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. 07, 2016
Filed:
Sep. 14, 2012
Akihiro Ogawa, Osaka, JP;
Takahiko Sawada, Osaka, JP;
Shotaro Kobaru, Osaka, JP;
SEKISUI CHEMICAL CO., LTD., Osaka, JP;
Abstract
Provided is a method for producing a propylene-based resin microporous film capable of forming a high-performance lithium ion battery. The method for producing a propylene-based resin microporous film includes an extrusion step of melt-kneading a propylene-based resin in an extruder, and extruding the resin to obtain a propylene-based resin film; a first stretching step of uniaxially stretching the propylene-based resin film at a surface temperature of −20 to 100° C.; second stretching step of repeating, a plurality of times, a stretching basic step in which the propylene-based resin film after the first stretching step is uniaxially stretched at a surface temperature that is equal to or lower than a temperature lower than the melting point of the propylene-based resin by 10 to 100° C., wherein between successive stretching basic steps, the stretching ratio in the forward-side stretching basic step is adjusted so as to be lower than that of the backward-side stretching basic step; and an annealing step of annealing the propylene-based resin film after the second stretching step.