US4289828A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium and process
Assignee: TDK Corp
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Filing: 1979-11-28
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Granted: 1981-09-15
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Expires: 1999-11-28
Abstract
Abstract A magnetic recording medium made by coating a base with a magnetic coating material which is a dispersion of magnetic particles in a binder of synthetic resins using a polyfunctional aromatic isocyanate as a curing agent, characterized by the addition of a sorbitan stearate type surface active agent which has a sorbitol derivative in the hydrophilic group. The present magnetic recording medium has superior mechanical properties, especially a superior running quality as well as superior electromagnetic properties.
Inventors
- 👤 Hiroshi Ota
- 👤 Eiji Horigome
- 👤 Hitoshi Azegami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/7013; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31565; Y10T428/31609; Y10T428/31786; Y10T428/31794; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
71 words
In a magnetic recording medium comprising a base coated with mixture containing magnetizable particles dispersed in a curable synthetic resin binder and a polyfunctional aromatic isocyanate curing agent which functions by chemical reaction with the binder resin to produce a crosslinked product, the improvement which comprises the addition to said mixture of up to 6% by weight based on the weight of said resin binder of a sorbitan stearate dispersing agent.
Claim 2
Dependent Claim
71 words
In a magnetic recording medium comprising a base coated with mixture containing magnetizable particles dispersed in a curable synthetic resin binder and a polyfunctional aromatic isocyanate curing agent which functions by chemical reaction with the binder resin to produce a crosslinked product, the improvement which comprises the addition to said mixture of up to 6% by weight based on the weight of said resin binder of a sorbitan stearate dispersing agent.
Claim 3
Dependent Claim
36 words
A magnetic recording medium according to claim 1 wherein said synthetic resin is selected from the group consisting of vinyl chloride-vinyl acetate copolymers, polyester resins, and polyurethane resins having groups reactive with said polyfunctional aromatic isocyanate.
Claim 4
Dependent Claim
87 words
In a process for manufacturing a magnetic recording medium which comprises preparing a liquid dispersion containing magnetic particles, a curable synthetic resin binder and a solvent, said curable resin binder containing groups reactive with a polyfunctional aromatic isocyanate to produce a cross-linked product, adding said polyfunctional aromatic isocyanate to said dispersion, coating a base with said dispersion and curing the same, the improvement which comprises the addition of up to 6% by weight based on the weight of the resin binder of a sorbitan stearate dispersing agent.
Claim 5
Dependent Claim
87 words
In a process for manufacturing a magnetic recording medium which comprises preparing a liquid dispersion containing magnetic particles, a curable synthetic resin binder and a solvent, said curable resin binder containing groups reactive with a polyfunctional aromatic isocyanate to produce a cross-linked product, adding said polyfunctional aromatic isocyanate to said dispersion, coating a base with said dispersion and curing the same, the improvement which comprises the addition of up to 6% by weight based on the weight of the resin binder of a sorbitan stearate dispersing agent.
Claim 6
Dependent Claim
34 words
A process according to claim 3 wherein said synthetic resin is selected from the group consisting of vinyl chloride-vinyl acetate copolymers, polyester resins, and polyurethane resins having groups reactive with said polyfunctional aromatic isocyanate.
References Cited (Backward Citations)
US3460984A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-14 | 1985-03-16 | 1985-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-14 | 1989-03-16 | 1989-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-14 | 1993-03-16 | 1993-09-15 | $7700.00 | Window Closed / Lapsed |