Patent ID: 8967391
Filing Date: 2015-03-03
Classification: B01D

Abstract:
1. A method of producing a composite multilayer porous hollow fiber membrane, comprising steps of: (1) mixing a thermoplastic macromolecule polymer resin, an organic pore-forming agent, an inorganic pore-forming agent, and an auxiliary agent in the ratio by weight of 30-50:20-40:10-30:0-5, extruding with melting and kneading through an extruder to obtain an uncured hollow fiber; (2) mixing a thermoplastic macromolecule polymer resin, a hydrophilic macromolecule pore-forming agent, a surfactant, a good solvent, and a poor solvent in the ratio by weight of 5-30:1-20:1-20:40-90:1-10 in a coating polymeric dope solution tank to obtain a coating polymeric dope solution; (3) passing the uncured hollow fiber obtained in said step (1) by travelling 0-5 cm into the coating polymeric dope solution obtained in said step (2) for the non-solvent phase separation (NIPS) technique, wherein, when the uncured hollow fiber obtained in said step (1) is being solidified, and its outer surface is simultaneously being coated by the coating polymeric dope solution obtained in said step (2), resulting in a hollow fiber with an ultra thin outer layer; (4) passing the hollow fiber with the ultra thin outer layer obtained in said step (3) through a sealing spinning nozzle of the coating device, and introducing it into a coagulation bath for coagulating coating layer to form a composite multilayer hollow fiber; (5) extracting to obtain the composite multilayer porous hollow fiber membrane.