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:
Jun. 26, 2007
Filed:
Feb. 15, 2002
Kiyoshi Sadamitsu, Yawata, JP;
Naoki Ikeda, Kyoto, JP;
Manabu Hoki, Joyo, JP;
Kenichiro Nagata, Kyoto, JP;
Koichi Ogino, Takatsuki, JP;
Kiyoshi Sadamitsu, Yawata, JP;
Naoki Ikeda, Kyoto, JP;
Manabu Hoki, Joyo, JP;
Kenichiro Nagata, Kyoto, JP;
Koichi Ogino, Takatsuki, JP;
New Japan Chemical Co., Ltd., Kyoto-Shi, JP;
Abstract
Disclosed is a successively biaxially stretched film obtained by successive biaxial stretching method comprising extruding a melt of a β-crystal nucleating agent-containing polypropylene-based resin composition from a T-die, cooling the extruded resin on a chill roll, and stretching the resulting web sheet longitudinally and then transversely, wherein the longitudinally stretched sheet is made to have a degree of β-crystal orientation of less than 0.3 by the following method (I) and/or (II), optionally subjected to annealing treatment, and transversely stretched: The porous polypropylene film has good breakage resistance during manufacture, excellent thickness uniformity, high porosity and air-permeability, and is useful for battery separators.