Hydrogen peroxide-containing bleach liquor and bleaching method thereby
CA 2220163 A1 · Owner: Takeuchi, Hideo · Inventors: Takeuchi, Hideo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A hydrogen peroxide-containing bleach liquor containing one or more compounds selected from organic phosphonic acids and their salts; and a water-soluble alkylamide. A bleaching method comprising using this bleach liquor or this bleach liquor deprived of the water-soluble alkylamide; and performing bleaching with the bleach liquor set at pH 10.0 to 10.7 and heated at 80 to 130°C (110 to 130°C in the absence of the alkylamide). The hydrogen peroxide-containing bleach liquor achieves an excellent bleaching effect without using a silicic acid-derived substance which causes a silicate-induced trouble. The bleaching method achieves an unsurpassed bleaching effect by use of the bleach liquor at a …
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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 November 4, 1997. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 4, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 4, 2019.
- 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.