Lightweight gypsum board product and method of manufacture
CA 2418949 A1 · Owner: Weldon, Walter · Inventors: Downs, David; Weldon, Walter; Butler, Steven Roy
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Lightweight gypsum board product can be produced by modifying the calcined gypsum prior to introduction in a gypsum slurry and introducing a foaming agent by the use of a foam generator and high pressure air. The foaming agent has uniform and stable size and distribution of bubbles. The foam imparts these advantageous void properties and results in a lightweight gypsum product that has adequate strength and nail pull characteristics.
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 August 7, 2001. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended August 7, 2021.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 7, 2023.
- 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.