US4305995A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1980-08-05
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Granted: 1981-12-15
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Expires: 2000-08-05
Abstract
Abstract A magnetic recording medium comprises a substrate coated with a magnetic layer comprising a magnetic powder, a thermosettable binder and a mixture of sorbitane mono-, di- and tri- higher fatty acid ester surfactants.
Inventors
- 👤 Hiroshi Ota
- 👤 Eiji Horigome
- 👤 Hitoshi Azegami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:44
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/71; G11B5/702; G11B5/7028; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
54 words
A magnetic recording medium which comprises a substrate coated with a magnetic layer comprising a magnetic powder, a thermosettable binder and a mixture of sorbitane mono-, di- and tri- higher fatty acid ester surfactants, the ratio in said mixture being 1:0.2-5:0.2-5, and the ratio of said mixture to said binder being from 1-15 wt.%.
Claim 2
Dependent Claim
54 words
A magnetic recording medium which comprises a substrate coated with a magnetic layer comprising a magnetic powder, a thermosettable binder and a mixture of sorbitane mono-, di- and tri- higher fatty acid ester surfactants, the ratio in said mixture being 1:0.2-5:0.2-5, and the ratio of said mixture to said binder being from 1-15 wt.%.
Claim 3
Dependent Claim
21 words
The magnetic recording medium according to claim 1 wherein the ratio of said mixture to said binder is from 2-10 wt.%.
Claim 4
Dependent Claim
22 words
The magnetic recording medium according to claim 1 wherein said surfactants are a mixture of sorbitane monostearate, sorbitane distearate and sorbitane tristearate.
Claim 5
Dependent Claim
25 words
The magnetic recording medium according to claim 1 wherein said thermosettable binder comprises a resin having hydroxyl groups and a polyisocyanate as a crosslinking agent.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-14 | 1985-06-15 | 1985-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-14 | 1989-06-15 | 1989-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-14 | 1993-06-15 | 1993-12-15 | $7700.00 | Window Closed / Lapsed |