High impact polystyrene containing low molecular weight brominated polystyrene
CA 2033332 C · Owner: Dever, James L. · Inventors: Gill, James C.; Dever, James L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Effective amounts of low molecular weight brominated polystyrenes unexpectedly provide good property retention and yet achieve desired flame retardance, for example; UL-94 VO in high impact polystyrene. In contrast, high molecular weight brominated styrene polymers (degree of polymerization equals 2,000) do.not provide good property retention such as impact strength and toughness in high impact polystyrene. The degree of polymerization of the brominated polystyrenes of the present invention is generally from'about 3 to about 20 and can have a considerable variation in the amount of halogenation. The high impact polystyrenes blended with the low molecular weight brominated polystyrenes …
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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 June 4, 1990 and granted March 20, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 4, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 4, 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.