Process for high purity tetrabromobisphenol-a
CA 2102289 C · Owner: Albemarle Corporation · Inventors: Sharp, Gary L.; Williams, Robert E.; Mckinnie, Bonnie G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The purity of a tetrabromobisphenol-A(TBBPA) product can be enhanced so as to make it more valuable as a flame retardant by contacting it with a quality-enhancing amount of water having a resistivity >50,000 ohms and subsequently heat-treating it to provide a TBBPA product containing <20 ppm of total ionic impurity. The tetrabromobisphenol-A product subjected to this treatment may be a TBBPA prepared by any known process but is preferably a TBBPA having a low organic impurity content and most preferably a TBBPA prepared by (1) adding 3.9-4.2 molar proportions of bromine and optionally also a methanol solvent to a solution of one molar proportion of bisphenol-A in a methanol solvent while …
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 March 19, 1993 and granted January 26, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 19, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 19, 2015.
- 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.