US4720332A
Expired / Lapsed
US
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Nickel strip formulation
Assignee: Individual
•
Filing: 1986-04-21
•
Granted: 1988-01-19
•
Expires: 2006-04-21
Abstract
Abstract The present invention relates to the chemical stripping of nickel and nickel alloys from metallic and non-metallic substrates wherein at least one compound that is, or can form in solution, a zwitterion acts as a complexing agent for the metal being dissolved and as a buffer to control the pH of the stripping solution. The present invention discloses an electrical method for the rapid stripping of high-phosphorus electroless nickel plating. The present invention provides an electrical process for the efficient removal of the residual smut that ensues from the sulfide ion catalysis of the chemical stripping process.
Inventors
- 👤 Barry W. Coffey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:47
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44; C23F1/10; C23F1/14; C23F1/32; C23F1/40; C25; C25F; C25F1/00; C25F1/02; C25F5/00
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
98 words
A nickel stripping composition suitable for use in an aqueous electroless stripping bath, said nickel stripping composition consisting essentially of: (1) a zwitterion, (2) an oxidizing agent in the form of a soluble organic nitro compound, (3) a pH-adjusting compound selected from the group consisting of a soluble salt that forms an alkaline solution when dissolved in water, sodium hydroxide and potassium hydroxide, to adjust the stripping solution to an operating pH range of 7 to 11, and (4) a compound that forms the sulfide ion in solution to act as a catalyst in the chemical stripping process.
Claim 2
Dependent Claim
98 words
A nickel stripping composition suitable for use in an aqueous electroless stripping bath, said nickel stripping composition consisting essentially of: (1) a zwitterion, (2) an oxidizing agent in the form of a soluble organic nitro compound, (3) a pH-adjusting compound selected from the group consisting of a soluble salt that forms an alkaline solution when dissolved in water, sodium hydroxide and potassium hydroxide, to adjust the stripping solution to an operating pH range of 7 to 11, and (4) a compound that forms the sulfide ion in solution to act as a catalyst in the chemical stripping process.
Claim 3
Dependent Claim
15 words
A nickel stripping composition according to claim 1 wherein the zwitterion is an aminocarboxylic acid.
Claim 4
Dependent Claim
17 words
A nickel stripping composition according to claim 2 wherein the soluble salt is sodium or potassium carbonate.
Claim 5
Dependent Claim
17 words
A nickel stripping composition according to claim 1 wherein the soluble salt is sodium or potassium carbonate.
Claim 6
Dependent Claim
25 words
A nickel stripping composition according to claim 1 including at least one iron complexor of the group consisting of hydroxycarboxylic acids, polyphosphates, polyols and monosaccharides.
Claim 7
Dependent Claim
27 words
A nickel stripping composition according to claim 1, wherein the zwitterion is an aminocarboxylic acid and the compound forming the sulfide ion is sodium or potassium thiosulfate.
Claim 8
Dependent Claim
17 words
A nickel stripping composition according to claim 6 wherein the soluble salt is sodium or potassium carbonate.
Claim 9
Dependent Claim
17 words
A nickel stripping composition according to claim 7 wherein the zwitterion is glycine, beta-alanine or monosodium glutamate.
Claim 10
Dependent Claim
14 words
A nickel stripping composition according to claim 1 free of volatile nitrogen containing compounds.
Claim 11
Dependent Claim
45 words
The stripping composition according to claim 1, wherein there is employed as the oxidizing agent a soluble organic nitro compound selected from the group consisting of ortho-, meta- and para-nitrobenzene sulfonic acids and their salts, and ortho-, meta- and para-nitrobenzoic acids and their soluble salts.
Claim 12
Dependent Claim
40 words
The stripping composition according to claim 1, wherein the pH-adjusting compound is a soluble salt selected from the group consisting of sodium carbonate, potassium carbonate, potassium phosphate, disodium phosphate, tripotassium phosphate, trisodium phosphate, tetrasodium pyrophosphate, dipotassium phosphate and sodium tetraborate.
Claim 13
Dependent Claim
17 words
The stripping composition according to claim 1, wherein the sulfide ion compound is sodium or potassium thiosulfate.
Claim 14
Dependent Claim
62 words
The stripping composition according to claim 1, including at least one iron complexor of the group consisting of hydroxycarboxylic acids, polyphosphates, polyols and monosaccharides, wherein the compound used to form an iron complexor is a hydroxycarboxylic acid selected from the group consisting of gluconic acid, hydroxyacetic acid, tartaric acid, malic acid, alpha- and beta-hydroxypropionic acid, citric acid, glucuronic acid and lactic acid.
