Anionic associative rheology modifiers

Polymer comprising as polymerized units

• a) 25 to 85% by weight of acrylic acid,
• b) 10 to 60% by weight of N-vinyl pyrrolidone,
• c) 0.3 to 10% by weight of at least one cationic monomer,
• d) 1 to 6% by weight of at least one of compounds d1) or d2)
• wherein
• the order of the alkylene oxide units is arbitrary,
• k and l
• are, independently of one another, an integer from 0 to 1000, the sum of k and 1 being at least 5,
• R8 is hydrogen or C1-C4-alkyl,
• R9 is C8-C30-alkyl, C8-C30-alkenyl or C8-C30 alkylaryl, and
• X is O or a group of the formula NR10, in which R10 is H, alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,
• e) 0.01 to 2% by weight of at least one crosslinking agent,
• f) 0.2 to 5% by weight of at least one further monomer f) comprising a group of formula (I)
• wherein
• # is the bonding site to a group with a free-radically polymerizable, □-ethylenically unsaturated double bond,
• Ra is H or C1-C4-alkyl,
• Rb is H or C1-C4-alkyl, or
• Ra and Rb together are (CH2)1-4,
• Rc is H or C1-C30-alkyl,
• g) 0 to 30% by weight of further monomers different from a) to f), the total of a) to g) adding up to 100% by weight.