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US 5,296,041 AGranted
Aqueous electronic circuit assembly cleaner and method
AssigneeChurch & Dwight Co., Inc.
InventorsAlfredo Vinci, M. Stephen Lajoie
Life of this patent
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Abstract
The present invention relates to environmentally safe aqueous saponifier compositions for cleaning electronic circuit assemblies, such as printed circuit or printed wiring boards, during their fabrication. Alkali metal carbonate and bicarbonate salts are utilized preferably with various adjuvants, such as a reducing agent, antioxidant, or antifoam agent, to achieve a variety of objectives, among which are the removal of solder flux, oils, waxes, and greasy substances and adhesive and other residues.
Claims13
A method for removing rosin soldering flux from a printed wiring board, comprising
- (a) contacting the board with an aqueous saponifier solution comprising from about 1 to 15 percent by weight of a saponifier composition comprising alkali metal carbonate and bicarbonate salts so combined that they have a pH of from about 10 to 12 and an adequate reserve of titratable alkalinity, at least equivalent to from about 0.3 to 4.5 percent caustic potash when titrated to the colorless phenolphthalein end point;
- (b) allowing the contact to continue for sufficient time to loosen the soldering flux from said board;
- and
- (c) removing the combined saponifier composition and soldering flux from the board.
1 more element
Dependencies are inferred from the claim text.