2 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms, (2) the elastomer contains constituent units derived from ethylene, propylene, butene or 4-methyl-1-pentene in an amount of less than 90% by mol, and (3) the elastomer has a glass transition temperature (Tg) of not higher than 10.degree. C.; and (E) an olefin polymer which contains constituent units derived from one monomer selected from the group consisting of ethylene, butene and 4-methyl-1-pentene in an amount of not less than 90% by mol; said propylene polymer composition containing the propylene homopolymer (A5) in an amount of 5 to 95% by weight, the olefin elastomer (D) in an amount of not more than 95% by weight and the olefin polymer (E) in an amount of not more than 95% by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also impact resistance. The twelfth propylene polymer composition of the invention comprises: (A5) a propylene homopolymer which is obtained by polymerizing propylene in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair; (A6) a propylene polymer which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene homopolymer (A5); (D) an olefin elastomer which is characterized in that: (1) the elastomer is a polymer or copolymer of at least one monomer selected from olefins of 2 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms, (2) the elastomer contains constituent units derived from ethylene, propylene, butene or 4-methyl-1-pentene in an amount of less than 90% by mol, and (3) the elastomer has a glass transition temperature (Tg) of not higher than 10.degree. C.; and (E) an olefin polymer which contains constituent units derived from one monomer selected from the group consisting of ethylene, butene and 4-methyl-1-pentene in an amount of not less than 90% by mol; said propylene polymer composition containing the propylene homopolymer (A5) in an amount of 5 to 95% by weight, the propylene polymer (A6) in an amount of not more than 95% by weight, the olefin elastomer (D) in an amount of not more than 95% by weight and the olefin polymer (E) in an amount of not more than 95% by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability and impact resistance. The thirteenth propylene polymer composition of the invention comprises: (A7) a propylene copolymer, in an amount of 5 to 95% by weight, which is characterized in that: (1) the propylene copolymer is obtained by copolymerizing propylene and at least one .alpha.-olefin selected from ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair, and (2) the propylene copolymer contains constituent units derived from propylene in an amount of not less than 90% by mol; and (A6) a propylene polymer, in an amount of 5 to 95% by weight, which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene copolymer (A7). Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability. The fourteenth propylene polymer composition of the invention comprises: (A7) a propylene copolymer, in an amount of 5 to 95% by weight, which is characterized in that: (1) the propylene copolymer is obtained by copolymerizing propylene and at least one .alpha.-olefin selected from ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair, and (2) the propylene copolymer contains constituent units derived from propylene in an amount of not less than 90% by mol; and (D) an olefin elastomer, in an amount of 5 to 95% by weight, which is characterized in that: (1) the elastomer is a polymer or copolymer of at least one monomer selected from olefins of 2 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms, (2) the elastomer contains constituent units derived from ethylene, propylene, butene or 4-methyl-1-pentene in an amount of less than 90% by mol, and (3) the elastomer has a glass transition temperature (Tg) of not higher than 10.degree. C. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also impact resistance. The fifteenth propylene polymer composition of the invention comprises: (A7) a propylene copolymer, in an amount of 5 to 95% by weight, which is characterized in that: (1) the propylene copolymer is obtained by copolymerizing propylene and at least one .alpha.-olefin selected from ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair, and (2) the propylene copolymer contains constituent units derived from propylene in an amount of not less than 90% by mol; and (E) an olefin polymer, in an amount of 5 to 95% by weight, which contains constituent units derived from one monomer selected from the group consisting of ethylene, butene and 4-methyl-1-pentene in an amount of not less than 90% by mol. Such propylene polymer composition is excellent in heat resistance, rigidity and tensile elongation at break. The sixteenth propylene polymer composition of the invention comprises: (A7) a propylene copolymer which is characterized in that: (1) the propylene copolymer is obtained by copolymerizing propylene and at least one .alpha.