| 摘要 |
1,188,183. Permeable membranes. AMICON CORP. 19 April, 1967 [26 April, 1966], No. 17950/67. Heading B2E. [Also in Divisions B5 and C3] An unwoven web of fibres, e.g. of polyester, is coated with an anisotropic permeable membrane consisting of gel structure having a lattice formed of two ionically associated solid, film-forming synthetic organic linear polymers, the first polymers having dissociable anionic and cationic groups respectively attached to their polymeric chains which without there respective groups form water-insoluble film forming resins, each polymer having sufficient dissociable groups to render it water-soluble in the absence of the other, the membrane having a zone adjacent one face of permeability which is one half or less of the permeability of the remainder of the membrane. The coating process consists in casting an aq. solution, containing the above two polymers, at least 10% by wt. of an electrolyte having a pK less than 2.0 and at least 10% of an organic solvent miscible therewith, on a casting surface, on which has been disposed already the unwoven web of fibres, in a layer of the desired thickness and washing the layer, while on the surface and while containing 1-99% of the electrolyte and solvent, with a solvent for the electrolyte maintained at 40-100‹C and then stripping the layer from the surface. The two polymers may be poly (sodium styrene sulphonate) and poly (vinyl benzyl trimethyl ammonium chloride), the electrolyte may be hydrochloric or sulphuric acid, the solvent may be dioxane, ethanol or dimethylsulphoxide and an aq. solution of the dioctyl ester of sodium sulpholsuccinate or water may be used for washing. |
