| abstract |
PROBLEM TO BE SOLVED: To easily and inexpensively provide a porous membrane excellent in fractionation performance, permeation performance and physical strength suitable for water treatment such as water purification treatment, drinking water production, industrial water production and wastewater treatment. SOLUTION: A porous film made of a vinylidene fluoride-based resin, wherein the porous film has circular or elliptical micropores having an average ratio of major axis to minor axis of 1: 1 or more and smaller than 5: 1 on one surface. Vinylidene fluoride resin characterized by having a fractional particle diameter of 0.2 μm or more having an average ratio of major axis to minor axis of 5: 1 or more on the other surface Porous membrane. [Selection figure] None |