Green and Sustainable Method to Improve Fixation of a Natural Functional Dye onto Cotton Fabric Using Cationic Dye-Fixing Agent/D5 Microemulsion

The low fixation rate and colorfastness of natural dyes limit their practical application in modern textile coloration. Further, hazardous mordants are used in conventional natural dyeing to achieve better fixation and colorfastness. Herein, a green, sustainable, and environmental benign fixation process of natural dye was developed using a non-aqueous medium in the absence of mordants to enhance the fixation rate and colorfastness of the dyed fabric. The process was executed by the treatment of the cacao husk extracts/decamethylcyclopentasiloxane (D5) dyed cotton fabric with a cationic dye-fixation agent (CFA)/D5 microemulsion. The conditions of optimal dye fixation process including water content, fixation time, fixation temperature, and CFA mass were determined by using L9 orthogonal array. Significant improvements in the fixation rate (95.03%) and color strength (15.26) were found after CFA treatment under the optimal conditions. Although the light fastness of the CFA-treated dyed fabrics was poor, the colorfastness to rubbing and washing were remarkable. The cacao husk extracts natural functional dye significantly enhanced the UV resistance of the dyed fabric, and the CFA treatment improved the crease recovery characteristic of the dyed fabric. The stiffness of the fabric decreased slightly after dyeing and CFA treatment. Consequently, this study paved the way for the sustainable and green dyeing process.