Super-absorbents and a process for their preparation
CA 2124665 C · Owner: Chemische Fabrik Stockhausen Gmbh · Inventors: Kelkenberg, Heike
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
New super-absorbents comprising chitosan salts are disclosed. They are prepared by reacting a pulverulent chitosan with an acid in an organic solvent and contain from 1 to 30 mmol of acid per gram of chitosan. The salts are preferably cross-linked with a crosslinking agent applied in an amount of from 0.0001 to 10 mmol per gram of chitosan. The products have a high absorption rate and capacity and are biologically degradable. They are useful as super-absorbent agents in hygiene articles.
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 30, 1994 and granted October 17, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 30, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 30, 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.