POLYTETRAFLUOROETHYLENE POROUS MATERIAL AND MANUFACTURE THEREOF

摘要

PURPOSE:To obtain a porous PTF molding of a porosity of 40% or more with a pore diameter of 0.1mum or less by using PTFE fine powder of an extremely high number average molecular weight. CONSTITUTION:PTFE fine powder of a molecular weight of ten million or more is mixted with a liquid lubricant, and the mixture is extruded or molded by rolling or a combination of extrusion and rolling. The unbaked molding is stretched to at least one direction with a stretching ratio of 200% or more in order to obtain a molding of a pore diameter of 0.2mum or less. To stabilize and strengthen the porous structure of such a porous molding of 0.2mum or less fine pore diameters, the molding is preferably heated and baked at about 327 deg.C under a condition that thermal shrinkage is prevented afterwards.