Improvements in the heat-treatment of yarns having a basis of a thermoplastic material

Abstract

Abstract <PICT:0689175/IV (a)/1> <PICT:0689175/IV (a)/2> In the heat-treatment, e.g. heat-stretching or heat - shrinking, of thermoplastic yarns, e.g. cellulose acetate yarns, the yarns 12 (Fig. 1) are passed continuously through a tubular chamber 8 arranged vertically or at an angle not exceeding 25 degrees to the vertical, the chamber walls being heated, e.g. electrically heated, to a temperature above the softening temperature of the yarn and an inert gas, e.g. air or nitrogen, being passed down the chamber at a substantially constant rate, e.g. by means of an injector 11 or by an ejector placed at the bottom of the chamber. The yarn may be passed downwardly or upwardly. The gas may be preheated by first passing it through a jacket 24 (Fig. 2), the outer wall 21 of which is heated. To effect stretching of the yarn, rollers 4 and 5 (Fig. 1) are provided. The chamber may be provided with steps or baffles to promote turbulence. The Provisional Specification states that the process is applicable to filaments and films, and to polyacrylonitrile yarns, and also to the cold drawing of synthetic linear polyamide, polyester and polyamino-triazole yarns.

Inventors

• 👤 Donald Finlayson
• 👤 Maitland Walton Alford
• 👤 Albert William Mortimer Cooke

Bibliographic Details