| 摘要 |
A composition of certain dyes with a category-2 hair bleach can simultaneously lighten hair up to seven levels and deposit various shades of color in a single step. The dyes are bleach-stable derivatives of azo, triarylmethane, thiazine, or nitro dyes. When linked at the ortho- and/or para-positions relative to the chromophoric centers and auxochrome groups located on or attached to the aromatic rings of these dyes, deactivating or weakly activating chemical groups enhance the dye stability in the alkaline bleach. The absence of ortho and/or para positioned deactivating or weakly-activating substituents, or the presence of strongly activating groups in these positions render the dye molecule susceptible to attack by the bleach and the eventual destruction of these dyes. These deactivating and protective chemical groups may be nitro, halogen, cyano, carboxyl, sulfonic, alkyl or aromatic groups, but not amino, hydroxy, alkoxy or alkylamide groups. |
