Gypsum-cement system for construction materials
CA 2314382 C · Owner: United States Gypsum Company · Inventors: Bonen, David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A compositioii for use in construction materials which may be substituted for high performance concrete patching materials, joint compounds, and the like such as backer boards or panels, which includes a settable calcium sulfate preferably a hemihydrate, Portland cement a finely divided pozzolanic material, lime and an aggregate, optionally including other additives. The volume ratio of the aggregate to the combined calcium sulfate Portland cement, pozzolanic material, and lime (a cementitious binder) is equal to or greater than 2/1. Panels made from this composition are useful particularly when exposed to water since they have good dimensional stability.
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 24, 2000 and granted January 11, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 24, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 24, 2022.
- 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.