US4713144A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composition and method for stripping films from printed circuit boards
Assignee: Brent America Inc
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Filing: 1986-08-01
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Granted: 1987-12-15
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Expires: 2006-08-01
Abstract
Abstract A composition and method for stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board with a single application of the composition. An aqueous solution of nitric acid, ferric nitrate and sulfamic acid, which may be sprayed directly onto the printed circuit board for removing both the solder and the alloy.
Inventors
- 👤 Harold Schiller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:17
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44; H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
66 words
A metal dissolving liquid for stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, consisting essentially of an aqueous solution of about 5 to 50 volume percent of 69% nitric acid aqueous solution, about 1 to 50 volume percent of 45% ferric nitrate aqueous solution, about 5 grams per liter to saturation of sulfamic acid, and the balance water.
Claim 2
Dependent Claim
66 words
A metal dissolving liquid for stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, consisting essentially of an aqueous solution of about 5 to 50 volume percent of 69% nitric acid aqueous solution, about 1 to 50 volume percent of 45% ferric nitrate aqueous solution, about 5 grams per liter to saturation of sulfamic acid, and the balance water.
Claim 3
Dependent Claim
65 words
A metal dissolving liquid for stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, consisting essentially of an aqueous solution of about 1 to 35 volume percent of 69% nitric acid aqueous solution, about 5 to 25 volume percent of 45% ferricanitrate aqueous solution, about 5 to 70 grams per liter of sulfamic acid, and the balance water.
Claim 4
Dependent Claim
65 words
A metal dissolving liquid for stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, consisting essentially of an aqueous solution of about 1 to 35 volume percent of 69% nitric acid aqueous solution, about 5 to 25 volume percent of 45% ferricanitrate aqueous solution, about 5 to 70 grams per liter of sulfamic acid, and the balance water.
Claim 5
Dependent Claim
68 words
A metal dissolving liquid for stripping solder and the underlying tin-copper from the copper substrate of a printed circuit board, consisting essentially of an aqueous solution of nitric acid in an amount sufficient to dissolve solder, sulfamic acid in an amount sufficient to react with and eliminate nitrous acid initially present and/or formed during the stripping operation, and ferric nitrate in an amount sufficient to dissolve tin-copper alloy.
Claim 6
Dependent Claim
68 words
A metal dissolving liquid for stripping solder and the underlying tin-copper from the copper substrate of a printed circuit board, consisting essentially of an aqueous solution of nitric acid in an amount sufficient to dissolve solder, sulfamic acid in an amount sufficient to react with and eliminate nitrous acid initially present and/or formed during the stripping operation, and ferric nitrate in an amount sufficient to dissolve tin-copper alloy.
Claim 7
Dependent Claim
76 words
A metal dissolving liquid for stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, consisting essentially of 15 to 30 volume percent of an aqueous solution of 69% nitric acid aqueous solution, 15 to 20 volume percent of an aqueous solution of 45% ferric nitrate aqueous solution, and sulfamic acid in an amount sufficient to react with and eliminate nitrous acid initially present and/or formed during the stripping operation.
Claim 8
Dependent Claim
76 words
A metal dissolving liquid for stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, consisting essentially of 15 to 30 volume percent of an aqueous solution of 69% nitric acid aqueous solution, 15 to 20 volume percent of an aqueous solution of 45% ferric nitrate aqueous solution, and sulfamic acid in an amount sufficient to react with and eliminate nitrous acid initially present and/or formed during the stripping operation.
Claim 9
Dependent Claim
78 words
In a method of rapidly stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, the steps of: providing an aqueous solution consisting essentially of about 5 to 50 volume percent of 69% nitric acid aqueous solution, about 1 to 50 volume percent of 45% ferric nitrate aqueous solution, about 5 grams per liter to saturation of sulfamic acid, and the balance water; and applying the solution to the printed circuit board.
Claim 10
Dependent Claim
78 words
In a method of rapidly stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, the steps of: providing an aqueous solution consisting essentially of about 5 to 50 volume percent of 69% nitric acid aqueous solution, about 1 to 50 volume percent of 45% ferric nitrate aqueous solution, about 5 grams per liter to saturation of sulfamic acid, and the balance water; and applying the solution to the printed circuit board.
Claim 11
Dependent Claim
19 words
The method as defined in claim 5 including applying the solution by spraying directly onto the printed circuit board.
Claim 12
Dependent Claim
78 words
In a method of rapidly stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, the steps of: providing an aqueous solution consisting essentially of about 10 to 35 volume percent of 69% nitric acid aqueous solution, about 5 to 25 volume percent of 45% ferric nitrate aqueous solution, about 5 to 70 grams per liter per sulfamic acid, and the balance water; and applying the solution to the printed circuit board.
Claim 13
Dependent Claim
78 words
In a method of rapidly stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, the steps of: providing an aqueous solution consisting essentially of about 10 to 35 volume percent of 69% nitric acid aqueous solution, about 5 to 25 volume percent of 45% ferric nitrate aqueous solution, about 5 to 70 grams per liter per sulfamic acid, and the balance water; and applying the solution to the printed circuit board.
Claim 14
Dependent Claim
19 words
The method as defined in claim 7 including applying the solution by spraying directly onto the printed circuit board.
Claim 15
Dependent Claim
81 words
In a method of rapidly stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, the steps of: proving an aqueous solution consisting essentially of nitric acid in an amount sufficient to dissolve solder, sulfamic acid in an amount sufficient to react with and eliminate nitrous acid initially present and/or formed during the stripping operation, and ferric nitrate in an amount sufficient to dissolve tin-copper alloy; and applying the solution to the printed circuit board.
Claim 16
Dependent Claim
81 words
In a method of rapidly stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, the steps of: proving an aqueous solution consisting essentially of nitric acid in an amount sufficient to dissolve solder, sulfamic acid in an amount sufficient to react with and eliminate nitrous acid initially present and/or formed during the stripping operation, and ferric nitrate in an amount sufficient to dissolve tin-copper alloy; and applying the solution to the printed circuit board.
Claim 17
Dependent Claim
19 words
The method as defined in claim 9 including applying the solution by spraying directly onto the printed circuit board.
Claim 18
Dependent Claim
84 words
In a method of rapidly stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, the steps of: providing an aqueous solution consisting essentially of 15 to 30 volume percent of 69% nitric acid aqueous solution, 15 to 20 volume percent of 45% ferric nitrate aqueous solution, and sulfamic acid in an amount sufficient to react with and eliminate nitrous acid initially present and/or formed during the stripping operation: and applying the solution to the printed circuit board.
Claim 19
Dependent Claim
84 words
In a method of rapidly stripping solder and the underlying tin-copper alloy from the copper substrate of a printed circuit board, the steps of: providing an aqueous solution consisting essentially of 15 to 30 volume percent of 69% nitric acid aqueous solution, 15 to 20 volume percent of 45% ferric nitrate aqueous solution, and sulfamic acid in an amount sufficient to react with and eliminate nitrous acid initially present and/or formed during the stripping operation: and applying the solution to the printed circuit board.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-12-14 | 1991-06-15 | 1991-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-14 | 1995-06-15 | 1995-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-14 | 1999-06-15 | 1999-12-15 | $7700.00 | Window Closed / Lapsed |