COMPOSITION COMPRISING AT LEAST ONE 2-PYRROLIDONE FUNCTIONALIZED IN THE 4 POSITION WITH A CARBOXYLIC ACID OR AMIDE, AND AT LEAST ONE DIRECT DYE OR A PIGMENT FOR DYEING KERATIN FIBRES
The invention relates to a composition for dyeing keratin fibres, and in particular human keratin fibres such as the hair, comprising at least one 2-pyrrolidone functionalized in the 4 position with a carboxylic acid or amide radical, and at least one hydrophobic direct dye or a pigment a dyeing process using this composition. Similarly, the invention relates to the use of the said pyrrolidone combined with a direct dye or a pigment for dyeing keratin fibres, and especially to the use of the said pyrrolidone for improving the colour uptake onto the fibres of direct dyes that are sparingly soluble or insoluble in aqueous-alcoholic supports. The invention also relates to novel pyrrolidone derivatives. The present invention makes it possible in particular to obtain direct dyeing on keratin fibres that is fast, resistant to washing, chromatic and powerful.