Process for the production of rigid polyurethane foams
CA 2049516 C · Owner: Wiedermann, Rolf · Inventors: Schmitz, Wolfgang; Wiedermann, Rolf; Heilig, Gerhard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Rigid polyurethane foams are produced by reacting a polyisocyanate with a polyester containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight of 400 to 10,000 in the presence of water an organic, blowing agent, a flameproofing agent and a compound containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight in the range from 32 to 399 as crosslinking agent, optionally in the presence of known auxiliaries and additives. The polyester, the flameproofing agent and the crosslinking agent are used in quantities such that from about 15 to about 35 parts by weight of polyester from about 50 to, about 80 parts by weight flameproofing agent …
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 20, 1991 and granted December 10, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 20, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 20, 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.