STABLE AQUEOUS METALLIC FLAKE DISPERSION USING PHOSPHATED ACRYLIC POLYMER DISPERSANT

摘要

A pigment dispersion useful for forming aqueous coating compositions containing metallic flake pigment, an aqueous carrier and a graft copolymer dispersant (binder); wherein the graft copolymer has a weight average molecular weight of about 5,000-100,000 and comprises a polymeric backbone and macromonomer side chains attached to the backbone wherein (1) the polymeric backbone is formed of polymerized ethylenically unsaturated monomers and (2) the side chains are macomonomers that are attached to the backbone at a single terminal point and formed from polymerized ethylenically unsaturated monomers that are polymerized in the presence of a cobalt chain transfer agent and have a weight average molecular weight of about 1,000-30,000; wherein the graft copolymer contains about 2 to 70 % by weight, based on the weight of the graft copolymer, of polymerized constituents having a phosphate moiety and phospheric acid moieties that are polymerized into the backbone, the side chains or both and the polymer is neutralized with an inorganic base or an amine; and the metallic flake pigment is present in a binder to pigment weight ratio of least 10/100; coating compositions containing the novel dispersion, the graft copolymer and the process for making the graft copolymer and pigment dispersions are part of the invention.