Patent US4313989A successfully refreshed from Google Patents.
US4313989A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Hitachi Ltd
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Filing: 1980-02-05
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Granted: 1982-02-02
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Expires: 2000-02-05
Abstract
Abstract A magnetic recording medium having a metamorphosed layer on the surface of the magnetic layer of conventional magnetic recording media, said metamorphosed layer being derived from some of a binder component included in the magnetic layer, can prevent the sticking trouble taking place between the magnetic recording medium and the magnetic head. Said metamorphosed layer can be formed by irradiation with ultraviolet rays in the course of the production of magnetic recording media at the step of coating a dispersion of magnetic particles on a flexible support or after the coating step. Said metamorphosed layer can also be formed on the surface of once produced magnetic recording media irrespective of having caused the sticking trouble by irradiation with ultraviolet rays. Suitable apparatuses for producing such improved magnetic recording media are also provided.
Inventors
- 👤 Yoshihisa Suzuki
- 👤 Takanoli Kaizuka
- 👤 Yoshiaki Hanyu
- 👤 Mituyoshi Otake
- 👤 Yoichi Hidano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:08
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/728; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31554
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
64 words
A magnetic recording medium comprising a support, a magnetic layer containing magnetic particles bonded by a polyurethane binder and being adhered to the support, and a metamorphosed layer, formed by irradiating the magnetic layer with ultraviolet rays, which is derived from some of said polyruethane binder and is formed on the surface of the magnetic layer, whereby stickness of said medium is substantially prevented.
Claim 2
Dependent Claim
64 words
A magnetic recording medium comprising a support, a magnetic layer containing magnetic particles bonded by a polyurethane binder and being adhered to the support, and a metamorphosed layer, formed by irradiating the magnetic layer with ultraviolet rays, which is derived from some of said polyruethane binder and is formed on the surface of the magnetic layer, whereby stickness of said medium is substantially prevented.
Claim 3
Dependent Claim
57 words
A magnetic recording medium according to claim 1, wherein said polyurethane binder is formed of a binding material having as a component thereof a substance which, absent said metamorphosed layer, oozes out of the magnetic layer and causes stickness of said medium, and wherein said metamorphosed layer prevents said substance from oozing out of the magnetic layer.
Claim 4
Dependent Claim
25 words
A magnetic recording medium according to claim 2, wherein said substance has a molecular weight of 10,000 to 100,000, converted to the styrene molecular weight.
Claim 5
Dependent Claim
19 words
A magnetic recording medium according to claim 1, consisting of said support, said magnetic layer and said metamorphosed layer.
Claim 6
Dependent Claim
28 words
A magnetic recording medium according to claim 1, wherein the polyurethane binder has a molecular weight of 10,000 to 100,000, molecular weight converted to the styrene molecular weight.
Claim 7
Dependent Claim
24 words
A magnetic recording medium according to claim 5, wherein said polyurethane binder comprises an ester polyurethane produced by reacting adipic acid, butanediol, and 4,4'-diphenylmethane-diisocyanate.
Claim 8
Dependent Claim
63 words
A magnetic recording medium according to claim 1 or 5, wherein layer contains a decreased amount of a polymer derived from said binder having a molecular weight of 10,000 to 100,000, converted to the styrene molecular weight, in comparison to the amount of said polymer in said magnetic layer, with the decrease being greater as the irradiation time with said ultraviolet rays increases.
Claim 9
Dependent Claim
27 words
A magnetic recording medium according to claim 1, 5 or 2, wherein the support is a tape, whereby the magnetic recording medium formed is a magnetic tape.
Claim 10
Dependent Claim
27 words
A magnetic recording medium according to claim 1, 5 or 2, wherein the support is a disk, whereby the magnetic recording medium formed is a magnetic disk.
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) | 1985-02-01 | 1985-08-03 | 1986-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-02-01 | 1989-08-03 | 1990-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-02-01 | 1993-08-03 | 1994-02-02 | $7700.00 | Window Closed / Lapsed |