PRODUCTION OF FILAMENTARY MATERIALS BY FIBRILLATION

摘要

1,235,122. Fibrillating ribbons or tapes of synthetic polymers. IMPERIAL CHEMICAL INDUSTRIES Ltd. 30 July, 1969 [19 Aug., 1968], No. 39488/68. Heading B5B. [Also in Division D1] A longitudinally oriented fibrillatable ribbon or tape consisting of a synthetic organic polymeric material such as a polypropylene, a polyamide, a polyester or a mixture of any of these polymers, is fibrillated by subjecting the ribbon or tape while travelling under tension to the action of a series of at least two gaseous fluid false-twisting means such that the direction of twist imparted to the strand is completely reversed between adjacent false-twisting means. There may be no change in longitudinal direction of movement of the strand between the first and second or succeeding false-twisting means. The twist imparted by the first falsetwisting means may be allowed to run back over or into a hotplate or heating zone positioned before the false-twisting means. The material after passage through the false-twisting means may be allowed to relax at least partially and the relaxed material may be further heat treated. The ribbon or tape may be heated in the absence of twist before passing into the fluid falsetwisting means. The gaseous fluid in the falsetwisting means may be air or steam and a series of four fluid false-twisting means may be used, the direction of twist alternating throughout the series. Twist stopping guides may be positioned upstream and downstream of the fluid false-twisting means to confine the false twist effects within a shorter length. In an example, an undrawn tape consisting of a melt blend of 95À5% of polyhexamethylene adipamide and 4À5% of polypropylene and having a width of 9À5 mm. and a thickness of 0À055 mm. is drawn at a draw ratio of 5 and continuously fed at a speed of 18 metres per minute to a heating zone maintained at a temperature of 160‹ C. and then passed at a tension of 49 grams through two contra-rotating air vortices produced by a jet device (see Division D1) fed with air at a line pressure of 10À2 kg./cm.2 gauge. The fibrillated tape thereby produced is wound up on a constant tension winder.