POLYOLEFIN POROUS SHEET AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain a homogeneous polyolefin porous sheet having a high strength and a high porosity and suitable for uses such as a separator for cells or batteries. SOLUTION: This polyolefin porous sheet is obtained by heating and sintering a polyolefin powder having a median diameter within the range of 30-200μm, a geometrical standard deviation of the particle diameter within the range of 0.68-0.95 and an average particle circularity within the range of 0.86-1 at a temperature of the melting point thereof or above. The resultant polyolefin porous sheet has a porosity within the range of 25-60 vol.%, a bubble point pore diameter within the range of 20-70μm and >=1500 N/cm<2> tensile breaking strength.