Polymeric diphenyldiamines
CA 2026074 C · Owner: Tazuma, James Junkichi · Inventors: Wideman, Lawson Gibson; Sandstrom, Paul Harry; Tazuma, James Junkichi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to a novel class of polymeric compositions which have molecular weights ranging from 300 to 3000 and are the reaction product of (a) an alkyl or cycloalkyl substituted diphenyldiamine and (b) a conjugated or nonconjugated dime. The polymeric diphenyldiamine compounds are particularly useful as an antiozonant in diene containing polymers.
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 September 24, 1990 and granted May 23, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 24, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 24, 2012.
- 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.