Parkhurst & Oliff
Thin transparent polytetrafluoroethylene film and production process thereof
 Disclosed herein is a thin transparent polytetrafluoroethylene film having: PA1 (1) a film thickness of 0.1-100 .mu.m; PA1 (2) a parallel light transmittance of at least 70% (as measured in accordance with JIS K 7105); and PA1 (3) a tensile strength of at least 1 kg/mm.sup.2 (as measured in accordance with JIS K 6887 except for the use of a pulling speed of 10 mm/min.). The film is produced by fluorinating with a fluorine gas a thin film formed from a solution of a fluoroethylene polymer having an inherent viscosity of at least 2.5 dl/g (as measured at a temperature of 30.degree. C. and a solution concentration of 0.4 g/dl) in accordance with the casting process and having a thickness of 0.1-100 .mu.m. 
Kureha Chemical Industry Co.
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inventional inventional additional additional
Naohiro Teruo Noriyuki
Murayama Sakagami Arakawa