Polymerization process for the preparation of poly(butylene terephthalate)
CA 1333118 C · Owner: Doerr, Marvin L. · Inventors: Doerr, Marvin L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is disclosed for the preparation of polymeric butanediol ester of terephthalic acid by means of ester interchange process having improved rates of polymerization to produce polyesters having improved color. The process employs the neat addition of terephthalic acid on completion of the ester interchange reaction and maintains the ratio of glycol to dimethyl terephthalate in the ratio of not more than 1.3 to 1. Preferably the process is conducted with titanium containing catalysts and has a polymerization rate greater than 700 deciliters per hour.
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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 November 15, 1994. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 15, 2011.
- 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.