Method of preparing polyvinyl alcohol gel and mri phantom
CA 2006644 A1 · Owner: Tomokazu Kobayashi · Inventors: Toshio Morihiro; Tomokazu Kobayashi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of preparing a polyvinyl alcohol hydrogel contains the steps of charging an aqueous solution of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mol% and an average polymerization degree of not less than 500 into a container, the aqueous solution containing the polyvinyl alcohol in a concentration of not less than 5 wt.%, cooling the aqueous solution of the polyvinyl alcohol at a temperature of from - (minus) 9°C to - (minus) 3°C, subjecting the aqueous solution of the polyvinyl alcohol to physical stimulation and then, maintaining the aqueous solution of the polyvinyl alcohol at a temperature of from - (minus) 5°C to + (plus) 5°C. The polyvinyl alcohol …
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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 27, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 27, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 27, 2011.
- 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
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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.