GB426905A - Improved production of tubular artificial textile threads - Google Patents

Abstract

In the production of tubular artificial fibres of less than 2 deniers from viscose solutions, coagulating baths containing sulphuric acid and sodium sulphate are used, and the concentrations of these coagulating agents indicated in Specification 255,527, [Class 2 (ii)], are increased by 20 per cent at least and preferably by 25--20 per cent for 1 denier filaments, and are increased on this basis for filaments having a titre greater or less than 1 denier by a quantity proportional to the difference between the titre of the filament and 2 deniers, the ratio between the sulphuric acid and the sodium sulphate remaining substantially constant. Preferably the filaments are given a short path such as 25 centimetres or less in the coagulating bath. In an example, viscose of specified ripeness and alkalinity, and containing sodium carbonate is spun into a coagulating bath containing sulphuric acid, sodium sulphate, and zinc sulphate, in proportions in accordance with Specification 255,527. Satisfactory filaments of 1 denier could not be obtained with this bath, although it is assumed to be satisfactory for filaments of 2 deniers. The solution is then spun into a bath in which the proportions of sulphuric acid and sodium sulphate are increased by 27,6 per cent, and satisfactory tubular filaments of 1 denier are obtained. A bath in which the proportions are increased by 13,8 per cent is found to give similar results for filaments of 1,5 deniers. The threads obtained have good suppleness, feel, and curl, and provide noncreasing fabrics. They may be obtained in the form of a sliver on a frame on which the sliver is spun and undergoes all the subsequent treatments as far as the final drying. The sliver is cut to staple lengths. The softness and curl of the filaments may be varied by slight variation of the ratio of sulphuric acid to sodium sulphate. Specifications 163,817, [Class 2 (ii)], and 421,157 also are p referred to.