Composition for dyeing keratin fibres comprising a direct dye bearing a disulphide/thiol function, a non-cellulose-based thickening polymer, an alkaline agent and a reducing agent

Abstract

The invention relates to a process for dyeing and/or lightening keratin fibres such as the hair, using i) at least one direct dye bearing a disulfide, thiol or protected-thiol function and ii) at least one non-cellulose-based thickening organic polymer, iii) at least one alkaline agent, iv) at least one reducing agent and optionally v) at least one surfactant. The invention also relates to a composition comprising the ingredients i) to iv) and optionally v), to the use of the combination of i), ii), iii), iv) and optionally v) for the dyeing and/or lightening of keratin fibres, and to a multi-compartment kit comprising the ingredients i) to iv) and optionally v). The dyeing process and the composition according to the invention especially afford a long-lasting coloration on keratin fibres, which is strong, chromatic and/or homogeneous, with or without the use of an oxidizing agent.