Water-based coatings with improved sagging and popping characteristics

Abstract

This invention relates to a water-based coating composition in which solvent or water popping and sagging are eliminated or substantially reduced. The composition comprises a thermosetting, film-forming organic binder dispersed in an aqueous medium containing from 60 to 100 parts by weight of water and 0 to 40 parts by weight of a volatile organic solvent. The organic binder is formulated from (a) and acid-containing interpolymer adapted to be dissolved or dispersed in water with the acid of a base; (b) a water-soluble or water-dispersible polyether polyol or polyester polyol having a molecular weight of at least 300 and (c) a water-soluble or water-dispersible aldehyde condensation resin. The interpolymer consists essentially of a carboxylic acid amide in units of the structure: ##STR1## wherein R' is hydrogen or lower alkyl and R is lower alkyl; an alpha, beta-ethylenically unsaturated carboxylic acid; and at least one other monomer containing a CH.sub.2 =CH< group. In addition to the elimination of, or substantial reduction in solvent or water popping and sagging of the composition, films formed from the compositions exhibit excellent properties, such as hardness, water resistance, salt spray resistance and stain resistance.

Dependencies are inferred from the claim text.