GB1001813A - Opening crimped filamentary tow - Google Patents

Abstract

1,001,813. Opening crimped tow. CELANESE CORPORATION OF AMERICA. Feb. 14, 1962 [Feb. 21, 1961], No. 5637/62. Headings DiD and D1F. Crimped tow of artifical filaments is opened and the crimps in individual filaments moved out of registration with those in adjacent filaments by passing the running tow between a pair of rolls at least one of which has grooves and ridges in its surface running at an acute angle to the axis of the roll (and may be driven) so that filaments are only gripped between the rolls at the ridges and little or no grip is applied to the remaining filaments, whereby successive sections of the tow across its direction of movement are gripped and released and at the same time some filaments move laterally relative to other filaments. Crimping may have been effected by passage of the tow through gear wheels or a stuffer-box. The filaments may be of regenerated cellulose, cellulose esters or ethers e.g. acetate or triacetate, polyacrylonitrile, polyamides or polyesters, and the total denier may range up to 160, 000. The opened tow may be made into filter, "non-woven" and/or bonded and/ or multi-layered mats or fabrics, or bulky yarn. One roll may have a smooth surface and the grooved roller is biased theretowards. If both rollers are grooved, the opposing grooves may run in the same or opposed direction provided there is no registry between the ridges on one roller and the grooves in the other e.g. rolls are of different diameter or rotated at different peripheral speeds or one or both reciprocated axially. The grooves are helical or parallel and endless and each roll may have two grooves or sets thereof of opposite sense running from the centre of the roll to each end, Figs. 4 and 5 (not shown). Spaced pairs of rolls may act successively and at progressively increased or decreased speeds on the tow. In the operation of the apparatus shown in Figs. 1 and 3, crimped tow 11 withdrawn from a bale 12 is fed through a straightening device 13, to remove folds and prevent twisting of the tow, and a compressed air jet 14, to flatten the tow. The band of filaments passes over guides 15 and 16 and through an opening mechanism comprising pairs of rolls 17 and 18, 19 and 20, 21 and 22, the lower rolls being driven with any predetermined speed differential from mechanism 31 through chains 34, 37 and 40 and sprockets 33, 35, 36, 38, 39, 41. Modified apparatus, Fig. 6, includes tension rolls 52 and 53 which smooth out crimp variation. These rolls may have smooth surfaces of elastic material such as rubber and be positively driven or rotated by the drag of the running tow.