US4397753A
Expired / Lapsed
US
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Solder stripping solution
Assignee: Circuit Chemistry Corp
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Filing: 1982-09-20
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Granted: 1983-08-09
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Expires: 2002-09-20
Abstract
Abstract Solder stripping solution having an extended life for stripping and removing tin-lead alloy solder or tin deposits from entire circuits or tabs with an insignificant amount of attack on the base epoxy laminate or underlay copper or nickel substrate while leaving a residue-free substrate surface. This solution can be utilized at room temperature or preferably slightly above, and has a prolonged useful life of weeks to months. The composition of the solution includes a hydroxyphenol in an aqueous solution of a nitro-substituted aromatic compound, an inorganic acid, and thiourea.
Inventors
- 👤 James J. Czaja
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:46
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44; C09; C09K; C09K13/00; C09K13/04; C09K13/08; H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
86 words
Solution for the removal of tin or tin-lead alloy solder from a copper or nickel base, said solution comprising: (a) 20-150 g/l of a m-nitro substituted aromatic compound; (b) 0.5-10 g/l of a thiourea selected from a group of thiourea per se, an alkyl thiourea or an aromatic thiourea; (c) 0.1-50 percent by volume of an inorganic acid selected from a group including fluoboric acid, fluosilicic acid, sulfamic acid, or nitric acid; and, (d) 0.1-50.0 g/l of a hydroxyphenol providing extended life to the stripping solution.
Claim 2
Dependent Claim
86 words
Solution for the removal of tin or tin-lead alloy solder from a copper or nickel base, said solution comprising: (a) 20-150 g/l of a m-nitro substituted aromatic compound; (b) 0.5-10 g/l of a thiourea selected from a group of thiourea per se, an alkyl thiourea or an aromatic thiourea; (c) 0.1-50 percent by volume of an inorganic acid selected from a group including fluoboric acid, fluosilicic acid, sulfamic acid, or nitric acid; and, (d) 0.1-50.0 g/l of a hydroxyphenol providing extended life to the stripping solution.
Claim 3
Dependent Claim
11 words
Solution of claim 1 where the inorganic acid is nitric acid.
Claim 4
Dependent Claim
35 words
Solution of claim 1 which also contains an ammonium ion of the formulation NH 4 X in the range of 0.1-300 g/l, X being an ion consisting of either nitrate, fluoborate, acetate, halogen, or hydroxide.
Claim 5
Dependent Claim
35 words
Solution of claim 1 which also contains a fluoborate ion of the formulation RBF 4 in the range of 0.1-750 g/l, R being a cation consisting of either a hydrogen, ammonium, sodium or potassium ion.
Claim 6
Dependent Claim
52 words
Non-peroxide solder stripper solution comprising: (a) nitro-substituted aromatic compound of 20-150 g/l; (b) fluoborate compound of 0.1-750 g/l; (c) hydroxyphenol of 0.1-50 g/l; (d) ammonium compound of 0.1-300 g/l; (e) inorganic acid of 0.1-400 g/l; (f) thiourea of 0.1-30 g/l; (g) boric acid of 2-60 g/l; and (h) water to one liter.
Claim 7
Dependent Claim
52 words
Non-peroxide solder stripper solution comprising: (a) nitro-substituted aromatic compound of 20-150 g/l; (b) fluoborate compound of 0.1-750 g/l; (c) hydroxyphenol of 0.1-50 g/l; (d) ammonium compound of 0.1-300 g/l; (e) inorganic acid of 0.1-400 g/l; (f) thiourea of 0.1-30 g/l; (g) boric acid of 2-60 g/l; and (h) water to one liter.
Claim 8
Dependent Claim
28 words
Solution of claim 5 wherein said nitro-substituted aromatic compound is selected from o, m, or p-nitrochlorobenzenes, o, m, or p-nitrobenzenes, sulfonic acids, and o, m, or p-nitrobenzonic acids.
Claim 9
Dependent Claim
7 words
Solution of claim 6 comprising sodium meta-nitrobenzenesulfonate.
Claim 10
Dependent Claim
30 words
Solution of claim 5 wherein said ammonium compound is selected from ammonium nitrate, ammonium halides, ammonium acetate, or ammonium hydroxide in combination with sodium fluoborate, potassium fluoborate, or fluoboric acid.
Claim 11
Dependent Claim
7 words
Solution of claim 8 comprising ammonium fluoborate.
Claim 12
Dependent Claim
17 words
Solution of claim 5 wherein said inorganic acid is selected from fluoboric, fluosilic, sulfamic, or nitric acid.
Claim 13
Dependent Claim
7 words
Solution of claim 10 comprising nitric acid.
Claim 14
Dependent Claim
9 words
Solution of claim 5 wherein said hydroxyphenol comprises 3-hydroxyphenol.
Claim 15
Dependent Claim
14 words
Solution of claim 5 wherein said thiourea is selected from alkyl and aromatic thiourea.
Claim 16
Dependent Claim
51 words
Non-peroxide solder stripping solution comprising: (a) sodium m-nitrobenzenesulfonate of 80 g/l; (b) fluoboric acid of 276 g/l; (c) boric acid of 8 g/l; (d) 3-hydroxyphenol of 8 g/l; (e) ammonium nitrate of 36 g/l; (f) nitric acid of 90 ml/l; (g) thiourea of 14 g/l; (h) to one liter of water.
Claim 17
Dependent Claim
51 words
Non-peroxide solder stripping solution comprising: (a) sodium m-nitrobenzenesulfonate of 80 g/l; (b) fluoboric acid of 276 g/l; (c) boric acid of 8 g/l; (d) 3-hydroxyphenol of 8 g/l; (e) ammonium nitrate of 36 g/l; (f) nitric acid of 90 ml/l; (g) thiourea of 14 g/l; (h) to one liter of water.
Claim 18
Dependent Claim
13 words
Solution of claim 14 for stripping solder or tin in an SMOBC process.
Claim 19
Dependent Claim
17 words
Solution of claim 14 for stripping solder or tin from printed circuit boards in a nickel-gold process.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-08 | 1987-02-07 | 1987-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-08 | 1991-02-07 | 1991-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-08 | 1995-02-07 | 1995-08-09 | $7700.00 | Window Closed / Lapsed |