Clean production using supercritical processing: An example of dyeing Tencel® and Nylon66 fabrics with recycling hydrophobic reactive dyes

Abstract

In current industrial textile dyeing processes, large amounts of wastewater are produced. This is an environmental burden and, due to the ever more stringent regulations on water pollution, also an economical problem. Only industrial waste minimization can give consideration to environment-friendly concerns. Now we have the notion of Reduce, Reuse and Recycle for environmental protection and economic development. The use of supercritical fluid processes such as the dyeing method solves this problem: the residual dye remaining in the dye bath after the process can easily be separated and can be recycled. The supercritical dyeing method has several benefits, such as being nonflammable, nontoxic, easy to use, economic and with favorable waste treatment processes. In order to achieve Green Production, this paper explores the feasibility of using Cationic surfactant KC-3A (Quaternary ammonium salt), recycling C.I. Reactive Blue 4 (DCT type) and C.I. Reactive Blue 19 (VS type) dyes to the original dyeing process and further dyeing Tencel® and Nylon66 fabrics with supercritical fluid. The recycled dye's structure is determined by spectroscopy. This paper also discusses both recycling dyes, dyeing Tencel® and Nylon66 fabrics in exhaustive dyeing processes. The experimental results showed that Tencel® fabrics after pre-treatment were dyed by the supercritical dyeing method with good fastness properties and acceptable color depth, and dyeing Nylon66 fabrics with recycling dyes is satisfactory using the supercritical dyeing method. Finally, this paper also shows that dyed Tencel® achieved optimum dyeing results at 140°C and 300 bar and dyed Nylon66 obtained optimum dyeing results at 120°C and 300 bar. The fixations on Nylon66 and Tencel® being above 77%, are also dependent on pressure and temperature. The washing and rubbing fastness of all dyed fiber is rated at between 3-4 and 5. © 201 WIT Press.