Transparent lead-free and cadmium-free glazes
CA 2068440 A1 · Owner: Corning Incorporated · Inventors: Rose, Paul L.; Stempin, John L.; Nigrin, Jaroslava M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to glass frit compositions free from lead and cadmium which, when combined with an organic medium and fired to a glaze, yield a glaze exhibiting a grayish discoloration caused by the presence of a carbonaceous residue therein. The grayish discoloration can be eliminated by incorporating tin oxide in the frit composition which acts to catalyze the oxidation of and/or to directly oxidize that 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 May 12, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 12, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 12, 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.