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US4537832A
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Magnetic recording medium
Assignee: TDK Corp
•
Filing: 1983-12-20
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Granted: 1985-08-27
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Expires: 2003-12-20
Abstract
Abstract A magnetic recording medium for use in video and other applications is presented which comprises a substrate, a continuous thin magnetic layer of cobalt and at least one selected from nickel, chromium, and oxygen, preferably obliquely evaporated on the substrate, and a topcoat formed over the magnetic layer and made of a phosphate compound having the formula: <IMAGE> where R is selected from alkyl radicals having 10 to 22 carbon atoms, and Y and Y' are independently selected from the group consisting of hydrogen atom, alkyl radicals and monovalent cations, and Y and Y' may together represent a divalent cation.
Inventors
- 👤 Osamu Kohmoto
- 👤 Yasufumi Takasugi
- 👤 Hiroshi Sugihara
- 👤 Masaharu Nishimatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:26
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/24975; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/2964; Y10T428/2967
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
83 words
A magnetic recording medium comprising a substrate, a continuous thin magnetic layer on the substrate, and a topcoat formed over the magnetic layer deposited by evaporation or sputtering, characterized in that the topcoat consists of a compound having the formula: ##STR6## where R is selected from alkyl radicals having 10 to 22 carbon atoms, and Y and Y' are independently selected from the group consisting of hydrogen atom, alkyl radicals and monovalent cations, and Y and Y' may together represent a divalent cation.
Claim 2
Dependent Claim
83 words
A magnetic recording medium comprising a substrate, a continuous thin magnetic layer on the substrate, and a topcoat formed over the magnetic layer deposited by evaporation or sputtering, characterized in that the topcoat consists of a compound having the formula: ##STR6## where R is selected from alkyl radicals having 10 to 22 carbon atoms, and Y and Y' are independently selected from the group consisting of hydrogen atom, alkyl radicals and monovalent cations, and Y and Y' may together represent a divalent cation.
Claim 3
Dependent Claim
16 words
The magnetic recording medium according to claim 1 wherein R is a straight chain alkyl radical.
Claim 4
Dependent Claim
15 words
The magnetic recording medium according to claim 1 wherein R is an unsubstituted alkyl radical.
Claim 5
Dependent Claim
27 words
The magnetic recording medium according to claim 1, 2 or 3 wherein R is selected from straight chain, unsubstituted alkyl radicals having 12 to 20 carbon atoms.
Claim 6
Dependent Claim
26 words
The magnetic recording medium according to claim 1 wherein Y and/or Y ' is a monovalent cation, or Y and Y' together represent a divalent cation.
Claim 7
Dependent Claim
19 words
The magnetic recording medium according to claim 5 wherein the cation is selected from metal ions and onium ions.
Claim 8
Dependent Claim
16 words
The magnetic recording medium according to claim 5 wherein Y and/or Y' is an onium ion.
Claim 9
Dependent Claim
19 words
The magnetic recording medium according to claim 7 wherein the onium ion is a C 10-22 alkyl ammonium ion.
Claim 10
Dependent Claim
19 words
The magnetic recording medium according to claim 8 wherein the alkyl of the alkyl ammonium is of straight chain.
Claim 11
Dependent Claim
39 words
The magnetic recording medium according to claim 1 wherein R and Y are independently selected from alkyl radicals, with the proviso that the total number of carbon atoms contained in R and Y radicals is not more than 44.
Claim 12
Dependent Claim
40 words
The magnetic recording medium according to claim 1 wherein R, Y, and Y' are independently selected from alkyl radicals, with the proviso that the total number of carbon atoms contained in R, Y, and Y' is not more than 44.
Claim 13
Dependent Claim
18 words
The magnetic recording medium according to claim 10 or 11 wherein the alkyl radicals are of straight chain.
Claim 14
Dependent Claim
21 words
The magnetic recording medium according to claim 1 or wherein the topcoat has a thickness of not more than 0.3 microns.
Claim 15
Dependent Claim
31 words
The magnetic recording medium according to claim 1 wherein the magnetic layer consists of cobalt and optionally, at least one member selected from the group consisting of nickel, chromium, and oxygen.
Claim 16
Dependent Claim
26 words
The magnetic recording medium according to claim 14 wherein the magnetic layer contains nickel and the weight ratio of cobalt to nickel is at least 1.5.
Claim 17
Dependent Claim
27 words
The magnetic recording medium according to claim 14 wherein the magnetic layer contains chromium and the weight ratio of chromium to cobalt ranges from 0.001 to 0.1.
Claim 18
Dependent Claim
33 words
The magnetic recording medium according to claim 15 wherein the magnetic layer further contains chromium and the weight ratio of chromium to the sum of cobalt and nickel ranges from 0.001 to 0.1.
Claim 19
Dependent Claim
27 words
The magnetic recording medium according to claim 14 wherein the magnetic layer contains oxygen and the atomic ratio of oxygen to cobalt is not more than 0.45.
Claim 20
Dependent Claim
33 words
The magnetic recording medium according to claim 15 wherein the magnetic layer further contains oxygen and the atomic ratio of oxygen to the sum of cobalt and nickel is not more than 0.45.
Claim 21
Dependent Claim
31 words
The magnetic recording medium according to claim 1 or 14 wherein the magnetic layer consists of a coalescence of particles of columnar structure oriented oblique to the normal to the substrate.
Claim 22
Dependent Claim
20 words
The magnetic recording medium according to claim 20 wherein the magnetic layer has a thickness of 0.05 to 0.5 microns.
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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) | 1988-08-26 | 1989-02-25 | 1989-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-26 | 1993-02-25 | 1993-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-26 | 1997-02-25 | 1997-08-27 | $7700.00 | Window Closed / Lapsed |