Patent US4367261A successfully refreshed from Google Patents.
US4367261A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1981-01-12
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Granted: 1983-01-04
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Expires: 2001-01-12
Abstract
Abstract A magnetic recording medium having a magnetic layer and a backing layer on opposite sides of a support is disclosed. The backing layer comprises an inorganic filler dispersed in a binder wherein the binder comprises one or more cellulosic resins, one or more thermoplastic polyurethane elastomers and one or more polyisocyanates.
Inventors
- 👤 Takahito Miyoshi
- 👤 Toshimitu Okutu
- 👤 Masaaki Fujiyama
- 👤 Yasuyuki Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:25
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/7085; G11B5/73; G11B5/735; G11B5/7356; G11B5/7358; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/258; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31971
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
113 words
In a magnetic recording medium comprising a support having a magnetic layer and a backing layer on opposite sides of said support, the backing layer comprising an inorganic filler disbursed in a binder, the improvement wherein the binder consists essentially of one or more cellulosic resins, one or more thermoplastic polyurethane elastomers and one or more polyisocyanates, and wherein said backing layer has a thickness in the range of from about 0.5 to about 1.0 micron, and wherein the surface roughness of said backing layer is less than 0.024 microns expressed as center-line average roughness and the surface roughness of said magnetic layer is less than 0.02 microns expressed as center-line average roughness.
Claim 2
Dependent Claim
113 words
In a magnetic recording medium comprising a support having a magnetic layer and a backing layer on opposite sides of said support, the backing layer comprising an inorganic filler disbursed in a binder, the improvement wherein the binder consists essentially of one or more cellulosic resins, one or more thermoplastic polyurethane elastomers and one or more polyisocyanates, and wherein said backing layer has a thickness in the range of from about 0.5 to about 1.0 micron, and wherein the surface roughness of said backing layer is less than 0.024 microns expressed as center-line average roughness and the surface roughness of said magnetic layer is less than 0.02 microns expressed as center-line average roughness.
Claim 3
Dependent Claim
88 words
A magnetic recording medium according to claim 1 wherein the surface roughness of the magnetic layer is less than 0.02 micron expressed as center-line average roughness, the surface roughness of the backing layer is less than 0.024 micron expressed as center-line average roughness, the thickness of the backing layer is between 0.5 and 1 micron, the backing layer comprising calcium carbonate having an average particle size of 0.02 to 0.1 micron dispersed in the binder comprising nitrocellulose, one or more thermoplastic polyurethane elastomers and one or more polyisocyanate.
Claim 4
Dependent Claim
37 words
A magnetic recording medium according to claim 1 wherein the backing layer contains 2.5 to 20 parts by weight of an aliphatic acid of 18 to 22 carbon atoms per 100 parts by weight of the binder.
Claim 5
Dependent Claim
29 words
A magnetic recording medium according to claim 1 wherein the filler in the backing layer has an average particle size in the range of from 0.02 to 0.1 micron.
Claim 6
Dependent Claim
28 words
A magnetic recording medium according to claim 1 wherein the filler in the backing layer has a hardness between 2.5 and 3.5 on the Mohs' scale of hardness.
Claim 7
Dependent Claim
18 words
A magnetic recording medium according to claim 1 wherein the filler in the backing layer is calcium carbonate.
Claim 8
Dependent Claim
18 words
A magnetic recording medium according to claim 1 wherein the cellulosic resin contained in the binder is nitrocellulose.
References Cited (Backward Citations)
US4189514A
Cited
US4234438A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-03 | 1986-07-05 | 1987-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-03 | 1990-07-05 | 1991-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-03 | 1994-07-05 | 1995-01-04 | $7700.00 | Window Closed / Lapsed |