Effects of the Dyeing Conditions on Dyeing of Wool Fiber with Oxidation Dyes

Abstract

Dyeing behavior for wool fibers from the couple system of p-phenilendiamine/p-amino-o-cresol and p-aminophenol/p-amino-o-cresol in use in current hair dye formulation was investigated. This paper describes the variation of dye uptake with factors such as pH in the bath solution, concentration of hydrogen peroxide, dyeing temperature and liquor ratio. Generally, the apparent dye uptakes increased with increasing of dyeing time, hydrogen peroxide concentration, dye temperature, and liquor ratio. However, indo dye decomposition by excess hydrogen peroxide is a competitive process in both couple systems. Particularly, the following fact was definitely observed above pH10.0: the higher dyeing temperature and the higher concentration of hydrogen peroxide led to the increase of the rate of dye formation reaction and the extent of dye decomposition. On the other hand, below pH10.0, the dye decomposition was also decreased due to the suppressing hydrolysis of hydrogen peroxide to perhydroxyl anion. Ultimately, it could be verified that the dyeing behavior of oxidation dye into wool fibers was subjected to a certain balance between dye formation and dye loss by hydrogen peroxide.