Perfectionnements à la fabrication de pulpe chimique raffinée de bois, transformée en rayonne viscose, fibres d'acétate de cellulose, films de cellulose et produits analogues

In the manufacture of regenerated cellulose filamentary materials from prehydrolysed sulphate chemical wood pulp by the viscose process, there is incorporated in the viscose an additive of the formula:- where R is a polypropylene radical having 9, 12 or 15 carbon atoms and is predominantly the C-12 radical, or a mixture thereof with up to 15% of the 4-chloro-isomer, in an amount of 0,01-0,5% by weight of the bone dry pulp. The additive or additive mixture may be added at any stage prior to regeneration, but preferably prior to the completion of xanthation, in an amount of about 0,1%. In examples, the additive is added (1) to the pulp sheet, as a 25% aqueous solution, (2) to the aged alkali cellulose, as a 25% aqueous solution (3) during the shredding of the alkali cellulose (4) to the viscose. Viscoses so made are spun into acid coagulating baths which may contain zinc salts in conventional manner. The additive is characterized by high solubility in water, forming aqueous solutions of low viscosity, solubility in steeping caustic below 0,1 g./100 mls., solubility in dissolving caustic above 20 g./100 mls., regenerating bath compatability, and delustrant dispersion effectiveness, without adverse effect on yarn colour, dye index, textile yarn properties and spinneret incrustation. Filtration of the viscose and the dispersion of delustering oils and pigments in the viscose is enhanced in the presence of the additive. U.S.A. Specifications 689,336 (re-issue) and 1,251,237 are referred to.