Abstract: Reactive dyes were applied to dyeing soybean/casein/polyvinyl alcohol blend fibers (short for double protein fibers). The influence of dyeing temperature, dyeing time, dosage of sodium carbonate and sodium chloride on dyeing percent of exhaustion and fixation were studied. The dyeing performance of double protein fiber and soybean protein fiber were compared. The building up properties of these dyes were also discussed. The results showed that the optimal process of medium temperature reactive dyeing double protein fiber was sodium carbonate 1-2g/L, sodium chloride 20-40g/L, dyeing at 60℃ for more than 60min; The optimal process of high temperature reactive dyeing double protein fiber was sodium carbonate 0g/L, sodium chloride 20-40g/L, dyeing at 80 to 90℃ for more than 60min; The dyeing percent of exhaustion and fixation of double protein fiber at the same dyeing conditions was higher than that of soybean protein fiber. The building up power of reactive dyes on double protein fiber was good.

Key words: dyeing, reactive dye, regenerated protein fiber, soybean, casein