Patent ID: 8227559

Claim:
A process for the preparation of a copolymer by reacting a maleic acid monoester derivative with a vinyl ester in the presence of a free radical polymerization initiator and of an acid having a pK a of less than 1.8 so that i) 10 to 75 mol % of a maleic acid monoester derivative structural unit α, and ii) 25 to 90 mol % of a vinyl ester structural unit β are produced in the copolymer, the maleic acid monoester derivative structural unit a being represented by the following general formula (I): where X is identical or different and is represented by —O—(C m H 2m O) n —R 1 where R 1 is identical or different and is represented by a branched or straight-chain C 1 to C 20 alkyl radical, C 5 to C 8 cycloalkyl radical and/or C 6 to C 14 alkylaryl radical, m is identical or different and is represented by 2, 3 and/or 4, n is identical or different and is represented by an integer from 1 to 150; the vinyl ester structural unit β being represented by the following general formula (II): where R 2 is identical or different and is represented by a branched or straight-chain C 1 to C 12 alkyl radical, and the reaction of the maleic acid monoester derivative with the vinyl ester is effected in a reaction mixture which has less than 10% by weight of water.