technique to improve the dyeing affinity of verstreckten fibres and filaments from linear polyalkylenterephthalaten

摘要

1,105,944. Polyester filaments. FARBWERKE HOECHST A..G. 6 Sept., 1965 [17 Sept., 1964], No.37948/65. Heading B5B. In a process for improving the dyeability of previously stretched filaments or cables of filaments of linear polyalkylene terephthalates by heat treatment, the previously stretched filament or cable of filaments is heated by means of a jet of gas having a temperature within the range of 180‹ C. to 280‹ C. and which meets the filament or cable of filaments at a speed within the range of 2 to 40 metres per second, and the filament or cable of filaments is then cooled to a temperature below the second order transition temperature. Polyalkylene terephthalates are defined as polyesters of terephthalic acid and a glycol containing 2 to 18 carbon atoms, especially ethylene glycol. Cooling is preferably brought about in a cooling bath or a violently agitated gaseous medium, for example, air. Preferably the filament or/cable of filaments consists of polyethylene terephthalate, and the jet of heated gas consists of air or nitrogen. The time of residence of the filament or cable of filaments is desirably less than one second, and the filament or cable of filaments may shrink to a degree of 10% to 30% during the heat treatment. The process may be improved by preheating the filament or cable of filaments to 100‹ to 170‹ C., and by effecting the preceding stretching treatment at 50-100‹ C., using a low stretching ratio.