Process for hydrotreating resins to lighten color
CA 2116903 C · Owner: Goodfellow, Dane G. · Inventors: Daughenbaugh, Norman E.; Goodfellow, Dane G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The color of hydrocarbon resins having carbon-carbon double bonds and containing color bodies is lightened by a hydrotreating process comprising the single step of contacting the resin with hydrogen in the presence of a catalyst that promotes the hydrogenation of the color bodies without substantially changing the content of carbon-carbon double bonds in the resin. The preferred catalysts are copper chromite and copper/zinc. are prefer
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 March 3, 1994 and granted August 14, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 3, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 3, 2016.
- 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.