Coupling components

摘要

Keratin fibers are colored by an agent comprising a coupler which is a m-phenylenediamine derivative of the formula (I) wherein R¹ is a C₁-C₄ alkyl group or a C₁-C₄ monohydroxyalkyl group; R² is a methyl or an ethyl group; each of R³ and R⁴ is independently a branched or unbranched C₂-C₆ hydroxyalkyl group; and a cosmetically acceptable carrier. These couplers exhibit improved toxicological and dermatological properties and permit hair colorations in a broad color spectrum with good fastness properties.