The production of crimped filaments and bulk yarns incorporating such filaments

摘要

1,016,100. Crimping yarns. CHEMCELL (1963) Ltd. Dec. 12, 1963 [Dec. 12, 1962; March 22,1963], No. 49193/63. Heading D1F. [Also in Division B5] Crimped filaments are made by passing filaments of an extrudable organic thermoplastic material through a heating zone in which each filament is eccentrically or non-uniformly heated so that it is rendered elastic and latent stress factors are imparted to it, subsequently stretching the filaments at a lower temperature to orient them, and to allow the latent stress factors to develop, and then relaxing the filaments at a temperature higher than the second order transition temperature but below the softening point. The heating zone may be a heated surface e.g.a bar or rod, and the filaments, e.g. isotactic polypropylene filaments, may be heated thereon above their melting point. The subsequent stretching e.g. 1. 5 to 5 times, may be carried out on heated rolls. In one embodiment, Fig. 1,filaments F, from meltspinning jet 15 pass over guide bars 17 and 21, between which is an electrically heated metal rod 19, which the filaments contact in spaced-apart relationship. The filaments then pass over feed rolls 25 and guide 27 to heated stretch rolls 29, 30 and thence via guides 31, 33 and 35 to a heating chamber 37. During its passage therethrough, the filament yarn is relaxed under very low tension to develop crimp. The crimped yarn then passes over feed rolls 39 guide 41 and tension control device 43 to take up device 45. If desired, the crimp may be partially developed in chamber 37 and crimp development completed by subsequent heating of the yarn or of the fabric into which the yarn is made. The yarn emerging from the heating zone may be wound on to a bobbin with low twist before being unwound from the bobbin and stretched.