GB1040561A — Improvements in the production of crimped yarns

USPTO Abstract

A crimped continuous filament yarn is obtained by subjecting a yarn which is molecularly stabilized to a first molecular modifying treatment under such yarn tension conditions as to shrink the yarn longitudinally, molecularly stabilizing the yarn at least in part, and then crimping it and setting the crimp. The yarn may be shrunk longitudinally by a heat treatment in which the yarn may contract by up to 5%, or by using an appropriate swelling agent -for example phenol or alcohol-the agent being removed by rinsing or evaporation before the yarn is crimped. The heating step and the heat setting of the crimp may be carried out by hot air, steam, radiation or dielectric heaters, or by contact with a hot surface. Alternatively the crimp may be set using a swelling agent. The yarn may be composed of thermoplastic material-e.g. polyester or polyamide-or of cellulose. In the embodiments of Figs. 1-8 (not shown) a yarn is passed successively through a heater, a cooling zone, twist stop, the first heater again or a separate heater, and a false twist tube. Alternatively the process may be carried out in discrete steps, and/or the yarn may be edge crimped or stuffer-boxed crimped.