Stretched films of polypropylene
CA 2017246 C · Owner: Inoue, Takeo · Inventors: Yamada, Takayuki; Inoue, Takeo; Yamamoto, Kazuhiko
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A stretched film of polypropylene which is excellent in transparency, substantially free of an antiblocking agent and at least uniaxially stretched and which is characterized in that it has uniformly distributed projections having a height of from 0.05 to 0.50 µ and a diameter of from 10 to 100 µ at least on the surface thereof as well as a method for preparing the foregoing stretched film of polypropylene which comprises the steps of forming, into a sheet polypropylene, which comprises a nucleating agent in an amount selected so that the crystallization temperature of polypropylene is increased by 1 to 10°C by the addition thereof and then stretching the sheet at a temperature ranging from …
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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 May 22, 1990 and granted January 11, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 22, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 22, 2012.
- 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.