GB373406A - Improvements relating to the production of staple fibres from continuous filaments or threads - Google Patents

Abstract

373,406. Producing staple fibre from continuous filaments or threads. BRITISH CELANESE, Ltd., 22, Hanover Square, London. May 21, 1931, No. 15008. Convention date, May 21, 1930. [Class 120 (iii).] Staple fibre is produced from continuous filaments or threads by stretching the filaments and cutting them directly, say within onetenth to one-fifth of a second, after stretching. The method is particularly suitable for the production of staple fibre from filaments of organic derivatives of cellulose, such as organic esters of cellulose and cellulose ethers continuously with their production. When treating filaments of the reconstituted cellulose type such as viscose, nitrocellulose or cuprammonium, it is preferred to defer the operation until they have been subjected to the usual washing, bleaching, desulphurizing, denitrating or similar treatment. The stretching may be carried out within the elastic limit so that the fibres return to substantially their original length, or beyond the elastic limit so that they are still stretched after contraction. In forming staple fibre from filaments of cellulose acetate continuously with their production by the dry or evaporative method, three or more bundles are drawn from the spinning-machine, passed over a moistening wick, around a feed roller or guide and a stretching roller rotating at a peripheral speed approximately 20 per cent higher than that of the feed roller to a cutting-machine, such as described in Specifications 317,025 or 317,026, [both in Class 120 (iii), Yarns &c.], and are severed into fibres of, say, 1¢" length. The stretching may be imparted in more than one stage. The filaments may proceed from wound packages and may have been twisted prior to stretching, but it is preferred to employ untwisted filaments so as to facilitate the subsequent spinning. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the winding of filaments in the stretched condition on a drum, or winding upon a drum which is expansible for the purpose of stretching, and then severing them, the drum being slotted for the reception of cutting-means, means being provided to clamp the filaments to maintain them stretched. This subject-matter does not appear in the Specification as accepted.