US4297257A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal stripping composition and method
Assignee: Plastic Specialties and Technologies Inc
•
Filing: 1980-04-17
•
Granted: 1981-10-27
•
Expires: 2000-04-17
Abstract
Abstract A composition for stripping solder and tin from a copper substrate having an extended life is provided by the inclusion of a polyacrylamide in a peroxide-fluoride based stripping composition. The presence of the polyacrylamide minimizes the adverse effect of the stripping composition on the copper substrate of the material undergoing treatment.
Inventors
- 👤 Moenes L. Elias
- 👤 Narendra K. Shah
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:22
CPC Classifications
C; C23; C23G; C23G1/00; C23G1/02; C23G1/04; C23G1/06; C23F; C23F1/00; C23F1/44; H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
46 words
An aqueous stripping solution which contains in solution from about 0.5% to about 35% of hydrogen peroxide, from about 5% to about 50% of a reactive composition of ammonia and hydrofluoric acid or a salt thereof, and from about 0.01% to about 10% of a polyacrylamide.
Claim 2
Dependent Claim
46 words
An aqueous stripping solution which contains in solution from about 0.5% to about 35% of hydrogen peroxide, from about 5% to about 50% of a reactive composition of ammonia and hydrofluoric acid or a salt thereof, and from about 0.01% to about 10% of a polyacrylamide.
Claim 3
Dependent Claim
36 words
An aqueous stripping solution which contains in solution from about 2% to about 10% of hydrogen peroxide, from about 10% to about 30% of ammonium bifluoride, and from about 0.05% to about 1.0% of a polyacrylamide.
Claim 4
Dependent Claim
36 words
An aqueous stripping solution which contains in solution from about 2% to about 10% of hydrogen peroxide, from about 10% to about 30% of ammonium bifluoride, and from about 0.05% to about 1.0% of a polyacrylamide.
Claim 5
Dependent Claim
20 words
A composition according to claim 2 wherein the polyacrylamide has a molecular weight of from about 2,000 to about 5,000,000.
Claim 6
Dependent Claim
13 words
A composition according to claim 3 wherein trichloroacetic acid is present in solution.
Claim 7
Dependent Claim
21 words
A composition according to claim 4 wherein the trichloroacetic acid is present in an amount of about 0.01% to about 10%.
Claim 8
Dependent Claim
11 words
A composition according to claim 3 wherein the polyacrylamide is polyacrylamide.
Claim 9
Dependent Claim
22 words
An aqueous stripping solution which contains 21% of ammonium bifluoride, 1% of trichloroacetic acid, 7% of hydrogen peroxide and 0.2% of polyacrylamide.
Claim 10
Dependent Claim
22 words
An aqueous stripping solution which contains 21% of ammonium bifluoride, 1% of trichloroacetic acid, 7% of hydrogen peroxide and 0.2% of polyacrylamide.
Claim 11
Independent Claim
111 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper without adversely affecting the copper, said process comprising the steps of exposing the solder to a composition comprising from about 0.05% to about 35% of hydrogen peroxide, from about 5% to about 50% of a reactive composition of ammonia and hydrofluoric acid or a salt thereof, and from about 0.01% to about 10% of a polyacrylamide for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper has been adversely affected.
Claim 12
Independent Claim
111 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper without adversely affecting the copper, said process comprising the steps of exposing the solder to a composition comprising from about 0.05% to about 35% of hydrogen peroxide, from about 5% to about 50% of a reactive composition of ammonia and hydrofluoric acid or a salt thereof, and from about 0.01% to about 10% of a polyacrylamide for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper has been adversely affected.
Claim 13
Independent Claim
101 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper without adversely affecting the copper, said process comprising the steps of exposing the solder to a composition comprising from about 2% to about 10% of hydrogen peroxide, from about 10% to about 30% of ammonium bifluoride, and from about 0.05% to about 1.0% of a polyacrylamide for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper has been adversely affected.
Claim 14
Independent Claim
101 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper without adversely affecting the copper, said process comprising the steps of exposing the solder to a composition comprising from about 2% to about 10% of hydrogen peroxide, from about 10% to about 30% of ammonium bifluoride, and from about 0.05% to about 1.0% of a polyacrylamide for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper has been adversely affected.
Claim 15
Dependent Claim
20 words
A method according to claim 8 wherein the polyacrylamide has a molecular weight of from about 2,000 to about 5,000,000.
Claim 16
Dependent Claim
15 words
A method according to claim 9 wherein trichloroacetic acid is also present in the composition.
Claim 17
Independent Claim
93 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper without adversely affecting the copper, said process comprising the steps of exposing the solder to a composition comprising about 21% of ammonium bifluoride, about 1% of trichloroacetic acid, about 7% of hydrogen peroxide and about 0.2% of polyacrylamide for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper has been adversely affected.
Claim 18
Independent Claim
93 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper without adversely affecting the copper, said process comprising the steps of exposing the solder to a composition comprising about 21% of ammonium bifluoride, about 1% of trichloroacetic acid, about 7% of hydrogen peroxide and about 0.2% of polyacrylamide for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper has been adversely affected.
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) | 1984-10-26 | 1985-04-27 | 1985-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-26 | 1989-04-27 | 1989-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-26 | 1993-04-27 | 1993-10-27 | $7700.00 | Window Closed / Lapsed |