| 摘要 |
<p>PURPOSE:To obtain the title porous body with improved strength property useful for a filter material or the like by a mechanism wherein an unsintered polytetrafluoroethylene porous body produced by a drawing method is heat treated from a certain portion in the condition for preventing heat shrinkage. CONSTITUTION:An unsintered polytetrafluoroethylene mixture added by a liquid lubricant such as white oil or the like is molded in a desired shape and drawn to at least unidirection to obtain a porous body. Subsequently, the obtained porous body is heated to above 327 deg.C from a certain portion in the condition for preventing heat shrinkage and subijected to a sintering treatment until the orentation of a fine fibrous texture of the said portion becomes larger to the direction vertical against the drawing direction than to the drawing direction. Thereby, the heated surface becomes a net like structure having pore size of aobut few mum-few mm finally and excellent strength and permeation property are imparted, and an appropriate property as an electrolysis memberane or the like is obtained.</p> |
