| abstract |
Disclosed is a polyethylene microporous membrane that has high permeability and excellent strength at high temperatures and high-temperature thermothermal stability, and can be used as a battery separator to improve thermal safety and long-term performance stability of batteries. provide. A polyethylene microporous membrane is produced from a resin composition containing 20 to 50% by weight of polyethylene and 80 to 50% by weight of a diluent, and has a film thickness of 5 to 40 μm, a porosity of 35 to 55%, and a permeability of 2. 5 × 10 −5 to 10.0 × 10 −5 Darcy, puncture strength at 90 ° C. is 0.10 N / μm or more, burst angle is 90 ° or more at 90 ° C., and free at 120 ° C. for 1 hour The permeability after shrinkage is 2.0 × 10 −5 to 8.0 × 10 −5 Darcy. [Selection figure] None |