processes for dyeing keratin fibers, preparing dyes of formula and preparing dyes, dyeing process, use of at least one direct dye, direct dye and composition

摘要

A subject of the invention is a process for dyeing keratin fibers, such as hair, using at least one cationic direct dye containing a protected disulfide, thiol or thiol function and comprising at least one aliphatic chain-containing ammonium group. ). Another subject of the invention is the use of (i) at least one cationic direct dye containing a protected disulfide, thiol or thiol function (i) combined with ii) steam and / or a heating iron for smoothing keratin fibers for keratin fiber dyeing, and novel cationic direct dyes containing a protected disulfide, thiol or thiol function (i), and also a cosmetic composition comprising them. The process used and the use of the thiol, protected thiol or disulfide dyes combined with steam make it possible in particular to obtain a lasting color with a valence of care in the keratin fibers.