Contact lens and process for preparing the same
CA 1182614 A · Owner: Toyo Contact Lens Co. Ltd. · Inventors: Nakajima, Tatsutoshi; Tanaka, Kyoichi; Toyoshima, Nobuyuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A water-absorptive contact lens is prepared by polymerizing a monomer mixture containing a monomer having a ketalized glycitol and a hydrophilic monomer and/or a hydrophobic monomer, and after forming the resulting copolymer into a contact lens if necessary, treating the copolymer having a shape of contact lens with an acid to convert the ketal groups into hydroxyl groups. The contact lens has excellent oxygen permeability and affinity for the eye and can be worn continuously for a long period of time.
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
- Granted February 19, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 19, 2002.
- 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.