Manufacturing viscose

Viscose solutions are prepared by xanthating ripened or unripened alkali cellulose in the presence of a water-soluble sulphide in an amount not exceeding 10 per cent of the weight of the cellulose; whereby the viscosity of the viscose solution is reduced and the time of ripening is reduced for normal solutions, or, with normal ripening, the concentration of cellulose is increased. In examples: (1) 1 part of sulphite cellulose is immersed for 2 hours in 36 parts of a solution containing 15,7 per cent NaOH and 2,7 per cent sodium sulphide, squeezed to 3 times the weight of the cellulose, disintegrated and ripened for 22 hours at 20 DEG C. After xanthating with 0,5 parts carbon disulphide, the product is dissolved in 9,5 parts of 7 per cent NaOH. The solution has a viscosity approximately that of a solution of the same concentration prepared from alkali cellulose obtained with 18 per cent caustic soda and ripened for 3-4 days at 20 DEG C. (2) 1 part of sulphite cellulose is immersed in 27 parts of a solution containing 13,25 per cent NaOH and 4,3 per cent sodium sulphide, squeezed to 3 parts and ripened for 1 day. The product is xanthated with 0,5 part carbon disulphide and dissolved in 3,3 parts of 7,5 per cent NaOH giving a solution containing 14 per cent of cellulose and of a viscosity approximately that of viscose containing 7 per cent cellulose made from alkali cellulose ripened for 1 day.