Oxidative dyeing compositions containing 4-hydroxy or 4-aminobenzimidazole or derivatives thereof as couplers, and process for implementation
AssigneeL'oreal
InventorsMarie P. Audousset, Jean Cotteret
Life of this patent
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Abstract
Processes for the dyeing of keratinous fibers with compositions which contain 4-hydroxy- or 4-aminobenzimidazole or their derivatives corresponding to the formula (I): ##STR1## in which: R.sub.1 and R.sub.2 represent hydrogen or alkyl, one at least of the substituents being equal to hydrogen, R.sub.3 denotes OH or NH.sub.2, as coupler for dyeing keratinous fibers, in particular hair, in the presence of a p-phenylenediamine, the ratio between the p-phenylenediamine and the coupler of formula (I) being greater than or equal to 1.2.
Claims18
A process for dyeing keratinous fibres, in particular hair, comprising applying to the keratinous fibres as a coupler 4-hydroxy- or 4-aminobenzimidazole or their derivatives corresponding to the formula (I):
- ##STR6## in which:
- R.sub.1 and R.sub.2 represent hydrogen or alkyl, one at least of the substituents being equal to hydrogen;
- R.sub.3 denotes OH or NH.sub.2,
- in the presence of a paraphenylenediamine, the weight ratio between the paraphenylenediamine and the coupler of formula (I) being greater than or equal to 1.2/1.
Dyeing composition for keratinous fibres, comprising in a medium suitable for dyeing keratinous fibres, at least one coupler of formula (I):
- ##STR10## in which:
- R.sub.1 and R.sub.2 represent hydrogen or alkyl, one at least of the substituents being equal to hydrogen;
- R.sub.3 denotes OH or NH.sub.2, and at least one p-phenylenediamine, the weight ratio of the p-phenylenediamine and the coupler of formula (I) being greater than or equal to 1.2/1.
Process for colouring keratinous fibres, comprising as a dyeing composition in a medium suitable for dyeing keratinous fibres, at least one coupler of formula (I):
- ##STR12## in which:
- R.sub.1 and R.sub.2 represent hydrogen or alkyl, one at least of the substituents being equal to hydrogen;
- R.sub.3 denotes OH or NH.sub.2, and at least one p-phenylenediamine, the weight ratio of the p-phenylenediamine and the coupler of formula (I) being greater than or equal to 1.2/1, said dyeing composition being mixed with an oxidizing agent and then applied to the keratinous fibres in amounts sufficient to develop the colouring during application to the keratinous fibres.
Process for colouring keratinous fibres, comprising applying to the keratinous fibres a composition (A) containing, in a medium suitable for dyeing, a coupler of formula (I):
- ##STR13## in which:
- R.sub.1 and R.sub.2 represent hydrogen or alkyl, one at least of the substituents being equal to hydrogen;
- R.sub.3 denotes OH or NH.sub.2, and a p-phenylenediamine, said coupler being present in proportions between 0.008 and 3.5% by weight with respect to the total weight of the composition, and, after rinsing, applying to the keratinous fibres a composition (B) containing an oxidizing agent, the weight ratio between the p-phenylenediamine and the coupler of formula (I) being greater than or equal to 1.2/1.
Process for dyeing keratinous fibres, comprising applying to the keratinous fibres, in a first step, a composition (A) containing a p-phenylenediamine in a medium suitable for dyeing and, after rinsing, applying to the keratinous fibres a composition (B) containing, in a medium suitable for dyeing, a coupler of formula (I):
- ##STR14## in which:
- R.sub.1 and R.sub.2 represent hydrogen or alkyl, one at least of the substituents being equal to hydrogen;
- R.sub.3 denotes OH or NH.sub.2, and an oxidizing agent, the said coupler being present in proportions such that the p-phenylenediamine/coupler of formula (I) weight ratio is greater than or equal to 1.2/1.
Dependencies are inferred from the claim text.