Non-water dyeing process of reactive dyes in two organic solvents with temperature-dependent miscibility:

In this paper, a non-water dyeing process using two organic solvents with temperature-dependent miscibility was developed. Fixation of three conventional reactive dyes on cotton yarn could reach 97% using one dyeing bath consisting of two solvents. Only one washing step at room temperature was needed to get satisfactory fastness after the fixation process. In particular, the two selected organic solvents could interconvert from immiscible to miscible when the temperature interchanged from 30 to 90℃. This unique physical property makes the separation and recycling processes of organic solvents extremely easy and energy saving. A 1 kg yarn package was dyed using this dyeing process: the color deviation (△E) of the inner and outer yarns was less than 1.0 and the tensile strength decreased by 8.5–18.0%. The results show that this dyeing process is extremely promising.