Single bath two-step dyeing of 50/50 acrylic/cotton blends:an industrial scale investigation

Abstract

Although one-bath dyeing of acrylic/cotton blend fabrics has been investigated at laboratory scale, its industrial application remains poorly understood. This study provides mechanistic insights into dye-fibre interactions, pH and ionic effects, and efficiency limitations, defining the operational boundaries for industrial implementation. Laboratory-scale trials were conducted for one-bath two-step dyeing of acrylic/cotton blends, followed by industrial-scale trials. Results reveal that light- and medium-shade fabrics achieve satisfactory fastness and levelness, whereas dark shades exhibit substantial fastness deterioration under industrial conditions due primarily to uncontrolled dye interactions and insufficient reductive clearing. Experiments, performed by dyeing acrylic first and cotton second without draining the bath, gave successful results in light-medium shades, demonstrating the conditions under which one-bath two-step dyeing is feasible. These findings provide a framework for industrial process decision-making rather than a universally applicable dyeing method.