| abstract |
A titanium dioxide slurry comprises (a) a titanium dioxide pigment; (b) a combination of dispersants comprising: (1) a graft copolymer having a weight average molecular weight of about 4,000 to 100,000, comprising about 90 to 50% by weight of a polymeric backbone and correspondingly about 10 to 50% by weight of macromonomer side chains attached to the backbone, the polymeric backbone and macromonomer side chains comprising 100 wt % of the graft copolymer, wherein (i) the polymeric backbone is hydrophobic in comparison to the macromonomer side chains and comprises one or more polymerized ethylenically unsaturated hydrophobic monomers and, optionally, up to about 20% by weight, based on the weight of the graft copolymer, of polymerized ethylenically unsaturated acid monomers; and (ii) each of the macromonomer side chains individually is a hydrophilic polymer containing acid groups attached to the polymeric backbone at a single terminal point and (A) has a weight average molecular weight of about 1,000 to 30,000, and (B) comprises from about 2% to about 100% by weight, based on the weight of the macromonomer side chain, of a polymerized ethylenically unsaturated acid monomer and (C) wherein the acid groups are at least partially neutralized with an inorganic base and/or an amine; (2) a block copolymer of type AB, ABA, or ABC wherein at least one of the blocks in the block copolymer is an adsorbing segment and wherein at least one of the blocks in the block copolymer is a stabilizing segment; and (c) a liquid carrier. |