| 摘要 |
PROBLEM TO BE SOLVED: To provide a PTFE porous film which is tough to damages by external forces and has good radiation resistance and dimensional stability, and to provide a method for producing the same and a filter comprising the same. SOLUTION: A PTFE fine powder is incorporated with a liquid lubricant to preform a paste mixture, which is formed to a sheet by paste extrusion or calendaring. The liquid lubricant is removed before the PTFE sheet molding is stretched in at least one direction, preparing the PTFE porous film. Then, the PTFE porous film is irradiated with radiation, substantially in the absence of oxygen, and in an environment of a temperature in the range of 340±20 deg.C, preferably in the range of 340±10 deg.C. |
