Novel yarn like structures from extruded thin walled tubing

摘要

950,213. Tubular filaments. IMPERIAL CHEMICAL INDUSTRIES Ltd. May 23, 1962 [May 29, 1961], No. 19264/61. Heading B5B. Tubular filaments are made by melt-spinning fibre-forming synthetic linear polymers in the form of a thin-walled tube, e.g. through an annular orifice, and introducing a gas supply into the tube, the annulus dimensions and the rate of introduction of the gas being so related to the wind-up speed and final desired diameter of the filament that the wall thickness does not exceed 8 microns, and is preferably less than 5 microns. Preferably during melt-spinning the gas contained within any finite section or portion of the tube is of substantially the same volume as that contained within any other section or portion of the tube of the same total weight as the said first section, due allowance being made for variation of temperature and further expansion of the gas during the process. Gas may be introduced at such a rate that after solidification no inflation of the tube to a diameter greater than that of the annular spinneret aperture takes place, but sufficient to prevent undue contraction of the tube. The tube may be collapsed by pulling it through a narrow shaped guide, nip, or die, perforated or slit, and oriented by winding at high speeds using fluid, liquid or mechanical drag forces, especially by drawing between feed rolls and draw rolls.- The final denier of the filaments is preferably 25-150. Specified materials include nylon, polyesters and copolyesters based on terephthalic acid, especially polyethylene terephthalate, and stereospecific polypropylene. Optimal spinning conditions may be ascertained from a formula given in the Specification.