Process for manufacturing molded articles of cellulose

Abstract

A process for manufacturing molded articles of cellulose, such as fibers films, which includes (a) providing an aqueous solution comprising cellulose in a tertiary amine N-oxide, (b) extruding jets of the aqueous solution through an extrusion die into a non-precipitating medium for cellulose, the extrusion die having nozzle passages the length L of which is in the range from 200 to 800 .mu.m and the capillary section of which has a length l in the range from 50 to 240 .mu.m and a ratio l/d of length l to its diameter d in the range from 0.5 to 2.0, the molecules of cellulose in the jets of solution being pre-orientated by the extrusion die through a shear force gradient in the nozzle passages, (c) additionally orientating the cellulose molecules by stretching the extruded jets of solution in said non-precipitating medium with a spinning stretch ratio V of linear velocity of the precipitated molded article to the linear velocity of the solution leaving the die in the range 0.5>V>3, and (d) precipitating the molded cellulose articles from said jets of solution by contacting with a precipitating medium without stretching. The shortened shearing section of the nozzle passages allows a reduction of the spinning pressure. The safety of the spinning operation is increased by the low spinning stretch. The stretch interval in the non-precipitating medium is reduced, and the elongation and loop strength data of the spun fibers are improved.