Claims
- 1. A polypropylene composition consisting essentially of 100 parts by weight of a crystalline propylene polymer produced by polymerization using a Ziegler-Natta catalyst containing Ti, Mg and Cl as the essential components and having a molecular weight distribution (Mw/Mn) of less than 5.0 and from 0.001 to 1.0 part by weight of a crystal nucleating agent, the composition having a crystallization temperature at least 1.5.degree. C. higher than the crystallization temperature of the crystalline propylene polymer.
- 2. A polypropylene composition as claimed in claim 1, wherein the crystalline propylene polymer has the melt flow rate of from 3.0 to 50 g/10 minutes.
- 3. A polypropylene composition as claimed in claim 1, wherein the crystalline propylene polymer is a crystalline propylene homopolymer or a crystalline propylene-.alpha.-olefin copolymer.
- 4. A polypropylene composition as claimed in claim 3, wherein the crystalline propylene-.alpha.-olefin copolymer is a propylene-ethylene copolymer, a propylene-butene-1 copolymer or a propylene-ethylene-butene-1 copolymer.
- 5. A polypropylene composition as claimed in claim 3, wherein the crystalline propylene-.alpha.-olefin copolymer has an .alpha.-olefin content of from 2.0 to 30% by weight.
- 6. A polypropylene composition as claimed in claim 1, wherein the crystalline propylene polymer has the molecular weight distribution of 4.5 or less.
- 7. A polypropylene composition as claimed in claim 1, wherein the crystalline propylene polymer has the molecular weight distribution of 4.0 or less.
- 8. A polypropylene composition as claimed in claim 1, wherein the crystal nucleating agent is an inorganic crystal nucleating, an organic crystal nucleating agent, a polymeric crystal nucleating agent, or .alpha.-crystal crystal nucleating agents for propylene.
- 9. A polypropylene composition as claimed in claim 1, wherein the crystal nucleating agent is talc, an aromatic carboxylic acid metal salt or a vinyl cycloalkane polymer.
- 10. A polypropylene composition as claimed in claim 1, wherein the amount of the crystal nucleating agent is from 0.0003 to 0.5 part by weight.
- 11. A polypropylene composition as claimed in claim 1, wherein the crystal nucleating agent has a mean particle size of 6.0 .mu.m or less.
- 12. A polypropylene composition as claimed in claim 1, wherein the crystal nucleating agent has a mean particle size of 4.5 .mu.m or less.
- 13. A polypropylene composition as claimed in claim 1, having a crystallization temperature at least 2.0.degree. C. higher than the crystallization temperature of the crystalline propylene polymer.
- 14. A polypropylene film obtained by melt-extruding the polypropylene composition as claimed in claim 1.
Priority Claims (1)
Number |
Date |
Country |
Kind |
4-214040 |
Aug 1992 |
JPX |
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Parent Case Info
This is a Continuation of application Ser. No. 08/102,821, filed on Aug. 6, 1993 now abandoned.
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Continuations (1)
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Number |
Date |
Country |
Parent |
102821 |
Aug 1993 |
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