Process for making and/or modifying polyurethanes
CA 1136331 A · Owner: Kemerica, Incorporated · Inventors: Cook, William H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Polyurethane resins of higher than desired molecular weight with or without gel fractions which comprise insoluble material due to crosslinking or excessive degree of polymerization are treated in the solid state with a liquid or gaseous primary or secondary amina under thermal conditions which cause aminolysis of both linear linkages and crosslinkages. By this procedure, the average molecular weights of the products can be reduced to acceptable levels. Also, if the product contains gel fractions, these too can be reduced to negligible levels. The procedure is applicable to both polyether and polyester urethanes and is effective to provide improved polymer characteristics for thermoplastic …
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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
- Granted November 23, 1982. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 23, 1999.
- 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.