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US4130455A
Expired / Lapsed
US
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Dissolution of metals-utilizing H2 O2 -H2 SO4 -thiosulfate etchant
Assignee: Dart Industries Inc
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Filing: 1977-11-08
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Granted: 1978-12-19
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Expires: 1997-11-08
Abstract
Abstract Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of a thiosulfate of sodium or potassium.
Inventors
- 👤 Moenes L. Elias
- 👤 Millard F. Good
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:06
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067; C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
56 words
A method of metal dissolution which comprises contacting a metal with an aqueous solution containing from about 0.2 to about 4.5 gram moles per liter of sulfuric acid, from about 0.25 to about 8 gram moles per liter of hydrogen peroxide and a catalytically effective amount of an additive selected from thiosulfates of sodium or potassium.
Claim 2
Independent Claim
56 words
A method of metal dissolution which comprises contacting a metal with an aqueous solution containing from about 0.2 to about 4.5 gram moles per liter of sulfuric acid, from about 0.25 to about 8 gram moles per liter of hydrogen peroxide and a catalytically effective amount of an additive selected from thiosulfates of sodium or potassium.
Claim 3
Dependent Claim
21 words
The method of claim 1, wherein said additive is provided at a concentration of at least about 2 millimoles per liter.
Claim 4
Dependent Claim
25 words
The method of claim 1, wherein said additive is provided at a concentration in the range from about 5 to about 50 millimoles per liter.
Claim 5
Dependent Claim
27 words
The method of claim 1, wherein the aqueous solution contains sodium phenolsulfonate as a stabilizer to reduce the degrading effect of heavy metal ions on hydrogen peroxide.
Claim 6
Dependent Claim
22 words
The method of claim 1, wherein the hydrogen peroxide concentration is maintained between about 1 and about 4 gram moles per liter.
Claim 7
Dependent Claim
22 words
The method of claim 1, wherein the sulfuric acid concentration is maintained between about 0.3 and about 4 gram moles per liter.
Claim 8
Dependent Claim
15 words
The method of claim 1, wherein the metal is copper or an alloy of copper.
Claim 9
Dependent Claim
25 words
The method of claim 1, wherein the dissolution is carried out in the presence of free chloride or bromide ions in excess of 2 ppm.
Claim 10
Dependent Claim
51 words
A composition for metal dissolution comprising an aqueous solution of from about 2.0 to about 4.5 gram moles per liter of sulfuric acid, from about 0.25 to about 8 gram moles per liter of hydrogen peroxide and a catalytically effective amount of an additive selected from thiosulfates of sodium or potassium.
Claim 11
Dependent Claim
51 words
A composition for metal dissolution comprising an aqueous solution of from about 2.0 to about 4.5 gram moles per liter of sulfuric acid, from about 0.25 to about 8 gram moles per liter of hydrogen peroxide and a catalytically effective amount of an additive selected from thiosulfates of sodium or potassium.
Claim 12
Dependent Claim
21 words
The composition of claim 9, wherein the additive is provided at a concentration of at least about 2 millimoles per liter.
Claim 13
Dependent Claim
25 words
The composition of claim 9, wherein the additive is provided at a concentration in the range from about 5 to about 50 millimoles per liter.
Claim 14
Dependent Claim
24 words
The composition of claim 9 additionally containing sodium phenolsulfonate as a stabilizer for reducing the degrading effect of heavy metal ions on hydrogen peroxide.
Claim 15
Dependent Claim
22 words
The composition of claim 9, wherein the hydrogen peroxide concentration is maintained between about 1 and about 4 gram moles per liter.
Claim 16
Dependent Claim
22 words
The composition of claim 9, wherein the sulfuric acid concentration is maintained between about 0.3 and about 4 gram moles per liter.
Claim 17
Dependent Claim
16 words
The composition of claim 9 containing more than 2 ppm of free chloride or bromide ions.
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) | 1981-12-18 | 1982-06-19 | 1982-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-18 | 1986-06-19 | 1986-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-18 | 1990-06-19 | 1990-12-19 | $7700.00 | Window Closed / Lapsed |