Sustainable production processes in textile dyeing

Abstract

Value addition for textiles is an important process and it is required for all products including yarn, fabric, garment, fashion apparel, floor covering, and the majority of technical textiles. Value addition may be either an additive or subtractive process. In the subtractive process part of the fiber components may be removed by some physical or chemical process because textile fibers have natural as well as added impurities during production. In the additive process, either color or functional chemicals may be added to improve aesthetic as well as functional properties. For each textile processing, the processor used enormous amounts of chemicals and water in order to attain the desired result. After processing the residual processed chemicals and waters are treated with effluent treatment and discharged into the mainstream. The amount of residual unfixed dyes, metal compounds, formaldehyde-based dye-fixing agents, hydrocarbon-based softeners, and all types of dye-bath auxiliaries as well as their degradation nature against the environment are the deciding factors for its sustainability. Technologies have been developed for the past five decades starting from fiber to finished product in order to reduce the effluent load, energy, processing cost, and manpower as well as increase the process efficiency and reproducibility. There are many factors influencing the overall efficiency or value addition of a textile product, which play an important role in its sustainability. This chapter deals with the basic theory of dyeing processes, factors influencing their performance, potential pollutants, sustainable technologies developed thus far, and future perspectives in dyeing.