Asymmetrical membranes for liq.-vapour and vapour-vapour permeation - made by immersing layer of polymer soln. and substrate in non-aq. coagulation bath of defined solubility parameter

摘要

Asymmetrical membranes for liquid-vapour or vapour-vapour permeation are made from a dispersion of a macromolecular material (I) in at least one organic dispersing agent (II) in which the (I) may be soluble, by applying the dispersion to a substrate and immersing the coated substrate in a coagulation bath comprising a non-aq. non-solvent (III) for the polymer (I), the difference in solubility parameters between the non-solvent (III) and the solvent (II) being less than or equal to (6 cal/cm3) power 1/2=12.24 x 10 power 3 (J/ cm3) power 1/2).