GB372351A - Manufacture of cellulose xanthates - Google Patents

Abstract

In the manufacture of viscose, carbon bisulphide is used in the stoichiometric proportion corresponding with the formation of a mono- or dicellulose xanthate, and the sulphiding is begun at a temperature not above 16 DEG C. and terminated at a temperature not lower than 22 DEG C. The viscose obtained is homogeneous and uniform and can be used for making artificial silk of either coarse or fine titre with the same spinning orifices, say of 0.1 mm. diameter the silk has uniform dyeing properties. The mono-cellulose xanthate, dissolved to the amount of 8 per cent in 7 per cent caustic soda solution, gives a solution of no measurable immediate ripeness, while the dicellulose xanthate under similar conditions has an immediate ripeness of 15 DEG Hottenroth, and can either be used forthwith or stored for some time; if the solution is to be spun immediately, weaker caustic alkali, say 6-7 per cent, may be used for dissolution. In an example, dicellulose xanthate is made by treating ripened alkali cellulose with carbon bisulphide first at 14 DEG C. and finally at 25 DEG C. Specifications 183,882, 193,926, 212,865, and 216,828, [all in Class 2 (ii), Cellulose &c.], are referred to. According to the Specification as open to inspection under Sect. 91 (3) (a) tri- or tetracellulose xanthates may be made by employing corresponding amounts of carbon bisulphide; viscose made from lower xanthates can be transformed into higher xanthates by adding carbon bisulphide; and in an example of the manufacture of tricellulose xanthate the temperature rises from 5-15 DEG C. This subject-matter does not appear in the Specification as accepted.