Polymerization inhibitor for vinyl aromatics
CA 2118045 A1 · Owner: Grossi, Anthony V. · Inventors: Demassa, John M.; Friedman, Howard S.; Grossi, Anthony V.
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 vinyl aromatic especially styrene, polymerization inhibitor system comprising a reaction product of an alkyl phenol with sulfuric acid and nitric acid and optionally an aryl-substituted phenylenediamine. The reaction product has as its major component compounds of Structure (I) wherein R is, C9-C20 alkyl, Y is NO2, SO3R' or H R' is C1-C20 alkyl, X is NO2 or C1-C20 alkyl and R" is H or C1-C20 alkyl, m is 2 or 3 and n is 0 1, 2, 3, with the proviso that when R is C9 and n=0, X and Y may not both be NO2. The invention is also directed to vinyl aromatic compositions stabilized against polymerization by such polymerization inhibitor system as well as to, a method of …
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 April 13, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 13, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 13, 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.