Patent US4761331A successfully refreshed from Google Patents.
US4761331A
Expired / Lapsed
US
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Magnetic recording medium having a back coat layer containing carbon black treated with fatty acids
Assignee: Victor Company of Japan Ltd
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Filing: 1986-05-28
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Granted: 1988-08-02
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Expires: 2006-05-28
Abstract
Abstract A magnetic recording medium comprises a back coat layer on one side of a non-magnetic support which is opposite to a side on which a magnetic recording layer has been formed. The back coat layer is made of a composition which comprises, in a resin binder, carbon black treated with a fatty acid of the formula, RCOOH, in which R represents a linear saturated or unsaturated hydrocarbon having from 13 to 17 carbon atoms. The medium is particularly suitable for high density recording.
Inventors
- 👤 Hiroshi Ogino
- 👤 Yukio Matsumoto
- 👤 Hiroshi Togashi
- 👤 Kumiko Ojima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:40
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; G11B5/7356; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2998; Y10T428/30
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
164 words
In a magnetic recording medium which comprises a nonmagnetic support, a magnetic recording layer formed on one side of the support, and a back coat layer formed on the other side of the support, said back coat layer being made of a composition comprising from 25 to 400 parts by weight of carbon black dispersed in 100 parts by weight of a resin binder, the improvement characterized in that said carbon black has a specific surface area not larger than 800 m 2 /g as determined by the BET absorption method and an average size of from 0.01 to 0.05 micrometers, and said carbon black is treated, prior to dispersion in the resin binder, with a fatty acid of the formula, RCOOH, in which R represents a linear saturated or unsaturated hydrocarbon residue having from 13 to 17 carbon atoms, in such a way that said fatty acid is deposited on the carbon black in an amount of from 1 to 20 wt %.
Claim 2
Dependent Claim
164 words
In a magnetic recording medium which comprises a nonmagnetic support, a magnetic recording layer formed on one side of the support, and a back coat layer formed on the other side of the support, said back coat layer being made of a composition comprising from 25 to 400 parts by weight of carbon black dispersed in 100 parts by weight of a resin binder, the improvement characterized in that said carbon black has a specific surface area not larger than 800 m 2 /g as determined by the BET absorption method and an average size of from 0.01 to 0.05 micrometers, and said carbon black is treated, prior to dispersion in the resin binder, with a fatty acid of the formula, RCOOH, in which R represents a linear saturated or unsaturated hydrocarbon residue having from 13 to 17 carbon atoms, in such a way that said fatty acid is deposited on the carbon black in an amount of from 1 to 20 wt %.
Claim 3
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein the fatty acid is deposited in an amount of from 5 to 20 wt %.
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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) | 1991-08-02 | 1992-02-01 | 1992-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-02 | 1996-02-01 | 1996-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-02 | 2000-02-01 | 2000-08-02 | $7700.00 | Window Closed / Lapsed |