Method for preparing low free formaldehyde methylolhydantoins and compositions thereof
CA 2093045 C · Owner: Lonza Inc. · Inventors: Farina, Thomas E.; Rosen, Marvin
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Compositions of dimethyloldimethylhydantoin monomethyloldimethylhydantoin, and dimethylhydantoin having less than 0.1% by weight of free formaldehyde based upon 100% by weight of total composition; and wherein the weight ratio of dimethyloldimethylhydantoin to monomethyloldimethylhydantoin ranges from about 1:1.25 to about 3.5:1, are provided. These compositions may be prepared (1) by reacting dimethylhydantoin and a formaldehyde-containing source wherein the molar ratio of formaldehyde to dimethylhydantoin ranges from about 1.2:1 to about 1.55:1 or (2) by admixing (a) from about 80 to about 90% by weight of an aqueous solution of methyloldimethylhydantoin having greater than about 0.1% by …
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 20, 1993 and granted March 18, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 20, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 20, 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.