The present invention relates to novel comb polymers which bear poly-C.sub.2-C.sub.4-alkylene ether side chains A and functional groups B which at a pH of >12 are present in the form of anionic groups on a carbon backbone and also the salts of such comb polymers. The invention also relates to the use of these comb polymers as additives in preparations comprising a mineral binder. The polyalkylene ether side chains A have the following formula: *--U--(C(O)).sub.k--X-(Alk-O).sub.n--Y-Z A where * indicates the point of bonding to the carbon backbone of the comb polymer, U is a chemical bond or an alkylene group having from 1 to 8 carbon atoms, X is oxygen or an NR group, k is 0 or 1, n is an integer whose average value, based on the comb polymer, is in the range from 5 to 300, Alk is C.sub.2-C.sub.4-alkylene, with the Alk radicals within the group (Alk-O).sub.n being able to be identical or different, Y is a linear or branched alkylene group which has from 2 to 8 carbon atoms and may bear a phenyl ring, Z is a 5- to 10-membered nitrogen heterocycle which is bound via nitrogen and can have, in addition to the nitrogen atom and carbon atoms, 1, 2 or 3 additional heteroatoms selected from among oxygen, nitrogen and sulfur as ring members, with the nitrogen ring members being able to bear a group R' and 1 or 2 carbon ring members being able to be present as carbonyl groups, R is hydrogen, C.sub.1-C.sub.4-alkyl or benzyl and R' is hydrogen, C.sub.1-C.sub.4-alkyl or benzyl.