IE39089L - Filamentary material - Google Patents

Abstract

1459398 Fibrillating films SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 21 March 1974 [23 March 1973] 14208/73 Heading B5B A film, preferably of polyethylene or polypropylene, is fibrillated by passing it under tension through the nip of a pair of contrarotating drums or rollers, each of which is provided with needles projecting from its surface. The needles are so arranged that, during operation, they do not touch each other. The drums or rollers are driven at a peripheral speed greater than the linear film speed, but do not necessarily have the same speed as each other. Means are provided to vary the arc of contact formed by the film with at least one of the drums or rollers. In Fig. 3(a) this means takes the form of allowing the drum 22 to rotate around drum 23. Other means include a feed roller 24 which, as shown in Fig. 3(c), may be moved in a direction other than parallel to the film. Two films may be fibrillated simultaneously as shown in Fig. 3(d). Each film is then provided with an adjustable degree of wrap, for instance by the movable feed rollers 25, 26. Alternatively the films may be fed together as in Fig. 5(a) (not shown). The needle clearance may be provided by causing the needles on one roller to intermesh with those on the other, by keeping the rollers far enough apart to avoid contact, by providing grooves on the roller surface into which the needles of the other roller fit or, similarly, by fixing the needles on axially arranged bars which stand proud of the roller surface leaving a space for the other roller needles to fit. The resulting filaments acquire a crimp if the cutting elements are heated. [GB1459398A]