Preparation of hard urethane foams
CA 2042353 C · Owner: Basf Aktiengesellschaft · Inventors: Henn, Rolf; Hinz, Werner; Vorspohl, Klaus
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a process for the preparation of a hard foam containing urethane groups or urethane and isocyanurate groups by the polyisocyanate polyaddition process, by reacting, a) a polyoxypropylene- or polyoxyethylene-polyoxypropylenepolyol containing secondary hydroxyl groups having a, functionality of from 3.5 to 4.3 a hydroxyl number of from, 350 to 650 and a viscosity of from 500 to 2,500 mPas at 23 °C and prepared by anionic polymerization of 1,2-propylene oxide or ethylene oxide and 1,2-propylene oxide onto an initiator molecule mixture containing, based on the total weight, a1) from 40 to 80% by weight of a hexanetetrol a2) from 1 to 30% by weight of a …
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 10, 1991 and granted April 23, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 10, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 10, 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.