Method of preparing a mixture of polyphenylene ether and polyvinylaromatic compound
CA 2085654 C · Owner: Viersen, Frits-Jan · Inventors: Viersen, Frits-Jan
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a method of preparing a mixture of polyphenylene ether and polystyrene having a content of polyphenylene ether of at least 20% by weight by radical polymerisation of a vinylaromatic compound in the presence of polyphenylene ether which, method is characterised in that the polymerisation is carried out in a dispersion of an organic phase in an aqueous phase, in the presence of an emulsifier in that, the polymerisation is initiated partly from the aqueous phase and partly from the organic phase and in that, after completion of the poymerisation the product, obtained by the initiation from the aqueous phase is separated at least partly from the product obtained by …
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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 December 17, 1992 and granted August 5, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 17, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 17, 2014.
- 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.