Dyeing of Textiles in Super Critical form

摘要

The environmental pollution problems have driven impetus in developing the novel concepts in wet processing using supercritical fluid .This novel concept is used for dyeing of synthetic fibers and natural fibers, since, some supercritical fluids are inexpensive, non-toxic, environmentally friendly, chemically inert under many conditions and easily available that can be utilized in textile wet processing at supercritical stage. In SC dyeing process, there is no salt and auxiliaries required hence, the cost of the effluent treatment drastically reduced. One of the supercritical fluids, which can be used, is carbon dioxide (CO_2). Supercritical CO_2 SC-CO_2 is a clean and versatile solvent and a promising alternative to noxious organic solvents and Chlorofluorocarbons. It has attracted particular attention as a supercritical fluid in the synthesis as well as processing areas. Color fastness of fibers dyed in supercritical CO_2 is similar to fibers dyed in water. Due to the low viscosity of SC-CO_2, dissolved dyes readily penetrate into pores and capillaries of fibers more easily as compared to others SCFs (Supercritical fluids). The diffusion coefficient of dye molecules in SC-CO_2 is greater than those of liquids and other SCFs which allow faster mass transport and therefore, significant higher dyeing rates result in a short dyeing time. The review of the fundamental properties, the procedure of dyeing and scope of supercritical fluids in textile wet processing is discussed in this paper.