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US4737188A
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Reducing agent and method for the electroless deposition of silver
Assignee: Lilly London Inc
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Filing: 1987-05-18
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Granted: 1988-04-12
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Expires: 2007-05-18
Abstract
Abstract A brighter, more uniform deposit of electroless silver is achieved over a wider temperature range by employing as a reducer a compound represented by the general formula: R.sup.2 --(CHR.sup.1).sub.n --CH.sub.2 OH where n is two (2) to seven (7), R 2 is represented by the formula COOH or CH 2 R 1 , each R 1 group is independently selected from the class consisting of OH, NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 and at least one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 . Preferred reducers are N-methylglucamine, d-glucamine and glucosaminic acid.
Inventors
- 👤 Harry J. Bahls
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:40
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C18/42; C23C18/44
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
138 words
In a method for the electroless deposition of metallic silver wherein a substrate is contacted with 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 represented by the general formula, R.sup.2 --(CHR.sup.1).sub.n --CH.sub.2 OH where n is two (2) to seven (7), R 2 is represented by the formula COOH or CH 2 R 1 , each R 1 group is independently selected from the class consisting of OH, NH 2 , NHCH 3 , NHC 2 H 5 and NHC 3 H 7 and at least one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 .
Claim 2
Dependent Claim
138 words
In a method for the electroless deposition of metallic silver wherein a substrate is contacted with 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 represented by the general formula, R.sup.2 --(CHR.sup.1).sub.n --CH.sub.2 OH where n is two (2) to seven (7), R 2 is represented by the formula COOH or CH 2 R 1 , each R 1 group is independently selected from the class consisting of OH, NH 2 , NHCH 3 , NHC 2 H 5 and NHC 3 H 7 and at least one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 .
Claim 3
Dependent Claim
11 words
A method according to claim 1 wherein n is four (4).
Claim 4
Dependent Claim
36 words
A method according to claim 1 wherein only one of R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 the remaining R 1 groups being OH.
Claim 5
Dependent Claim
11 words
A method according to claim 3 wherein n is four (4).
Claim 6
Dependent Claim
20 words
A method according to claim 4 wherein R 2 is CH 2 NH 2 or CH 2 NHCH 3 .
Claim 7
Dependent Claim
16 words
A method according to claim 4 wherein the reducer compound is N-methylglucamine, d-glucamine or glucosaminic acid.
Claim 8
Dependent Claim
24 words
A method according to claim 6 wherein the molar ratio of reducer to ionic silver compound is in the range of 1:10 to 1:0.5
Claim 9
Dependent Claim
24 words
A method according to claim 6 wherein the molar ratio of reducer to ionic silver compound is in the range of 1:6 to 1:2.
Claim 10
Dependent Claim
24 words
A method according to claim 1 wherein the molar ratio of reducer to ionic silver compound is in the range of 1:10 to 1:0.5
Claim 11
Dependent Claim
14 words
A method according to claim 1 wherein the silver composition comprises ammoniacal silver nitrate.
Claim 12
Dependent Claim
36 words
A method according to claim 1 wherein the reducer compound is N-methylglucamine, d-glucamine, or glucosaminic acid, the ionic silver composition comprises ammoniacal silver nitrate, and the deposition is effected in the presence of a strong base.
Claim 13
Dependent Claim
13 words
A method according to claim 11 wherein the strong base is sodium hydroxide.
Claim 14
Dependent Claim
50 words
A method according to claim 1 wherein the aqueous alkaline medium containing the water soluble ionic silver composition forms a first solution and the reducer is mixed with a strong base in an aqueous medium to form a second solution, the two solutions being used in a two-part silvering method.
Claim 15
Dependent Claim
56 words
A method according to claim 1 wherein the aqueous alkaline medium containing the water soluble ionic silver composition is mixed with the reducer to form a first solution and a complexing agent and strong base are mixed in an aqueous medium to form a second solution, the two solutions being used in a two-part silvering method.
Claim 16
Dependent Claim
15 words
A method according to claim 14 wherein a buffer is added to the first solution.
Claim 17
Dependent Claim
15 words
A method according to claim 15 wherein the buffer is ammonium nitrate or ammonium citrate.
