n The invention relates to an agent for obtaining a stable aqueous solution comprising a polymer made up of: at least one monomer A of acrylic acid and/or methacrylic acid and/or any one of their salts at least one monomer B of alkyl acrylate and/or methacrylate at least one monomer C corresponding to the following formula (I): T [(EO)(PO)n (BO)n ] Z where: T represents an end allowing the copolymerization of the monomer C [(EO)n(PO)n (BO)n ] represents a polyalkoxylated chain made up of alkoxylated units distributed into distributed into block alternating or statistical units chosen from among ethyoxylated units EO propoxylated units PO and butoxylated units BO n n n representing independently of one another 0 or an integer varying from 1 to 150 the sum of n n and n not being zero and Z represents a fatty linear or branched chain of at least 16 carbon atoms at least one cross linking monomer D.
