Method of forming shaped hydrogel articles including contact lenses
CA 2003806 C · Owner: Rastrelli, Edmund C. · Inventors: Heaton, John C.; Rastrelli, Edmund C.; Kindt-Larsen, Ture
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Shaped hydrogel articles such as soft contact lenses are prepared by (1) molding or casting a polymerization mixture comprising: (a) a monomer mixture comprising a major proportion of a hydrophilic (meth)acrylate ester such as 2-hydroxyethyl methacrylate, and a cross-linking monomer; and (b) a water-displaceable diluent wherein, said diluent has a viscosity of at least 100 MPa Sec at 30°C, and wherein said diluent consists essentially of a boric acid ester of certain dihydric alcohols said, dihydric alcohols having Hansen polar (.delta.p) and Hansen hydrogen bonding (.delta.h) cohesion parameters falling within the area of a circle defined as having a center at .delta.h = 20.5, .delta.p = …
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 November 24, 1989 and granted June 20, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 24, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 24, 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.