US4439289A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removal of magnetic coatings from computer memory discs
Assignee: Lockheed Martin Corp
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Filing: 1981-07-06
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Granted: 1984-03-27
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Expires: 2001-07-06
Abstract
Abstract Removal of magnetic coatings from computer memory discs is achieved by immersing the discs in a bath of a sulphuric-acid and glycerine solution while applying an electrical potential between electrodes in the bath, one of which is the disc itself. After removal of the disc from the sulphuric-acid glycerine solution, it is sequentially immersed in alcohol and then water; any remaining coating is next mechanically removed and then the disc is immersed in high purity water and dried.
Inventors
- 👤 Gaetano T. Viglione
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:30
CPC Classifications
C; C25; C25F; C25F1/00; C25F5/00
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
60 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing an acid solution which does not readily react with aluminum yet will cause disassociation of the binder from the disc substrate, said acid solution comprising sulfuric acid and a wetting agent; and immersing the discs in said solution.
Claim 2
Independent Claim
60 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing an acid solution which does not readily react with aluminum yet will cause disassociation of the binder from the disc substrate, said acid solution comprising sulfuric acid and a wetting agent; and immersing the discs in said solution.
Claim 3
Dependent Claim
11 words
The method of claim 1, wherein said wetting agent comprises glycerine.
Claim 4
Dependent Claim
17 words
The method of claim 1, further including the step of generating an electric potential in said solution.
Claim 5
Independent Claim
56 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing an acid solution which does not readily react with aluminum yet will cause disassociation with the binder from the disc substrate, said acid solution comprising sulfuric acid; and immersing the discs in said solution.
Claim 6
Independent Claim
56 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing an acid solution which does not readily react with aluminum yet will cause disassociation with the binder from the disc substrate, said acid solution comprising sulfuric acid; and immersing the discs in said solution.
Claim 7
Dependent Claim
15 words
The method of claim 4, wherein said acid solution is at least 95% sulfuric acid.
Claim 8
Dependent Claim
17 words
The method of claim 4, further including the step of generating an electrical potential in said solution.
Claim 9
Independent Claim
71 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing an acid solution which does not readily react with aluminum yet will cause disassociation of the binder from the disc substrate, said acid solution comprising sulfuric acid and a wetting agent; immersing the discs in said solution; generating an electrical potential in said acid solution; and applying ultrasonic energy.
Claim 10
Independent Claim
71 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing an acid solution which does not readily react with aluminum yet will cause disassociation of the binder from the disc substrate, said acid solution comprising sulfuric acid and a wetting agent; immersing the discs in said solution; generating an electrical potential in said acid solution; and applying ultrasonic energy.
Claim 11
Dependent Claim
15 words
The method of claim 7, further including the step of immersing said discs in alcohol.
Claim 12
Dependent Claim
15 words
The method of claim 8, further including the step of immersing said discs in water.
Claim 13
Dependent Claim
15 words
The method of claim 9, further including the step of mechanically removing any remaining coating.
Claim 14
Dependent Claim
23 words
The method of claim 10, wherein said mechanically removing step includes the step of brushing said discs for removing any remaining coating therefrom.
Claim 15
Dependent Claim
26 words
The method of claim 10, wherein said mechanically removing step includes the step of spraying said discs with water to hydraulically remove any remaining coating therefrom.
Claim 16
Dependent Claim
20 words
The method of claim 11 or claim 12, further including the step of immersing said discs in high purity water.
Claim 17
Dependent Claim
13 words
The method of claim 13, further including the step of drying the discs.
Claim 18
Independent Claim
72 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing a hydrogen peroxide-acid solution; immersing the discs in said solution; providing an acid solution which does not readily react with aluminum yet will cause disassociation with the binder from the disc substrate, said acid solution comprising sulfuric acid and a wetting agent; and immersing the discs in said acid solution.
Claim 19
Independent Claim
72 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing a hydrogen peroxide-acid solution; immersing the discs in said solution; providing an acid solution which does not readily react with aluminum yet will cause disassociation with the binder from the disc substrate, said acid solution comprising sulfuric acid and a wetting agent; and immersing the discs in said acid solution.
Claim 20
Dependent Claim
16 words
The method of claim 15, wherein said hydrogen peroxide-acid solution is a hydrogen peroxide-sulfuric acid solution.
Claim 21
Independent Claim
62 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing an acid solution which does not readily react with aluminum yet will cause disassociation of the binder from the disc substrate, said acid solution comprising sulfuric acid, a wetting agent and hydrogen peroxide; and immersing the discs in said solution.
Claim 22
Independent Claim
62 words
A method for removal of magnetic coatings, including a binder and metal oxide, from computer memory discs, comprising the steps of: providing an acid solution which does not readily react with aluminum yet will cause disassociation of the binder from the disc substrate, said acid solution comprising sulfuric acid, a wetting agent and hydrogen peroxide; and immersing the discs in said solution.
Claim 23
Dependent Claim
13 words
The method of claim 17, further including the step of applying ultrasonic energy.
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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) | 1987-03-27 | 1987-09-26 | 1988-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-27 | 1991-09-26 | 1992-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-27 | 1995-09-26 | 1996-03-27 | $7700.00 | Window Closed / Lapsed |