Aqueous dispersions of polymer-enclosed particles, related coating compositions and coated substrates
AssigneePPG Industries Ohio, Inc.
InventorsJoseph M. Ferencz, W. David Polk, Dennis L. Faler
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Abstract
Disclosed are aqueous dispersions of polymer-enclosed particles, such as nanoparticles. Also disclosed are methods for making an aqueous dispersion of polymer-enclosed particles, polymerizable polymers useful in such a method, powder coating compositions formed from such an aqueous dispersion, substrates at least partially coated with such a composition, and reflective surfaces comprising a non-hiding coating layer deposited from such a composition.
Claims23
A powder coating composition formed from an aqueous dispersion comprising polymer-enclosed particles, wherein the polymer-enclosed particles comprise particles enclosed by a friable polymer.
An aqueous dispersion comprising polymer-enclosed particles, wherein the polymer-enclosed particles comprise particles enclosed by a friable polymer, wherein the friable polymer comprises the reaction product of (i) a polymerizable polyester polyurethane, and (ii) an ethylenically unsaturated monomer.
A method for making a powder coating composition comprising:
- (1) introducing to an extruder components comprising:
- (a) an aqueous dispersion of comprising polymer-enclosed particles, wherein the polymer-enclosed particles comprise particles enclosed by a friable polymer, and
- (b) dry materials;
- (2) blending (a) and (b) in the extruder;
- (3) devolatilizing the blend to form an extrudate;
- (4) cooling the extrudate, and
- (5) milling the extrudate to a desired particle size.
A method for making an aqueous dispersion of polymer-enclosed particles comprising:
- (1) providing a mixture, in an aqueous medium, of:
- (a) particles,
- (b) an ethylenically unsaturated monomer, and
- (c) a water-dispersible polymerizable dispersant comprising a polymerizable polyester polyurethane, and
- (2) polymerizing the ethylenically unsaturated monomer and polymerizable dispersant to form polymer-enclosed particles comprising a water-dispersible polymer,
- wherein the method does not include the step of subjecting the mixture to high stress shear conditions.
A reflective surface at least partially coated with a color-imparting non-hiding coating layer deposited from a powder coating composition comprising a plurality of polymer-enclosed nanoparticles having a maximum haze of 10%.
Dependencies are inferred from the claim text.