Aqueous acrylic polymer dispersions
AssigneePPG Industries, Inc.
InventorsSuryya K. Das, Charles M. Kania
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Abstract
Ungelled, stable aqueous dispersions of acrylic polymers, containing carboxyl and epoxy functionality, and their method of preparation are disclosed. The dispersions are useful in water-based coating compositions. As long as the polymeric product remains dispersed in aqueous medium, stable, curable, one-package coating compositions result. However, when the dispersions are applied to a substrate as a film and the water evaporated, a curing reaction occurs as evidenced by the film becoming harder and more solvent resistant with the passage of time.
Claims30
A stable, curable, aqueous dispersion of a polymeric product which is prepared by polymerizing in aqueous medium under free radical polymerization conditions:
- (1) a dispersed phase of a polymerizable alpha, beta-ethylenically unsaturated monomer component which includes 1 to 7 percent by weight of an epoxy group-containing monomer;
- the percentage by weight being based on total weight of monomers used in preparing the polymeric product, in the presence of
- (2) an at least partially base neutralized acid group-containing acrylic polymer dispersant;
- the molar ratio of acid used in preparing the acrylic polymer to epoxy group-containing monomer being at least 3/1.
A process for preparing ungelled, curable, polymeric products which comprises:
- (1) dispersing in aqueous medium, in the presence of an at least partially base neutralized acid group-containing acrylic polymer dispersant, an alpha, beta-ethylenically unsaturated monomer component which includes 1 to 7 percent by weight of an epoxy group-containing monomer;
- the percentage by weight being based on total weight of the monomers used in preparing the polymeric product;
- the molar ratio of acid used in preparing the acrylic polymer dispersant to epoxy group-containing monomer being at least 3/1;
- (2) subjecting said dispersion to free radical polymerization conditions to form the polymeric product dispersed in aqueous medium in a stable condition.
Dependencies are inferred from the claim text.