Abstract:

The use of natural dyes has increased in the last few decades due to the eco-friendly approach of dyeing. There are still some limitations that are associated with natural dyes, such as dyeing efficiency, reproducibility of shades, process complexity, availability etc. The main problem associated with the dyeing property of natural dyes is “low exhaustion”. In this study, natural dyestuff from Curcuma longa L. was extracted and polyethylene terephthalate fabric was dyed with it in the same bath by employing the supercritical carbon dioxide method. The method was developed to improve the dye-ability of natural dyes and reduce the process time and effluent. Curcuminoid dye exhaustion on PET fabric showed almost 80% by using supercritical carbon dioxide dyeing methods, and the highest colour strength (K/S = 12) was obtained. Coloured polyethylene terephthalate fabric treated with supercritical carbon dioxide showed deeper shades (L* = 72.92) and better fastness properties as compared with high temperature exhaust dyeing methods.