Dye composition comprising at least one particular dissymetrical polycationic direct dye, dyeing process, use and multi-compartment devices

A process for direct dyeing human keratin fibers, comprising applying to the keratin fibers at least one dye composition comprising, in a medium suitable for dyeing, at least one dissymetrical polycationic direct dye of formula (I) below:

• Col1-Z-Col2 (I)
• wherein:
• Col1 and Col2, which differ in structure, are chosen from azo dyes, methine dyes, azomethine dyes, phenothiazine dyes, triarylmethane dyes, xanthene dyes, phenanthridine dyes and phthalocyanin dyes, and
• Z is chosen from linear and branched, saturated and unsaturated and cyclic C1–C20 hydrocarbon-based groups comprising at least one nitrogen atom and bearing at least one cationic charge.

A process for oxidation dyeing of human keratin fibers comprising applying to the keratin fibers, in the presence of at least one oxidizing agent, at least one dye composition, comprising, in a medium suitable for dyeing, at least one dissymetrical polycationic direct dye of formula (I) below:

• Col1-Z-Col2 (I)
• wherein:
• Col1 and Col2, which differ in structure, are chosen from azo dyes, methine dyes, azomethine dyes, phenothiazine dyes, triarylmethane dyes, xanthene dyes, phenanthridine dyes and phthalocyanin dyes, and
• Z is chosen from linear and branched, saturated and unsaturated and cyclic C1–C20 hydrocarbon-based groups comprising at least one nitrogen atom and bearing at least one cationic charge;
• at least one oxidation base;
• and
• optionally, at least one coupler.

A method for preparing a composition for direct dyeing keratin fibers comprising including in the composition at least one dissymetrical polycationic direct dye of formula (I) below:

• Col1-Z-Col2 (I)
• wherein:
• Col1 and Col2, which differ in structure, are chosen from azo dyes, methine dyes, azomethine dyes, phenothiazine dyes, triarylmethane dyes, xanthene dyes, phenanthridine dyes and phthalocyanin dyes, and
• Z is chosen from linear and branched, saturated and unsaturated and cyclic C1–C20 hydrocarbon-based groups comprising at least one nitrogen atom and bearing at least one cationic charge.

A multi-compartment device or kit, for dyeing human keratin fibers comprising

• a first compartment comprising at least one dye composition comprising, in a medium suitable for dyeing, at least one dissymetrical polycationic direct dye of formula (I) below:
• Col1-Z-Col2 (I)
• wherein:
• Col1 and Col2, which differ in structure, are chosen from azo dyes, methine dyes, azomethine dyes, phenothiazine dyes, triarylmethane dyes, xanthene dyes, phenanthridine dyes and phthalocyanin dyes, and
• Z is chosen from linear and branched, saturated and unsaturated and cyclic C1–C20 hydrocarbon-based groups comprising at least one nitrogen atom and bearing at least one cationic charge, and
• a second compartment comprising at least one oxidizing composition.