Improvements in and relating to the manufacture of threads, fibres, filaments and the like from viscose

Threads of cellulosic products are produced by extruding viscose of gamma value 15-45 into an aqueous coagulating solution of sodium bicarbonate, of greater than 50% saturation, at 35-45 DEG C. to form water-soluble threads of sodium cellulose xanthate, removing the water-soluble threads from the coagulating solution and treating them with one or more reactants to convert the sodium cellulose xanthate into a stable cellulose derivative. After removal from the coagulating bath, the freshly formed sodium cellulose xanthate threads are preferably washed with sodium chloride solution or with sodium bicarbonate solution, alone or followed by a mixture of two volumes of acetone with one volume of water, and finally with acetone alone, and are then air-dried. The acetone may be replaced by ethyl or methyl alcohol. The solubility of the air-dry sodium cellulose xanthate threads p depends upon the age of the viscose prior to spinning. The sodium bicarbonate may be replaced by potassium bicarbonate or ammonium bicarbonate and the threads may be stretched either during spinning or after washing with the acetone-water mixture. The threads of sodium cellulose xanthate may be converted partly (i.e. on the surface only) or completely to threads of regenerated cellulose by suitable treatment, e.g. with dilute acids, mixtures or alcohol and water, and hot water, either directly or after immersion in aqueous solutions of salts of metals, e.g. calcium, zinc and thallium. Treatment of threads of sodium cellulose xanthate with methyl iodide gives threads of methyl cellulose xanthate, and treatment with sodium monochloracetate gives threads of sodium cellulose xantho acetate which upon subsequent reaction with dilute mineral acid, give threads of cellulose xanthoacetic acid. Threads of cellulose thiourethane (cellulose xanthamide) are obtained by reaction of threads of methyl cellulose xanthate, or of sodium cellulose xantho-acetate, with ammonia. Specification 183,882 is referred to.