Combinations of associative thickeners and aqueous latex paints containing the same

Abstract

Alkaline aqueous latex paints are disclosed which have a pH of at least about 7.5 and contain an effective amount of a combination of thickeners constituted by: (I) a urethane polymer having at least three hydrophobic groups, at least two of which are terminal hydrophobic groups, the hydrophobic groups being linked by hydrophilic groups: and (II) an alkali-soluble aqueous emulsion copolymer of: (A) about 20-70 weight percent of an alpha, beta-monoethylenically unsaturated carboxylic acid, typically methacrylic acid; (B) about 20-80 weight percent of a monoethylenically unsaturated monomer lacking surfactant capacity, typically ethyl acrylate; (C) about 0.5-60 weight percent of a nonionic urethane monomer which is the urethane reaction product of a monohydric nonionic surfactant with a monoethylenically unsaturated monoisocyanate; and (D) from 0 up to about 2 weight percent of a polyethylenically unsaturated monomer. Semi gloss paints based on copolymers of at least 55% vinyl acetate are preferred, and the paints are desirably buffered with alkaline agent and/or a polycarboxylic acid electrolyte.

Dependencies are inferred from the claim text.