HYDROPHILIC POLYTETRAFLUOROETHYLENE FILTER MEMBRANE AND ITS PRODUCTION

摘要

PURPOSE:To obtain the title hydrophilic porous membrane having resistance to both heat and chemicals and suitable for purifying an acidic etching liq. by cross-linking a nonmetallic ion-type fluorine surfactant on a PTFE filter membrane until the surfactant is made insoluble in an aq. soln. CONSTITUTION:A fluorine surfactant is coated on the porous surface of a PTFE filter membrane having narrow pore diameter distribution. At this time, the PTFE filter membrane is placed under 100-150mmHg reduced pressure and immersed in a dilute soln. of the fluorine surfactant to reduce the necessary time. After hydrophilicity is provided to the surface of the PtFE filter membrane by complete immersion in the soln., high-energy radiation rays are irradiated to make the fluorine surfactant insoluble in water. The reaction is preferably carried out under conditions were oxygen is substantially absent.