USE OF POLYETHERS FOR PIGMENT DISPERSIONS

The present invention relates to the use of a polymer containing acid groups as a dispersant for stabilising an aqueous inorganic pigment slurry, wherein the polymer containing acid groups comprises polyether groups of the structural unit (I) *-U-X-(AlkO)n-W (I) where * indicates the bonding site to the polymer containing acid groups. U represents a chemical bond or an alkylene group having 1 to 8 carbon atoms. X is oxygen or an NR1 group, n is an integer with a mean, based on the polymer containing acid groups, in the range from 3 to 300, Alk is C2-C4-alkylene, where Alk may be the same or different within the (Alk-O)n group, W is a hydrogen, C1-C6-alkyl or aryl radical or is the Y-F group where Y is a linear or branched alkylene group which has 2 to 8 carbon atoms and may bear a phenyl ring, F is a nitrogen-bonded 5- to 10-membered nitrogen heterocycle which may have, as ring members, as well as the nitrogen atom and as well as carbon atoms, 1, 2 or 3 additional heteroatoms selected from oxygen, nitrogen and sulphur, where the nitrogen ring members may have an R2 group, and where 1 or 2 carbon ring members may be in the form of carbonyl groups, R1 is hydrogen, C1-C4-alkyl or benzyl, and R2 is hydrogen, C1-C4-alkyl or benzyl, wherein the inorganic pigment slurry is selected from the group consisting of titanium dioxide slurry, calcium hydroxide slurry, ultrafine precipitated calcium carbonate (PCC) slurry and ground calcium carbonate (GCC) slurry. The invention provides pigment slurries having improved viscosity characteristics together with improved stability over time.