Polytetrafluoroethylene Porous Film and Method of Manufacturing the same (POLYTETRAFLUOROETHYLENE POROUS FILM AND METHOD FOR MANUFACTURING THE SAME)

摘要

A polytetrafluoroethylene porous membrane is provided which is excellent as an air filter used as a cleaning chamber in the semiconductor industry and which is suitable for collection of fine particles in a gas such as air and exhibits a low pressure drop. The membrane has an average pore size of 0.2 to 0.4 [mu] m and has an air permeability of 20 to 50 mmH₂O pressure drop appears. The membrane is prepared by stretching the untreated polytetrafluoroethylene at a specified temperature.