| abstract |
The present invention relates to a stable aqueous pigment dispersion including: an aqueous medium, pigment particles, and from 0.1% to 15% by weight based on pigment weight of a dispersant, the dispersant including: (1) a water soluble polymer having an acidity index of 0 to 80 and a calculated mn of 450 daltons to 10,000 daltons; and 2) a second water-soluble polymer comprising, as copolymerized units, 30% and 100% by weight based on the weight of the second sulfonic acid monomer polymer or a salt thereof; and from 0% to 10% by weight, based on the weight of the second polymer, carboxylic acid monomer, or a salt thereof; wherein the second polymer has a calculated mn of 1000 to 25,000 daltons; wherein the dispersant comprises a ratio of the first polymer to the second polymer from 0.1: 1 to 10: 1 on a solids basis, and the first polymer and second polymer are miscible in these proportions; and wherein the dispersant is substantially free of structural units of phosphorus acid monomers and salts thereof. The invention also relates to a method for forming the stable aqueous dispersion and a dry coating formed from the aqueous dispersion. The stable aqueous dispersion is useful, inter alia, for the formation of certain composite particles. |