Patent ID: 11603443

Abstract:
A composite porous membrane contains at least one porous base layer and at least one uniaxially stretched coating layer located on at least one side surface of the porous base layer. For example, the composite porous membrane comprises at least one porous base layer and at least one nanofiber-like non-polyolefin polymer porous layer oriented along the transverse stretching direction of the composite porous membrane and located on one or two side surfaces of the porous base layer, or the composite porous membrane comprises a biaxially stretched polypropylene porous base layer and a uniaxially stretched coating layer located on at least one side surface of the porous base layer. The composite porous membrane is coated with a coating solution prior to transversely stretching. The nanofiber-like non-polyolefin polymer porous layer may reduce cracking of the composite porous membrane in the machine direction.