Patent ID: 7182870
Filing Date: 2007-02-27
Classification: B01D,C02F

Abstract:
1. A hollow fiber membrane consisting essentially of a polyvinylidene fluoride resin; the membrane made by the process of discharging a solution of polyvinylidene fluoride of average molecular weight about 358,000–417,000 in y-butyrolactone or propylene carbonate at a temperature above the phase separation into a cooling bath below the pahse separation temperature; the membrane having spherical structures that have an average diameter in the range of 1.8 to 3.2 μm, wherein the hollow fiber membrane has a water permeability in the range of 1.3 to 4.5 m 3 /m 2 hr at 100 kPa and 25° C., a tensile strength in the range of 1.8 to 2.1 kg per fiber, an elongation at break in the range of 75% to 85%, and a rejection of polystyrene latex having a particle size of 0.309 μm of 78% –95% or more.