Method of preparing intermediate ds starch esters in aqueous solution
CA 2112079 C · Owner: National Starch And Chemical Investment Holding Corporation · Inventors: Tessler, Martin M.; Billmers, Robert L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Starch esters having an intermediate DS of about 0.5 to 1.8 are prepared in an aqueous one step process by reacting starch with high treatment levels of organic acid anhydride and high concentrations of alkaline reagent.
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 December 21, 1993 and granted September 30, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 21, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 21, 2015.
- 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.