Abstract: Polyester yarn is produced from melt spun filament by prestretching the filaments individually in counterflow with a gaseous medium and then afterstretching the polyester filaments with an individual titer of 1.0 dtex to 7.5 dtex with a stretching ratio of 1:1.5 to 1:1.15 at a temperature of 80.degree. to 250.degree. C. The filaments are collected and then wound up as a yarn at a speed of 5000 to 8000 m/min.

Abstract: The invention relates to a process for the treatment of contaminated ethylene glycol resulting during a polycondensation process for the production of polyester. In the course of this polycondensation process contaminated ethylene glycol is continuously predistilled, subjected as a distillation residue to secondary distillation, condensed and then returned to the polycondensation process as decontaminated ethylene glycol, so that an in-line recovery is achieved, which makes superfluous an external distillation installation for the treatment of contaminated ethylene glycol.

Abstract: The invention relates to a polyester resin for producing a thick-walled bottles having high transparency and a neutral color. The polyester resin, containing at least one antimony compound, one germanium compound and one phosphorus compound, is produced by reacting a dicarboxylic acid with polyhydric alcohols and also contains cyclohexane dimentanol. The polyhydric alcohols are a mixture of ethylene glycol and at least 0.5% cyclohexane dimethanol. The result, more particularly, is a low rate of crystallization for obtaining thick-walled hollow members.