DIALYSEMEMBRAN FUER DIE HAEMODIALYSE

A dialyzing membrane, especially for hemodialysis, formed as a hollow fiber, tubular foil or flat sheet by regeneration of cellulose from a cuprammonium solution, the membrane comprising at least two firmly adhered cellulosic layers including at least one dialyzing layer consisting essentially of a semipermeable regenerated cellulose and at least one adsorbent layer consisting of said regenerated cellulose containing embedded therein fine particles of an adsorbent material in an amount of up to 95% by weight with reference to the dry weight of the adsorbent layer, preferably 1 to 90% and especially 20 to 70% by weight, when the adsorbent layer is part of a hollow fiber structure. The dialyzing membrane of the invention is produced by a method requiring at least two cuprammonium cellulose solutions, one of which is free of adsorbent particles and another of which contains a suspension of adsorbent particles, the different solutions being spun from adjacent spinning slots for immediate layer to layer contact and then introduced over a short air gap into a coagulating or precipitating bath to entrap the adsorbent particles in the spun layer in which the particles were originally suspended. Isopropyl myristate is particularly advantageous as a liquid filler for the axial duct or canal of a hollow membrane.