Additives for lead- and cadmium-free glazes
CA 2066496 C · Owner: Wexell, Kathleen A. · Inventors: Wexell, Kathleen A.; Nigrin, Jaroslava M.; Wexell, Dale R.
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 eliminating the grayish discoloration which commonly develops when leadfree and cadmium-free glass frits axe applied to substrates utilizing an organic medium and thereafter fired to fuse the frit particles into a glaze. The grayish discoloration contains a carbonaceous residue from the organic medium. The method comprises the four general steps: (1) adsorbing a coating of a strongly oxidizing metal ion species onto the surface of the frit particles; (2) mixing the coated frit particles with an organic medium;, (3) applying that mixture to a substrate; and (4) firing the mixture to eliminate the organic medium and to oxidize the carbonaceous residue …
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 April 21, 1992 and granted October 28, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 21, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 21, 2014.
- 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.