US4537833A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1984-05-02
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Granted: 1985-08-27
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Expires: 2004-05-02
Abstract
Abstract A magnetic recording medium which comprises a non-magnetic support having thereon a magnetic recording layer containing ferromagnetic metal particles and a binder, wherein the ferromagnetic metal particles have a specfic area of about 35 to about 80 m 2 /g, and the magnetic recording layer has a surface roughness of about 0.001 to 0.04 μm and a residual amount of the solvent is about 0.5 to about 30 mg/m 2 .
Inventors
- 👤 Akira Kasuga
- 👤 Nobuyuki Yamamoto
- 👤 Hajime Miyatsuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/714; G11B5/708; G11B5/7085; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31786
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
76 words
A magnetic recording medium comprising a non-magnetic support having thereon a magnetic recording layer comprising ferromagnetic metal particles and a binder, wherein the ferromagnetic metal particles have a specific surface area of about 35 to about 80 m 2 /g, and the magnetic recording layer has a surface roughness of about 0.001 to about 0.04 μm and the residual amount of solvent in the magnetic recording layer is about 0.5 to about 30 mg/m 2 .
Claim 2
Dependent Claim
76 words
A magnetic recording medium comprising a non-magnetic support having thereon a magnetic recording layer comprising ferromagnetic metal particles and a binder, wherein the ferromagnetic metal particles have a specific surface area of about 35 to about 80 m 2 /g, and the magnetic recording layer has a surface roughness of about 0.001 to about 0.04 μm and the residual amount of solvent in the magnetic recording layer is about 0.5 to about 30 mg/m 2 .
Claim 3
Dependent Claim
26 words
The magnetic recording medium as claimed in claim 1, wherein the ferromagnetic metal particles have a specific surface area of 40 to 70 m 2 /g.
Claim 4
Dependent Claim
23 words
The magnetic recording medium as claimed in claim 1, wherein the magnetic recording layer has a surface roughness of 0.005 to 0.03 μm.
Claim 5
Dependent Claim
22 words
The magnetic recording medium as claimed in claim 1, wherein the residual amount of solvent is 0.5 to 20 mg/m 2 .
Claim 6
Dependent Claim
23 words
The magnetic recording medium as claimed in claim 1, wherein the ferromagnetic metal particles are composed of pure iron or an iron alloy.
Claim 7
Dependent Claim
25 words
The magnetic recording medium as claimed in claim 5, wherein the ferromagnetic metal particles are selected from the group consisting of Fe, Fe-Ni and Fe-Ni-Co.
Claim 8
Dependent Claim
23 words
The magnetic recording medium as claimed in claim 6, wherein the ferromagnetic metal particle contain a non-magnetic metal element or a non-metallic element.
Claim 9
Dependent Claim
28 words
The magnetic recording medium as claimed in claim 7, wherein the non-magnetic metal element is selected from the group consisting of Al, Ti, Cr, Mn, Cu and Zn.
Claim 10
Dependent Claim
27 words
The magnetic recording medium as claimed in claim 7, wherein the non-metallic element is selected from the group consisting of B, C, N, Si, P and S.
Claim 11
Dependent Claim
36 words
The magnetic recording medium as claimed in claim 7, wherein the amount of the non-metallic element or non-magnetic metal element is 0.1 to 15% by weight based on the total weight of the ferromagnetic metal particles.
Claim 12
Dependent Claim
36 words
The magnetic recording medium as claimed in claim 10, wherein the amount of the non-metallic element or non-magnetic metal element is 3 to 12% by weight based on the total weight of the ferromagnetic metal particles.
Claim 13
Dependent Claim
36 words
The magnetic recording medium as claimed in claim 11, wherein the amount of the non-metallic element or non-magnetic metal element is 4 to 10% by weight based on the total weight of the ferromagnetic metal particles.
Claim 14
Dependent Claim
29 words
The magnetic recording medium as claimed in claim 1, wherein the ferromagnetic metal particles have an oxidized layer with a thickness of about 20 Å to about 100 Å.
Claim 15
Dependent Claim
25 words
The magnetic recording medium as claimed in claim 1, wherein the magnetic recording layer has a saturation magnetization of about 120 to about 180 emu/g.
Claim 16
Dependent Claim
23 words
The magnetic recording medium as claimed in claim 14, wherein the magnetic recording layer has a saturation magnetization of 125 to 180 emu/g.
Claim 17
Dependent Claim
32 words
The magnetic recording medium as claimed in claim 1, wherein the binder is selected from the group consisting of a thermosetting resin, a thermoplastic resin, a reactive type resin and mixtures thereof.
Claim 18
Dependent Claim
46 words
The magnetic recording medium as claimed in claim 16, wherein the binder is selected from the group consisting of a vinyl chloride-vinyl acetate copolymer, a cellulose resin, an acryl resin, a polyamide type resin, a butadiene type resin, a urethane elastomer and an isocyanate curable resin.
Claim 19
Dependent Claim
35 words
The magnetic recording medium as claimed in claim 17, wherein the binder is selected from the group consisting of a vinyl chloride-vinyl acetate copolymer, a cellulose resin, a urethane elastomer and an isocyanate curable resin.
Claim 20
Dependent Claim
34 words
The magnetic recording medium as claimed in claim 1, wherein the amount of the binder is about 8 to about 25 parts by weight per 100 parts by weight of the ferromagnetic metal particles.
Claim 21
Dependent Claim
24 words
The magnetic recording medium as claimed in claim 1, wherein the magnetic recording layer additionally contains a fatty acid or a fatty acid ester.
Claim 22
Dependent Claim
37 words
The magnetic recording medium as claimed in claim 1, wherein the magnetic recording layer additionally contains at least one additive selected from the group consisting of a lubricant, an abrasive, a surfactant, a plasticizer and an antioxidant.
Claim 23
Dependent Claim
30 words
The magnetic recording medium as claimed in claim 21, wherein the lubricant is selected from the group consisting of a silicone oil, graphite, molybdenum disulfide, polyethylene, polytetrafluoroethylene and a fluorocarbon.
Claim 24
Dependent Claim
28 words
The magnetic recording medium as claimed in claim 21, wherein the abrasive is selected from the group consisting of fused alumina, silicon carbide, chromium oxide, corundum and diamond.
Claim 25
Dependent Claim
25 words
The magnetic recording medium as claimed in claim 1, wherein the non-magnetic support is a support of a synthetic resin, a non-magnetic metal or paper.
Claim 26
Dependent Claim
29 words
The magnetic recording medium as claimed in claim 24, wherein the synthetic resin is selected from the group consisting of a polyester, a vinyl polymer and a cellulose derivative.
Claim 27
Dependent Claim
15 words
The magnetic recording medium as claimed in claim 25, wherein the polyester is polyethylene terephthalate.
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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 |