3843761 is referenced by 93 patents and cites 9 patents.

A process for the preparation of an open-celled microporous polymer film. The process includes the steps of cold stretching a non-porous, crystalline, elastic film significantly below the polymeric crystalline melting point of the polymer. The cold stretched film is then stretched, at a temperature slightly below the polymeric crystalline melting point of the film. The hot stretching procedure embodies a plurality of discrete sequential stretching operations.

Title
Process for preparing a thermoplastic microporous film involving a cold stretching step and multiple hot stretching steps
Application Number
05/365,365
Publication Number
3843761
Application Date
May 30, 1973
Publication Date
October 22, 1974
Inventor
Hay Ian L
Zimmerman Daniel
Daley Lawrence R
Bierenbaum Harvey S
Agent
Bressler Marvin
Grim Linn I
Morgan Thomas J
Assignee
Celanese Corporation
IPC
B29d 27/00
B29d 07/24
B29C 67/20
B29C 55/06
B29C 55/04
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