Copolymers having polyether side chains and hydroxyalkyl structural units and acid structural units

Copolymer (I) having an isoprenol polyether derivative-structural unit (5-55 mol.%) (Ia), acrylic acid derivative-structural units (2-90 mol.%) (II) and a hydroxyalkyl acrylate-structural unit (2-90 mol.%) (III), is claimed. Copolymer (I) having an isoprenol polyether derivative-structural unit (5-55 mol.%) of formula (-(CH 2-C(CH 3)((C 2H 4)-O-(AO) a-H))-) (Ia), acrylic acid derivative-structural units (2-90 mol.%) (II) of formula (-(CH 2-C(H)((C=O)-X-R 1>))-) (IIa) and/or (-(CH 2-C(H)((C=O)-R 2>))-) (IIb), and a hydroxyalkyl acrylate-structural unit (2-90 mol.%) of formula (-(CH 2-C(H)((C=O)-O-R 3>))-) (III), is claimed. A : alkylene group of formula (C xH 2 x); x : 2-5, preferably 2; a : 5-45; X : NH-(C nH 2 n) or O-(C nH 2 n); n : 1-4; R 1>SO 3H, PO 3H 2, OPO 3H 2or C 6H 5-SO 3H; R 2>OH, OM or ONH 4; M : Na, K or Ca; and R 3>1-5C monohydroxyalkyl. An independent claim is included for the preparation of (I) by radical solution polymerization at 0-40[deg] C in the presence of a redox initiator, where water is used as a solvent.