Polypropylene composition and film thereof

• US 5,340,878 A
• Filed: 06/22/1993
• Issued: 08/23/1994
• Est. Priority Date: 06/30/1992
• Status: Expired due to Term

• Current Assignee: Sumitomo Chemical Company Limited
• Original Assignee: Sumitomo Chemical Company Limited
• Inventors: Shiratani, Eisuke, Ima, Seiichiro, Sadatoshi, Hajime
• Primary Examiner(s): Seccuro, Jr., Carman J.
• Application Number:
  US08/079,558
• Time in Patent Office: 427 Days
• Field of Search: 525/240, 525/88
• US Class Current: 525/240
• CPC Class Codes: C08L 23/06 Polyethene
• CPC Class Codes: C08L 23/10 Homopolymers or copolymers of propene
• CPC Class Codes: C08L 23/142 at least partially crystalline copolymers of propene with other olefins
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/06 Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof

Abstract

A polypropylene composition comprising 100 parts by weight of a crystalline propylene polymer having a melt flow rate of at least 3.0 g/10 minutes and a molecular weight distribution of less than 5.0 and from 0.01 to less than 4.0 parts by weight of a crystalline ethylene polymer having a melt flow rate of from 0.5 to 300 g/10 minutes, a density of at least 0.910 g/cm³, and a crystallization temperature of at least 85° C. and which is at least 1° C. higher than the crystallization temperature of the crystalline propylene polymer.

Claims

1. A polypropylene composition comprising 100 parts by weight of a crystalline propylene polymer containing at least 70% by weight propylene having a melt flow rate of at least 3.0 g/10 minutes and a molecular weight distribution of less than 5.0 and from 0.01 to less than 4.0 parts by weight of a crystalline ethylene polymer having a melt flow rate of from 0.5 to 300 g/10 minutes, a density of at least 0.910 g/cm³, and a crystallization temperature of at least 85°

C. and which is at least 1°

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-α

-olefin copolymer.

4. A polypropylene composition as claimed in claim 3, wherein the crystalline propylene-α

-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-α

-olefin copolymer has an α

-olefin content of from 2.0 to 30% by weight and the molecular weight distribution of 4.5 or less.

6. A polypropylene composition as claimed in claim 1, wherein the crystalline ethylene polymer has the melt flow rate of from 1 to 100 g/10 minutes and the crystallization temperature of at least 85°

C. and which is at least 2°

C. higher than the crystallization temperature of the crystalline propylene poisoner.

7. A polypropylene composition as claimed in claim 1, wherein the crystalline ethylene polymer is a straight-chain crystalline ethylene polymer having a crystallization temperature of at least 90°

C. and which is at least 5°

C. higher than the crystallization temperature of the crystalline propylene polymer.

8. A polypropylene composition as claimed in claim 1, wherein the crystalline ethylene polymer is used in an amount of from 0.01 to 2.5 parts by weight.

9. A polypropylene composition as claimed in claim 1, wherein the crystalline ethylene polymer is used in an amount of from 0.02 to 1.0 parts by weight.

10. A polypropylene film obtained by melt-extruding the polypropylene composition as claimed in claim 1.

11. A polypropylene polymer composition comprising crystalline polypropylene polymer containing at least 70% by weight propylene and crystalline polyethylene polymer having a melt flow rate of 0.5 to 300 g/10 min and a density of at least 0.910 g/cm³, wherein the crystalline polypropylene polymer has a melt flow rate of at least 3.0 g/10 min and a molecular weight distribution (Mw/Mn) of less than 5.0 and is blended with the crystalline polyethylene polymer having a crystalline temperature higher than the crystalline temperature of the crystalline polypropylene polymer by at least 1°

C., the crystalline temperature of the crystalline polyethylene polymer being 85°

C. or higher, the crystalline polyethylene polymer being present in an amount of from 0.01 to 4 parts by weight per 100 parts by weight of the crystalline polypropylene polymer.