Patent ID: 7931154
Filing Date: 2011-04-26
Classification: B01D

Abstract:
1. A process for manufacturing an asymmetric hollow fibre membrane, comprising the steps of: extruding a polymer solution through an outer ring slit of a hollow fibre spinning nozzle and simultaneously extruding a centre fluid through an inner bore of the hollow fibre spinning nozzle into a precipitation bath, whereby the polymer solution contains 10 to 26 wt-% of polysulfone, polyethersulfone, or polyarylethersulfone, 8 to 15 wt-% polyvinyl pyrrolidone, and 60 to 80 wt-% N-alkyl-2-pyrrolidone, the centre fluid contains 60 to 70 wt-% N-alkyl-2-pyrrolidone and 30 to 40 wt-% water; and the precipitation bath contains 73 to 82 wt-% N-alkyl-2-pyrrolidone and 18 to 27 wt-% water.