Kaolin clay-based pigment
CA 1253659 A · Owner: Engelhard Corporation · Inventors: Slepetys, Richard A.; Catone, David L.; Huege, Fred R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A substantially white anhydrous, amorphous alumino-, silicate pigment is obtained by calcining a combination of previously uncalcined kaolin clay and an alumina source. The calcination is carried out at a temperature of about 870°C to 1400°C, preferably about 870°C to 1260°C for a, suitable period of time, e.g. 0.1 to 3 hours. The pigments obtained by the foregoing method display enhanced brightness greater than the merely additive brightness which would be obtained by mixing alumina with a previously calcined kaolin clay and are otherwise well suited for use as paper-filling or coating pigments.
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
- Granted May 9, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 9, 2006.
- 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.