Multi-stage opacifying polymer particles containing non-polymeric acid absorbed therein
CA 1303438 C · Owner: Vogel, Martin · Inventors: Vogel, Martin; Kowalski, Alexander
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Multi-stage polymer particles containing one or more void space(s) therein are produced by sequential emulsion polymerization of an essentially low-acid earlier polymer stage, encapsulation of said low-acid polymer stage with at least a final polymer stage, contacting said polymer particles with a non-polymeric carboxylic acid to permit the acid to be absorbed into said low-acid polymer stage and swelling the polymer particles by contacting the particles with an aqueous base. The low-acid polymer stage is formed by emulsion polymerizing a monomer system comprising ethylenically unsaturated monomer(s) and containing less than 5% by weight of monomer(s) eontaining acid functionality. The …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted June 16, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 16, 2009.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.