Claim 15
Dependent Claim
51 words
The stripping composition according to claim 1, including at least one iron complexor of the group consisting of hydroxycarboxylic acids, polyphosphates, polyols and monosaccharides, wherein the compound used to form an iron complexor is a polyphosphate selected from the group consisting of sodium polyphosphate, sodium metaphosphate, sodium tripolyphosphate and sodium pyrophosphate.
Claim 16
Dependent Claim
47 words
The stripping solution according to claim 1, including at least one iron complexor of the group consisting of hydroxycarboxylic acids, polyphosphates, polyols and monosaccharides, wherein the compound used to form an iron complexor is a polyol selected from the group consisting of glycerine, meso-erythritol, sorbitol and mannitol.
Claim 17
Dependent Claim
45 words
The stripping solution according to claim 1, including at least one iron complexor of the group consisting of hydroxycarboxylic acids, polyphosphates, polyols and monosaccharides, wherein the compound used to form an iron complexor is a monosaccharide selected from the group consisting of fructose and glucose.
Claim 18
Dependent Claim
32 words
The stripping composition according to claim 1, including an iron complexing compound selected from the group consisting of sodium gluconate, sodium glucoheptonate, disodium tartarate, sodium glycolate, potassium sodium tartarate and disodium malate.
Claim 19
Dependent Claim
18 words
The stripping composition according to claim 17, wherein the iron complexing compound is sodium gluconate or disodium tartarate.
Claim 20
Dependent Claim
69 words
The stripping composition according to claim 1, wherein the concentration range of the zwitterion compound is from 0.01 lbs./gal. to saturation; the concentration range of the organic nitro compound is from 0.01 lbs./gal. to saturation; the concentration range of the soluble salt, potassium hydroxide or sodium hydroxide, is from 0.01 lbs./gal. to saturation; and the concentration range of the sulfite ion compound is from 1 ppm to 5 oz./gal.
Claim 21
Dependent Claim
36 words
The stripping composition according to to claim 19, including an iron complexor which is a hydroxycarboxylic acid, a polyphosphate, a polyol or a monosaccharide, the concentration of the iron complexor being from 0.01 lbs./gal. to saturation.
Claim 22
Dependent Claim
72 words
The stripping composition according to claim 19, wherein the concentration range of the zwitterion compound is from 0.5 lbs./gal. to 1.5 lbs./gal.; the concentration range of the organic nitro compound is from 0.25 lbs./gal. to 1.0 lbs./gal.; the concentration range of the soluble salt, potassium hydroxide or sodium hydroxide, is from 0.5 lbs./gal. to 1.5 lbs./gal; and the concentration range of the sulfide ion compound is from 1 oz./gal. to 3 oz./gal.
Claim 23
Dependent Claim
37 words
The stripping composition of claim 19, including an iron complexor which is a hydroxycarboxylic acid, a polyphosphate, a polyol or a monosaccharide, wherein the concentration range of the iron complexor is from 0.25 lbs./gal. to 0.75 lbs./gal.
Claim 24
Dependent Claim
21 words
The stripping composition according to claim 19, wherein the concentration range of the zwitterion compound is from 0.01 lbs./gal. to saturation.
Claim 25
Dependent Claim
72 words
The stripping composition according to claim 19, wherein the concentration range of the zwitterion compound is from 0.5 lbs./gal. to 1.5 lbs./gal.; the concentration range of the organic nitro compound is from 0.25 lbs./gal. to 1.0 lbs./gal.; the concentration range of the soluble salt, potassium hydroxide or sodium hydroxide, is from 0.5 lbs./gal. to 1.5 lbs./gal.; and the concentration range of the sulfide ion compound is from 1 oz./gal. to 3 oz./gal.
Claim 26
Dependent Claim
22 words
The stripping compound according to claim 19, wherein the concentration range of the organic nitro compound is from 0.01 lbs./gal. to saturation.
Claim 27
Dependent Claim
72 words
The stripping composition according to claim 19, wherein the concentration range of the zwitterion compound is from 0.5 lbs./gal. to 1.5 lbs./gal.; the concentration range of the organic nitro compound is from 0.25 lbs./gal. to 1.0 lbs./gal.; the concentration range of the soluble salt, potassium hydroxide or sodium hydroxide, is from 0.5 lbs./gal. to 1.5 lbs./gal.; and the concentration range of the sulfide ion compound is from 1 oz./gal. to 3 oz./gal.
Claim 28
Dependent Claim
25 words
The stripping composition according to claim 19, including a soluble salt, wherein the concentration range of the soluble salt is from 0.01 lbs./gal. to saturation.
Claim 29
Dependent Claim
71 words
The stripping composition according to claim 19, including a soluble salt, wherein the concentration range of the zwitterion compound is from 0.5 lbs./gal. to 1.5 lbs./gal.; the concentration range of the organic nitro compound is from 0.25 lbs./gal. to 1.0 lbs./gal.; the concentration range of the soluble salt is from 0.5 lbs./gal. to 1.5 lbs./gal.; and the concentration range of the sulfide ion compound is from 1 oz./gal. to 3 oz./gal.
