Ultraviolet radiation resistant polyphthalatecarbonate resin
CA 2033904 A1 · Owner: Shafer, Sheldon J. · Inventors: Shafer, Sheldon J.; Clagett, Donald C.; Fox, Daniel W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An aromatic polyphthalatecarbonate resin having a small percentage of phthalate units therein exhibits improved resistance to hazing and yellowing upon exposure to ultraviolet radiation. The polyphthalate carbonate resin is derived from the reaction products of a phthalate compound a, dihydric phenol and a carbonate precursor.
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 January 10, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 10, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 10, 2013.
- 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.