US Patent 6930141 Aqueous polymer blend composition

An aqueous polymer blend composition including a predominant amount of soft polymer particles and a minor amount of hard polymer particles is provided. The soft polymer particles contain, as copolymerized units, 70 to 99.7% by weight monoethylenically unsaturated (meth)acrylic monomer and from 0.3 to 10% by weight monoethylenically unsaturated acid monomer, based on weight of soft polymer particles. The soft polymer particles are made by a select process including redox polymerization or polymerization in the presence of excess unreacted monomer. The aqueous polymer blend composition is useful for preparing dry coatings having improved dirt pickup resistance and acceptable scrub resistance. A method is provided for preparing a dry coating from the aqueous polymer blend composition.