GB1210644A - Improvements in or relating to apparatus and processes for fibrillating ribbons of thermoplastic plastics material, and products obtained thereby - Google Patents

Abstract

1,210,644. Making yarns by fibrillating oriented ribbons. HERCULES Inc. 7 Jan., 1969 [8 Jan., 1968; 22 July, 1968], No. 1053/69. Heading B5B. Artificial filamentary yarns are made by advancing a ribbon 3 (Fig. 1) a synthetic organic polymeric thermoplastic material, such as polypropylene, by a pair of draw rolls 2 from feed rolls 1 through a fibrillation zone. The ribbon has been oriented in the longitudinal direction and not, or only slightly, in the transverse direction. The ribbon is provided with closely spaced parallel ribs which extend along its length, which are of constant cross-section along their length, each pair of adjacent ribs being interconnected by webs which are thinner than the ribs. The section of the ribbon between the feed and draw rolls is maintained under tension and is angled over the beater 4 having an equilateral triangle cross-section and edges 5 serrated to define teeth 6 and valley 7 (Fig. 2). The beater 4 is journalled for rotation in supports 9, is parallel to the feed and draw rolls 1 and 2 and is offset with respect to the nips of the rolls so that the ribbon 3 is deflected over the edges 5 of the beater. As the beater is rotated in the direction of the arrow A, the edges 5 are successively brought into engagement with the ribbon 3. After engagement the edge 5 is advanced along the ribbon and then carried out of engagement with it. The teeth 6 of the edges 5 penetrate the ribbon and thereby separate it into filaments in the fibrillation zone. According to the spacing of the teeth 6 with respect to the spacing of the ribs of the ribbon and the linear speed of the beater edges 5 with respect to the speed of the ribbon in the fibrillation zone, the filamentary product obtained may comprise individual continuous filaments 12 with fins 13a and fibrils 16 (Fig. 4) or filaments 14b with fins 13b (Fig. 6), or a netlike sheet of parallel filaments 14a interconnected by a web of fibrils 16a (Fig. 5).