US4391874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-02-19
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Granted: 1983-07-05
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Expires: 2002-02-19
Abstract
Abstract A magnetic recording medium having a thin magnetic film on a non-magnetic support base is disclosed. A layer of isocyanic acid ester is formed in connection with the medium, and may be formed on either the surface of the metal film or the surface of the base opposite the metal film or both. The resulting medium has excellent running properties, wear resistance and electro-to-magnetic conversion characteristics which are maintained after repeated use.
Inventors
- 👤 Nobuyuki Yamamoto
- 👤 Kyoichi Naruo
- 👤 Tsutomu Okita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:01
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/725; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
41 words
A magnetic recording medium, comprising: a non-magnetic support base; a thin magnetic metal film formed on a surface of said non-magnetic support base; and a layer of an isocyanic acid ester having the formula RN═C═O, wherein R is an alkyl group.
Claim 2
Dependent Claim
41 words
A magnetic recording medium, comprising: a non-magnetic support base; a thin magnetic metal film formed on a surface of said non-magnetic support base; and a layer of an isocyanic acid ester having the formula RN═C═O, wherein R is an alkyl group.
Claim 3
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 1, wherein said layer of isocyanic acid ester is formed on an outer surface of said thin magnetic metal film.
Claim 4
Dependent Claim
43 words
A magnetic recording medium as claimed in any of claims 1 or 2, wherein said layer of isocyanic acid ester is formed on a surface of said non-magnetic support base opposite to said surface on which said thin magnetic metal film is formed.
Claim 5
Dependent Claim
26 words
A magnetic recording medium as claimed in claim 1, wherein said thin magnetic metal film has a thickness within the range of 0.05 to 2 μm.
Claim 6
Dependent Claim
21 words
A magnetic recording medium as claimed in claim 4, wherein said thickness is within the range of 0.1 to 0.4 μm.
Claim 7
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 1, wherein said alkyl group is a straight chain alkyl group having 8 or more carbon atoms.
Claim 8
Dependent Claim
30 words
A magnetic recording medium as claimed in claim 6, wherein said isocyanic acid ester is selected from the group consisting of octyl isocyanate, decyl isocyanate, dodecyl isocyanate and octadecyl isocyanate.
Claim 9
Dependent Claim
30 words
A magnetic recording medium as claimed in claim 1, wherein said layer of isocyanic acid ester has a dry weight within the range of 1 to 50 mg/m 2 .
Claim 10
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 8, wherein said dry weight is within the range of from 2 to 10 mg/m 2 .
Claim 11
Dependent Claim
30 words
A magnetic recording medium as claimed in claim 8, wherein said alkyl group of the isocyanic acid ester is a straight chain alkyl group having 8 to 18 carbon atoms.
Claim 12
Dependent Claim
30 words
A magnetic recording medium as claimed in claim 10, wherein said isocyanic acid ester is selected from the group consisting of octyl isocyanate, decyl isocyanate, dodecyl isocyanate and octadecyl isocyanate.
Claim 13
Dependent Claim
60 words
A magnetic recording medium as claimed in claim 11, wherein said thin magnetic metal film is composed of a ferromagnetic metal or alloy selected from the group consisting of Fe, Co, Ni, Fe-Co, Fe-Ni, Co-Ni, Fe-Si, Fe-Rh, Co-P, Co-B, Co-Si, Co-V, Co-Y, Co-La, Co-Ce, Co-Pr, Co-Sm, Co-Pt, Co-Mn, Fe-Co-Ni, Co-Ni-P, Co-Ni-B, Co-Ni-Ag, Co-Ni,Na, Co-Ni-Ce, Co-Ni-Zn, Co-Ni-Cu, Co-Ni-W, Co-Ni-Re and Co-Sm-Cu.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-07-04 | 1987-01-03 | 1987-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-07-04 | 1991-01-03 | 1991-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-07-04 | 1995-01-03 | 1995-07-05 | $7700.00 | Window Closed / Lapsed |