Selectively stripping tin or tin lead alloys from copper substrates
CA 1056701 A · Owner: Enthone · Inventors: Brindisi, Frank A. (Jr.)
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Acidic solutions for selectively stripping tin or tinlead alloys from copper substrates comprising an aqueous solution of at least one nitro-substituted aromatic compound; an inorganic acid capable of readily reacting with tin and lead to form watersoluble salts thereof and incapable of reacting with tin and lead to form a water-insoluble compound film on the tin or tin-lead alloy surface, preferably fluoboric acid; a thiourea; an organic acid of the formula RCOOH wherein R is 1-2C alkyl or hydrogen; and a haloacetic acid wherein the halogen is chloro or bromo. The result in a pronounced synergism in accelerating the rate of stripping the tin or tin-lead alloy deposit from the copper …
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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
- Granted June 19, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 19, 1996.
- 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.