Sustainable application of cochineal-based anthraquinone dye for the coloration of bio-mordanted silk fabric.

Natural colors particularly animal-based colorants are employed in the field of cosmetics, food, and flavors and also gaining popularity in textiles, due to their soothing nature. In this study, the microwave-assisted extraction of colorant from cochineal insects for dyeing of bio-mordanted silk has been carried out. Acidic, methanolic, and acidified methanol solubilized media were used to extract the natural colorant from cochineal under microwave irradiation for 1-6 min. Bio-mordants have been employed at optimized conditions to make the process greener and sustainable. It is found that acid solubilized extract of pH 4, employed at 55 °C for 55 min containing 5 g/100 mL of Glauber's salt as exhausting agent has given high color strength onto microwave-treated silk fabric. Suggested ISO standards for colorfastness have revealed that bio-mordants have given excellent color depth and excellent rating of fastness properties, compared with chemical mordants used. It is found that microwave treatment has not only improved the dyeing behavior of colorant extracted from cochineal in acid solubilized medium but also enhanced the color characteristics onto bio-mordanted silk fabric.