GB803105A - Textile yarns and methods of thermally processing them - Google Patents

Abstract

803,105. Treating and finishing yarns. SEEM, W. A., STODDARD, N. J., TECCE, F., and BERGER, H. P., '[trading as PERMATWIST CO]. Jan. 4, 1955 [Jan. 4, 1954], No. 257/55. Drawings to Specification. Classes 120(2) and 120(3) In order to impart to thermoplastic yarns an increased uniformity of appearance, denier size, dyeing properties, elongation, elasticity, strength or residual shrinkage, the travelling yarn is softened by heat while under constant and, preferably, regulatable tension and then cooled, the heating device being automatically controlled to maintain the yarn temperature within predetermined limits. These limits may be Œ 1 per cent. If it is desired to shrink or stretch the yarn, the tension applied will be less or greater respectively than the contractile force of the yarn at the treatment temperature. The yarns employed may be nylon or those sold under the Registered Trade Marks "Vinyon", "Orlon", "Velon", "Dacron" and "Saran". The apparatus used may be as described in Specification 803,106. Yarns for welts of ladies' stockings may be treated at an effective temperature of 350‹ F. to stabilize them and tensioned at 0.4 grammes per denier, or at a higher or lower tension according to whether shrinkage or stretch is desired. In another example, a yarn that had been re-drawn under tension at 400‹F. is twisted with an untreated yarn and heated to 400‹F., whereupon the untreated yarn shrinks and is wrapped by the other yarn to give a corkscrew effect. Crepe yarns may be produced by heating during uptwisting. The heat treatment may be carried out simultaneously with other processes, for example, yarns may pass through a dye solution on a cone winding machine and the dye be developed by the heat treatment. In one example of a plied yarn, two 70 denier ends are separately S twisted to 24 turns per inch at 350‹F. and 70 grammes tension, plied with 20 turns of Z twist at 380‹F. and 100 grammes then further Z twisted 20 turns at 400‹F. and 160 grammes. When plying with cotton yarns, the thermal stretching of synthetic yarns is carried out to obtain similar elongation at break as in the cotton yarns. Bulked yarns may be made by twisting on an uptwister provided with heating and tensioning devices followed by untwisting, or a false-twisting tube be used. Specification 803,107 also is referred to.