Patent GB-398820-A (GB)
Title: Improvements in or relating to textile materials and their treatment and manufacture
IPC: D06M15/05
Filed: 1932-03-10
Abstract: In the manufacture of spun yarn, from organic derivatives of cellulose, the material is provided, to minimize electrification difficulties, with an outer coating containing a hygroscopic substance, which is cellulose or cellulose derivative material or a degraded cellulose or a derivative of a degraded cellulose or a polyvinyl alcohol or derivative thereof, before the opening, carding, drawing and spinning operations.  The coating may also contain other hygroscopic non-colloidal materials and roughening media to assist spinning.  The production of the coating may be effected before or after cutting and, if desired, continuously with manufacture by dry or wet spinning.  A cellulose coating may be regenerated from a coating of viscose, ammonium viscose, nitrocellulose, or cellulose dissolved in ammoniacal copper or metallic salt solution and which is desirably of a degraded cellulose, or may result from a surface saponification of the filament or fibre.  A cellulose derivative coating may be of esters such as the acetate, propionate and the like or ethers such as methyl, ethyl, or benzyl cellulose, of a cellulose so degraded previous to, during or subsequent to the introduction of the substituent groups so that the product is hydrophile, or of a derivative containing substituent groups of a hydrophilic character, e.g. hydroxy, carboxy or carboxylic salt groups as, for example, esters of oxalic, maleic, glycollic, lactic, malic, tartaric or glyceric acid or hydroxy and carboxy alkyl ethers as in Specifications 166,767, 277,721, [both in Class 2 (ii), Cellulose &c.], 343,521, 344,528, and 344,775.  In the production of a cellulose coating by surface saponification, the processes of Specifications 314,446, 314,447, 316,521, 318,468, [all in Class 2 (ii), Cellulose &c.], and 351,417 may be employed.  The saponification may vary within wide limits but saponification corresponding to a loss of weight of 20 per cent is sufficient with cellulose acetate filaments.  In treating continuous filaments they are prevented from sticking together by employing combs, curved bars, &c., or with continuous filaments or already cut fibres by using dilute solutions of e.g. viscose, such as 1 to 2 or 5 per cent and/or by hydroextracting excess of the treating liquor before regeneration. If the filaments or fibres are steeped for a considerable time, the excess liquor may be removed by washing.  The filaments may be dried after coating and regeneration but are preferably cut while still wet containing e.g. about 100 per cent of their weight of liquid.  Other hygroscopic bodies which may be applied before, during or after the application of the colloidal hygroscopic material include glycerine, glycols, or other polyhydric alcohols or derivatives, inorganic bodies such as ammonium citrate, chlorides of magnesium, calcium, zinc, iron and strontium, nitrates of magnesium, calcium, zinc, iron, cobalt and nickel, acetates and formates of ammonium, sodium and potassium, sodium and ammonium phosphates, amines and amides and their salts e.g. acetamide and methylamine hydrochloride, and quaternary ammonium compounds and their salts. When the filament, say of cellulose acetate, is superficially saponified, e.g. by caustic soda or potash, or trisodium phosphate or ammonia, the resulting salts need not be washed out.  The cutting may be effected whilst the filaments are travelling but preferably whilst they are wet and in hank form.  Drying may be effected in the open air or by heat. Roughening media including silica, barytes, lithopone, kieselguhr and soluble salts may be applied with the cellulosic &c. coating or with the other hygroscopic materials.  The fibre may be lubricated, e.g. with olive oil, prior to winding or cutting.  After the formation of the spun yarns, the coating may, if desired, be removed as for example by scouring.  In examples (1) cellulose acetate yarn in hank form is soaked for about 15 mins. in a viscose solution containing about 2 to 3 per cent of cellulose prepared from a degraded cellulose The coating is then decomposed in e.g. a 25 to 35 per cent solution of sodium bisulphate, desulphurized, washed, hydroextracted, and cut into staples After partial drying, if necessary, they are put through the usual spinning processes, (2) cellulose acetate threads in warp formation are passed through a dilute alkaline solution of cellulose glycollic acid, then may be passed over a steam-heated drum and finally cut.  (3) A dry spun cellulose acetate thread is passed continuously with its production through a solution of oxyethyl cellulose in 5 per cent caustic soda containing about 10 per cent sodium acetate, and dried without washing.  The Provisional Specification describes also the use of other hygroscopic colloidal solid material, for example starch.