PRODUCTION OF POROUS MEMBRANE OF POLYTETRAFLUOROETHYLENE RESIN AND PRODUCTION OF MEMBRANE SEPARATION APPARATUS WITH THE SAME MEMBRANE

摘要

PURPOSE:To obtain a porous membrane capable of being made effectively hydrophilic and ensuring satisfactory water permeability by heat-treating a molded body of a mixture of polytetrafluoroethylene resin dispersed in a liq. with a fiber forming polymer, removing the polymer and sticking a surfactant. CONSTITUTION:Polytetrafluoroethylene(PTFE) resin dispersed in a liq. is mixed with a fiber forming polymer such as viscose and this mixture is molded. The molded body is heat-treated at the m.p. of the PTFE resin or above, then the fiber forming polymer is removed. A surfactant having <=30dyn/cm surface tension at 25 deg.C when dissolved in water to 0.1wt.% concn. is then stuck. Since the resulting porous membrane is made effectively hydrophilic by the surfactant and water can be passed through the membrane only by applying a slight water pressure, a significant separating effect is produced.