EFFECTS OF PROCESS VARIABLES ON THE FIXATION OF REACTIVE DYES TO COTTON USING INFRARED RADIATION

A series of experiments on the fixation of a reactive dye to a cotton fabric in a pilot-scale electric infrared dryer was designed and analyzed using two factorial plans. Equations were derived describing the influence of the controllable process variables on the dye fixation yield and also on the final fabric temperature and water content. Fabric speed (residence time) and the power supplied to the infrared emitters were the most important variables influencing the above responses. The dye fixation yield was also strongly dependent on the type of alkali and its concentration in the dye bath. The effects of increasing the NaCl and urea concentrations were minor. The use of vacuum slot extraction to remove superficial dye solution from the impregnated material prior to heating gave more efficient drying (higher fabric speeds and lower power consumption) and increased the dye fixation yield.