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. 17, 1987
Filed:
Jul. 03, 1985
Nippon Valqua Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A process for producing a polytetrafluoroethylene porous film having excellent mechanical strength wherein pores have a substantially perfect circle and it is possible to uniformly control its pore size to a predetermined size. The porous film is obtained by compression molding polytetrafluoroethylene resin molding powders obtained by a suspension polymerization method to prepare a preform, sintering said preform at a temperature of at least 327.degree. C., forming it into a film, resintering the film at a temperature of at least 327.degree. C., quenching it at a cooling rate of at least 70.degree. C. per hour to reduce the crystallinity of polytetrafluoroethylene to 55% or below, and thereafter stretching said film at a stretch ratio of from 1.3 to 6.5 while heating it to a temperature of from 100.degree. to 320.degree. C.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile