Producing a polyethylene terephthalate based polmer from a lower dialkyl ester of a dicarboxylic acid and a glycol
CA 2032358 A1 · Owner: Hoechst Celanese Corporation · Inventors: Engel-Bader, Monika; Furr, Bobby Neal
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for producing PET based polyester polymers from a lower dialkyl ester of a dicarboxylic acid and a glycol selected from the class of ethylene glycol, diethylene glycol polyethylene glycol, blends of ethylene glycol and propane and/or butane diol or mixtures, of two or more of these, using the novel catalyst system and a small amount of dicarboxylic acid is described. The novel catalyst composition includes from about 10 ppm to about 150 ppm manganese; from about 50 ppm to about 250 ppm lithium; preferably from about 10 ppm to about 40 ppm cobalt; and from about 200 ppm to about 400 ppm antimony, all amounts being based upon the expected yield of the polyester based polymer. The …
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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 14, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 14, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 14, 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.
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.