Patent GB-924088-A (GB)
Title: Improvements in or relating to yarn twisting
IPC: D02G1/16
Filed: 1959-07-30
Abstract: 924,088. Spinning and finishing yarns; twist tubes. E. I. DU PONT DE NEMOURS & CO. July 30, 1959 [Aug. 1, 1958; Aug. 12, 1958; March 17, 1959], No. 26229/59. Drawings to Specification. Classes 120 (2) and 120 (3). An " alternate-twist " multifilament yarn in which the net bundle twist is zero comprises successive sections of yarn which have bundle twist in opposite directions and in which the individual filaments are interlaced and these sections are separated from each other by sections of yarn which have zero bundle twist and in which individual filaments are interlaced to an extent which is sufficient to stabilize the alternate twist in the yarn, and may be greater than in the sections having bundle twist. In a process similar to that described in Specification 871,112, the yarn is produced by subjecting filamentary e.g. as spun or zero twist, material (which may be in the form of fibres, filaments, yarn, thread, roving or strand) under controlled constant tension in a passageway to one or more streams of compressible fluid e.g. hot or refrigerated air or steam, having at least half sonic velocity and exerting a twisting action on the filament bundle as a whole, and varying one or more of the process conditions so that equilibrium twisting is avoided. The twisting of individual filaments and groups of filaments within the yarn is random both in direction and amount and independent of the duration of the bundle twist. Equilibrium twisting may be prevented by variation in the speed of the yarn &c. or of one or more of the fluid streams, application of a plasticizing or sizing agent intermittently to the material before it enters the passageway, and/or by traversing the material from side to side of the passageway (" multiple vortex " method) in which case the passageway may consist of two or more adjacent parallel passages which overlap or are connected by a slot or slots through which the material passes as it is traversed. One or more of the fluid streams need not exert twisting action on the filament bundle as a whole when it is in -its means position, so that its action is confined to consolidating the yarn by causing twisting and interlacing of individual filaments, especially at the positions of twist reversal. The axes of the fluid streams may be perpendicular, to the axis of the passageway or inclined thereto in order to forward or brake the material. The passageway may be integral with or spaced from fluid conduits and the latter may be so positioned as to direct fluid tangentially to the inner periphery of the curved concave surface of the passageway. The yarn product may be backwound in such manner as to remove or retain twist which may also be " set " by means of heat (followed by cooling) residual solvents, size or adhesive. The process may be effected as an adjunct to normal textile operations such as spinning, drawing, beaming, weaving. The filamentary material may comprise or be composed of synthetic polymers such as polyamides, polyesters, acrylic and vinyl polymers, polyethylene, polypropylene, or elastomers or cellulose esters, rayon, protein, cotton, wool, silk, glass or asbestos, and the filaments may be of circular or non-circular e.g. Y or cruciform, cross-section. Composite yarns e.g. with components dyed different colours, may be produced by twisting components which have been doubled before the twisting, or by successive addition during twisting in a series of passageways. Specifications 447,812 and 924,089 also are referred to.