Process for producing and use of maleic acid (co-) polymer salt improved in biodegradability
CA 2015489 C · Owner: Yamaguchi, Shigeru · Inventors: Fujiwara, Teruaki; Yokoi, Tokihiro; Irie, Yoshio
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A specially defined amount of hydrogen peroxide is used as a polymerization catalyzer and under a condition, of that a specially defined amount and a specially defined kind of a polyvalent metal ion and a specially defined amount of an alkaline substance exist, only maleic acid or a monomer component composed of maleic acid and the other water-soluble unsaturated monomer in a specially defined proportion is polymerized in water, whereby a maleic acid ( co-)polymer salt improved in biodegradability is produced. The maleic acid (co-)polymer salt obtained is superior in biodegradability and little in amount of a residual monomer and useful as a detergent builder and a scale inhibitor etc.
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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 26, 1990 and granted November 19, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 26, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 26, 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.