Patent ID: 8709641
Filing Date: 2014-04-29
Classification: B01D,B29C,B32B,H01M,Y02E

Abstract:
1. A microporous membrane comprising layers, wherein: 1) at least one layer comprises a first polymer comprising an ethylene/α-olefin copolymer having a Tm of 121.0 to 125.0° C. and an Mw of 5.0×10 2) at least a second layer of the membrane comprises 15 wt. % to 40 wt. % of polypropylene having an Mw≧5.0×10 3) a third layer comprises the ethylene/α-olefin copolymer, 4) the second layer is located between the first and third layers, 5) the first and third layers each individually comprise from 3 wt. % to 50 wt. %, based on the weight of the respective first layer or third layer, and 6) the membrane has a shutdown temperature ≦130.5° C., a rupture temperature ≧170.0° C. and a normalized air permeability ≦700 seconds/100 cm