Optimization of an ecofriendly dyeing process in an industrialized supercritical carbon dioxide unit for acrylic fibers

Abstract

The feasibility of using supercritical CO2 as a cleaning dyeing medium to dye acrylic fibers was investigated on an industrialized unit. The influence of dyeing temperature, dyeing pressure, dyeing time, and dye concentration on the K/ S values of acrylic fibers was examined using the fractional factorial design of experiments. A second-order polynomial model was established to analyze the interactions between distinct parameters and to obtain the optimal K/ S values. The results showed that an excellent dyeing effect of acrylic fibers was obtained in the industrialized supercritical CO2 unit, but the dyeing effect was easily affected by variations of the dyeing parameters. In the experimental range, a calculated K/ S value could be up to 6.14 with the dyeing temperature of 100℃, dyeing pressure of 26 MPa, dyeing time of 60 min, and dye concentration of 3%. The dyed acrylic fibers presented good color fastness to washing, rubbing, and light. Furthermore, a commercially acceptable levelness and reproducibility for acrylic fibers were obtained in the supercritical CO2 dyeing process.