Patent GB-1215679-A (GB)
Title: A process for the continuous production of a non-woven filamentary web in which the filaments are arranged in random manner
Inventor: FELTGEN KARL-HEINZ
IPC: D04H3/16
Filed: 1969-08-08
Abstract: 1,215,679. Production of a non-woven fibrous web of melt spun filaments. FARBENFABRIKEN BAYER A.G. 8 Aug., 1969 [7 Sept., 1968], No. 39799/69. Heading B5B. [Also in Division D1] As shown in Figs. 1 and 2 a fleece or bat of randomly disposed synthetic organic polymeric filaments in the form of a web is continuously produced by melt extruding a filament forming material through a spinneret 3 the holes of which are uniformly distributed over an annular surface 4 to form a hollow bundle of filaments 1 and withdrawing the bundle of filaments over a distributer element 6 by means of an aerodynamic draw-off unit 7. The element 6 is mounted on a stem 5 projecting from the spinneret 3 and is coaxial with the annular surface 4. The element 6 uniformly distributes the filaments 1 before they are drawn into the draw-off unit 7. The latter comprises an annular chamber 8 supplied with air at a pressure of 28 to 85 p.s.i. gauge. The chamber 8 surrounds a tube 9 the lower end of which is flared in the form of a trumpet-mouth 10. The tube 9 is provided with an annular gas discharge slot orifice 11 extending over the entire periphery of the tube through which the compressor air is discharged from the chamber 8 downwards along and in contact with the wall of the tube 9, conveying the filaments 1 with it. The filaments are conveyed between the flared portion 10 of the tube 9 and a fixed guide member 12 mounted on the lower end of the stem 5 and having a shape conforming with that of the flared portion 9. The filaments are then projected radially outwardly in a substantially horizontal plane on to the inner surface of the perforated cylindrical collecting unit 13 which is coaxial with the filament bundle. The draw-off unit 7 is rotatably mounted in bearings 14 and is caused to oscillate about its vertical axes by drive mechanism 15, 16 and 17 whereby a uniform texture and density is imparted to the tubular web 18 of randomly disposed filament which is continuously deposited on the inner surface of the collecting means 13. The tubular web 18 is continuously withdrawn from the lower end of the cylindrical collecting means 13 (and flattened) by the drawoff pinch rolls 10 and slit longitudinally into two lay flat webs 22 and 23 which are collected on the wind-up rolls 24 and 25. The air by means of which the filaments are deposited on the inner surface of the unit 13 escapes through the holes of the unit, whereby the filaments and the tubular web formed therefrom are pressed against the inner surface of the unit 13. The tubular web is moistened with steam or some special preparing liquid by means of jets in the annular pipe 19 encircling the collecting unit 13. As shown in Fig. 2, the distributer element 6 is provided with an annular blow nozzle 26 supplied with compressed air or other gas through the hollow stem 5. The stream 27 of air or other gas discharged from the nozzle 26 prevents the travelling bundle of filaments 1 from contacting the distributer element 6 whereby friction between the filaments and the element is prevented. The collecting unit 13 may be continuously rotated in one direction in order to impart to the tubular web 18 in the course of its formation a spiral texture superimposed upon the random texture imparted by the oscillating draw-off unit 7. While the source of supply of the bundle of filaments described in the example and shown in the drawings is a spinning head, other means of supply, such as a frame with supply rollers and take-off rollers for forwarding a bundle of preformed filaments may be used instead.