Oxidative dyeing of keratin fibers

Dye uptake by hair and wool cloth has been measured by a reflectance technique. Using a statistical experimental design, color formation from a single pair of reactants has been used to define and quantify many of the factors that control the process. Although peroxide concentration has little effect, color intensity depends on the concentration of reactants and added surfactants and on the dyeing time. These results can, in some cases, be predicted from the solution kinetics of the coupling reaction where the rate-controlling step is formation of a reactive intermediate from hydrogen peroxide, followed by a series of faster oxidative and coupling steps to give the dye. However, there are significant differences between the dyeouts and solution chemistry reflecting the important role of the substrate on the dyeing process