Method for the preparation of a vinyl chloride polymer
CA 2074995 A1 · Owner: Shin-Etsu Chemical Co. Ltd. · Inventors: Amano, Tadashi; Kaneko, Ichiro
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 the suspension polymerization of vinyl chloride to give a resin powder having an increased bulk density and containing a decreased amount of fish eyes. The improvement can be obtained by using, as the suspending agent three kinds of water-soluble polymers in combination of which the, first two, which are dissolved in the aqueous suspension medium already at the start of the polymerization eaction are a specific, partially saponified polyvinyl alcohol and a specific hydroxypropyl methyl cellulose and the third polymer which is introduced into, the polymerization mixture ata specified moment during proceeding of the polymerization reacion, is also a specific …
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 July 30, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 30, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 30, 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.