Cleaner Production of Dyed and Functional Polyester Using Natural Dyes vis-avis Exploration of Secondary Shades

Natural dyes are known for their added benefits over synthetic dyes in terms of health and ecology. They are considered to present a limited range of shades, which limits their use in high-end value-added products. Thus, to explore natural dyes on large scales, it is essential to generate a wide range of shades like synthetic dyes. Therefore, it is important to explore the secondary shades of natural dyes especially those which can act as primary colors in the recipe (red, yellow and blue). In the present work, three natural dyes, namely indigo, pomegranate peels and kumkum were used to dye the polyester fabric. Along with color strength at different dye concentrations, functional properties such as antioxidant, antibacterial, and UV protection were also evaluated. The dyed polyester showed good color values (K/S 1.7) and also displayed satisfactory color fastness to light, washing and rubbing. The polyester fabric dyed with pomegranate and kumkum in self-shades displayed a variety of functional properties including a bacterial reduction of more than 90%, radical scavenging activity of greater than 90% and also displayed excellent UPF values (UPF 270). Indigo-dyed samples displayed antibacterial activity and UVprotection; however, their antioxidant activity was poor. The secondary shades of these dyes were produced on polyester fabric.