METHOD AND DEVICE FOR THE PRODUCTION OF MULTIFILAMENT YARNS

In a continuous process, the thread components (A, B) are manufactured separately and then combined. The combined thread (C) is only then wound onto a reel (9) for further processing. The component (A) has an irreversible extension property, when heated appropriately. It is first stretched, and heated to shrink it. It is then combined with the other multifilament component (B) and bound. This is stretched before combination, in parallel with treatment of the extensible component (A). The extensible component (A) is heated to a shrinkage temperature (Ts). It is supplied in excess during heating, to induce the extension capability, whilst avoiding mechanical contact. The shrinkage component (B) and the extension component (A) undergo tensioning before stretching. The extension component (A) is first stretched, the extension ratio exceeding unity. It is then relaxed with an extension ratio less than unity, before undergoing heat treatment for shrinkage. The components are drawn from storage reels (1A, 1B) and differential stressing arising, is regulated before the stretching process. The threads (A, B) undergo heat treatment during stretching. The extension component (A) runs up the heater (7) with the force of gravity acting upon it, from below. Before the heat treatment for shrinkage, extension component (A) undergoes a heat treatment in which its filaments are preheated to just below the shrinkage temperature (Ts). They are held at this temperature, until the shrinkage heat treatment starts. Bonding of the threads to a combined thread (C) is effected by air-twisting, with at least 100 nodules per meter, depending on the thread strength. Bonding is effected by air-texturing. An Independent claim is included for corresponding manufacturing equipment.