| abstract |
The present invention relates to a polyolefin microporous membrane, characterized in that it comprises a composition containing a polyolefin resin and a crystallization nucleating agent, and the MFR value of the polyolefin resin is 2.0 g/10 minutes or less, converted to an air resistance of 20 μm The degree is 100 seconds/100CC to 500 seconds/100CC, the porosity is 20% to 60%, and the average flow pore size is below 100nm. Such a polyolefin microporous film has excellent mechanical strength such as puncture strength and withstand voltage characteristics such as dielectric breakdown voltage, and is characterized by high versatility and safety. |