Package Dyeing of Acrylic Fibre Yarn: Important Parameters which Influence Level Dyeing

Flow rate, ramp (constant rate of temperature rise), and package density are recognised to be particularly important for obtaining uniform uptake in the package dyeing of acrylic fibre yarns. This paper is concerned with the contribution of these three parameters to levelness in this system. An attempt is made to define empirical mathematical relationships between these variables and the observed rate of dyeing, in order to be able to specify those values of these parameters which would be expected to give rise to unlevel dyeings. Linear relationships were found between these parameters and the rate of exhaustion per circulation of the dyebath, expressed either as the overall rate or as separate rates for the two successive stages of the exhaustion proces. The equations relating rate of exhaustion to package density, ramp and the reciprocal of the rate of liquor flow can be combined into a single equation. This enables the relative effects of these variables to be calculated