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:
Mar. 20, 1990
Filed:
Oct. 19, 1988
Applicant:
Inventors:
Michael C Coughlin, Kingston, CA;
Arthur Z Moss, Wilmington, DE (US);
Kenneth E Stevens, Kingston, CA;
Assignee:
Du Pont Canada Inc., Mississauga, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B29C / ;
U.S. Cl.
CPC ...
264 455 ; 264 453 ; 264 459 ; 264 461 ; 2642106 ; 2642888 ;
Abstract
A film having a porous core layer and nonporous outer layers is made from a composition of certain polymers, particularly ethylene polymers, a particulate filler which has little affinity for the polymer, and optionally an organic compound which decreases the tendency for affinity of the particulate for the polymer. The film is produced by extruding the composition through a die gap of at least 250 .mu.m, and subsequently stretching the film after cooling to a temperature below the melting temperature of the polymer.