GB648865A - Spinning young viscose - Google Patents

Abstract

Viscose containing about 7-8 per cent of cellulose and 4-13 per cent of sodium hydroxide, and having a salt point between 8 and 18 and at least 1.19x, where x is the percentage of sodium hydroxide, is extruded at 45-50 DEG C. into an aqueous spinning bath containing between 1.2x and 2x per cent of sulphuric acid and at least 21+0.66x per cent of soluble sulphates, the bath containing at least 18 per cent of sodium sulphate and at least 1 per cent of zinc sulphate. The filaments are then stretched by 90-110 per cent, products of high tenacity and high wet and dry extensibilities, useful for the production of type cords, being obtained. Viscose of the characteristics set out above may be unripened viscose, or viscose to which a ripening retarder such as sodium sulphite has been added, or ripened viscose which has been re-xanthated by addition of carbon bisulphide prior to spinning. The sulphate content of the bath may consist solely of sodium sulphate and zinc sulphate or may include sulphates of other polyvalent metals such as iron, magnesium, chromium, cadmium, manganese, nickel and aluminium. The stretching of the filaments is effected in known manner, optionally with the aid of a plasticizing agent such as hot water or steam. In a typical example, viscose containing 7.5 per cent of cellulose and 13 per cent of sodium hydroxide, and having a salt point of 15.5, is extruded at 45 DEG C. into a bath containing sulphuric acid 19.3, sodium sulphate 20 and zinc sulphate 9.6 per cent, and the filaments are stretched by 110 per cent in a hot water cascade between two godets.