Continuous production of gypsum board
CA 2009176 C · Owner: Celotex Corporation (The) · Inventors: Conroy, Alan P.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A continuous process fox the production of gypsum board of variable yet predictable density, wherein a fibrous form of stucco produced from gypsum crystals or fibers is combined with standard calcined gypsum and formed into the board. The density of the resultant board varies inversely with the content of fibrous stucco. The process yields lightweight boards suitable as standard wallboards and inorganic insulating boards.
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 February 2, 1990 and granted October 9, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 2, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 2, 2012.
- 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.