Powder coating compositions containing copolymers having hydroxyl and carboxylic acid anhydride groups as binders
CA 2047065 C · Owner: Zenner, Armin · Inventors: Klussmann, Henning; Zenner, Armin; Wamprecht, Christian
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to powder coating compositions wherein the binder contains copolymers which are solid below 30°C, prepared from olefinically unsaturated compounds and have a weight-average molecular weight (M w) of 1500 to 75,000, a content of free hydroxyl groups of 0.2 to 6.0% by weight and a content of intramolecular carboxylic acid anhydride groups (calculated as C4H2O3) of 1 to 30% by weight.
Read the whole patent
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
- Filed July 15, 1991 and granted September 11, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 15, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 15, 2013.
- 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
Timeline From CIPO dates
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.