Research On Acid And Reactive Dyeing Performance Of Soybean Fiber

Soybean fiber as a kind of new fiber has attracted much considerable attention. The investigation on its dyeing performance will play a significant role on practical dyeing process. In order to understand the principal dyeing performance of soybean fiber completely, the dyeing behaviors of Everacid N acid dyes and Everzol ED reactive dyes were tested systematically. And the application of Enzyme soaping agent to soybean fiber which was dyed by reactive dyes was explored. The recommended dyeing temperature of acid dyes (Everacid N dyes) for soybean fiber was 85-90℃. Acid dyes had good building-up performance on soybean fiber. The dyeing sensitivity to pH increased with the decrease in molecular weight of dyes and the increment in a ratio of sulfonic weight to dye molecular weight. The control of pH depended on desired shades: pH 6 for pale, pH 4-5 for medium and 4 for dark. Acid dyes exhibited better migration behavior on soybean fiber than that on wool and silk. The recommended trichromatic acid dyes were Everacid Orange N-G, Red N-B and Cyanine N-5R for dark color, and Everacid Yellow N-MR, Red N-RFL and Blue N-RL for brilliant color. Sulphatoethylsulphone and monochlorotriazinyl (VS/MCT) heterobifunctional reactive dyes (Everzol ED dyes) exhibited good building-up properties on soybean fiber, and were suitable for the dark dyeing of soybean fiber. The optimum dyeing temperature was 70℃. The dosage of soda ash for soybean fiber was lower than that for cotton, 4~6g/L for pale color and not above 10g/L even for dark color. Soda ash could not give rise to the damage of soybean protein under the conditions of medium temperature and normal soda ash dosage while caustic soda easily led to the hydrolysis and loss of soybean protein. Soyean fiber and silk exhibited different dyeing behaviors from cotton before the addition of alkali, i.e., the sorption and fixation of dyes simultaneously occurred. Therefore, only the SERF profile was not appropriate for characterizing the reactive dyeing performance of soybean fiber. The removal percent of unfixed VS reactive dyes on soybean fiber was nearly the same as that of VS/MCT reactive dyes. However, whether enzymatic rinse process was applicable the reactive dyeings or not should depend on individual dyes. The removal mechanism was that the chromophore of dyes was damaged by enzymatic system.