Patent ID: 8708161
Filing Date: 2014-04-29
Classification: B01D,C02F,D01D,D01F,Y02A

Abstract:
1. An anisotropic polyvinylidene fluoride hollow fiber microporous membrane comprising a polyvinylidene fluoride resin, wherein: (1) the hollow fiber microporous membrane does not include macrovoids, and has mainly a net-like structure; (2) the hollow fiber microporous membrane has a dense outer layer on an outer surface, and a homogeneous bulk layer that is internally adjacent to the outer layer and that has a coarser structure than the outer layer; (3) a porosity A of the bulk layer is at least 1.5 times a membrane surface porosity B of the outer layer; (4) the dense structure of the outer layer changes substantially discontinuously into the coarse structure of the bulk layer; (5) the membrane surface porosity of the outer layer is not more than 40%, and the porosity of the bulk layer ranges from 20% to 60%; and (6) a tensile strength at break ranges from 2 MPa to 20 MPa, and a tensile elongation at break ranges from 200% to 500%.