Dispersing agent containing copolymer mixture

Polymer composition containing 5 to 95% by weight of a copolymer H and 2 to 60% by weight of a copolymer K, the copolymers H and K each having polyether macromonomer structural units and acid monomer structural units, which are present in the copolymers H and K in each case in a molar ratio of 1:20 to 1:1, and at least 20 mol % of all structural units of the copolymer H and at least 25 mol % of all structural units of the copolymer K being present in each case in the form of acid monomer structural units, the polyether macromonomer structural units of the copolymer H having side chains containing in each case at least 5 ether oxygen atoms, the number of ether oxygen atoms per side chain of the polyether macromonomer structural units of the copolymer H varying in such a way that the corresponding frequency distribution diagram, in which the number of ether oxygen atoms per side chain of a polyether macromonomer structural unit is plotted along the abscissa and the associated frequency for the copolymer H is plotted along the ordinate, contains at least 2 maxima whose abscissa values differ by more than 8 ether oxygen atoms from one another, all polyether macromonomer structural units of the copolymer K having either side chains with a large number of ether oxygen atoms or alternatively side chains with a small number of ether oxygen atoms, side chains with a large number of ether oxygen atoms being those side chains which in each case have more ether oxygen atoms than the sum of the arithmetic mean of the ether oxygen atoms per side chain of the polyether macromonomer structural units of the copolymer H and the number 4, and side chains with a small number of ether oxygen atoms being those side chains which in each case have fewer ether oxygen atoms than the difference between the arithmetic mean of the ether oxygen atoms per side chain of the polyether macromonomer structural units of the copolymer H and the number 4.