| 摘要 |
PURPOSE:To obtain a porous film provided with uniform perforations each having an almost real circular shape and excellent in mechanical strength, by irradiating a baked body, which was obtained from a molding grade polytetrafluoroethylene resin (PTFE) powder prepared by a suspension polymerization method, with ionizable radioactive rays before stretching. CONSTITUTION:A molding grade PTFE powder with an average particle size of 25mu obtained by a suspension polymerization method is preparatorily molded in a mold and the molded one is baked at 350 deg.C for 1hr to form a molded body which is, in turn, cut into a cut film with a thickness of 0.1mm. Next, this PTFE cut film is irradiated with gamma rays from cobalt 60 in an irradiation dose of 10<4> rad at room temp. in air and stretched 6 times on the basis of the original length to obtain a PTFE porous film. |
