GB793711A - Improved process and apparatus for the continuous curling of synthetic thermoplasticthreads or yarns - Google Patents

Abstract

793,711. Crimping threads and controlling tension therein. NAAMLOOZE VENNOOTSCHAP ONDERZOEKINGSINSTITUUT RESEARCH. June 13, 1955 [Dec. 14, 1954], No. 16970/55. Classes 120(2) and 120(3) In a process for continuously curling yarns of synthetic thermoplastic polymerization or polycondensation products, e.g. polyvinyl chloride, polyethylene, polyvinylidene chloride, polyacrylonitrile polyamide, and polyesters, a curled formation is imparted to the yarn by falsetwisting during which the yarn is passed from a twist stop and under constant tension of less than 6 grms./100 denier and free of vibration around a heated polished rod according to a helical line with an angle of inclination of at least 70 degrees; and through a cooling zone. As shown, a yarn 2 is drawn from a package 1 by conical rollers 3 and 4 (the former driven), and passes through a guide 5, connected to one arm of a balance 6, and between toothed wheels 8 and 9, carried on the other arm thereof: pivotal movement of the balance (damped by a rod 10 the flattened end of which is immersed in a liquid 11), following a variation in tension of the yarn, causes the guide 5 to move the yarn to a corrective position on the roller 4. The yarn encircles an electrically heated resistance wire 12 according to the helical path and is led through a cooling zone to a false-twisting spindle 19 which it leaves in a ballooning manner via a cup 21 on a yarn-storage disc 20: the yarn is withdrawn by a roll 23 and wound on a roll 25 which may be replaced by a twisting device (not shown), optionally imparting twist opposite to that applied in the zone wherein the false-twist is fixed. The wire 12 may be enclosed in a removable box which eliminates the influence of undesired air currents, Fig. 2 (not shown). The Specification refers to yarns of 30-70 denier moving at speeds of 15-30 metres/ minute under tensions from 0.5 grms., heating paths (and cooling zones) of 70 m.m.- 140 m.m. length, encircling angles of 45- 860 degrees on rods of 0.2 m.m-125 m.m diameter maintained at temperatures of 160-170‹C. on helical lines having angles of inclination of 70-89 degrees, and a falsetwisting spindle speed of 54,000 r.p.m. Specification 779,800 is referred to.