US4400435A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
•
Filing: 1981-07-15
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Granted: 1983-08-23
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Expires: 2001-07-15
Abstract
Abstract A magnetic recording medium comprises a substrate coated with a magnetic layer comprising a magnetic powder and a binder comprising an urethane resin and a vinyl chloride-vinyl acetate-maleic acid copolymer having a content of maleic acid component of at least 1.5%.
Inventors
- 👤 Kuniichi Yoda
- 👤 Takehisa Ohkawa
- 👤 Hitoshi Azegami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:23
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; G11B5/7022; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31609
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
42 words
A magnetic recording medium which comprises a substrate coated with a magnetic layer comprising a magnetic powder and a binder comprising an urethane resin and a vinyl chloride-vinyl acetate-maleic acid copolymer having a content of maleic acid component of at least 1.5%.
Claim 2
Dependent Claim
42 words
A magnetic recording medium which comprises a substrate coated with a magnetic layer comprising a magnetic powder and a binder comprising an urethane resin and a vinyl chloride-vinyl acetate-maleic acid copolymer having a content of maleic acid component of at least 1.5%.
Claim 3
Dependent Claim
16 words
The magnetic recording medium according to claim 1 wherein said urethane resin is an urethane elastomer.
Claim 4
Dependent Claim
16 words
The magnetic recording medium according to claim 1 wherein said urethane resin is an urethane prepolymer.
Claim 5
Dependent Claim
18 words
The magnetic recording medium according to claim 1, 2 or 3 wherein said binder further comprises a polyisocyanate.
Claim 6
Dependent Claim
38 words
The magnetic recording medium according to claim 1 wherein said vinyl chloride-vinyl acetate-maleic acid copolymer comprises 20 to 95% of vinyl chloride component; 80 to 5% of vinyl acetate component; and 1.5 to 5.0% of maleic acid coponent.
Claim 7
Dependent Claim
29 words
The magnetic recording medium according to claim 1 wherein said vinyl chloride-vinyl acetate-maleic acid copolymer is incorporated at a ratio of 20 to 90 wt.% based on said binder.
References Cited (Backward Citations)
JPS539841A
Cited
US4256852A
Cited
JPS555170A
Cited
JPS5573929A
Cited
JPS5584033A
Cited
US4352859A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-22 | 1987-02-21 | 1987-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-22 | 1991-02-21 | 1991-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-22 | 1995-02-21 | 1995-08-23 | $7700.00 | Window Closed / Lapsed |