Abstract: A twisted spun fibre yarn with interlaced plies, in which the fibres have a spiral structure having open zones and closed zones, the cohesion factor of the spun fibre yarn being less than 100 and preferably between 20 and 80, the torsion factor of the spun yarn having a value of between 25 and 40% of the torsion factor normally used in the conventional processes for a spun yarn of the same count.A method and apparatus is also described for its manufacture this involving the use of a pneumatic interlacing means and which may be used either continuously or discontinuously.

Abstract: Spun-like fiber yarn with interlaced threads, in which the fibers are of the same length. The spun yarn has alternating open, relatively bulky zones and closed, relatively compact zones. The open zones have a non-twisted structure with parallel strands. In the closed zones, the fibers are interlaced and non-bonded. The open zones furthermore have free strands. The cohesion factor of the spun fiber yarns is greater than 100 and preferably being between 120 and 180. The spun yarns are produced by a process in which at least one sliver of fibers of equal lengths is fed to a drawing unit and then to at least one open single-jet interlacing nozzle fed with gaseous fluid at a pressure of between 1 and 6 bars, the angle formed by the axis of the channel for the passage of the yarn in the nozzle and the yarn being between 10.degree. and 80.degree., and the spun yarn obtained being wound up at a speed greater than 50 m/min.

Abstract: Textile articles comprise continuous filament yarns (or staple fibers obtained therefrom) of polyethylene terephthalate or another thermoplastic material, in which the individual filaments are of alternately decreasing and increasing thickness, the thinnest zones having the highest crystallinity index and molecular orientation and vice versa, but all the zones having a certain index of crystallinity, each filament having a non-spiral three dimensional crimp and a high apparent volume. The yarns are made by partially stretching the initial yarn in a crack or figure promoting agent, and relaxing the stretched yarn in two or more stages, in at least the last of which it is heated, preferably with a high temperature-time gradient.