THIN TRANSPARENT POLYTETRAFLUOROETHYLENE FILM AND PRODUCTION PROCESS THEREOF

摘要

Disclosed herein is a thin transparent polytetrafluoroethylene film having: (1) a film thickness of 0.1-100 mu m; (2) a parallel light transmittance of at least 70% (as measured in accordance with JIS K 7105); and (3) a tensile strength of at least 1 kg/mm2 (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 DEG 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.