Process for drawing tows of filaments in water

摘要

Polyesters are drawn in the form of thick tows in a predrawing and a main drawing step. Predrawing is carried out at 71 DEG -90 DEG C. in water, and the predraw ratio is chosen in such a manner that the main drawing can be carried out at a minimum of draw tension. Between predrawing and main drawing, the tows cool to below 40 DEG C. Suitable draw ratios for the predrawing are from 1:1.05 to 1:1.6. The main drawing is carried out either in steam or hot water. FIG. 2 shows the curve of draw tension in the main drawing step as function of the draw ratio in the predrawing: there is a distinct minimum.