Control of corrosion in aqueous systems using certain phosphonomethyl amines
CA 2022827 C · Owner: W.R. Grace & Co.-Conn. · Inventors: Hwa, Chih M.; Gaudette, Roger R.; Neton, Janet
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to a method for preventing corrosion and inhibiting the formation of scale deposition in aqueous systems. More specifically, it relates to using certain calcium insensitive phosphonomethyl amine compounds having the formula:, (see formula I) wherein either R1 is selected from hydrogen hydrocarbyl, hydroxy-substituted hydrocarbyl alkoxy-substituted, hydrocarbyl; and R2 is selected from hydrocarbyl hydroxy-substituted hydrocarbyl, alkoxy-substituted hydrocarbyl, carboxyl-substituted hydrocarbyl -CH2PO3H2, and -C2H4N(CH2PO3H2)2; or R1 and R2 together form an alicyclic ring having 3 to 5 carbon atoms optionally, along with oxygen atoms, phosphorus atoms or both oxygen and …
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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 August 7, 1990 and granted March 28, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 7, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 7, 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
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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.