Pigmented coating composition with a phosphorus acid functionalized binder

A process for preparing a coatings composition comprising the steps of contacting:

• a) an aqueous solution of a water-soluble polymer functionalized with structural units of a sulfonic acid monomer or a salt thereof;
• b) a stable aqueous dispersion of polymer particles functionalized with structural units of a phosphorus acid monomer or a salt thereof;
• and c) TiO2;
• wherein the weight percent of the sulfonic acid functionalized polymer is from 0.1 to 10 percent, based on the weights of the sulfonic acid functionalized and the phosphorus acid functionalized polymer particles;
• wherein the weight percent of the phosphorus acid functionalized polymer particles is from 20 to 80%, based on the weight of the sulfonic acid functionalized and the phosphorus acid functionalized polymer particles, and the TiO2;
• wherein the weight percent of the TiO2 is from 20 to 80% based on the weight of the sulfonic acid functionalized polymer, the phosphorus acid functionalized polymer particles, and the TiO2;
• and
• wherein the weight percent of structural units of the phosphorus acid monomer or a salt thereof is from 0.1 to 5 weight percent, based on the weight of the phosphorus acid functionalized polymer particles.