Method of manufacturing diphenylmethane dicarbamic acid diesters
CA 1249297 A · Owner: Nippon Kokan Kabushiki Kaisha · Inventors: Itagaki, Masanori; Sakai, Itaru; Ikariya, Takao
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
According to a method of manufacturing a diphenylmethane dicarbamic acid diester by reacting an N-phenyl carbamic acid ester with a methylating agent in an aqueous acid solution, the aqueous acid solution is an aqueous inorganic acid solution, and the concentration of the N-phenyl carbamic acid ester in the aqueous acid solution is not more than the solubility thereof at the reaction temperature.
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 January 24, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 24, 2006.
- 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.