| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a production method capable of producing a polytetrafluoroethylene porous film which easily stretches in the longitudinal direction. <P>SOLUTION: A mixture obtained by adding a liquid lubricant to polytetrafluoroethylene fine powders is molded into a sheet-like molding which stretches in the predetermined direction. The sheet-like molding is stretched in the width direction while including the liquid lubricant, and then the liquid lubricant is removed from the sheet-like molding. Then, the sheet-like molding is made into the polytetrafluoroethylene porous film having structure in which a fibril 32 stretches in the width direction and a node 31 stretches in the longitudinal direction by stretching the sheet-like molding in the width direction from which the liquid lubricant is removed. <P>COPYRIGHT: (C)2013,JPO&INPIT |
