Method for the preparation of polyvinyl chloride resin
CA 2036186 C · Owner: Koga, Toshimichi · Inventors: Amano, Tadashi; Koga, Toshimichi; Noguki, Genji
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An improvement is proposed for decreasing triboelectric static charging of a polyvinyl chloride resin powder so as to improve the flowability of the powder and prevent a decrease in the bulk density of the powder due to static electricity. The improvement comprises, in the polymerization process of vinyl chloride monomer in an aqueous medium, adding, to the aqueous polymerization mixture, a specified amount of an aqueous dispersion containing a salt of a long-chain carboxylic acid with a divalent metal and an ester of sorbitan with a long-chain carboxylic acid in a specified weight proportion and in a specified total concentration at a moment when conversion of the monomer to polymer is at …
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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 February 12, 1991 and granted July 27, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 12, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 12, 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.