The present invention relates to the field of copolymers which are water-soluble or water-dispersible at neutral pH or near-neutral pH, that is to say between 5.5 and 9.5, comprising at least one random copolymer comprising methacrylic acid, butyl acrylate, styrene and a monomer chosen from styrenesulfonic acid or salts thereof, vinylbenzoic acid or salts thereof, 2-acrylamido-2-methanesulfonic acid or salts thereof, N-vinylpyrrolidone, alone or in combination.