Claim 18
Dependent Claim
60 words
A method according to claim 1 wherein the aqueous alkaline medium containing the water soluble ionic silver composition forms a first solution, the reducer is mixed with an aqueous medium to form a second solution and a strong base is mixed with an aqueous medium to form a third solution, the three solutions being used in a three-part silvering method.
Claim 19
Dependent Claim
13 words
A method according to claim 1 wherein a second reducer is also employed.
Claim 20
Dependent Claim
22 words
The method of claim 18 wherein the second reducer is contained in an aqueous solution separate from the aqueous alkaline silver solution.
Claim 21
Dependent Claim
12 words
The method of claim 19 wherein a three-part silvering method is employed.
Claim 22
Dependent Claim
39 words
The method of claim 20 wherein the aqueous alkaline silver solution forms a first solution, the reducer of the invention is contained in an aqueous alkaline second solution, and the second reducer is contained in a third aqueous solution.
Claim 23
Dependent Claim
12 words
The method of claim 21 wherein the second reducer is invert sugar.
Claim 24
Dependent Claim
13 words
The method of claim 22 wherein the reducer of the invention is N-methylglucamine.
Claim 25
Dependent Claim
127 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 represented by the general formula, R.sup.2 --(CHR.sup.1).sub.n --CH.sub.2 OH where n is two (2) to seven (7), R 2 is represented by the formula COOH or CH 2 R 1 , each R 1 group is independently selected from the class consisting of OH, NH 2 , NHCH 3 , NCHC 2 H 5 and NHC 3 H 7 and at least one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 .
Claim 26
Dependent Claim
127 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 represented by the general formula, R.sup.2 --(CHR.sup.1).sub.n --CH.sub.2 OH where n is two (2) to seven (7), R 2 is represented by the formula COOH or CH 2 R 1 , each R 1 group is independently selected from the class consisting of OH, NH 2 , NHCH 3 , NCHC 2 H 5 and NHC 3 H 7 and at least one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 .
Claim 27
Dependent Claim
12 words
A silvering solution according to claim 24 wherein n is four (4).
Claim 28
Dependent Claim
38 words
A silvering solution according to claim 25 wherein only one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 the remaining R 1 groups being OH.
Claim 29
Dependent Claim
12 words
A silvering solution according to claim 26 wherein n is four (4).
Claim 30
Dependent Claim
16 words
A silvering solution according to claim 27 wherein said compound is N-methylglucamine, d-glucamine or glucosaminic acid.
Claim 31
Dependent Claim
127 words
In a reducer solution for silvering comprising an aqueous alkaline medium containing a strong base and a reducer capable of reducing an ionic silver composition to metallic silver, the improvement which comprises providing as said reducer an effective amount of a compound represented by the general formula. R.sup.2 --(CHR.sup.1).sub.n --CH.sub.2 OH where n is two (2) to seven (7), R 2 is represented by the formula COOH or CH 2 R 1 , each R 1 group is independently selected from the class consisting of OH, NH 2 , NHCH 3 , NHC 2 H 5 and NHC 3 H 7 and at least one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 .
Claim 32
Dependent Claim
127 words
In a reducer solution for silvering comprising an aqueous alkaline medium containing a strong base and a reducer capable of reducing an ionic silver composition to metallic silver, the improvement which comprises providing as said reducer an effective amount of a compound represented by the general formula. R.sup.2 --(CHR.sup.1).sub.n --CH.sub.2 OH where n is two (2) to seven (7), R 2 is represented by the formula COOH or CH 2 R 1 , each R 1 group is independently selected from the class consisting of OH, NH 2 , NHCH 3 , NHC 2 H 5 and NHC 3 H 7 and at least one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 .
Claim 33
Dependent Claim
12 words
A silvering solution according to claim 29 wherein n is four (4).
Claim 34
Dependent Claim
38 words
A silvering solution according to claim 30 wherein only one of the R 1 groups is NH 2 , NHCH 3 , NHC 2 H 5 or NHC 3 H 7 the remaining R 1 groups being OH.
Claim 35
Dependent Claim
12 words
A silvering solution according to claim 31 wherein n is four (4).
Claim 36
Dependent Claim
16 words
A silvering solution according to claim 32 wherein said compound is N-methylglucamine, d-glucamine or glucosaminic acid.
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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) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |