US5013602A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1988-09-21
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Granted: 1991-05-07
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Expires: 2008-09-21
Abstract
Abstract A magnetic recording medium is described, comprising a nonmagnetic support having thereon a single magnetic layer or plural magnetic layers containing ferromagnetic particles dispersed in a binder, wherein said ferromagnetic particles are ferromagnetic particles of the magnetic iron oxide type having an adsorption amount of stearic acid of from 3×10 -6 to 6×10 -6 mol/m 2 per a surface area thereof; said binder contains at least one polymer having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M, --OPO(OM') 2 , --COOM and --PO(OM') 2 , in which M represents Na, Li, K, a hydrogen atom, NR 4 or NHR 3 , M' represents Na, Li, K, a hydrogen atom, NR 4 , NHR 3 or an alkyl group, and R 3 and R 4 represent a lower alkyl group; and said magnetic layer further contains at least one fatty acid.
Inventors
- 👤 Nobuo Yamazaki
- 👤 Hiroo Inaba
- 👤 Kouichi Masaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:53
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7023; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
143 words
A magnetic recording medium comprising a nonmagnetic support having thereon a single magnetic layer or plural magnetic layers containing ferromagnetic particles dispersed in a binder, wherein said ferromagnetic particles are ferromagnetic particles of magnetic iron oxide having an adsorption amount of stearic acid of from 3×10 -6 to 6×10 -6 mol/m 2 per a surface area thereof; said binder contains at least one polymer having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M, --COOM, --PO(OM') 2 and --OPO(OM') 2 in which M represents Na, Li, K, a hydrogen atom, NR 4 or NHR 3 , M' represents Na, Li, K, a hydrogen atom, NR 4 , NHR 3 or an alkyl group, and R 3 and R 4 represent a lower alkyl group; and said magnetic layer further contains at least one fatty acid.
Claim 2
Dependent Claim
143 words
A magnetic recording medium comprising a nonmagnetic support having thereon a single magnetic layer or plural magnetic layers containing ferromagnetic particles dispersed in a binder, wherein said ferromagnetic particles are ferromagnetic particles of magnetic iron oxide having an adsorption amount of stearic acid of from 3×10 -6 to 6×10 -6 mol/m 2 per a surface area thereof; said binder contains at least one polymer having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M, --COOM, --PO(OM') 2 and --OPO(OM') 2 in which M represents Na, Li, K, a hydrogen atom, NR 4 or NHR 3 , M' represents Na, Li, K, a hydrogen atom, NR 4 , NHR 3 or an alkyl group, and R 3 and R 4 represent a lower alkyl group; and said magnetic layer further contains at least one fatty acid.
Claim 3
Dependent Claim
21 words
The magnetic recording medium as claimed in claim 1, wherein said lower alkyl group has from 1 to 8 carbon atoms.
Claim 4
Dependent Claim
20 words
The magnetic recording medium as claimed in claim 1, wherein said fatty acid has from 8 to 22 carbon atoms.
Claim 5
Dependent Claim
30 words
The magnetic recording medium as claimed in claim 1, wherein the content of said fatty acid is from 0.01 to 10.0 wt% based on the weight of the ferromagnetic particles.
Claim 6
Dependent Claim
53 words
The magnetic recording medium as claimed in claim 1, wherein said polymer is a copolymer of vinyl chloride and vinyl acetate type, a copolymer of vinyl chloride and vinylidene chloride, acrylic resins, polyester resins, polyvinyl fluoride, polyamide resins, polyvinyl butyrate and a copolymer of styrene and butadiene, having at least one polar group.
Claim 7
Dependent Claim
27 words
The magnetic recording medium as claimed in claim 5, wherein said polymer is a copolymer of vinyl chloride and vinyl acetate having at least one polar group.
Claim 8
Dependent Claim
34 words
The magnetic recording medium as claimed in claim 1, wherein the polymer having at least one polar group contains the polar group in an amount of from 1 ×10 -6 to 1×10 -3 equivalent/g.
Claim 9
Dependent Claim
40 words
The magnetic recording medium as claimed in claim 1, wherein the polymer having at least one polar group is used in an amount of from 10 to 100 parts by weight per 100 parts by weight of the ferromagnetic particles.
Claim 10
Dependent Claim
25 words
The magnetic recording medium as claimed in claim 1, wherein said ferromagnetic particles have a specific surface area of 25 m 2 /g or higher.
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) | 1994-05-06 | 1994-11-05 | 1995-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-06 | 1998-11-05 | 1999-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-06 | 2002-11-05 | 2003-05-07 | $7700.00 | Window Closed / Lapsed |