Patent US4952444A successfully refreshed from Google Patents.
US4952444A
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1988-03-18
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Granted: 1990-08-28
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Expires: 2008-03-18
Abstract
Abstract A magnetic recording medium comprising a non-magnetic support having provided thereon, in order: (a) a non-magnetic layer including at least one cellulose derivative, at least one polyurethane and at least one polyisocyanate where the concentration of the polyisocyanate is within a range of from 15 wt % to 45 wt %, and (b) a magnetic layer containing ferromagnetic particles, wherein the non-magnetic layer contains a lubricating agent and has a thickness of 1.0 mu m or more, a surface roughness (Ra) of 0.02 mu m or less, and a Young's modulus of 5x104 to 50x104 kg/cm2 at a temperature of from 5 DEG C. to 60 DEG C.
Inventors
- 👤 Toshio Kawamata
- 👤 Kazuhiko Morita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:05
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
107 words
A magnetic recording medium comprising a non-magnetic support having provided thereon in order: (a) a non-magnetic layer including at least one cellulose derivative, at least one polyurethane and at least one polyisocyanate in which the concentration of said polyisocyanate is within a range from 15 wt % to 45 wt %, and (b) a magnetic layer containing ferromagnetic particles. wherein said non-magnetic layer contains a lubricating agent and has a thickness of 1.0 μm or more, a surface roughness Ra of 0.02 μm or less, and a Young's modulus of 5×10 4 to 50×10 4 kg/cm 2 at a temperature of from 5° C. to 60° C.
Claim 2
Dependent Claim
107 words
A magnetic recording medium comprising a non-magnetic support having provided thereon in order: (a) a non-magnetic layer including at least one cellulose derivative, at least one polyurethane and at least one polyisocyanate in which the concentration of said polyisocyanate is within a range from 15 wt % to 45 wt %, and (b) a magnetic layer containing ferromagnetic particles. wherein said non-magnetic layer contains a lubricating agent and has a thickness of 1.0 μm or more, a surface roughness Ra of 0.02 μm or less, and a Young's modulus of 5×10 4 to 50×10 4 kg/cm 2 at a temperature of from 5° C. to 60° C.
Claim 3
Dependent Claim
19 words
The magnetic recording medium of claim 1, wherein said magnetic layer has a thickness of less than 1 μm.
Claim 4
Dependent Claim
13 words
The magnetic recording medium of claim 1, wherein said cellulose derivative is nitrocellulose.
Claim 5
Dependent Claim
17 words
The magnetic recording medium of claim 1, wherein said lubricating agent is at least one fatty acid.
Claim 6
Dependent Claim
22 words
The magnetic recording medium of claim 1, wherein said lubricating agent is an ester of an aliphatic alcohol or a fatty acid.
Claim 7
Dependent Claim
15 words
The magnetic recording medium of claim 1, wherein said non-magnetic layer contains an abrasive agent.
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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) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |