Scouring and dyeing of polyester fibers in supercritical carbon dioxide

This study presents a viable method for the scouring and dyeing of polyeste r fibers (polyethylene terephthalate, PET) by using supercritical carbon di oxide as a medium. Scouring of the PET fibers was carried out at pressures ranging from 96 to 350 bar and at temperatures ranging from 313 to 393 K, T he overall oil removal efficiency reached +99 %. The sorption behaviors of the fibers with three single and a mixture of disperse dyes (C.I. Disperse Blue 79, Yellow 119, and Red 153) in dense CO2 were investigated at 290 bar and 393 K, The solubilities of three single dyestuffs in dense CO2 were in the weight fraction range of 10(-7) to 10(-4). The uptake amount of the dy e at saturation fell in the range of 6.5 to 12.5 mg dye/g fiber under the d yeing conditions. The rate of dye sorption is correlated with dye solubilit y, and decreases in the order of Blue 79, Yellow 119, and Red 153, respecti vely. This dyeing approach offers superior fastness properties, which are e nhanced by increasing dyeing pressure and temperature.