| abstract |
The present invention relates to a polyolefin microporous membrane characterized by comprising a composition that includes a polyolefin resin and a crystal nucleating agent, wherein the MFR value of the polyolefin resin is 2.0 g/10 min or less, the air resistance converted to 20 μm is 100-500 sec/100 cc, the porosity is 20-60%, and the average flow pore size is 100 nm or less. Said polyolefin microporous membrane thus has characteristics such as excellent mechanical strength including puncture strength, and excellent voltage resistance characteristics including breakdown voltage, in addition to being highly versatile and safe. |