Polyamino acid derivatives and use thereof in compositions for treating keratin fibers

摘要

The invention concerns the use in a cosmetic composition of at least a poly-aminoacid of general formula (1) in which X is -O-, -S- or -NR₃; R₁ represents in particular a hydrogen atom or a C₁-C₄₀ alkyl radical; R₂ represents in particular a hydrogen atom or an optionally substituted alkyl radical; R₃ represents a hydrogen atom or an alkyl radical; R₄ represents a hydrogen atom or a radical such as NH₂, OH, SH, -CHOHCH₃, -CONH₂; n is a number greater than 1 such that the poly-aminoacid derivative molecular weight ranges between 200 and 200000. The invention also concerns the use of said derivatives for keratinous fibre strengthening and care.