ANIONIC DIRECT DYE HAVING A TETRAALKYLAMMONIUM COUNTERION, DYEING COMPOSITION COMPRISING THEM AND METHOD FOR DYEING KERATINOUS FIBRES STARTING FROM THESE DYES
The invention relates to the dyeing of human keratinous fibres, in particular the hair, using anionic direct dyes or acid dyes having a tetraalkylammonium counterion of formula (I) with Col(−)m. R1, R2, R3, R4, m, and n as defined in the description. A subject-matter of the invention is a dyeing composition comprising an anionic dye of formula (I) and a method for dyeing keratinous fibres, such as the hair, employing the said composition. A subject-matter of the invention is likewise novel dyes of formula (I) and their uses for the colouring of keratinous fibres. This composition makes it possible to obtain a chromatic, powerful and particularly persistent colouring on keratinous fibres.
