Crosslinked polyacrylic acid
CA 2003808 C · Owner: B.F. Goodrich Company (The) · Inventors: Sehm, Eugene Joseph
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Polycarbophil or crosslinked acrylic acid polymer is prepared in a solvent selected from acetone alkyl, acetates. and mixtures thereof, in the presence of an effective amount of divinyl glycol crosslinker and, in the presence of an effective amount of a suitable initiator allowing for polymerization to proceed at a temperature below 100°C at atmospheric pressure. The polymer produced has average particle size of less than 10 microns without grinding, its viscosity is greater than about 50,000 cps when measured in water at 1% concentration, and it adheres to mucous membranes. By preparing the polymer in a non-aqueous solvent, the need for aqueous washing is avoided and the subsequent and …
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 November 24, 1989 and granted November 9, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 24, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 24, 2011.
- 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.