| 摘要 |
PURPOSE:To obtain the subject porous material having high porosity and relatively large pore diameter by mixing two kinds of fine powder of polytetrafluoroethylene having high molecular weight and low molecular weight with a liquid lubricant, forming the mixture, drawing the formed mixture before sintering and heat-treating the drawn product. CONSTITUTION:The objective porous material is produced by mixing (A) 10-90 pts.wt. (preferably 15-85 pts.wt.) of polytetrafluoroethylene (PTFE) fine powder having an average molecular weight of >=2,000,000, (B) 90-10 pts.wt. (preferably 85-20 pts.wt.) of a PTFE having an average molecular weight of <=1,000,000 (preferably 200,000-1,000,000) and (C) preferably 15-40 pts.wt., especially 20-30 pts.wt. (based on 100 pts.wt. of A+B) of a liquid lubricant (e.g. solvent naphtha), forming the mixture in prescribed form, optionally removing the component C from the formed material, drawing the material in at least one direction before sintering and heat-treating the drawn product at a temperature higher than the melting point of PTFE. |
