The manner null which grants pressure tightness to the filtration membrane

摘要

PURPOSE:To obtain the titled pressure withstanding microporous hollow yarn filter membrane capable of being used at high pressure by cross-linking the microporous hollow yarn membrane consisting of polyethylene or its copolymer and having a uniform three-dimensional reticular structure under specified conditions. CONSTITUTION:For example, a fine silicic acid powder, dioctyl phthalate (DOP) and the powder of polyethylene resin are mixed, the mixture is extruded into a hollow yarn, the yarn is dipped in trichloroethane to extract the DOP, the yarn is then dipped in an aq. soln. of sodium hydroxide to further extract the fine silicic acid powder, and a hollow yarn membrane having 0.01-5mu mean pore diameter, 20-80% porosity, 0.5-10mm inner diameter, and =100% tensile elongation (Ebo) at 25 deg.C is obtained. The membrane is irradiated by gamma rays, and cross-linked at 20=Ebo/Ebc=1.5 [Ebc is the tensile elongation (%) at 25 deg.C after cross-linking], and the pressure withstanding microporous hollow yarn filter membrane is obtained.