US4857388A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1987-10-20
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Granted: 1989-08-15
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Expires: 2007-10-20
Abstract
Abstract A magnetic recording medium comprises a nonmagnetic support and a magnetic recording layer provided on the support which comprises two layers including a first magnetic recording layer and a second magnetic recording layer. Each of the two magnetic recording layers contains a ferromagnetic powder having a coercive force of not less than 500 Oe dispersed therein. The first magnetic recording layer is provided on the support has a Young's modulus of 500 to 1,000 kg/mm 2 ; and the second magnetic recording layer provided on the first magnetic recording layer has a Young's modulus of not less than 1,300 kg/mm 2 ; and the magnetic recording layers as a whole show a Young's modulus of not less than 900 kg/mm 2 .
Inventors
- 👤 Hiroshi Ogawa
- 👤 Yasuo Tamai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:31
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/716; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
139 words
A magnetic recording tape comprising a nonmagnetic support and a magnetic recording layer provided on the support which comprises two layers including a first magnetic recording layer and a second magnetic recording layer, each of said first and second magnetic recording layers comprising a binder and a ferromagnetic powder having a coercive force of not less than 500 Oe dispersed therein, wherein: said first magnetic recording layer provided on the nonmagnetic support has a Young's modulus in the longitudinal direction of 500 to 1,000 kg/mm 2 ; said second magnetic recording layer provided on the first magnetic recording layer has a Young's modulus in the longitudinal direction of not less than 1,300 kg/mm 2 ; and the magnetic recording layers as a whole show a Young's modulus in the longitudinal direction of not less than 900 kg/mm 2 .
Claim 2
Dependent Claim
139 words
A magnetic recording tape comprising a nonmagnetic support and a magnetic recording layer provided on the support which comprises two layers including a first magnetic recording layer and a second magnetic recording layer, each of said first and second magnetic recording layers comprising a binder and a ferromagnetic powder having a coercive force of not less than 500 Oe dispersed therein, wherein: said first magnetic recording layer provided on the nonmagnetic support has a Young's modulus in the longitudinal direction of 500 to 1,000 kg/mm 2 ; said second magnetic recording layer provided on the first magnetic recording layer has a Young's modulus in the longitudinal direction of not less than 1,300 kg/mm 2 ; and the magnetic recording layers as a whole show a Young's modulus in the longitudinal direction of not less than 900 kg/mm 2 .
Claim 3
Dependent Claim
32 words
The magnetic recording tape as claimed in claim 1, wherein said each of the binders of the first and second magnetic recording layers contains a vinyl chloride copolymer and a polyurethane resin.
Claim 4
Dependent Claim
34 words
The magnetic recording tape as claimed in claim 1, wherein the total thickness of the first magnetic recording layer and the second magnetic recording layer is in the range of 2 to 10 μm.
Claim 5
Dependent Claim
43 words
The magnetic recording tape as claimed in claim 1, wherein the thickness of the second magnetic recording layer is not larger than 2 μm, and the thickness of the first magnetic recording layer is larger than that of the second magnetic recording layer.
Claim 6
Dependent Claim
31 words
The magnetic recording tape as claimed in claim 1, wherein the binder of the first magnetic recording layer contains a polyurethane resin in an amount of not less than 60 wt.%.
Claim 7
Dependent Claim
42 words
The magnetic recording tape as claimed in claim 1, wherein the binder of the first magnetic recording layer contains a vinyl chloride copolymer and a polyurethane resin, the amount of the polyurethane being not less than 60 wt.% of the total binder.
Claim 8
Dependent Claim
25 words
The magnetic recording tape as claimed in claim 1, wherein the ferromagnetic powder of the first and second magnetic recording layers are Co-containing γ-magnetic powder.
References Cited (Backward Citations)
US4246316A
Cited
US4187341A
Cited
US4318957A
Cited
US4316927A
Cited
US4410590A
Cited
US4624883A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-14 | 1993-02-13 | 1993-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-14 | 1997-02-13 | 1997-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-14 | 2001-02-13 | 2001-08-15 | $7700.00 | Window Closed / Lapsed |