. . . "Emulsion according to any one of claims 17 to 20, in which Y represents: in which R5 represents a polyorganosiloxane chain, and T represents a group of formula: in which a, b and c are, independently, integers ranging from 1 to 10, and R10 is a hydrogen atom or a group such as those defined for R1, R2, R3 and R4, in claim 17. 23." . .