US3677949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selectively stripping tin and/or lead from copper substrates
Assignee: MacDermid Enthone Inc
•
Filing: 1970-09-04
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Granted: 1972-07-18
•
Expires: 1990-09-04
Abstract
Abstract ACIDIC SOLUTIONS FOR SELECTIVELY STRIPPING TIN AND/OR LEAD FROM COPPER SUBSTRATES OR SURFACES, COMPRISING AND AQUEOUS SOLUTION OF (1) AT LEAST ONE NITRO-SUBSTITUTED AROMATIC COMPOUND; (2) AN INORGANIC ACID CAPABLE OF READILY REACTING WITH TIN AND LEAD TO FORM WATER-SOLUBLE SALTS THEREOF AND INCAPABLE OF REACTING WITH TIN AND LEAD TO FORM A WATER-INSOLUBLE COMPOUND FILM ON THE TIN, LEAD OR TIN-LEAD ALLOY SURFACE, PREFERABLY FLUOBORIC ACID; AND (3) A THIOUREA.
Inventors
- 👤 Frank A Brindisi Jr
- 👤 Joseph S Nagy
- 👤 Eugene F Yarkosky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:05
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44; H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |