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:
Nov. 15, 2016
Filed:
Jun. 23, 2014
Sumitomo Electric Fine Polymer, Inc., Sennan-gun, Osaka, JP;
Fumihiro Hayashi, Osaka, JP;
Hiroyuki Tsujiwaki, Osaka, JP;
Aya Murata, Osaka, JP;
Atsushi Uno, Osaka, JP;
SUMITOMO ELECTRIC FINE POLYMER, INC., Sennan-gun, Osaka, JP;
Abstract
Provided is a method for producing a porous polytetrafluoroethylene film having good chemical resistance, good heat resistance, a high porosity, and good dimensional stability. The method for producing a porous polytetrafluoroethylene film includes a stretching step of stretching a sheet-like molded body composed of a fluororesin containing polytetrafluoroethylene as a main component in a longitudinal direction and/or a lateral direction at a temperature lower than a melting point of the fluororesin to make a porous fluororesin film, and, after the stretching step, an annealing step of holding the porous fluororesin film in a shape-fixed state, and maintaining the porous fluororesin film at a temperature lower than the melting point of the fluororesin but not lower than a temperature 30° C. lower than the melting point for 1 to 20 hours.