Preparation of vinyl chloride polymers
CA 2039765 A1 · Owner: Shin-Etsu Chemical Co. Ltd. · Inventors: Kaneko, Ichiro; Kitamura, Hajime
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Preparation of vinyl chloride polymers A process for preparation of a vinyl chloride polymer comprising the steps of subjecting an aqueous medium containing vinyl chloride monomer or a mixture of vinyl chloride monomer with other vinyl monomer a, polymerization initiator and a dispersant to high-speed shear agitation at a shear rate of 104 sec-1 or above to prepare a suspended dispersion containing fine particles of the monomer(s) dispersed therein, then subjecting the suspended dispersion to low-speed shear agitation at a shear rate of from 10 to 100 sec-1, and thereafter starting suspension polymerization. Even with a decreased amount of dispersant, the process inhibits the coarsening of …
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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 April 4, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 4, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 4, 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.