The Dow Chemical Company

Omnova Solutions Inc.

Dwayne J Nicholson

Do I Lee

Arthur N Leadbetter

Michael R Mulders

Ray E Drumright

James G Galloway

Melinda H Keefe

Michael J Devon

A process comprising heating an aqueous dispersion of first structured polymer particles at a temperature of at least about 155&#xb0; C., optionally in the presence of a base and/or a swelling agent, to produce an aqueous dispersion of heat treated structured polymer particles.

Process of heat treating structured polymer particles

Hollow polymer latex particles

This invention relates to a process of making hollow polymer latex particles without the use of acid in the swellable polymer core; the latexes are useful as opacifying plastic pigments for various coatings and particularly as gloss-enhancing plastic pigments for paper and paperboard coatings. Known methods for preparing hollow latexes require cores containing acid or acidic monomers to enable swelling to core at room temperature. The existence of acid in the polymer disadvantageously increases the polymer's affinity to water. Applicants have discovered that non-carboxylated latexes having a variety of T.sub.g 's will also swell at higher temperatures. The mechanism entails the use of acrylate and methacrylate ester monomers which are hydrolyzable and swellable at higher temperatures in alkaline environments. Such mechanisms for making swollen latexes provide for a wide variety of potential end-uses as well as a wide variety of potential latexes.

Process of making hollow polymer latex particles

Growing community of inventors

Sanford, MI, United States of America

Dwayne J Nicholson