Foaming system for rigid urethane and isocyanurate foams
CA 2016328 C · Owner: Dow Benelux N.V. · Inventors: Grunbauer, Henri J. M.; Smits, Guido F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to a process for preparing a rigid, closed-celled polyisocyanate-based foam in the presence of water and a blowing agent. The blowing agent comprises one or more organic compounds particularly halocarbons, having a boiling point of from 222K to 272K at atmospheric pressure, and is substantially free of organic compounds having a boiling point of 273K or greater. Preferred halocarbons are chlorofluoroethanes, especially chlorodifluoroethane (R-142b) and fluoroethanes.
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 9, 1990 and granted June 27, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 9, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 9, 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.