Polymers containing S-vinylthio alkanols

A copolymer comprising S-vinyl-2-thioethan-1-ol and one or more ethylenically unsaturated monomers selected from the group consisting of itaconic acid, maleic acid, maleic anhydride, and vinylphosphonic acid, and optionally comprising acrylic acid;

• wherein:
• from 10 to 50 mol. % of S-vinyl-2-thioethan-1-ol is used, based on the total amount of monomers;
• from 50 to 90 mol. % of the one or more ethylenically unsaturated monomers and, optionally, the acrylic acid are used, based on the total amount of monomers;
• the copolymer is free from monoethylenically unsaturated water-soluble monomers having one or more ester groups;
• and
• the copolymer has an upper critical solution temperature in water of 0 to 99° C.

A polymer comprising S-vinylthioalkanol as monomer, monoethylenically unsaturated water-soluble monomer having one or more acid groups, and, optionally, at least one further monomer different from the S-vinylthioalkanol, being prepared by a process comprising carrying out polymerization in aqueous solution, with the proviso that no N-vinylpyrrolidone is used as monomer for preparing the polymer, and

• wherein:
• the at least one further monomer is selected from the group consisting of monoethylenically unsaturated water-soluble monomer having one or more anhydride groups, monoethylenically unsaturated water-soluble monomer having one or more quaternized nitrogen groups, and monoethylenically unsaturated water-soluble monomer having one or more heteroaromatic groups;
• from 10 to 50 mol. % of S-vinylthioalkanol is used, based on the total amount of monomers;
• from 50 to 90 mol. % of the monoethylenically unsaturated water-soluble monomer having one or more acid groups and, optionally, the at least one further monomer different from the S-vinylthioalkanol are used, based on the total amount of monomers;
• the polymer is free from monoethylenically unsaturated water-soluble monomers having one or more ester groups;
• the polymer has an upper critical solution temperature in water of 0 to 99° C.;
• and
• as the S-vinylthioalkanol, unsaturated compounds of the general formula (I) are used
• where
• R1, R2, and R3 independently of one another, identically or differently, are H or CH3, and
• R4 is linear or branched C1-C30 alkylene.