Blowing agent and process for preparing polyurethane foam
CA 2109627 C · Owner: E. I. Du Pont De Nemours And Company · Inventors: Creazzo, Joseph A.; Bartlett, Philip L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The use of 1,1-difluoroethane (HFC-152a) with a minimum amount of water preferably in the absence of water, as the blowing agent is disclosed as an efficient route to a rigid closed-cell polyurethane or polyisocyanurate foam of improved cell structure and excellent insulation properties.
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 May 15, 1992 and granted August 13, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 15, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 15, 2014.
- 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.