Patent US4591528A successfully refreshed from Google Patents.
US4591528A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1984-08-01
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Granted: 1986-05-27
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Expires: 2004-08-01
Abstract
Abstract A magnetic recording medium comprising a plastic base film, a magnetic layer formed on one side of the base film and composed of a ferromagnetic alloy powder dispersed in a resin binder, and a backing layer formed on the other side of the base film, characterized in that said ferromagnetic alloy powder has a surface area of at least 48 m 2 /g as measured by BET method, said magnetic layer has a coercive force of at least 1,000 Oe and a surface roughness of at most 0.08 μm, and said backing layer is composed essentially of a thermoset or radiation-cured resin and carbon black dispersed in the resin, and has a surface roughness of from 0.05 to 0.6 μm, said carbon black having an average particle size of from 10 to 60 μm as measured by an electron microscope.
Inventors
- 👤 Masaharu Nishimatsu
- 👤 Toshiaki Ide
- 👤 Yuichi Kubota
- 👤 Yoshiaki Saito
- 👤 Hiroyuki Arioka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/714; G11B5/73; G11B5/735; G11B5/7356; G11B5/7358; G11B5/739; G11B5/73923; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/25; Y10T428/256; Y10T428/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
140 words
A magnetic recording medium comprising a plastic base film, a magnetic layer formed on one side of the base film and composed of a ferromagnetic alloy powder dispersed in a resin binder, and a backing layer formed on the other side of the base film, characterized in that said ferromagnetic alloy powder has a surface area of at least 48 m 2 /g as measured by BET method, said magnetic layer has a coercive force of at least 1,000 Oe and a surface roughness of at most 0.08 μm, and said backing layer is composed essentially of a thermoset or radiation-cured resin and carbon black dispersed in the resin, and has a surface roughness of from 0.05 to 0.6 μm, said carbon black having an average particle size of from 10 to 60 mμm as measured by an electron microscope.
Claim 2
Dependent Claim
140 words
A magnetic recording medium comprising a plastic base film, a magnetic layer formed on one side of the base film and composed of a ferromagnetic alloy powder dispersed in a resin binder, and a backing layer formed on the other side of the base film, characterized in that said ferromagnetic alloy powder has a surface area of at least 48 m 2 /g as measured by BET method, said magnetic layer has a coercive force of at least 1,000 Oe and a surface roughness of at most 0.08 μm, and said backing layer is composed essentially of a thermoset or radiation-cured resin and carbon black dispersed in the resin, and has a surface roughness of from 0.05 to 0.6 μm, said carbon black having an average particle size of from 10 to 60 mμm as measured by an electron microscope.
Claim 3
Dependent Claim
31 words
The magnetic recording medium according to claim 1, wherein the thermoset resin is made of a thermosetting binder comprising a vinyl chloride-vinyl acetate-vinyl alcohol copolymer, a polyurethane prepolymer and a polyisocyanate.
Claim 4
Dependent Claim
15 words
The magnetic recording medium according to claim 2, wherein the thermosetting binder further contains nitrocellulose.
Claim 5
Dependent Claim
35 words
The magnetic recording medium according to claim 1, wherein the radiation-cured resin is made of a radiation curable binder composed essentially of a radiation sensitive resin having radiation curable acrylic, maleic or allyl-type double bonds.
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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) | 1989-05-26 | 1989-11-25 | 1990-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-26 | 1993-11-25 | 1994-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-26 | 1997-11-25 | 1998-05-27 | $7700.00 | Window Closed / Lapsed |