Process for the production of a precipitated silica
CA 2129607 C · Owner: Esch, Heinz · Inventors: Otto, Karin; Neumuller, Matthias; Rausch, Ralf
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Precipitated silica which has a BET surface area of 10-130 m2/g, a CTAB surface area of 10-70 m2/g an average, particle diameter of 5-20 µm a Cu abrasion value in a 10%, glycerol dispersion of 4-50 mg and thickening behavior in a CMC solution (20% dispersion) of 300-3500 mPa.s is, produced by this invention. The process comprises simultaneously adding alkali metal silicate (weight modulus SiO2:alkali metal oxide = 2.5-3.9:1) and a mineral acid to an initial amount of water which has been adjusted to a pH value of 7.0 to 9.9 or 10.0 to 10.7 by the addition of water glass (sodium silicate). The pH value is held constant between 7.0 to 9.9 or 10.0 to 10.7 during addition of the alkali metal …
Read the whole patent
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 5, 1994 and granted March 9, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 5, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 5, 2016.
- 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.