| abstract |
PURPOSE: To obtain the semipermeable membrane which is superior in water permeability and endurance by extruding the organic solvent solution of vinyl (vinylidene) chloride-base polymer from a double-tube nozzle to form a hollow fiber and introducing the specific core solution into its hollow part. n CONSTITUTION: Vinyl (vinylidene) halide-base polymer or the like is dissolved in a water soluble organic solvent such as N,N-dimethyl formamide or the like and is forcedly fed from the raw liquid lead-in port 10 of a double-tube nozzle 4, whereby it is wet-type spun to hollow-fiber form. At this time, the core solution containing 25% or more of nonsolvent such as lower alkanol or alkyl myristate which is compatible with the foregoing solvent but does not dissolve the polymer and 25% or less of water is introduced into the core liquid lead-in port 12 of a capillary 11. The hollow semipermeable membrane formed by this method has semipermeability only at its both sides of the outside and therefore it is superior in water permeability and is also superior in chemical resistance, chemical stability, mechanical strength, etc. n COPYRIGHT: (C)1980,JPO&Japio |