Study On Improving Dyeing Fastness Of Natural Brazilwood Dye By Epoxy Cross-Linking Agent EH

The investigations are made on the improvement of dyeing fastness of cotton directly dyed with natural brazilwood dye by using epoxy cross-linking agent EH. The key factors are discussed on three methods of dipping , baking and steaming and the most favorable process conditions are determined. The result indicates that the color yield is obviously enhanced and the fastnesses to soaping, rubbing and the resistant to acid and alkali are improved. The cross-linking function is analyzed by FT-IR spectra, X-ray diffraction, DSC-TGA and acid-dissolving rate. The dynamics of cross-linking reaction was investigated with hematoxylin as substitute of brazilwood dye. Through the cross-linking reaction with epoxy groups of cross-linking agent, the hydroxyl groups of brazilwood dye are changed into ether bond so that the stabilization of the dye on cotton is improved. The cross-linking reaction mostly occurred in amorphism region so that almost no influence to crystal structure of fibre.