The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 05, 2003
Filed:
Aug. 30, 1999
Applicant:
Inventors:
Robert W. Callahan, Charlotte, NC (US);
Ron W. Call, Rock Hill, SC (US);
Ken J. Harleson, Fort Mill, SC (US);
Ta-Hua Yu, Dover, DE (US);
Assignee:
Celgard Inc., Charlotte, NC (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B32B 3/26 ; H01M 2/16 ;
U.S. Cl.
CPC ...
B32B 3/26 ; H01M 2/16 ;
Abstract
A split resistant microporous membrane is provided for use in preparing a battery separator. The microporous membrane has a TD tensile strength to MD tensile strength ratio of from about 0.12 to about 1.2, preferably from about 0.5 to about 1. The microporous membrane is made by a process which includes the steps of preparing a film precursor by blown film extrusion at a blow-up ratio of at least 1.5, annealing the film precursor, and stretching the resultant annealed film precursor to form the microporous membrane.