| abstract |
PROBLEM TO BE SOLVED: To provide a polyethylene hollow fiber-like porous membrane having both fine pores and high water permeability, which is suitable for filtration applications such as turbidity. SOLUTION: An outer surface dense type sponge-like anisotropic structure having a minimum pore size layer on an outer surface portion is provided, and the outer surface pore size is reduced to 1%. μm, the inner surface pore diameter is 1 μm or more, and the porosity is 50% or more and less than 95%. |