Dye composition for keratinic fibres based on paraphenylenediamine, metaphenylenediamines and benzimidazol derivates, and the dyeing process using same.

摘要

Use of benzimidazole derivatives as coupling agents for the oxidation dyeing of keratinous fibres and in particular human hair, in the presence of at least one meta-phenylenediamine and at least one para and/or ortho oxidation dye precursor, the benzimidazole derivative corresponding to the formula: <IMAGE> in which: R1 represents a hydrogen atom or a C1-C4 alkyl radical; R2 represents a hydrogen atom or a C1-C4 alkyl radical or a phenyl radical; R3 represents a hydroxyl, amino or methoxy radical; R4 represents a hydrogen atom, a hydroxyl or methoxy radical or a C1-C4 alkyl radical; with the proviso that: - when R3 denotes NH2, it occupies the 4-position; - when R3 is in the 4-position, R4 is in the 7-position; - when R3 is in the 5-position, R4 is then in the 6-position.