GB1287874A - - Google Patents

Abstract

1287874 Film fibrillation CHEMIE FASER LENZING AG 27 Jan 1970 [28 Jan 1969] 3891/70 Heading B5B Polymer film selected from polyethylene, polypropylene, polyester, polyamide, polyacrylonitrile, polytetrafluoroethylene and polyvinylchloride films is converted into filaments by continuously feeding it to a combined slitting and stretching zone, where it is simultaneously slit by passage over a series of cutting tools arranged less than 0À5 mm. apart in a row transverse to the feed direction of the film, and stretched by taking up the filaments from the cutting tools at a rate faster than that at which the film is supplied to them, the stretch point being localized in the said slitting and stretching zone by the braking effect of the cutting tools on the film. The film may be heated on one or both sides in the slitting zone, it may also be crimped by unilateral heating followed by drawing off the fibres under an obtuse angle. The film may be pre-stretched, prior to slitting. The continuous fibre product may be cut to staple fibres. In Fig. 1, the film 3 drawn off from roll 1 by the triple-roll assembly 2, is guided via vertically and horizontally movable and heatable tension pins 4 over the slitting device 5, whence it is drawn off under an obtuse bending angle (γ) by the triple roll assembly 7. The triple roll assembly 7 runs at a higher speed than assembly 2, so that the film is stretched, the braking effect of the cutting tools 5 confining the stretching to the slit film 8. A guiding device 6, which may be heated if so desired, may be arranged between the slitting device 5 and the triple roll assembly 7. From 7 the multifilaments are conveyed to the heat device 9, then finally wound on to a roll 11 via a further triple roll assembly 10. An embodiment of the slitting device 5 is shown in Fig. 2. It comprises the cutting members 12, illustrated in front and lateral view in Figs. 3(a) and 3(b) respectively, a heating plate 13 and a casing 16 heated by the heaters 14 and 15. 17 is an insulating layer which permits 12 and 13 to be at different temperatures.