Patent ID: 9415348
Filing Date: 2016-08-16
CPC Classification: B01D,B29C,B29K,B29L

Claim Text:
1. A method for preparing an aromatic polyamide porous hollow fiber membrane, comprising adopting a casting solution and a filming technology; wherein components of the casting solution and mass fractions thereof are: PPTA resin 1%-20%; pore-forming agents 5%-20%; solvent 60%-94%; wherein a sum of the mass fractions of the PPTA, pore-forming agents and solvent is 100%; inorganic particles 0.05-50% of the weight of PPTA resin; wherein logarithmic specific concentration viscosity of the PPTA resin is at a range of 4.5 dL/g-9.5 dL/g; the pore-forming agents are a water-soluble macromolecule and are selected from the group consisting of PEG with an average molecular weight of 1000-20000 and PVP with an average molecular weight of 10000-1000000; the solvent is sulfuric acid having a mass concentration at a range of 98%-106%; the inorganic particles are at least one member selected from the group consisting of silicon dioxide, calcium oxide and calcium carbonate; wherein the method for preparing the aromatic polyamide porous hollow fiber membrane comprises steps of: (1) pre-treating under 55° C. ultrasonic treatment, adding the PPTA resin in phosphoric acid solution having a mass concentration of 0.5-1% for 15-60 minutes, then drying the PPTA resin and the inorganic particles in vacuum under 100° C.-200° C. for more than 24 hours; and (2) preparing PPTA porous hollow fiber membrane mixing the PPTA resin, the inorganic particles and the solvent which are pretreated in a sealed stirring vessel, stirring for 1-2 hours under 40° C.-50° C. to obtain transparent yellow thick liquid, then adding the composite pore-forming agents to form casting solution, then injecting the casting solution into a double-screw extruder to be dissolved at 80-90° C. for 1-20 minutes, besides injecting sulfuric acid aqueous solution with a temperature at a range of 0-90° C., a flow velocity at a range of 10-100 ml/min and a volume fraction of 0-50% for serving as spinning bore liquid, while squeeze the casting solution into a hollow spinneret by a metering pump, wherein an extension ratio of a spinning jet is at a range of 1-10 times, finally extruding the casting solution by the hollow spinneret, thus an air bath is passed through a height range of 10-100 mm, and immersed in sulfuric acid aqueous solution having a volume fraction at a range of 0-50% for serving as coagulation bath to obtain a primary PPTA porous hollow fiber membrane, then winding, water scrubbing and neutralizing with alkaline liquor, extraction eluting in a room temperature water bath for over 48 hours to obtain the PPTA porous hollow fiber membrane.