The present invention relates to polyhydroxyalkanoate (PHA) copolymers bearing acetoacetate group(s) and derivative(s), to a composition comprising same, and also to a process for treating keratin materials using such PHAs, notably for making up the skin or for colouring or styling keratin fibres, preferably the hair.
Thus the main subject of the present invention is a) a polyhydroxyalkanoate (PHA) copolymer which contains, several units (A) below, and also the optical or geometrical isomers thereof, the organic or mineral acid or base salts thereof, and the solvates thereof such as hydrates: —[—O—CH(R1)—CH2—C(O)—]—  unit (A) in which polymer units (A): R1 represents a saturated or unsaturated, linear or branched, non-cyclic hydrocarbon-based chain, or a saturated or unsaturated non-aromatic cyclic hydrocarbon-based chain, comprising from 3 to 30 carbon atoms, said hydrocarbon-based chain being substituted with one or more groups chosen from: A) R3′—C(X)—C(R4)(R5)—C(X′)—[Y]n—* and B) R3′—C(X)—C(—[Y]n—*)(R4)—C(X)—R6 with R3′, R4, R5 and R6 as defined in the description.