GB1310203A - Bulky yarn and production thereof - Google Patents

Abstract

1310203 Bulky yarn E I DU PONT DE NEMOURS & CO 19 April 1971 [4 March 1970] 23108/71 Headings D1F and D1W A bulky yarn of at least 30 crimped entangled continuous thermoplastic filaments is characterized in that laterally-orientated filament loops penetrate within the yarn and bind other filaments of the yarn in place. The filaments are permanently crimped so as to provide partially recoverable stretch of 8% to 40% when the yarn is subjected to a load of 0.1 gm/denier. The degree of filament entanglement is such that there is at least 5% stabiliszed yarn bulk when the yarn is subjected to a load of 0.1 gm/denier and that there is less than 8.9 cm mean separation distance of filaments groups under a 454 gm load in the lateral pull-apart test with a standard deviation of individual determinations of less than 0.5 times the mean sepearation distance for ten determinations along the length of the yarn. The yarn is substantially free from any twist or surface filaments that wrap tightly around the yarn causing a decrease in yarn diameter. The yarn may be prepared by passing a true-twist-free and entanglement-free bundle of at least 30 filaments of thermoplastic polymer to a nozzle, and supplying to the nozzle a heated fluid such that the yarn is subjected to turbulent action. The heated fluid exerts a forwarding action on the yarn and causes the filaments to become entangled. The yarn is withdrawn from the nozzle at a speed which is less than the feed speed such that the overfeed is at least 20%. A yarn finish may be applied to the yarn prior to feeding to the nozzle, the finish preferably being a liquid having a viscosity of less than 5 centipoises at 150‹C and a sufficient boundary friction coefficient for the yarn to retain a specified degree of filament entanglement in subsequent processing steps. The process may be carried out in the apparatus shown in Fig. 1 wherein filaments 10 pass successively to a preheat chest 11, feed rolls 12 and 13 and fluid jet device 14. The bundle of filaments, in a splayed open configuration on emerging from the jet device is removed sideways to rolls 15 and 16. This sideways removal serves to collapse the splayed configuration. The bundle is eventually packaged at wind up device 22. The construction of the fluid jet device is shown in Fig. 2. Yarn passageway 25 has an entrance 26 and a venturi-shaped exit 27. Superheated steam or air introduced to chamber 28 passes through channels 29 to a main pair of opposed jet stream conduits 30 and 31. Additional pairs of smaller opposing conduits 32 and 33 which intersect the yarn passageway in the same plane as 30 and 31, are also provided (Fig. 3, not shown). The process is particularly applicable to polyamide filaments.