| abstract |
The invention concerns water-soluble cross-linkable copolymers having a molecular weight of 500000 and comprising: a) between 20 and 95 wt.% sulphonic-acid- or sulphonate-group-containing monomer units; b) between 4 and 80 wt.% N-methylol- or N-alkoxymethyl-group containing monomer units; and c) between 0.1 and 20 wt.% hydrophobic monomer units selected from the group comprising water-insoluble ethylenically unsaturated compounds and hydrophobic end groups of initiator radicals or regulator molecules, the portions in wt.% being relative to the total weight of the copolymer. The portion of sulphonic-acid- or sulphonate-group-containing monomer units can optionally be substituted by up to 50 wt.%, relative to the portion by weight of monomer units a), by carboxyl-group-containing monomer units d) or amide-group-containing monomer units e). |