Cement dispersant, method for production thereof, and cement composition using the dispersant
CA 2180989 C · Owner: Uno, Toru · Inventors: Tahara, Hideyuki; Tanaka, Yoshio; Ohta, Akira
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A cement dispersant having excellent ability to prevent slump loss and high water-reducing property which comprises a polycarboxylic acid type polymer having a specific molecular weight distribution a method for the production thereof, and a cement composition using the dispersant are provided. The cement dispersant comprises as a main component thereof a polycarboxylic acid type polymer (A) having a weight average molecular weight in the range of 10,000 to 500,000 in terms of polyethylene glycol determined by gel permeation chromatography and having a value determined by subtracting the peak top molecular weight from the weight average molecular weight in the range of 0 to 8,000.
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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 July 11, 1996 and granted June 24, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 11, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 11, 2018.
- 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.