Analyses of some undesirable effects in industrial exhaust dyeing of knitted fabrics of different grades of cotton with reactive dyes

Abstract

Dyeing of knitted fabrics from different grades of cotton in industrial conditions by a single recipe with bi-functional reactive dyes has been investigated in order to estimate the efficiency and reproducibility of the process. Quality control in different stages of the process was followed through the content of the non-cellulose components, alkaline and alkaline earth elements in raw and scoured cotton, the hydrophilic properties, and CIELab coordinates, color difference between different batch dyeing, purity of the electrolyte as well as the quality of the water through permanent hardness, temporary bicarbonates hardness, alkaline, earth-alkaline and heavy metal ions. Black dyed fabrics had high variance coefficients of ΔE*, indicating shade variations and unacceptable color levelness and reproducibility. Enzymatic scouring, quality of the raw cotton, water and electrolyte have significant influence on the dyed fabrics.