Activation of hydroxyethyl cellulose for use in heavy brines
CA 1189302 A · Owner: Nl Industries, Inc. · Inventors: Hoover, Lonnie D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A viscosifying composition containing hydroxyethyl cellulose slurried in certain polar organic liquids the compo-, sition having been aged for a period of time sufficient to activate the hydroxyethyl cellulose such that it will hydrate in heavy brines having a density greater than about 13.5 pounds per gallon at ambient temperatures.
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
- Granted June 25, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 25, 2002.
- 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.