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:
Jan. 02, 1996
Filed:
Jan. 31, 1995
Soji Nishiyama, Osaka, JP;
Hiroyuki Higuchi, Osaka, JP;
Kiichiro Matsushita, Osaka, JP;
Ryoichi Matsushima, Osaka, JP;
Nitto Denko Corporation, Osaka, JP;
Abstract
A porous film, a process for producing the same, a battery separator comprising the porous film, and a battery having incorporated therein the separator are disclosed. The porous film comprises a polyethylene and a polypropylene as the essential components, wherein the polyethylene content in the total weight of polyethylene and polypropylene is from 2 to 40% by weight and the polyethylene content is changed in the direction of the thickness of the film, and is produced by forming a laminate film comprising at least one polypropylene layer and at least one layer of a mixture of polyethylene and polypropylene as the essential components, the polyethylene content in the film being from 2 to 40% by weight, uniaxially stretching the laminate film at a low-temperature range of from -20.degree. C. to 80.degree. C. and then stretching the film at a high-temperature range of from 90.degree. C. to 150.degree. C.