The effects of dry heat, water vapor in superheated steam, and heating in hot water at varying temperatures, on the dyeing behavior and fine structure of nylon 6 fibers were examined, at 160, 175, 185 and 200 for dry heat, 100 and120 for steam and 130,140 and 150 for hot water by measuring saturation dye-uptake value. Two direct dyes, C.I. Direct Yellow 27 and C.I. Direct Yellow 12 and two acid dyes C.I. Acid violet 48 and C.I. Acid Orange 7 were used for measuring the saturation value of dye-uptake. With dry heat setting, a decreasing in the saturation dye-uptake value, occurs by increasing the heat temperature, minimum amount of dye-uptake observed, at 170°C in dry heat, at 130°C in hot water and 100°C in superheated steam setting, also dry heat increased shrinkage, crystallinity, and crystallite size according to the decreased saturation dye-uptake value compared to super heat steam and hot water treatment. Thermodynamic and synthetic studys shwos that affinity and enthalpy are almost fitted whit the exhaustion data as it expected. Nano dyeing result are upto that nanoscale fibers have better exhaustion result and close thermodynamic properties than regular fiber. Also we observed that synthetic data in dyeing of nano fibers is grater than regular ones. Key words: Nylon 6, Acid Dyes, Direct Dyes, nano Nylon 6, Heat setting
