GB830910A - Improvements in or relating to synthetic fibres - Google Patents

Abstract

Synthetic polymer is melt-spun through a spinneret having extrusion orifices each in the shape of a narrow slot with abruptly-expanded tips and the extruded filaments are drawn down and subsequently stretched, the dimensions of the slot orifices and the degree of draw-down and subsequently stretched, the dimensions of the slot orifices and the degree of draw-down and stretch being regulated so that the resulting filaments have a denier of 1.6 or less and a width/thickness ratio of 5 or more. The extrusion orifices have a width no greater than 2 mil., but they may contain at least one additional abrupt expansion, preferably at a distance of at least 10 mil., from a neighbouring abrupt expansion and/or from the abruptly expanded tips. The slot tips and any additional abrupt expansions are preferably circular but may be rectangular, square, diamond or oval in shape, provided that the longer dimension is approximately perpendicular to the length of the slot. The spinneret may contain a single orifice or multiple orifices. Filaments made by the above process may be spun into yarns, if desired in admixture with conventional filaments. Fabrics, whether knitted, felted or woven, may be made from yarns, themselves made from staple fibre comprising filaments made as above. Polyamides, e.g. polyhexamethylene adipamide, and polyesters are mentioned as synthetic polymers. Specifications 461,236, 540,134, 540,135, 569,184, 576,647, 710,087, 731,930, French Specification 844,830, and U.S.A. Specifications 2,002,153, 2,071,250, 2,071,251, 2,130,523, 2,130,948, 2,190,770, 2,217,743, 2,273,105, 2,354,435, 2,373,892, 2,465,150, 2,465,319 and 2,508,799 are referred to.