Light stable polystyrene polymethylmethacrylate laminate and method of preparation
CA 2035625 A1 · Owner: The Dow Chemical Company · Inventors: Barger, Mark A.; Chum, Pak-Wing S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A light-stable, optically clear laminate construction and method of making it which utilizes inexpensive styrenic polymers is provided. The laminate formed exhibits strong interfacial adhesion without the need for additional glue or adhesive layers through the use of pendant functionalized hydroxyl groups incorporated into the styrenic polymer by copolymerization. These pendant hydroxyl groups react with active pendant ester groups on the other polymer layer in the laminate to form strong covalent interfacial bonds by heating the layers, preferably either in a compression molding step or during coextrusion of the layers. 34,423-F
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 February 5, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 5, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 5, 2013.
- 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.