Method and apparatus for producing polymeric films
CA 2076873 A1 · Owner: Grady, Clyde C. · Inventors: Grady, Clyde C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An apparatus and method for the production of polymeric films by a blown film process is disclosed. Polymeric films produced from crystallizable linear polymers are extruded through a die extruder, expanded by the injection of a gas inside the tubular film (14), cooled at the point of extrusion from the die (11) and, further cooled at the point of maximal expansion or the frost line (18) to produce a film having substantially enhanced optical characteristics.
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 27, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 27, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 27, 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.