Method of producing sulfur-containing transparent polymer
CA 2116552 C · Owner: Oka, Koichiro · Inventors: Oka, Koichiro; Baba, Setsuo; Iguchi, Yuichiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a method of producing a sulfur-containing transparent polymer by polymerizing a composition containing a (metha)acrylate monomer having sulfur in its molecule, characterized by radical polymerization of a composition containing at least one compound selected from radical chain transfer compounds and radical trapping compounds in an amount of 0.1 to 7.0 % by weight of the total amount of the composition. The polymer obtained by polymerization is less colored. The method can provide a polymer having a high total light transmittance, a high refractive index and a light weight and is hardly yellowed during use.
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 June 29, 1993 and granted November 4, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 29, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 29, 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.