| 摘要 |
PURPOSE:To facilitate the formation of the titled porous body of a large pore diameter, by molding a powder/liquid lubricant mixture obtained by treating a specified polytetrafluoroethylene powder dispersion by adding a liquid lubricant thereto, removing the liquid lubricant from the molding and stretching it. CONSTITUTION:A dispersion obtained by dispersing by mixing 100pts.wt. polytetrafluoroethylene powder (A) (e.g., commercially available fine powder) having a content of secondary particles of a particle diameter of tens to hundreds of mu which is far higher than the content of primary particles in 1,000-10,000pts.wt. liquid (B) with which component A cannot be wetted, such as methanol, ethanol or water, is agitated to comminute the particles to 30mu or below. To this dispersion, 100-1,500pts.wt. liquid lubricant (C) (e.g., polychlorotrifluoroethylene) incompatible with component B is added to transfer the comminuted powder to component C and component B is removed from the mixture by decantation. The mixture comprising the powder and component C is molded into any desired shape. Component C is removed from the molding, and this molding is stretched at a stretch ratio of 200-20,000% and a temperature higher than the m.p. of component A to obtain the title porous body of a porosity of 60-90% and a pore diameter of 20-60mu. |
