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:
Sep. 07, 1999
Filed:
Oct. 28, 1996
Kazuo Yagi, Yamaguchi-ken, JP;
Akinao Hashimoto, Yamaguchi-ken, JP;
Hitoshi Mantoku, Yamaguchi-ken, JP;
Mitsui Chemicals, Inc., Tokyo, JP;
Abstract
A porous biaxially oriented film comprising a copolymer of an ethylene having an intrinsic viscosity �.eta.! of from 3.5 to 10.0 dl/g and an .alpha.-olefin having 4 to 8 carbon atoms, the content of the .alpha.-olefin being in a number of from 1.0 to 7.5 per 1000 carbon atoms and the film retaining the structure which is based upon the microfibrils when it is heat-treated at 160.degree. C. under a constrained state and is then observed at room temperature, and a separator made of this film for batteries. The porous biaxially oriented film exhibits excellent gas permeating property over a practicable temperature range, exhibits excellent mechanical strength and, particularly, tensile strength, and loses gas permeating property when a maximum practicable temperature is exceeded. The film can be favorably used as a separator for batteries.