Patent US4236957A successfully refreshed from Google Patents.
US4236957A
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Dissolution of metals utilizing an aqueous H2 SOY --H2 O.sub. -mercapto containing heterocyclic nitrogen etchant
Assignee: Plastic Specialties and Technologies Inc
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Filing: 1979-06-25
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Granted: 1980-12-02
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Expires: 1999-06-25
Abstract
Abstract Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of a heterocyclic nitrogen compound containing at least one free mercapto group substitution.
Inventors
- 👤 Silvester P. Valayil
- 👤 Moenes L. Elias
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:32
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
60 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 a heterocyclic nitrogen compound additive containing at least one free mercapto group substitution.
Claim 2
Independent Claim
60 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 a heterocyclic nitrogen compound additive containing at least one free mercapto group substitution.
Claim 3
Dependent Claim
21 words
The method of claim 1, wherein said additive is provided at a concentration of at least about 0.05 gram 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 0.2 to about 10 grams per liter.
Claim 5
Dependent Claim
10 words
The method of claim 1, wherein said additive is 2-mercaptothiazoline.
Claim 6
Dependent Claim
10 words
The method of claim 1, wherein said additive is 2-benzimidazolethiol.
Claim 7
Dependent Claim
10 words
The method of claim 1, wherein said additive is 2-benzothiazolethiol.
Claim 8
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 9
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 10
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 11
Dependent Claim
15 words
The method of claim 1, wherein the metal is copper or an alloy of copper.
Claim 12
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 13
Dependent Claim
55 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 a heterocyclic nitrogen compound additive containing at least one free mercapto group substitution.
Claim 14
Dependent Claim
55 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 a heterocyclic nitrogen compound additive containing at least one free mercapto group substitution.
Claim 15
Dependent Claim
21 words
The composition of claim 12, wherein the additive is provided at a concentration of at least about 0.1 gram per liter.
Claim 16
Dependent Claim
25 words
The composition of claim 12, wherein the additive is provided at a concentration in the range from about 0.5 to about 10 grams per liter.
Claim 17
Dependent Claim
10 words
The composition of claim 12, wherein said additive is 2-mercaptothiazoline.
Claim 18
Dependent Claim
10 words
The composition of claim 12, wherein said additive is 2-benzimidazolethiol.
Claim 19
Dependent Claim
10 words
The composition of claim 12, wherein said additive is 2-benzothiazolethiol.
Claim 20
Dependent Claim
24 words
The composition of claim 12, additionally containing sodium phenolsulfonate as a stabilizer for reducing the degrading effect of heavy metal ions on hydrogen peroxide.
Claim 21
Dependent Claim
22 words
The composition of claim 12, wherein the hydrogen peroxide concentration is maintained between about 1 and about 4 gram moles per liter.
Claim 22
Dependent Claim
22 words
The composition of claim 12, wherein the sulfuric acid concentration is maintained between about 0.3 and about 4 gram moles per liter.
Claim 23
Dependent Claim
16 words
The composition of claim 12, containing more than 2 ppm of free chloride or bromide ions.
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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) | 1983-12-02 | 1984-06-02 | 1984-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-02 | 1988-06-02 | 1988-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-02 | 1992-06-02 | 1992-12-02 | $7700.00 | Window Closed / Lapsed |