| 摘要 |
PURPOSE:To provide a porous membrane which has a very low water permeation pressure and excellent durability and is hydrophilic, by retaining a specified polymer on at least part of the pore surface of a porous polyolefin membrane. CONSTITUTION:0.5-50wt% monomer having an HLB value of 2-20, at least one polymerizable unsaturated groups, a hydrophilic moiety and a hydrophobic moiety, represented by formulas I-III (wherein l-n, h are each an integer; EO is ethylene oxide; R1 is H, CH3; R2 is propylene oxide, etc.; R5, R6 are each a 4-20C alkyl; M is an alkali metal), is deposited on at least part of the pore surface of a porous polyolefin membrane having a pore size of 0.01-5mu in an arbitrary form of a hollow yarn membrane, a flat membrane, a tubular membrane, etc. and graft-polymerized by thermal polymn. or photopolymerization to form a polymer layer of 0.2-30mg/m<2> of surface area of pore on the surface of pore.
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