A process for the preparation of random radical copolymers which comprisesa) at least one olefinically unsaturated sulfonic acid of the formula (I),where n is 0 to 10 X is O or NR5 R1 is hydrogen or methyl R2, R3 independently of one another are hydrogen or C1- to C6-alkyl and R5 is hydrogen, alkyl, aryl, alkylaryl, arylalkyl, alkoxyalkyl, aryloxyalkyl, alkoxyaryl, hydroxyalkyl, (di)alkylaminoalkyl, (di)alkylaminoaryl, (di)arylaminoalkyl, alkylarylaminoalkyl or alkylarylaminoaryl, it being possible for the aryl radicals to be monosubstituted or polysubstituted, salts thereof or mixtures of acid and salts and b) at least two structurally different olefinically unsaturated monomers of the formula (II),where Y is O or NR7 R5 is hydrogen or methyl R6 is alkyl, hydroxyalkyl, (di)alkylaminoalkyl or (di)alkylaminoaryl and R7 is hydrogen, alkyl, aryl, alkylaryl, arylalkyl, alkoxyalkyl, aryloxyalkyl, alkoxyaryl, hydroxyalkyl, (di)alkylaminoalkyl, (di)alkylaminoaryl, (di)arylaminoalkyl, alkylarylaminoalkyl or alkylarylaminoaryl, it being possible for the aryl radicals to be monosubstituted or polysubstituted, and c) if appropriate, one or more olefinically unsaturated monomers which differ structurally from components (a) and (b), d) at least one initiatorbeing dissolved either (i) in a solvent mixture comprising water and a water-soluble organic solvent with a boiling point of less than 140° C. or (ii) being dissolved in one or more pure alcohols by heating, and being polymerized in solution, where the polymer formed remains in solution. The copolymers which are obtainable by the process are suitable as formulation adjuvants in agrochemical active substance compositions.
