US4223361A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Maxell Ltd
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Filing: 1978-11-16
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Granted: 1980-09-16
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Expires: 1998-11-16
Abstract
Abstract A magnetic recording medium improved in durability which comprises a substrate and a magnetic layer of about 1.0 to 10 mu in thickness comprising magnetic particles and a binder and being formed on the substrate, characterized in that the magnetic layer further comprises (a) a liquid hydrocarbon having a melting or flowing point of about -20 DEG to -60 DEG C. with (b) alpha -iron oxide particles having a particle size of 0.5 to 2 mu and/or (c) a higher fatty acid having a melting point of about 45 DEG C. or higher.
Inventors
- 👤 Hiroshi Zaitsu
- 👤 Takashi Yamase
- 👤 Sadao Yamashita
- 👤 Kunio Mizushima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/716; G11B5/718; G11B5/708; G11B5/7085; G11B5/71; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
82 words
A magnetic recording medium which comprises a substrate and a magnetic layer of about 1.0 to 10μ in thickness comprising magnetic powders and a binder being formed on the substrate, characterized in that the magnetic layer further comprises a liquid hydrocarbon selected from the group consisting of liquid paraffin, squalane, α-olefin and polymerized oil and having a melting or flowing point of about -20° to 60° C. with a higher fatty acid having a melting point of about 45° C. or higher.
Claim 2
Dependent Claim
82 words
A magnetic recording medium which comprises a substrate and a magnetic layer of about 1.0 to 10μ in thickness comprising magnetic powders and a binder being formed on the substrate, characterized in that the magnetic layer further comprises a liquid hydrocarbon selected from the group consisting of liquid paraffin, squalane, α-olefin and polymerized oil and having a melting or flowing point of about -20° to 60° C. with a higher fatty acid having a melting point of about 45° C. or higher.
Claim 3
Dependent Claim
15 words
The magnetic recording medium according to claim 1, wherein the liquid hydrocarbon is liquid paraffin.
Claim 4
Dependent Claim
38 words
The magnetic recording medium according to claim 1, wherein the liquid hydrocarbon is used in an amount of about 70 to 99.5% by weight based on the combined weight of the liquid hydrocarbon and the higher fatty acid.
Claim 5
Dependent Claim
38 words
The magnetic recording medium according to claim 1, wherein the combined amount of the liquid hydrocarbon and the higher fatty acid is about 0.5 to 50 parts by weight to one part by weight of the magnetic powders.
Claim 6
Dependent Claim
17 words
The magnetic recording medium according to claim 1, wherein the magnetic layer further comprises α-iron oxide powders.
Claim 7
Dependent Claim
15 words
The magnetic recording medium according to claim 5, wherein the liquid hydrocarbon is liquid paraffin.
Claim 8
Dependent Claim
18 words
The magnetic recording medium according to claim 5, wherein the α-iron oxide powders are in a granular form.
Claim 9
Dependent Claim
29 words
The magnetic recording medium according to claim 5, wherein the α-iron oxide powders are used in an amount of about 0.5 to 5% by weight of the magnetic powders.
Claim 10
Dependent Claim
37 words
The magnetic recording medium according to claim 5, wherein the liquid hydrocarbon is used in an amount of 70 to 99.5% by weight based on the combined weight of the liquid hydrocarbon and the higher fatty acid.
Claim 11
Dependent Claim
38 words
The magnetic recording medium according to claim 5, wherein the combined amount of the liquid hydrocarbon and the higher fatty acid is 0.5 to 50 parts by weight to one part by weight of the α-iron oxide powders.
Claim 12
Dependent Claim
15 words
The magnetic recording medium according to claim 1, which is formed in a disk form.
Claim 13
Dependent Claim
19 words
The magnetic recording medium according to claim 11, which has the magnetic layer on both surfaces of the substrate.
Claim 14
Dependent Claim
24 words
A magnetic disk cartridge comprising a jacket and the magnetic disk according to claim 11 contained therein in a state permitting its free rotation.
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) | 1983-09-16 | 1984-03-17 | 1984-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-16 | 1988-03-17 | 1988-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-16 | 1992-03-17 | 1992-09-16 | $7700.00 | Window Closed / Lapsed |