Viscose Staple Fibre {BIRLA}, India

Viscose fibres are derived from cellulosic wood pulp. The wood pulp is immersed in aqueous sodium hydroxide to swell the cellulose fibres and to convert cellulose to alkali cellulose. The swollen alkali cellulose mass is squeezed to extract excess alkali. The alkali cellulose is next shredded to yield finely divided, fluffy particles called "crumbs". The alkali cellulose is aged under controlled conditions of ‘time & temperature’ in order to depolymerize the cellulose. Next, in Xanthation stage, the aged alkali cellulose crumbs are placed in vats and are allowed to react with carbon disulphide under controlled temperature to form cellulose xanthate. The orange cellulose xanthate crumb is dissolved in dilute sodium hydroxide under high-shear mixing conditions to obtain a viscous orange coloured solution called "viscose", which is the basis for the manufacturing process. The viscose solution is then filtered and is deaerated and allowed to "ripen". The viscose solution is metered through a spinneret into a spin bath where fibre is regenerated in the form of filaments which is followed by simultaneous stretching. The regenerated fibre contains salts and water soluble impurities which need to be removed. The fibre is cut in cutter to different sizes depending upon customer requirement. In the following steps, the fibre is given treatment to get desired fibre properties, which dried to get required moisture & then packed in a bale form.