GB890331A - Method and apparatus for processing torque stretch yarn - Google Patents

Abstract

890,331. Crimping and finishing yarns. STODDARD, N. J., and SEEM, W. A. Feb. 28, 1958 [April 19, 1957; Sept. 9, 1957], No. 6525/58. Classes 120(2) and 120(3) Improved control over the physical characteristics of "torque-stretch" yarns is obtained by subjecting such yarns to selected temperatures and tensions (which may be ambient or zero respectively) that in correlation modify the latent and/or manifest properties. The treatment may be effected continuously with the production of "torque-stretch" yarns, or may follow shortly after production, or may be carried out when yarn packages have been stored for varying periods and serves to equalize yarn characteristics regardless of the period of storage. The tension during a part of the yarn treatment may be such as to stretch the yarn followed by treatment at minimum tension. In addition to heat and tension false twist may also be applied, preferably in reverse order to the prior falsetwisting. In one example, a running 70 denier polyester "torque-stretch" yarn is subjected to 2 grams tension at 300‹F. whereby extensibility is reduced from 300% to 3%, residual shrinkage and lustre are reduced and bulk is increased. The degree of dimensional stability is said to depend upon the amount of tension applied to a heated yarn; 60 grams of tension at 350‹F. results in a 30 denier nylon yarn having good stability and low stretch which, when the yarn is knitted into a stocking, produces an article that does not twist on a bias. In another example, a "no-torque" yarn produced from a 70 denier nylon yarn that has previously been twisted with 70 turns per inch Z, set at 435‹F. and reverse twisted 70 turns S is passed through a false twist tube which first imparts 50 turns S at a tension of 30 grams and at 450‹F., followed by 50 turns Z. This yarn has high bulk. Apparatus may consist of a preliminary tensioning device 2, Fig. 2, feed rolls 3, a heater 5, tensioning device 6 and take-up package 8 rotating at a speed sufficient to tension and extend the yarn forwarded by the feed rolls 3. Instead of the tensioning device 6, further feed rolls may be employed to apply the necessary tension. Where it is desired to prepare the "torque-stretch" yarn continuously with the after-treatment, the arrangement of machine elements may be feed rollers, heater, false-twist tube, feed rollers, heater, followed by either a tensioning device or further feed rollers. The heaters may be plates as in Fig. 2, insulated tubular heaters as 251 in Fig. 13a, or rollers rotating in a hot liquid as 285 in Fig. 13a. Thermostats may control the heaters. In the apparatus illustrated in this Figure, the "torquestretch" yarn is prepared between package 246 and rollers 254, and the after-treatment follows rollers 254. Anti-static arrangements may be utilized. Specifications 803,106, 803,107, 803,108, 803,110, 850,230 and 890,332 are referred to.