Patent US3776740A successfully refreshed from Google Patents.
US3776740A
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Electroless silvering composition and method
Assignee: London Laboratories Ltd Co
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Filing: 1972-07-13
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Granted: 1973-12-04
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Expires: 1992-07-13
Abstract
Abstract Higher rates of silver deposition from silvering compositions such as ammoniacal silver nitrate solutions are achieved by employing as a reducer an aldonic acid having 4 - 7 carbon atoms, or a salt or lactone thereof. Preferred reducers are gluconic acid, sodium gluconate, sodium glucoheptonate or glucono delta lactone. Since the reducer is stable in the strong base normally employed in silvering, it can be added to the strong base prior to admixing the strong base with the silvering solution.
Inventors
- 👤 C Sivertz
- 👤 J Soltys
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:44
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C18/42; C23C18/44
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
21 words
A method according to claim 1 wherein said compound is an aldohexonic or aldoheptonic acid, or a salt or lactone thereof.
Claim 2
Dependent Claim
18 words
A method according to claim 1 wherein said compound is gluconic acid, sodium gluconate, or glucono delta lactone.
Claim 3
Dependent Claim
14 words
A method according to claim 1 wherein said silver composition comprises ammoniacal silver nitrate.
Claim 4
Dependent Claim
16 words
A method according to claim 1 wherein said reducer compound is heptaconic acid or sodium heptagluconate.
Claim 5
Dependent Claim
32 words
A method according to claim 1 wherein said compound is gluconic acid, said ionic silver composition comprises ammoniacal silver nitrate, and the deposition is effected in the presence of a strong base.
Claim 6
Dependent Claim
13 words
A method according to claim 6 wherein said strong base is sodium hydroxide.
Claim 7
Dependent Claim
64 words
In a silvering solution comprising an aqueous alkaline medium containing a water soluble ionic silver composition capable of reduction to metallic silver and a reducer for said composition, the improvement which comprises providing as said reducer an effective amount of a compound selected from an aldonic acid having 4-7 carbon atoms, a salt of said aldonic aciD, and a lactone of said aldonic acid.
Claim 8
Dependent Claim
22 words
A silvering solution according to claim 8 wherein said compound is an aldohexonic or aldoheptonic acid, or a salt or lactone thereof.
Claim 9
Dependent Claim
27 words
A silvering solution according to claim 8 wherein said compound is gluconic acid, sodium gluconate, or glucono delta lactone and said silver composition comprises ammoniacal silver nitrate.
Claim 10
Dependent Claim
14 words
A silvering solution according to claim 1 having a pH of at least 12.
Claim 11
Dependent Claim
88 words
A silvering solution according to claim 8 containing sodium hydroxide and silver nitrate, and having a pH of about 12 to about 12.7, wherein said ionic silver composition is silver diammine nitrate, said compound is gluconic acid, heptagluconic acid or the sodium salt thereof, the molar ratio of said compound to said silver nitrate is about 1:2 to about 1:1, the weight ratio of sodium hydroxide to silver nitrate is about 1:1, and the molar ratio of hydroxyl ion to silver diammine ion is at least about 4:1.
Claim 12
Independent Claim
130 words
A method of preparing a silvering solution which comprises: a. admixing in water a silver salt and an amount of a complexing agent effective to render the silver salt soluble and to reduce the tendency of the silver solution to precipitate silver oxide with increase of pH, to form a first aqueous solution containing a complexed silver salt, b. admixing in water an alkali metal hydroxide and a reducer compound selected from an aldonic acid having 4-7 carbon atoms, a salt of said aldonic acid, and a lactone of said aldonic acid to form a second aqueous solution, and c. mixing said first and second solutions, wherein the amounts of said complexed silver salt, alkali metal hydroxide and reducer are effective for deposition of metallic silver from said silvering solution.
Claim 13
Independent Claim
96 words
A method of preparing a silvering solution which comprises: a. admixing in water a silver salt and a reducer compound selected from an aldonic acid having 4-7 carbon atoms, a salt of said aldonic acid, and a lactone of said aldonic acid, to form a first aqueous solution, b. admixing in water an alkali metal hydroxide and ammonia to form a second aqueous solution, and c. admixing said first and second solutions, wherein the amounts of said silver salt, reducer compound, alkali metal hydroxide and ammonia are effective to deposit metallic silver from said silvering solution.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |