Process for preparing low density porous cross-linked polymeric materials
CA 2136534 A1 · Owner: Bass, Ronald M. · Inventors: Gergen, William P.; Wong, Pui K.; Bass, Ronald M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for the preparation of a low density porous cross-linked polymeric material comprises polymerizing a water-in-oil emulsion and reducing the polymerization and cross-linking time of the monomers without adversely affecting polymer properties or substantially affecting the emulsion by carrying out the curing in multiple-stages. Thus, the emulsion is first pre-cured at a temperature of less than 65 ·C until the emulsion reaches a rheometrics dynamic shear modulus of at least 500 pascal and then cured by heating at a temperature above 70 ·C.
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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 February 23, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 23, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 23, 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.