-olefin selected from ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair, and (2) the propylene copolymer contains constituent units derived from propylene in an amount of not less than 90% by mol; (A6) a propylene polymer which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene copolymer (A7); and (D) an olefin elastomer which is characterized in that: (1) the elastomer is a polymer or copolymer of at least one monomer selected from olefins of 2 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms, (2) the elastomer contains constituent units derived from ethylene, propylene, butene or 4-methyl-1-pentene in an amount of less than 90% by mol, and (3) the elastomer has a glass transition temperature (Tg) of not higher than 10.degree. C.; said propylene polymer composition containing the propylene copolymer (A7) in an amount of 5 to 95% by weight, the propylene polymer (A6) in an amount of not more than 95% by weight and the olefin elastomer (D) in an amount of not more than 95% by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability and impact resistance. The seventeenth propylene polymer composition of the invention comprises: (A7) a propylene copolymer which is characterized in that: (1) the propylene copolymer is obtained by copolymerizing propylene and at least one .alpha.-olefin selected from ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair, and (2) the propylene copolymer contains constituent units derived from propylene in an amount of not less than 90% by mol; (A6) a propylene polymer which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene copolymer (A7); and (E) an olefin polymer which contains constituent units derived from one monomer selected from the group consisting of ethylene, butene and 4-methyl-1-pentene in an amount of not less than 90% by mol; said propylene polymer composition containing the propylene copolymer (A7) in an amount of 5 to 95% by weight, the propylene polymer (A6) in an amount of not more than 95% by weight and the olefin polymer (E) in an amount of not more than 95% by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability. The eighteenth propylene polymer composition of the invention comprises: (A7) a propylene copolymer which is characterized in that: (1) the propylene copolymer is obtained by copolymerizing propylene and at least one .alpha.-olefin selected from ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of olefins polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair, and (2) the propylene copolymer contains constituent units derived from propylene in an amount of not less than 90% by mol; (D) an olefin elastomer which is characterized in that: (1) the elastomer is a polymer or copolymer of at least one monomer selected from olefins of 2 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms, (2) the elastomer contains constituent units derived from ethylene, propylene, butene or 4-methyl-1-pentene in an amount of less than 90% by mol, and (3) the elastomer has a glass transition temperature (Tg) of not higher than 10.degree. C.; and (E) an olefin polymer which contains constituent units derived from one monomer selected from the group consisting of ethylene, butene and 4-methyl-1-pentene in an amount of not less than 90% by mol; said propylene polymer composition containing the propylene copolymer (A7) in an amount of 5 to 95% by weight, the olefin elastomer (D) in an amount of not more than 95% by weight and the olefin polymer (E) in an amount of not more than 95% by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also impact resistance. The nineteenth propylene polymer composition of the invention comprises: (A7) a propylene copolymer which is characterized in that: (1) the propylene copolymer is obtained by copolymerizing propylene and at least one .alpha.-olefin selected from ethylene and .alpha.-olefins of 4 to 20 carbon atoms in the presence of an olefin polymerization catalyst comprising: (i) (h) a transition metal compound represented by the above formula (I), and (ii) at least one compound selected from the group consisting of (b) an organoaluminum oxy-compound, and (i) a compound which reacts with the transition metal compound (h) to form an ion pair, and (2) the propylene copolymer contains constituent units derived from propylene in an amount of not less than 90% by mol; (A6) a propylene polymer which contains constituent units derived from propylene in an amount of not less than 90% by mol and is different from the propylene copolymer (A7); (D) an olefin elastomer which is characterized in that: (1) the elastomer is a polymer or copolymer of at least one monomer selected from olefins of 2 to 20 carbon atoms and polyenes of 5 to 20 carbon atoms, (2) the elastomer contains constituent units derived from ethylene, propylene, butene or 4-methyl-1-pentene in an amount of less than 90% by mol, and (3) the elastomer has a glass transition temperature (Tg) of not higher than 10.degree. C.; and (E) an olefin polymer which contains constituent units derived from one monomer selected from the group consisting of ethylene, butene and 4-methyl-1-pentene in an amount of not less than 90% by mol; said propylene polymer composition containing the propylene copolymer (A7) in an amount of 5 to 95% by weight, the propylene polymer (A6) in an amount of not more than 95% by weight, the olefin elastomer (D) in an amount of not more than 95% by weight and the olefin polymer (E) in an amount of not more than 95% by weight. Such propylene polymer composition is excellent in not only heat resistance, rigidity and tensile elongation at break but also moldability and impact resistance. |
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