Patent Number: 6,252,004

Title: Process for preparing multi-stage polymer emulsions and multi-stage polymers formed therefrom

Abstract: A process for preparing emulsion polymer particles comprising: (a) providing an aqueous emulsion of a multistage core-shell polymer with a hydrophilic core, (b) adding one or more inhibitors to substantially stop any polymerization, (c) adding monomer to the emulsion polymer, (d) adding swelling agent and (e) reducing the level of monomer by at least fifty percent. The process produces multistage polymers having low dry-bulk density useful in coating compositions such paints and paper coatings.

Inventors: Blankenship; Robert Mitchell (Harleysville, PA), Bardman; James Keith (Green Lane, PA)

Assignee: Rohm and Haas Company

International Classification: C08F 291/00 (20060101); C08F 265/00 (20060101); C08F 265/06 (20060101); C08F 265/04 (20060101); C08F 265/02 (); C08F 267/02 (); C08F 265/04 (); C08F 291/08 (); C08F 267/06 ()

Expiration Date: 06/26/2018