| abstract |
(57) [Summary] [Object] To provide a method for efficiently producing a polyolefin microporous membrane having good permeability, stable pore opening with a fine pore size, and high strength. [Structure] A polyolefin containing 1% by weight or more of a component having a molecular weight of 7 × 10 5 or more is melted in an extruder, and 10 to 80% by weight of the polyolefin in a molten state, and 90 to 20% by weight of a solvent such as liquid paraffin. Is melt-kneaded by supplying from the middle of the extruder, the resulting kneaded product is extruded from an annular die, cooled to form a gel tube raw material, the gel tube raw material is heated and stretched, and then remains. A method for producing a microporous polyolefin membrane, which comprises removing a solvent. |