Patent ID: 8349983

Claim:
Process for the preparation of an aqueous solution comprising 30 to 95% by weight of water and 5 to 70% by weight of a copolymer dissolved in the water by free radical solution polymerizations of an isoprenol polyether derivative with an acrylic acid derivative, so that the copolymer has i) 20 to 45 mol % of an isoprenol polyether derivative structural unit α) and ii) 55 to 80 mol % of an acrylic acid derivative structural unit β), the isoprenol polyether derivative structural unit a being represented by the following general formula (Ia) where A is identical or different and is represented by an alkylene group according to C x H 2x where x=2, 3, 4 or 5, a is identical or different and is represented by an integer between 11 and 34, the acrylic acid derivative structural unit β being represented by the following general formula (IIa), and optionally additionally represented by the following general formula (IIb) where X is identical or different and is represented by NH—(C n H 2n ) where n=1, 2, 3 or 4 or represented by O—(C n H 2n ) where n=1, 2, 3 or 4; R 1 is identical or different and is represented by SO 3 H, PO 3 H 2 , OPO 3 H 2 and/or C 6 H 4 —SO 3 H R 2 is identical or different and is represented by OH, OM where M=Na, K, or Ca, and/or ONH 4 .