Claim 30
Dependent Claim
23 words
The stripping composition according to claim 19, wherein the concentration range of the sulfide ion compound is from 1 ppm to 5 oz./gal.
Claim 31
Dependent Claim
72 words
The stripping composition according to claim 19, wherein the concentration range of the zwitterion compound is from 0.5 lbs./gal. to 1.5 lbs./gal.; the concentration range of the organic nitro compound is from 0.25 lbs./gal. to 1.0 lbs./gal.; the concentration range of the soluble salt, potassium hydroxide or sodium hydroxide, is from 0.5 lbs./gal. to 1.5 lbs./gal.; and the concentration range of the sulfide ion compound is from 1 oz./gal. to 3 oz./gal.
Claim 32
Dependent Claim
31 words
The stripping composition according to claim 19, including a hydroxycarboxylic acid, a polyphosphate, a polyol or a monosaccharide as an iron complexing compound in an amount of 0.01 lbs./gal. to saturation.
Claim 33
Dependent Claim
97 words
The stripping composition according to claim 19, including a hydroxycarboxylic acid, a polyphosphate, a polyol or a monosaccharide as an iron complexing compound in an amount of 0.25 lbs./gal. to 0.75 lbs./gal., wherein the concentration range of the zwitterion compound is from 0.5 lbs./gal. to 1.5 lbs./gal.; the concentration range of the organic nitro compound is from 0.25 lbs./gal. to 1.0 lbs./gal.; the concentration range of the soluble salt, potassium hydroxide or sodium hydroxide, is from 0.5 lbs./gal. to 1.5 lbs./gal.; and the concentration range of the sulfide ion compound is from 1 oz./gal. to 3 oz./gal.
Claim 34
Dependent Claim
34 words
An electrical process for the removal of high-phosphorus electroless nickel plating from an article comprising the application of a reverse current to the said plated article immersed in the stripping solution of claim 1.
Claim 35
Dependent Claim
34 words
An electrical process for the removal of high-phosphorus electroless nickel plating from an article comprising the application of a reverse current to the said plated article immersed in the stripping solution of claim 2.
Claim 36
Dependent Claim
34 words
An electrical process for the removal of high-phosphorus electroless nickel plating from an article comprising the application of a reverse current to the said plated article immersed in the stripping solution of claim 3.
Claim 37
Dependent Claim
34 words
An electrical process for the removal of high-phosphorus electroless nickel plating from an article comprising the application of a reverse current to the said plated article immersed in the stripping solution of claim 6.
Claim 38
Dependent Claim
34 words
An electrical process for the removal of high-phosphorus electroless nickel plating from an article comprising the application of a reverse current to the said plated article immersed in the stripping solution of claim 7.
Claim 39
Dependent Claim
34 words
An electrical process for the removal of high-phosphorus electroless nickel plating from an article comprising the application of a reverse current to the said plated article immersed in the stripping solution of claim 9.
Claim 40
Dependent Claim
42 words
An electrical process for the removal of residual smut from article that has been stripped of nickel comprising reverse-plating the stripped article in the stripping solution of claim 1 using the stripped article as the anode and the tank as the cathode.
Claim 41
Dependent Claim
43 words
An electrical process for the removal of residual smut from an article that has been stripped of nickel comprising reverse-plating the stripped article in the stripping solution of claim 2 using the stripped article as the anode and the tank as the cathode.
Claim 42
Dependent Claim
43 words
An electrical process for the removal of residual smut from an article that has been stripped of nickel comprising reverse-plating the stripped article in the stripping solution of claim 3 using the stripped article as the anode and the tank as the cathode.
Claim 43
Dependent Claim
43 words
An electrical process for the removal of residual smut from an article that has been stripped of nickel comprising reverse-plating the stripped article in the stripping solution of claim 6 using the stripped article as the anode and the tank as the cathode.
Claim 44
Dependent Claim
43 words
An electrical process for the removal of residual smut from an article that has been stripped of nickel comprising reverse-plating the stripped article in the stripping solution of claim 7 using the stripped article as the anode and the tank as the cathode.
Claim 45
Dependent Claim
43 words
An electrical process for the removal of residual smut from an article that has been stripped of nickel comprising reverse-plating the stripped article in the stripping solution of claim 9 using the stripped article as the anode and the tank as the cathode.
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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) | 1991-01-18 | 1991-07-20 | 1992-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-18 | 1995-07-20 | 1996-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-18 | 1999-07-20 | 2000-01-19 | $7700.00 | Window Closed / Lapsed |