GB905895A - Improvements relating to the treatment of textile materials - Google Patents

Abstract

905,895. Spinning and finishing yarns. DU PONT DE NEMOURS & CO., E.I. Nov. 20, 1958 [Nov 12, 1957], No. 37418/58. Drawings to Specification. Class 120 (3). A mono- or multi-filament or staple fibre yarn of low or zero twist, or a filamentary bundle or tow, of a synthetic linear polymer, is bulked by passing the yarn &c. through a turbulent stream of compressible fluid, e.g. hot air or steam within a jet apparatus, at a temperature (of at least 300‹ F.) at which the polymer becomes plastic and is above its second order transition temperature and under conditions such that the fluid has a plasticizing action on the material of the yarn where it first contacts it and also causes the individual fibres of the yarn to shrink longitudinally by at least 12%, to increase in denier by at least 12%, and to become separated and crimped, e.g. up to 80 crimps per inch ; bringing the yarn &c. again to non-plastic condition by cooling, e.g. by passage through air at room temperature ; withdrawing the yarn &c. so that the respective rates of feed and withdrawal are such as to give an overfeed of at least 30%. The yarn may be withdrawn under a tension to remove filamentary loops or packing of the filaments. A dye may be applied to the yarn &c. immediately before it is fed into the fluid stream. The polymer may be a polyamide, polyalkylene, e.g. polyethylene or polypropylene, polyester, polyvinyl, polyacrylic, e.g. polyacrylonitrile, or copolymer thereof. Two or more yarns &c. of different polymers may be fed separately and under similar or different tensions to the turbulent stream, subjected simultaneously to the action of the stream, and thereafter blended or separated. The high-tenacity fibre or yarn product consists of or comprises filaments having at least 75% greater dye-rate and 15% lower orientation angle than untreated filaments of the same polymer, cross-section and tenacity : the filaments also possess independent, random, permanent, three-dimensional, non-helical curvi - linear configuration along the line of the material (with freedom from, or a minimum of, crunodal loops) and a randomly twisted configuration, i.e. the number of turns and length of filament between twist reversals are random and the angle of twist varies continuously and randomly, with an average twist angle of at least 5 degrees. Specifications 684,046, 732,929, 735,171, 842,742, 871,112, 905,896 and U.S.A. Specifications 2,852,906 and 2,931,090 are referred to.