Producing articles by coextruding polyvinyl alcohol and another thermoplastic material
CA 1090971 A · Owner: Montedison S.P.A. · Inventors: Tisi, Quinto; Ranalli, Franco; Ortolani, Leone
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
There is disclosed a new process for preparing coupled and coextruded multilayer articles (consisting of two or more layers) made of thermoplastic materials and closed-surface, bodies comprising the same. The process comprises (a) feeding, to an extruder connected with a coextrusion head, a polyvinyl alcohol having a high degree of hydrolysis mixed with an aqueous mixture of plasticizing compounds and heated under pressure to bring it to the plastisol state; (b) subjecting the plastisol polyvinyl alcohol to rapid decompression with simultaneous venting of the evolved vapors, before it enters the coextrusion head and while it is at a temperature at least equal to, and preferably higher than, …
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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 December 9, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 9, 1997.
- 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.