GB1035657A - Polyolefine tapes - Google Patents

Abstract

1,035,657. Making polyolefine tapes. COURTAULDS Ltd. May 13, 1963 [May 14, 1962; [March 1, 1963], Nos. 18380/62 and 8235/63. Heading B5B. A polyolefine tape having closely spaced parallel continuous ribs along its length, the cross-sections of the ribs being constant along their length and corresponding in magnitude to those of filaments of less than 80 denier, the filaments of pairs of adjacent ribs being connected to one another by a continuous web extending along the whole length of the ribs at least some of the webs having longitudinal slits at intervals along their length may be made by melt extruding a polyolefine through a generally slot-shaped extrusion orifice consisting of a straight row of holes (which may be of circular cross-section) joined by short narrow slots whose width is much less than the mean diameters of the holes, stretching the ribbed tape thus formed and slitting at least some of the webs longitudinally at intervals along their length. The slitting may be effected by combing the tape by moving it longitudinally into contact with an endless assembly of pointed members moving in the same direction as and more quickly than the tape, whereby the points pierce and slit at least some of the webs. The assembly of points may be a roller clothed with points which are raked backwards, a cylindrical wire brush rotatable on its axis or contra-rotating interdigitating spiders carrying points on the extremities of the fingers, the tape passing through the nip of the spiders. The tape may be continuous or in short lengths. When continuous it may be twisted on itself or together with similar tapes to form a yarn. The tape may be cut into short lengths to form both discrete staple fibres and arrays of staple fibres joined by webs, some of which are slit. This material may be converted into staple fibres by conventional opening and carding machinery.