Patent GB-425416-A (GB)
Title: Improvements in the manufacture of artificial filaments, films and the like
IPC: D01F2/28
Filed: 1933-09-14
Abstract: In a process for the manufacture of artificial filaments, yarns, threads, films, foils, and like products the said products are obtained by forming compositions or extruding solutions containing organic derivatives of cellulose which are insoluble in dilute aqueous alkali and do not swell or dissolve in cold water, and finely divided metallic derivatives of sugars.  By treating the products thus obtained with a solvent for the sugar derivatives contained therein, products having a subdued lustre are obtained.  The sugar derivatives are preferably soluble in water or dilute aqueous solutions, and may be slightly soluble in the composition or solution containing the cellulose derivative, in which case they are present in excess of their solubilities. Suitable metallic derivatives of sugars which may be employed, particularly with solutions of cellulose derivatives in acetone are those of mono-, di-, tri- and tetra-saccharoses which may be for example pentoses, hexoses, or heptoses.  Examples are derivatives of rhamnose, glucose, galactose, fructose, mannoheptose, maltose, lactose, mycose, melibiose, raffinose, and sucrose in the form of cane or beet sugar, formed with alkali or alkaline earth metals, e.g. the glucosates, fructosate or sucrates of calcium, strontium or barium.  The sugar is preferably present in from 0,1 to 10 per cent of the weight of the cellulose and most advantageously from 1 to 2 per cent and is preferably very fine having a diameter of 0,1 to 5 microns and preferably 1--2 microns. The material may be ground in a ball or colloid mill either with the solvent used in the solution of the cellulose derivative or with part of the solution itself.  Suitable substances such as diethylene glycol, heavy white mineral oil, olive oil, or castor oil may be added to the spinning solution as dispersing agents for the finely divided solid material.  The products may be formed by the dry or wet process, the bulk of the solvent medium in the case of the evaporative process being preferably a relatively volatile liquid. Medium or high boiling solvents or plasticizers may also be incorporated in the mixture. To delustre the materials the coagulating medium may be a solvent for the incorporated sugar derivative or the formed materials may be treated with a medium which is a solvent for the sugar derivative, such treatments being carried out at any suitable temperature which is advantageously raised but may be low when sugar derivatives such as calcium or barium sucrates are employed which are more soluble in the cold.  The delustring may be effected during dyeing or scouring, or in a separate operation, and the medium may be an alkaline solution which in the case of cellulose ester materials may simultaneously saponify the ester. In an example dry barium glucosate is ground in a ball mill with a 5 per cent solution of acetone-soluble cellulose acetate in acetone until the particle size is less than 1 micron.  The dispersion is incorporated with a solution of cellulose acetate in acetone to form a solution containing about 25 per cent of cellulose acetate and 0,25--0,5 per cent of glucosate.  The mass is mixed, filtered, and extruded into an evaporative atmosphere to form yarn which itself or in the form of fabric or garments, e.g. hose is thus treated with an aqueous liquid such as a scouring or dyeing bath at a temperature between 25 and 100 DEG  C. to subdue its lustre.