The present invention relates to a composition comprising (α) at least one inorganic binder and (β) at least one water-soluble copolymer based on (a) 0.1 to 20 wt % of at least one monomer of the formula (I) and (b) 25 to 99.9 wt % of at least one hydrophilic monomer (b) which is different from monomer (a), where the at least one copolymer has a molar mass average M of 1 500 000 to 30 000 000 g/mol. Furthermore, a process for producing this composition is disclosed. A further aspect of the present invention is the use of the copolymer of component (β) as rheological additive in a composition of the invention.