CROSS-REFERENCE TO RELATED APPLICATIONS

This is the U.S. national phase of International Application No. PCT/EP2019/082009, filed Nov. 21, 2019, which claims the benefit of European Patent Application No. 18207425.2, filed on Nov. 21, 2018.

The presently claimed invention relates to the field of dyeing keratin fibers and in particular human keratin fibers such as the hair.

The presently claimed invention relates to a composition for dyeing keratin fibers. The presently claimed invention also relates to a process for dyeing keratin fibers using the dye composition.

BACKGROUND OF THE INVENTION

It is a known practice to dye keratin fibers, and in particular the hair, with dye compositions containing one or more direct dyes, according to a “direct dyeing” process. The process involves applying a composition comprising one or more direct dyes to the keratin fibers, allowing the composition to contact with the fibers for a requisite time, and then rinsing the fibers. The direct dyes used hitherto are generally nitrobenzene dyes, anthraquinone dyes, nitropyridine dyes, dyes of azo, xanthene, acridine or azine type or triarylmethane-based dyes.

However, the use of these direct dyes is associated with drawbacks. The colorations resulting therefrom are temporary or semi-permanent. The nature of the interactions that bind these direct dyes to the keratin fiber and their desorption from the surface and/or the core of the fiber are responsible for their weak dyeing power. Further, the above mentioned direct dyes provide poor fastness with respect to washing, inclement weather or perspiration.

Moreover, such direct dyes are generally sensitive to the action of oxidizing agents such as aqueous hydrogen peroxide solution, which makes them difficult to use in lightening direct dye compositions that are formulated with aqueous hydrogen peroxide solution and a basifying agent, these compositions resembling the compositions used for oxidation dyeing. In other words, direct dyes are generally sparingly compatible with dye compositions intended for lightening fibers, and, consequently, their use in a lightening dyeing process, as an alternative to oxidation dyeing, is unsatisfactory.

These direct dyes are also associated with the drawback of lacking light-fastness because of the poor resistance of the chromophore to photochemical attack. This lack of stability leads to fading over time of the coloration of the keratin fibers.

US 2015/000688 A1 discloses direct dyes of azomethine type and their use for dyeing keratin fibers.

FR 2968947 A1 discloses a dye composition comprising benzyl alcohol, at least one C1-C4monoalcohol and at least one direct dye of azomethine type for dyeing keratin fibers.

GB 2141437 A discloses direct dyes based on indoaniline and indophenol compounds and compositions thereof for hair dyeing.

There is thus a need for compositions containing direct dyes that dye keratin fibers satisfactorily and that are light-fast. Further, it is desired that these compositions are capable of providing colorations that are both resistant to the various attacking factors to which the fibers may be subjected, such as inclement weather, sunlight, washing and perspiration, and that are also sufficiently stable in the presence of oxidizing agents such as aqueous hydrogen peroxide solution in order to be able to obtain simultaneous lightening of the fibers with the advantages outlined above.

Hence, it is an object of the presently claimed invention to provide compositions containing direct dyes that dye keratin fibers satisfactorily, that are light-fast, that are capable of providing colorations that are both resistant to the various attacking factors to which the fibers may be subjected, such as inclement weather, sunlight, washing and perspiration, and that are also sufficiently stable in the presence of oxidizing agents such as aqueous hydrogen peroxide solution.

SUMMARY OF THE INVENTION

It was surprisingly found that the above identified object is met by the subject matter of the claims.

In the following, specific embodiments of the present invention are described:1. A composition for dyeing keratin fibers comprisinga. at least one azomethine compound of the formula (1);

wherein,R1is hydrogen, or C1-C5alkyl;R2is hydrogen, C1-C5alkyl, a radical of formula *—O—(CH2)n—OH; orR1and R2together form a radical of formula

A is NH, or O;X1is


or *—N=*;R3is a radical of formula

R4is hydrogen, or NH2;R5, R6, R7and R8, independently from each other are hydrogen, or C1-C5alkyl; andn is a number from 1 to 3;andb. water.2. The composition according to embodiment 1, wherein

R1is hydrogen; or R1and R2together form a radical of formula

3. The composition according to any of embodiments 1 to 2, whereinR3is a radical of formula

4. The composition according to any of embodiments 1 to 3, whereinR1is hydrogen; or R1and R2form a radical of formula;

R2is hydrogen, methyl or a radical of formula *—O—(CH2)2—OH;A is ═NH, or O—;X1is


or* —CH═; andR3is a radical of formula

5. The composition according to any of embodiments 1 to 4, wherein compound of the formula (1) is selected from

6. The composition according to any of embodiments 1 to 5, wherein the amount of azomethine compound is in the range from 0.001% to 10% by weight based on the total weight of composition.7. The composition according to any of embodiments 1 to 6 having a pH in the range from 3 to 12.8. The composition according to any of embodiments 1 to 7 further comprising a nonionic surfactant.9. The composition according to any of embodiments 1 to 8 further comprising an organic solvent selected from the group consisting of C1-C4alkanols, polyols, polyol ethers, and aromatic alcohols.10. The composition according to any of embodiments 1 to 9 further comprising at least one oxidation dye in an amount in the range of 0.001% to 10% by weight based on the total weight of composition, and at least one coupler in an amount in the range of 0.001% to 10% by weight based on the total weight of composition.11. The composition according to any of embodiments 1 to 10 further comprising an adjuvant in amount in the range of 0.01% to 20% by weight based on the total weight of composition, wherein the adjuvant is at least one selected from the group consisting of surfactants, polymers, thickeners, antioxidants, penetrants, solubilizers, sequestrants, fragrances, buffers, dispersants, conditioning agents, film-forming agents, ceramides, preserving agents, opacifiers, conductive polymers and combinations thereof.12. A use of the composition according to any of embodiments 1 to 11 for dyeing keratin fibers.13. The use of the composition according to embodiment 12 for dyeing human hair.14. A process for dyeing keratin fibers, characterized in that the composition according to any of embodiments 1 to 11 is applied to the wet or dry fibers for a time that is sufficient to obtain the desired coloration, after which the fibers are rinsed, optionally washed with shampoo and rinsed again, and the resulting fibers are dried or left to dry to obtain dyed keratin fibers.15. A process for lightening keratin fibers, characterized in that(i) the dye composition according to any of embodiments 1 to 11, free of oxidizing agent, and(ii) a cosmetic composition comprising one or more oxidizing agents are applied to the fibers; compositions (i) and (ii) being applied to the keratin fibers sequentially or simultaneously for a time that is sufficient to obtain the desired lightening, and the fibers are then rinsed, optionally washed with shampoo and rinsed again, and the resulting fibers are dried or left to dry.

