US4571364A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1984-09-10
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Granted: 1986-02-18
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Expires: 2004-09-10
Abstract
Abstract A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a magnetic layer comprising ferromagnetic particles dispersed in a binder, said ferromagnetic particles having a BET specific surface area of 25 m 2 /g or more, said binder comprising a modified polyurethane resin containing 0.1 meq/g or more of functional groups selected from carboxyl groups, hydroxyl groups, sulfonic acid groups, and epoxy groups, and containing at least three functional groups per molecule of the resin.
Inventors
- 👤 Akira Kasuga
- 👤 Akihiro Matsufuji
- 👤 Yasuyuki Yamada
- 👤 Nobuo Tsuji
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/714; G11B5/702; G11B5/7021; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
76 words
A magnetic recording medium comprising a nonmagnetic support having provided thereon a magnetic layer comprising ferromagnetic particles dispersed in a binder, said ferromagnetic particles having a BET specific surface area of 25 m 2 /g or more, said binder comprising a modified polyurethane resin containing 0.1 meq/g or more of functional groups selected from carboxyl groups, hydroxyl groups, sulfonic acid groups, and epoxy groups, and containing at least three functional groups per molecule of the resin.
Claim 2
Dependent Claim
76 words
A magnetic recording medium comprising a nonmagnetic support having provided thereon a magnetic layer comprising ferromagnetic particles dispersed in a binder, said ferromagnetic particles having a BET specific surface area of 25 m 2 /g or more, said binder comprising a modified polyurethane resin containing 0.1 meq/g or more of functional groups selected from carboxyl groups, hydroxyl groups, sulfonic acid groups, and epoxy groups, and containing at least three functional groups per molecule of the resin.
Claim 3
Dependent Claim
68 words
A magnetic recording medium as in claim 1, wherein the ferromagnetic particles are selected from magnetic particles of oxide selected from the group consisting of γ-Fe 2 O 3 , Co-γ-Fe 2 O 3 , Fe 3 O 4 and CrO 2 , and magnetic fine metal particles selected from the group consisting of Fe, Co, and Ni, and alloy particles containing one or more of said metals.
Claim 4
Dependent Claim
34 words
A magnetic recording medium as in claim 1, wherein the modified polyurethane resin has five or more functional groups per molecule of the resin and has a molecular weight of from 5,000 to 100,000.
Claim 5
Dependent Claim
34 words
A magnetic recording medium as in claim 2, wherein the modified polyurethane resin has five or more functional groups per molecule of the resin and has a molecular weight of from 5,000 to 100,000.
Claim 6
Dependent Claim
18 words
A magnetic recording medium as in claim 3, wherein the average molecular weight is from 8,000 to 60,000.
Claim 7
Dependent Claim
18 words
A magnetic recording medium as in claim 4, wherein the average molecular weight is from 8,000 to 60,000.
Claim 8
Dependent Claim
22 words
A magnetic recording medium as in claim 1, wherein the modified polyurethane resin is an epoxy modified polyurethane resin containing hydroxyl groups.
Claim 9
Dependent Claim
22 words
A magnetic recording medium as in claim 3, wherein the modified polyurethane resin is an epoxy modified polyurethane resin containing hydroxyl groups.
Claim 10
Dependent Claim
22 words
A magnetic recording medium as in claim 4, wherein the modified polyurethane resin is an epoxy modified polyurethane resin containing hydroxyl groups.
Claim 11
Dependent Claim
20 words
A magnetic recording medium as in claim 1, wherein the modified polyurethane resin is a polyurethane resin containing carboxyl groups.
Claim 12
Dependent Claim
20 words
A magnetic recording medium as in claim 3, wherein the modified polyurethane resin is a polyurethane resin containing carboxyl groups.
Claim 13
Dependent Claim
20 words
A magnetic recording medium as in claim 4, wherein the modified polyurethane resin is a polyurethane resin containing carboxyl groups.
Claim 14
Dependent Claim
44 words
A magnetic recording medium as in claim 1, wherein the binder is used in an amount of from 8 to 25 parts by weight per 100 parts by weight of ferromagnetic particles and the thickness of the magnetic layer is from 0.5 to 6μ.
Claim 15
Dependent Claim
44 words
A magnetic recording medium as in claim 2, wherein the binder is used in an amount of from 8 to 25 parts by weight per 100 parts by weight of ferromagnetic particles and the thickness of the magnetic layer is from 0.5 to 6μ.
Claim 16
Dependent Claim
44 words
A magnetic recording medium as in claim 3, wherein the binder is used in an amount of from 8 to 25 parts by weight per 100 parts by weight of ferromagnetic particles and the thickness of the magnetic layer is from 0.5 to 6μ.
Claim 17
Dependent Claim
44 words
A magnetic recording medium as in claim 4, wherein the binder is used in an amount of from 8 to 25 parts by weight per 100 parts by weight of ferromagnetic particles and the thickness of the magnetic layer is from 0.5 to 6μ.
Claim 18
Dependent Claim
44 words
A magnetic recording medium as in claim 7, wherein the binder is used in an amount of from 8 to 25 parts by weight per 100 parts by weight of ferromagnetic particles and the thickness of the magnetic layer is from 0.5 to 6μ.
Claim 19
Dependent Claim
44 words
A magnetic recording medium as in claim 10, wherein the binder is used in an amount of from 8 to 25 parts by weight per 100 parts by weight of ferromagnetic particles and the thickness of the magnetic layer is from 0.5 to 6μ.
Claim 20
Dependent Claim
22 words
A magnetic recording medium as in claim l, wherein the binder contains 10 to 60% by weight of the modified polyurethane resin.
Claim 21
Dependent Claim
19 words
A magnetic recording medium as in claim 1, wherein the binder further comprises a vinyl chloride-vinyl acetate type copolymer.
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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) | 1989-02-17 | 1989-08-19 | 1990-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-17 | 1993-08-19 | 1994-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-17 | 1997-08-19 | 1998-02-18 | $7700.00 | Window Closed / Lapsed |