Process for the suspension polymerization of 4-acetoxystyrene and hydroylsis to 4-hydrozystyrene polymers
CA 1340528 C · Owner: Hoechst Celanese Corporation · Inventors: Vicari, Richard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Poly (4-acetoxystyrene) is prepared by forming a suspension of 4-acetoxystyrene monomer in water in the presence, of polyacrylic acid and at least two free-radical polymerization catalysts, one of which has a half life of one hour at a temperature below 100°C and the other of which as a half life of one hour at a temperature above 100°C. The suspension is heated at a temperature of about 70°C to about 95°C until the conversion of monomer to polymer is at least about 50 percent by weight and, then heated at a temperature above 95°C to about 100°C until conversion of monomer to polymer is substantially complete. The obtained poly (4-acetoxystyrene) can be hydrolysed to poly …
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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
- Granted May 4, 1999. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 4, 2016.
- 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.