method and device for drawing of synthetic multifilamentgarnen

摘要

In drawing synthetic monofilament yarns, the yarn is fed continuously at a given speed through a feed unit, and then taken continuously from a take-off unit at a higher speed. The yarn is allowed to shrink on the take-off unit, where it is held at a constant length for at least one preset time span. Pref. the yarn is held at a constant length, immediately after shrinking, for a time span of 0.002-4.0 sec.At the take-off unit, the yarn is heated to a temp. above the glazing temp. of its material, pref. 120-250 deg. C., through contact heat with the take-off unit. The yarn is shrunk in a first stage, and then held at a constant length in a second stage, with repetition of the first and second stages a number of times, pref. two to four times. Each of the two stages lasts 0.01-2.0 sec. Before the yarn is taken through the take-off unit, it passes round a pin, pref. an unheated pin with a dia. of less than 10mm, at an angle of 180-360 deg. round the pin. Before and/or after the take-off unit, the yarn is wetted with a fluid, pref. a watery fluid. While the yarn is held at a constant length, its tension is held at 0.05-2.5 cN/dtex for the preset time span. ADVANTAGE - Directly after it leaves the take-off unit, the yarn has a low residual shrinkaf