Use of copolymers containing alkylene oxide units as an additive to aqueous systems

A composition comprising:

• (1) a copolymer comprising alkylene oxide repeat units, wherein the copolymer comprises incorporated randomly or blockwise by polymerization:
• (a) 50-93 mol % of acrylic acid and/or a water-soluble salt of acrylic acid;
• (b) 5-30 mol % of methacrylic acid and/or a water-soluble salt of methacrylic acid;
• and
• (c) 2-20 mol % of at least one nonionic monomer of the formula I:
• wherein
• R1 is hydrogen or methyl,
• R2 is a chemical bond or an unbranched or branched C1-C6-alkylene,
• R3 is an identical or different, unbranched or branched C2-C4-alkylene,
• R4 is an unbranched or branched C1-C6-alkyl, and
• n an integer of 3-50;
• and
• (2) one or more phosphonates selected from the group consisting of 1-hydroxyethane- 1,1-diphosphonic acid, 2-phosphonobutane-1,2,4-tri-carboxylic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylene phosphonate, hexamethylenediaminetetramethylene phosphonate and diethylenetriaminepentamethylene phosphonate.