Patent US4601946A successfully refreshed from Google Patents.
US4601946A
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US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1984-07-26
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Granted: 1986-07-22
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Expires: 2004-07-26
Abstract
Abstract A magnetic recording medium is disclosed which comprises a non-magnetic support having provided thereon a magnetic recording layer consisting ferromagnetic powder and containing graphite and a fatty acid ester.
Inventors
- 👤 Shinobu Iida
- 👤 Nobutaka Yamaguchi
- 👤 Fumiaki Tsukuda
- 👤 Masaaki Fujiyama
- 👤 Eiichi Tadokoro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:54
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/71; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/258; Y10T428/259; Y10T428/30
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
140 words
A magnetic recording medium comprising a non-magnetic support having provided thereon a magnetic recording layer consisting essentially of a ferromagnetic powder and containing graphite, a fatty acid ester and a binder, wherein the graphite is selected from the group consisting of flake shaped graphite, granular graphite or plumbago shaped graphite, the graphite having an average primary particle size of about 0.01 to 3 micron and being present in an amount from about 0.1 to 10 parts by weight per 100 parts by weight of the ferromagnetic powder and the fatty acid ester being an ester of a fatty acid having 6 to 22 carbon atoms and an alcohol having 2 to 27 carbon atoms, the fatty acid ester being present in an amount from about 0.05 to 10 parts by weight per 100 parts by weight of the ferromagnetic powder.
Claim 2
Dependent Claim
140 words
A magnetic recording medium comprising a non-magnetic support having provided thereon a magnetic recording layer consisting essentially of a ferromagnetic powder and containing graphite, a fatty acid ester and a binder, wherein the graphite is selected from the group consisting of flake shaped graphite, granular graphite or plumbago shaped graphite, the graphite having an average primary particle size of about 0.01 to 3 micron and being present in an amount from about 0.1 to 10 parts by weight per 100 parts by weight of the ferromagnetic powder and the fatty acid ester being an ester of a fatty acid having 6 to 22 carbon atoms and an alcohol having 2 to 27 carbon atoms, the fatty acid ester being present in an amount from about 0.05 to 10 parts by weight per 100 parts by weight of the ferromagnetic powder.
Claim 3
Dependent Claim
22 words
The magnetic recording medium claimed in claim 1, wherein said average primary particle size of graphite is from about 0.1 to 0.5μ.
Claim 4
Dependent Claim
33 words
The magnetic recording medium claimed in claim 1, wherein said graphite is present in an amount of from about 0.5 to 5 parts by weight per 100 parts by weight of magnetic particles.
Claim 5
Dependent Claim
35 words
The magnetic recording medium claimed in claim 1, wherein said fatty acid ester is an ester of a fatty acid having 6 to 18 carbon atoms and an alcohol having 2 to 14 carbon atoms.
Claim 6
Dependent Claim
15 words
The magnetic recording medium claimed in claim 4, wherein said alcohol is a monohydric alcohol.
Claim 7
Dependent Claim
35 words
The magnetic recording medium claimed in claim 1, wherein said fatty acid ester is present in an amount of from about 0.1 to 5 parts by weight per 100 parts by weight of magnetic particles.
Claim 8
Dependent Claim
24 words
The magnetic recording medium claimed in claim 1, wherein said magnetic layer further comprises an abrasive have a Mohs hardness of at least 6.
Claim 9
Dependent Claim
31 words
The magnetic recording medium claimed in claim 7, wherein said abrasive is selected from the group consisting of Cr 2 O 3 , alumina, garnet, α--Fe 2 O 3 and SiC.
Claim 10
Dependent Claim
33 words
The magnetic recording medium claimed in claim 8, wherein said abrasive is present in an amount of from about 0.1 to 30 parts by weight per 100 parts by weight of magnetic particles.
Claim 11
Dependent Claim
33 words
The magnetic recording medium claimed in claim 9, wherein said abrasive is present in an amount of from about 1 to 20 parts by weight per 100 parts by weight of magnetic particles.
Claim 12
Dependent Claim
22 words
The magnetic recording medium claimed in claim 7, wherein said abrasive has an average particle size of from about 0.05 to 5μ.
Claim 13
Dependent Claim
27 words
The magnetic recording medium claimed in claim 1, wherein said magnetic layer further comprises carbon black having an average particle size of about 30 mμ or less.
Claim 14
Dependent Claim
23 words
The magnetic recording medium claimed in claim 12, wherein said carbon black has an average particle size of about 10 to 30 mμ.
Claim 15
Dependent Claim
23 words
The magnetic recording medium claimed in claim 13, wherein said carbon black has an average particle size of about 15 to 25 mμ.
Claim 16
Dependent Claim
34 words
The magnetic recording medium claimed in claim 12, wherein said carbon black is present in an amount of from about 0.1 to 10 parts by weight per 100 parts by weight of magnetic particles.
Claim 17
Dependent Claim
34 words
The magnetic recording medium claimed in claim 15, wherein said carbon black is present in an amount of from about 0.5 to 5 parts by weight per 100 parts by weight of magnetic particles.
Claim 18
Dependent Claim
32 words
The magnetic recording medium claimed in claim 1, wherein said magnetic recording medium further comprises a backing layer containing a lubricant on the surface of the support opposite to the magnetic layer.
Claim 19
Dependent Claim
19 words
The magnetic recording medium claimed in claim 1, wherein said magnetic layer further comprises an abrasive and carbon black.
Claim 20
Dependent Claim
18 words
A magnetic recording medium as claimed in claim 1 exhibiting a good still life and reduced head wear.
Claim 21
Dependent Claim
34 words
A magnetic recording medium as claimed in claim 19, wherein said fatty acid ester is selected from the group consisting of amyl stearate, butyl stearate, ethyl stearate, butyl myristate, oleyl oleate and butyl palmitate.
Claim 22
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 19, wherein said fatty acid ester is selected from the group consisting of amyl stearate, butyl stearate and ethyl stearate.
Claim 23
Dependent Claim
26 words
A magnetic recording medium as claimed in claim 19, wherein said fatty acid ester is selected from the group consisting of amyl stearate and butyl stearate.
Claim 24
Dependent Claim
24 words
The magnetic recording medium as claimed in claim 1, wherein the average primary particle size of the graphite is from about 0.05 to 1μ.
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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) | 1989-07-21 | 1990-01-20 | 1990-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-21 | 1994-01-20 | 1994-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-21 | 1998-01-20 | 1998-07-22 | $7700.00 | Window Closed / Lapsed |