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. 17, 2017
Filed:
Mar. 30, 2011
Shunsuke Noumi, Osaka, JP;
Kouji Tadokoro, Osaka, JP;
Yoshihiko Kondou, Osaka, JP;
Masatoshi Kawamura, Osaka, JP;
Shunsuke Noumi, Osaka, JP;
Kouji Tadokoro, Osaka, JP;
Yoshihiko Kondou, Osaka, JP;
Masatoshi Kawamura, Osaka, JP;
NITTO DENKO CORPORATION, Osaka, JP;
Abstract
The present invention relates to a method for producing a polyolefin porous film, the method including the steps of: (a) melt-kneading a solution containing a polyolefin having a weight average molecular weight of 500,000 or more and a solvent to obtain a kneaded product; (b) extruding and cooling the kneaded product to obtain a gel-like molded product; (c) drawing the gel-like molded product to obtain a drawn sheet; (d) removing the solvent from the drawn sheet, followed by drying to obtain a film in which fine pores are formed; (e) conducting heat treatment, while fixing the film in both directions of a MD and a TD thereof and drawing the film at a draw ratio of exceeding 0% to less than 0.1% in at least one direction of the MD and the TD thereof; and (f) conducting heat treatment while decreasing a width of the film in at least one direction of the MD and the TD of the film.