Process for crystallization of polyethylene naphthalate
CA 2019546 C · Owner: M&G Polimeri Italia S.P.A. · Inventors: Duh, Ben
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
High molecular weight polyester resins are sometimes produced from low molecular weight polyester prepolymers having the same composition by solid state polymerization. Polyester prepolymers are generally converted from the amorphous state to the crystalline state prior to solid state polymerization in order to raise their sticking temperature. This is done to keep the polyester prepolymer from sticking together as a solid mass in the solid state polymerization reactor. Such polyester prepolymers are traditionally crystallized by simply heating them to an elevated temperature at which crystallization occurs. However polyethylene naphthalate prepolymer cannot be crystallized by utilizing …
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 June 21, 1990 and granted July 17, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 21, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 21, 2012.
- 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.