Process for the preparation of high molecular weight polyesters
CA 2118833 A1 · Owner: Grosse-Puppendahl, Thomas · Inventors: Homann, Walter K.; Grosse-Puppendahl, Thomas
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for preparing high molecular weight polyesters is disclosed. In the process, an aromatic acid is first polycondensated with a mixture of alkane- and alkenediols in the presence of a catalyst and in the absence of oxygen to obtain a, polyester having a viscosity number of from about 50 to about 140 cm3/g. A free radicals forming agent is then added to the polyester which is further reacted in the melt until a predetermined final viscosity number, usually less than 400 cm3/g is obtained. The agent is so selected as to dissociate with a half life of from 5 seconds to 120 minutes at temperatures from 130 to 350°C. The process, which does not adversely affect the properties of …
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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 March 11, 1994. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended March 11, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 11, 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
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.