Thermoplastic rubber film

• US 4,305,990 A
• Filed: 05/07/1979
• Issued: 12/15/1981
• Est. Priority Date: 11/03/1977
• Status: Expired due to Term

• Current Assignee: Chicopee Incorporated (Berry Global Group Inc.)
• Original Assignee: Chicopee Incorporated (Berry Global Group Inc.)
• Inventors: Kelly, William G. F.
• Primary Examiner(s): Ziegler, J.
• Application Number:
  US06/036,726
• Time in Patent Office: 953 Days
• Field of Search: 525/98, 525/84, 525/240, 428/220
• US Class Current: 428/220
• CPC Class Codes: B29C 48/0018 combined with shaping by orienting, stretching or shrinking, e.g. film blowing B29C48/0017 takes precedence
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29D 28/00 Producing nets or the like, e.g. meshes, latticesby knotting D04G
• CPC Class Codes: B29K 2007/00 Use of natural rubber as moulding material
• CPC Class Codes: B29K 2019/00 Use of rubber not provided for in a single one of main groups B29K2007/00 - B29K2011/00, as moulding material
• CPC Class Codes: B29K 2096/04 Block polymers
• CPC Class Codes: B29L 2007/00 Flat articles, e.g. films or sheets B29L2024/00 takes precedence
• 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 53/02 of vinyl-aromatic monomers and conjugated dienes

Abstract

Thermoplastic rubber containing minor amounts of amorphous polypropylene is extruded into films. The films retain characteristic elastomeric properties of pure rubber, but are significantly more processable owing to the presence of the amorphous polypropylene.

Claims

1. A film comprising thermoplastic rubber and sufficient amorphous polypropylene to improve the processability of said thermoplastic rubber, wherein the thickness of said film is not more than about 10 mils, and wherein said thermoplastic rubber is a block copolymer of styrene with isoprene or butadiene.

2. The film of claim 1 wherein said thermoplastic rubber is a radial block copolymer of styrene with isoprene or butadiene.

3. The film of claim 2 wherein the amorphous polypropylene contains less than about 20 weight percent isotactic polypropylene.

4. The film of claim 2 wherein the amorphous polypropylene contains less than about 10 weight percent isotactic polypropylene.

5. The film of claim 2 wherein the amorphous polypropylene is employed in an amount within the range of from about 10 to about 35 weight percent, based on weight of thermoplastic rubber plus amorphous polypropylene.