Process for suspension polymerization of vinyl compound
CA 2058416 C · Owner: Yuki, Ken · Inventors: Takada, Shigeki; Tanaka, Taku; Maruyama, Hitoshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed herein is a process for suspension polymerization of a vinyl polymer which comprises using as the suspending agent a polyvinyl ester polymer having an ionic group at an end thereof or a polyvinyl alcohol polymer having a degree of hydrolysis of 90 mol% or less which is obtained by hydrolysis of the above polyvinyl ester polymer. According to the above-mentioned process vinyl polymer, granules having a sharp granulometric dispersion high bulk, density, high plasticizer absorption and low vinyl monomer residue are obtained.
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 March 29, 1991 and granted November 24, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 29, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 29, 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.