Medium density chlorinated polyvinyl chloride foam and process for preparing

• US 5,789,453 A
• Filed: 04/10/1997
• Issued: 08/04/1998
• Est. Priority Date: 04/10/1997
• Status: Expired due to Term

• Current Assignee: Noveon, Inc. (Berkshire Hathaway Incorporated)
• Original Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Detterman, Robert Edwin
• Primary Examiner(s): Foelak, Morton
• Application Number:
  US08/831,671
• Time in Patent Office: 481 Days
• Field of Search: 521/79, 521/81, 521/92, 521/93, 521/94, 521/134, 521/139, 521/140, 521/145
• US Class Current: 521/92
• CPC Class Codes: C08J 2201/03 Extrusion of the foamable blend
• CPC Class Codes: C08J 2327/04 containing chlorine atoms
• CPC Class Codes: C08J 2327/24 halogenated
• CPC Class Codes: C08J 2421/00 Characterised by the use of unspecified rubbers
• CPC Class Codes: C08J 9/0061 characterized by the use of several polymeric components
• CPC Class Codes: C08J 9/06 by a chemical blowing agent
• CPC Class Codes: C08J 9/08 developing carbon dioxide
• CPC Class Codes: C08K 5/57 Organo-tin compounds
• CPC Class Codes: C08L 27/24 halogenated

Abstract

The present invention relates to a medium density chlorinated polyvinyl chloride foam and the method of preparing such a foam using a blend of chemical blowing agents. The foam having a specific gravity in the range of about 0.3 to about 1.5 comprises chlorinated polyvinyl chloride, a blend of decomposition type blowing agents, a tin stabilizer, a optional impact modifier and a optional high molecular weight process aid.

Claims

1. A medium density foam having a specific gravity in the range of 0.3 to 1.5 having been foamed from a composition comprising chlorinated polyvinyl chloride, decomposition type blowing agent(s) or blends thereof, a tin stabilizer, and an impact modifier, wherein said decomposition blowing agent comprises a blend of bicarbonate and azodicarbonamide blowing agent.

2. A medium density foam according claim 1, wherein said bicarbonate blowing agent comprises from about 30 to about 60% of the decomposition blowing agent.

3. A medium density foam according to claim 2, wherein said bicarbonate blowing agent comprises about 50% of the decomposition blowing agent.

4. A medium density foam according to claim 1, wherein said azodicarbonamide blowing agent comprising from about 40 to about 70% of the decomposition type blowing agent.

5. A medium density foam according to claim 1 wherein said impact modifier is chosen from the group consisting essentially of acrylic impact modifiers, MBS impact modifiers, ABS impact modifiers, silicon rubber/acrylic copolymer impact modifiers and chlorinated polyethylene impact modifier.

6. A medium density foam according to claim 5, wherein said impact modifier is an acrylic impact modifier.

7. A medium density foam according to claim 5, wherein said impact modifier is found in the range of about 0.1 to about 10 parts per 100 parts of CPVC.

8. A medium density foam according to claim 7, wherein 6 parts of impact modifier are used.

9. A medium density foam according to claim 1, further comprising a high molecular process aid.

10. A medium density foam according to claim 1, wherein said chlorinated polyvinyl chloride has 67% chlorine, 0.68 inherent viscosity and a fused density of 1.5757 grams/cc.

11. A medium density foam according to claim 1, the composition further comprising an optional costabilizer.