GB537499A - Improvements in or relating to yarns and the manufacture thereof - Google Patents

Abstract

537,499. Stretching yarns. BELL, A. S., and WYLDE. J. R. Dec. 20, 1939, No. 14550/40. Divided out of 32553/39. [Class 2 (ii)] [Also in Group IX] Staple fibre yarns of a mixture of wool fibres and artificial staple fibres having a cellulosic basis are given an elastic and voluminous character by wetting them, stretching by approximately 15-25 per cent. and then drying the stretched yarn under conditions that permit release of the strain set up under the stretching operation. The fibres having a cellulosic basis may be of cellulose acetate or other organic derivative of cellulose, of cellulose acetate or other cellulose ester that has been wholly or partly regenerated by saponification, or of viscose or cuprammonium cellulose. The wetting agent may be water and a shrinking agent may be added to the wetting liquid. Alternatively or in addition, a shrinking agent may be applied after the yarn has been stretched. The liquids may be employed in a heated condition and may contain agents to promote or inhibit the delustring of the cellulose acetate. Examples of wetting liquids and of yarn compositions are given. As shown in Fig. 1, the yarn is stretched in hank form, the hank being supported over pins 6, 8. The pin 6 is radially adjustable in a slowly rotated disc 1 and the pin 8 is carried by a slide 9 adjustably fixed in slots in the frame 11. The pins may carry freely rotatable reels. As shown in Fig. 6, the yarn 14 may be stretched as it is wound from bobbin to bobbin by passage around rollers 15, 16 dipping into a bath 17, the roller 16 running at a speed about 15-25 per cent. in excess of that of the roller 15. The stretched yarn is washed by a spray 18 and then passes around rollers 19, 20, the roller 20 moving at a lower speed than the roller 19 to permit the yarn to contract while it is dried by a hot-plate 21.