ANALYTICAL TECHNIQUE FOR CHARACTERIZING THE INITIAL-STAGE OF THE DYEING PROCESS

A convenient experimental apparatus is developed for analyzing the ini tial stage of several seconds at the start of the dyeing process under rapid adsorption conditions. A cationic dyeable acrylic fiber is dyed at 90 degrees C and pH 6.4 with 0.002% methylene blue solution at a 5 00:1 liquor ratio. The fiber is left in the 90 degrees C steamed atmos phere for 30 minutes before dyeing. The wavelength of the 668 nm monoc hromatic Light beam transmittance is detected with multiple optical gl ass fibers inserted directly in the dyebath. Six percent of the dye up take in the fibers after 2 hours' dyeing is adsorbed before 1 second. In case of a cationic dyeable polyester fiber, 9% is adsorbed in the s ame period.