Patent US4749608A successfully refreshed from Google Patents.
US4749608A
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1987-04-22
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Granted: 1988-06-07
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Expires: 2007-04-22
Abstract
Abstract A magnetic recording medium comprising a substrate, a ferromagnetic metal thin film on the substrate, and a topcoat on the thin film exhibits improved strength and durability when the topcoat is comprised of a plasma-polymerized film prepared by activating a gaseous hydrocarbon monomer or a mixture thereof with a carrier gas into a plasma under specific conditions. The plasma-polymerized film consists of carbon and hydrogen in an atomic ratio of C/H of from 1:1 to 6:1 and has a thickness of 3 to 15 Å and a contact angle with water in the range from 60° to 120°. An organic coating may be present on the plasma-polymerized film.
Inventors
- 👤 Masatoshi Nakayama
- 👤 Yasufumi Takasugi
- 👤 Kunihiro Ueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:05
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; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T428/31678; Y10T428/31692; Y10T428/31699; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
155 words
In a magnetic recording medium comprising a substrate, a ferromagnetic metal thin film formed on the substrate, and a topcoat formed on the thin film, the improvement wherein the topcoat is comprised of a plasma-polymerized film prepared by activating a gaseous hydrocarbon monomer optionally containing an amount of a carrier gas to give a volume ratio of carrier to monomer of up to 1 into a plasma with the parameter W/F.M set to 10 8 to 10 10 joule/kg where W is an input power applied for plasma generation in joule/sec., F is a flow rate of the monomer in kg/sec., and M is the molecular weight of the monomer, whereby said plasma-polymerized film consists essentially of carbon and hydrogen in an atomic ratio of carbon to hydrogen of from 1:1 to 6:1 and has a thickness of 3 to 15 angstroms and a contact angle with water in the range from 60° to 120°.
Claim 2
Dependent Claim
155 words
In a magnetic recording medium comprising a substrate, a ferromagnetic metal thin film formed on the substrate, and a topcoat formed on the thin film, the improvement wherein the topcoat is comprised of a plasma-polymerized film prepared by activating a gaseous hydrocarbon monomer optionally containing an amount of a carrier gas to give a volume ratio of carrier to monomer of up to 1 into a plasma with the parameter W/F.M set to 10 8 to 10 10 joule/kg where W is an input power applied for plasma generation in joule/sec., F is a flow rate of the monomer in kg/sec., and M is the molecular weight of the monomer, whereby said plasma-polymerized film consists essentially of carbon and hydrogen in an atomic ratio of carbon to hydrogen of from 1:1 to 6:1 and has a thickness of 3 to 15 angstroms and a contact angle with water in the range from 60° to 120°.
Claim 3
Dependent Claim
19 words
The magnetic recording medium of claim 1 wherein the plasma-polymerized film has a thickness of 3 to 8 angstroms.
Claim 4
Dependent Claim
24 words
The magnetic recording medium of claim 1 wherein the plasma-polymerized film is prepared by activating essentially a gaseous hydrocarbon monomer alone into a plasma.
Claim 5
Dependent Claim
20 words
The magnetic recording medium of claim 1 wherein the ferromagnetic metal thin film is a vapor deposited cobalt base film.
Claim 6
Dependent Claim
15 words
The magnetic recording medium of claim 4 wherein the ferromagnetic metal thin film contains oxygen.
Claim 7
Dependent Claim
163 words
In a magnetic recording medium comprising a substrate, a ferromagnetic metal thin film formed on the substrate, and a topcoat formed on the thin film, the improvement wherein the topcoat comprises a plasma-polymerized film and an organic coating applied thereon, said plasma-polymerized film being prepared by activating a gaseous hydrocarbon monomer optionally containing an amount of a carrier gas to give a volume ratio of carrier to monomer of up to 1 into a plasma with the parameter W/F.M set to 10 8 to 10 10 joule/kg where W is an input power applied for plasma generation in joule/sec., F is a flow rate of the monomer in kg/sec., and M is the molecular weight of the monomer, whereby said plasma-polymerized film consists essentially of carbon and hydrogen in an atomic ratio of carbon to hydrogen of from 1:1 to 6:1 and has a thickness of 3 to 15 angstroms and a contact angle with water in the range from 60° to 120°.
Claim 8
Dependent Claim
163 words
In a magnetic recording medium comprising a substrate, a ferromagnetic metal thin film formed on the substrate, and a topcoat formed on the thin film, the improvement wherein the topcoat comprises a plasma-polymerized film and an organic coating applied thereon, said plasma-polymerized film being prepared by activating a gaseous hydrocarbon monomer optionally containing an amount of a carrier gas to give a volume ratio of carrier to monomer of up to 1 into a plasma with the parameter W/F.M set to 10 8 to 10 10 joule/kg where W is an input power applied for plasma generation in joule/sec., F is a flow rate of the monomer in kg/sec., and M is the molecular weight of the monomer, whereby said plasma-polymerized film consists essentially of carbon and hydrogen in an atomic ratio of carbon to hydrogen of from 1:1 to 6:1 and has a thickness of 3 to 15 angstroms and a contact angle with water in the range from 60° to 120°.
Claim 9
Dependent Claim
19 words
The magnetic recording medium of claim 6 wherein said organic coating has a thickness of 10 to 50 angstroms.
Claim 10
Dependent Claim
16 words
The magnetic recording medium of claim 7 wherein said organic coating comprises an organic fluorine compound.
Claim 11
Dependent Claim
16 words
The magnetic recording medium of claim 8 wherein said organic fluorine compound contains a perfluoroalkyl radical.
Claim 12
Dependent Claim
28 words
The magnetic recording medium of claim 7 wherein said organic coating is a coating of an organic fluorine compound having an unsaturated bond, said coating being radiation cured.
Claim 13
Dependent Claim
26 words
The magnetic recording medium of claim 10 wherein said organic fluorine compound having an unsaturated bond contains a perfluoroalkyl radical and an acrylic or methacrylic radical.
Claim 14
Dependent Claim
19 words
The magnetic recording medium of claim 6 wherein the plasma-polymerized film has a thickness of 3 to 8 angstroms.
Claim 15
Dependent Claim
24 words
The magnetic recording medium of claim 6 wherein the plasma-polymerized film is prepared by activating essentially a gaseous hydrocarbon monomer alone into a plasma.
Claim 16
Dependent Claim
20 words
The magnetic recording medium of claim 6 wherein the ferromagnetic metal thin film is a vapor deposited cobalt base film.
Claim 17
Dependent Claim
15 words
The magnetic recording medium of claim 14 wherein the ferromagnetic metal thin film contains oxygen.
Claim 18
Dependent Claim
18 words
The magnetic recording medium according to claim 1, wherein said topcoat is formed directly on said thin film.
Claim 19
Dependent Claim
22 words
The magnetic recording medium according to claim 6, wherein the plasma-polymerized film of said topcoat is formed directly on said thin film.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-06-07 | 1991-12-07 | 1992-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-07 | 1995-12-07 | 1996-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-07 | 1999-12-07 | 2000-06-07 | $7700.00 | Window Closed / Lapsed |