Dialysis membrane comprising hollow cellulose fibre - with improved exchange surface in wavy form, mfd. from cuprammonium soln. of cellulose

摘要

A dialysis membrane of cellulose regenerated from cuprammonium solns. is in the form of a hollow fibre with a continuous empty space. The fibre surface shows periodic variations in the longitudinal direction (e.g. comprising longitudinal waves) and/or in the peripheral direction. Thus the cross-section, perpendicular to the fibre axis, varies periodically over the fibre length. The membrane can be mfd. by extrusion of a cuprammonium soln. of cellulose into an aq. caustic soda soln. through the annular slit of a hollow fibre die immersed in the aq. caustic soda soln. A liq. which will shape the empty space is extruded through the inner passage of the die. The ratio of the speed of drawing of the hollow fibre over the first drawing roller to the speed of extrusion of the cuprammonium soln. of cellulose from the annular slit is 1-1.05. The direction the fibre follows from the die to the first drawing roller forms an acute angle, pref. 15-70 degrees, with the axis of the die apertures. Subsequent treatment of the fibre is as usual. The membrane is used partic. in haemodialysis. The efficiency of dialysis is increased owing to an improved exchange surface.