US4241139A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
•
Filing: 1979-04-05
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Granted: 1980-12-23
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Expires: 1999-04-05
Abstract
Abstract A magnetic recording medium which has a protective layer on a magnetic recording layer coated on a substrate and said protective layer comprises polyurethane and nitrocellulose in which isopropyl alcohol originally present has been replaced by a resin selected from the group consisting of polyurethane resins, polybutadiene resins, butadiene-acrylonitrile copolymers, vinyl chloride-vinyl acetate-vinyl alcohol copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinylidene chloride copolymers, vinylidene chloride-acrylonitrile-copolymers, vinyl acetate resins, epoxy resins, phenoxy resins, polyvinylbutyral resins, polyvinyl formal resins and polyester resins.
Inventors
- 👤 Yuichi Kubota
- 👤 Tsunayoshi Saito
- 👤 Yoshiaki Makino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31511; Y10T428/31551; Y10T428/31554; Y10T428/31565; Y10T428/31609; Y10T428/31786; Y10T428/31855; Y10T428/31859; Y10T428/31877; Y10T428/31931; Y10T428/31935
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
87 words
A magnetic recording medium which comprises a protective layer coated on a magnetic recording layer which is coated on a substrate and said protective layer comprises polyurethane and nitrocellulose in which isopropyl alcohol originally present in the nitrocellulose has been replaced by a resin selected from the group consisting of polyurethane resins, polybutadiene resins, butadiene-acrylonitrile copolymers, vinyl chloride-vinyl acetate-vinyl alcohol copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinylidene chloride copolymers, vinylidene chloride-acrylonitrile copolymers, vinyl acetate resins, epoxy resins, phenoxy resins, polyvinylbutyral resins, polyvinyl formal resins and polyester resins.
Claim 2
Dependent Claim
87 words
A magnetic recording medium which comprises a protective layer coated on a magnetic recording layer which is coated on a substrate and said protective layer comprises polyurethane and nitrocellulose in which isopropyl alcohol originally present in the nitrocellulose has been replaced by a resin selected from the group consisting of polyurethane resins, polybutadiene resins, butadiene-acrylonitrile copolymers, vinyl chloride-vinyl acetate-vinyl alcohol copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinylidene chloride copolymers, vinylidene chloride-acrylonitrile copolymers, vinyl acetate resins, epoxy resins, phenoxy resins, polyvinylbutyral resins, polyvinyl formal resins and polyester resins.
Claim 3
Dependent Claim
34 words
A magnetic recording medium according to claim 1 wherein a crosslinking agent is incorporated in the protective layer or is coated on the magnetic layer or the protective layer before a final heat treatment.
Claim 4
Dependent Claim
33 words
A magnetic recording medium according to claim 2 wherein the crosslinking agent is a trifunctional isocyanate compound, a polyurethane having terminal isocyanate groups, a butylated melamine resin, a butylated urea resin or benzoguanamine.
Claim 5
Dependent Claim
33 words
A magnetic recording medium according to claim 2 wherein the crosslinking agent is incorporated at a ratio of 0.5 to 40 wt.% based on a total of the modified nitrocellulose and the polyurethane.
Claim 6
Dependent Claim
48 words
A magnetic recording medium according to claim 1 wherein isopropyl alcohol in the nitrocellulose is replaced by a vinyl chloride-vinyl acetate-vinyl alcohol copolymer or a polyurethane and the modified nitrocellulose and a polyurethane are dissolved in a solvent to form a lacquer for production of the protective layer.
References Cited (Backward Citations)
US3466156A
Cited
US4075384A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |