Dendritic polyether-polyurethane thickeners

A polymer comprising, in polymerized-in form,

• a) at least one polyisocyanate;
• b) at least one alcohol of the general formula I
• where
• R1 is selected from C6-C40-alkyl, C6-C40-alkenyl, C3-C10-cycloalkyl, C6-C30-aryl, C7-C40-arylalkyl,
• R2 is selected from C2-C10-alkylene, C6-C10-arylene, C7-C10-arylalkylene, n 0 to 200;
• c) at least one dendritic polyetherpolyol;
• d) optionally at least one compound, different from b) and c), with a molecular weight of at least 300 g/mol, comprising
• i. at least two OH groups and
• ii. at least two groups selected from ether groups and ester groups;
• and
• e) optionally further compounds with in the region of 1 to 9 groups reactive toward isocyanate groups per molecule,
• wherein c) is obtained by condensation of at least one tri- or higher-functional alcohol and optionally further di- and/or monofunctional alcohols and/or modifying reagents with the help of an acidic catalyst, and wherein 75 to 95% of OH groups present in c) prior to polymerization are also present as OH groups after polymerization.