Patent GB-893758-A (GB)
Title: Improvements in or relating to textile materials
IPC: D04H1/42
Filed: 1958-04-28
Abstract: 893,758. Yarns, woven fabrics &c. DU PONT DE NEMOURS & CO., E.I. April 28, 1958 [April 30, 1957], No. 13389/58. Drawings to Specification. Classes 120(3) and 142(4) [Also in Group VIII] A textile material comprises 50-95% of "hard" staple fibres mixed with 5-50% "elastomeric" staple fibres. "Hard" and "elastomeric" are defined, with examples, below. The materials (or their products) have high recovery with high or low stretch characteristics and may take the form of fibre blends, webs, tows, slivers, batts, all of which may be conventionally processed, e.g. by spinning on the cotton, cotton-American, woollen or worsted systems, or yarns, or knitted, woven or non-woven fabrics or felts, and may be used for household, medical, and industrial products and for universal-fitting apparel and accessories. The mixing of the two components may be effected on hopper-fed woollen or Rando-webber blenders, or on cotton pickers, or by card-blending, or draw roving, or by plying two or more yarns. In the case of yarns, the requisite characteristics are developed by processing a roving made from the required mix in a drafting-arrangement at the spinning stage which provides a nip between the back and front rollers, being provided by a floating roll on an apron, or by the cradle bars of a double-apron, and is such as to hold the elastomeric fibres, but not the hard fibres and the position of the nip and the pressure applied thereat may be adjustable to vary the degree of stretching of the elastomeric fibres. In the case of yarns with low stretch, high recovery characteristics, the nip is positioned from the forward draft rolls at a distance at least as long as the length of the elastomeric fibres used, the hard fibres being not curled. In the case of high stretch, high recovery yarns, the nip is positioned from the forward rolls at a distance shorter than the length of the elastomeric fibres, the hard fibres being curled. In each case, the distance between the front and back rollers is longer than the length of the hard fibres, while the length of the hard fibres exceeds or is equal to the length of the elastomeric fibres. The point of twist insertion is generally maintained near the front rollers, and different effects are obtained by varying count, twist multiplier and the weight of the floating roll providing the nip. Prior to spinning, the fibre bundle is generally attenuated without stretching and the fibres may be treated with anti-static finish during blending. The yarns according to the invention may be made into fabrics with other yarns so that the percentage of elastomeric fibres in the material as a whole is less than 5%. "Hard" fibres are defined as natural or synthetic fibres suitable for processing on conventional textile machinery, i.e. those having a high modulus and an elongation at break of less than 100%; "elastomeric" fibres are those having an elongation at break of at least 100% with a low initial modulus, i.e. 0À05% or less which prevents them being processed on conventional machinery. The hard fibres may be of cotton, wool, silk, fur, jute, linen, glass, cellulose derivatives, polyesters, polymers and copolymers of amides, acrylics, vinyls, poly (ethylene oxide) terephthalate/ethyleneterephthalate, tetrafluorethylene or monochlorotrifluoroethylene, hexafluoropropylene, polyethylene. The elastomeric fibres may be copolymers of butadiene/ styrene, butadiene/acrylonitrile, butadiene/2- vinyl pyridine, monochloro-trifluoroethylene/ vinylidene fluoride, isobutylene/butadiene or chloro-sulphonated polyethylene or polychlorobutadiene. They may also be of difunctional polymers of low molecular weight with terminal groups of active hydrogen (e.g. polyesters, polyesteramides or polyhydrocarbons, polyamides and polyurethanes as described in Specification 731,071) reacted with small molecules (e.g. diisocyanates or diacid halides) to give difunctional intermediates which are coupled with compounds containing active hydrogen such as water, diamines, and dibasic acids. They may also be of the product formed by condensing a polyether glycol with aliphatic glycol and an aromatic dibasic acid. They may also be the N-alkyl-substituted copolyamides described in Specification 692,026, e.g. adipic acid reacted with hexamethylene diamine and its N. isobutyl and NN<SP>1</SP> diisobutyl derivatives, the linear elastic copolyesters prepared by reacting glycols with a mixture of aromatic and a-cyclic dicarboxylic acids described in Specification 711,279, e.g. ethylene glycol with terephthalic and sebacic acids or the elastic polyamides as described in U.S.A. Specification 2,430,860 produced by reacting polycarbonamides with formaldehyde.