US4340644A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1979-11-19
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Granted: 1982-07-20
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Expires: 1999-11-19
Abstract
Abstract A magnetic recording medium consisting of a base coated with magnetic coating material which is a dispersion of magnetic particles using a vinyl chloride-vinyl acetate copolymer and a polyester resin as binder, characterized by the addition of a vinyl chloride-vinyl acetate copolymer containing at least 10% of vinyl alcohol. The use of the last-mentioned copolymer improves the frequency response characteristic as well as the mechanical properties such as the running quality.
Inventors
- 👤 Hiroshi Ota
- 👤 Eiji Horigome
- 👤 Hitoshi Azegami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:21
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7028; C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/4009; C08G18/4063; C08G18/62; C08G18/6212; C09; C09D; C09D127/00; C09D127/02; C09D127/04; C09D127/06; C09D131/00; C09D131/02; C09D131/04; G11B5/7023; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31565; Y10T428/31609; Y10T428/31786; Y10T428/31797; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
90 words
A magnetic recording medium of improved frequency response and running quality comprising a base coated with a magnetic coating material which is a dispersion of magnetic particles in a three resin component binder containing a vinyl chloride-vinyl acetate copolymer resin, a polyester resin together with an amount which is effective to achieve such improvements of up to 50% by weight based on the total weight of the binder of a vinyl alcohol-vinyl chloride-vinyl acetate copolymer resin containing at least 10% vinyl alcohol monomer, and a polyfunctional aromatic isocyanate curing agent.
Claim 2
Dependent Claim
90 words
A magnetic recording medium of improved frequency response and running quality comprising a base coated with a magnetic coating material which is a dispersion of magnetic particles in a three resin component binder containing a vinyl chloride-vinyl acetate copolymer resin, a polyester resin together with an amount which is effective to achieve such improvements of up to 50% by weight based on the total weight of the binder of a vinyl alcohol-vinyl chloride-vinyl acetate copolymer resin containing at least 10% vinyl alcohol monomer, and a polyfunctional aromatic isocyanate curing agent.
Claim 3
Dependent Claim
35 words
A magnetic recording medium according to claim 1, in which the proportion of said vinyl chloride-vinyl acetate copolymer containing vinyl alcohol is about 40% or less by weight of the total weight of said binder.
Claim 4
Dependent Claim
21 words
A magnetic recording medium according to claim 1 or 3 in which said base is in the form of a tape.
Claim 5
Dependent Claim
18 words
A magnetic recording medium according to claim 3, in which the tape is formed of a polyester film.
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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) | 1985-07-19 | 1986-01-18 | 1986-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-19 | 1990-01-18 | 1990-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-19 | 1994-01-18 | 1994-07-20 | $7700.00 | Window Closed / Lapsed |