Method for molding syndiotactic polypropylene and molded article
CA 2040008 C · Owner: Inoue, Takeo · Inventors: Kimura, Shigeru; Inoue, Takeo; Asanuma, Tadashi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for molding a polypropylene or a propylene copolymer having a syndiotactic structure which comprises the steps of melting, molding, if desired quenching and, then stretching a propylene homopolymer or a copolymer of propylene and a small amount of ethylene or another .alpha.-olefin which has a substantially syndiotactic structure, or a mixture of the same and a small amount of a polypropylene having a substantially isotactic structure. The molded and stretched article can be heated at a temperature of a molding temperature or more while a, load is applied to the article. Furthermore the molded, and stretched article, if desired can be treated with a, hydrocarbon vapor while a load …
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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 April 8, 1991 and granted August 2, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 8, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 8, 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.