US4404259A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1981-10-21
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Granted: 1983-09-13
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Expires: 2001-10-21
Abstract
Abstract A magnetic recording medium having a substrate coated with a magnetic layer comprises a magnetic powder and a binder, essentially consisting of 40 to 80 wt. % of a polyester resin, 60 to 20 wt. % of a nitrocellulose impregnated with vinyl chloride-vinyl acetate copolymer as a protective component and a polyisocyanate.
Inventors
- 👤 Akihiko Hosaka
- 👤 Yukihiro Isobe
- 👤 Kiyotaka Okuyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:29
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; Y10T428/31565; Y10T428/31609; Y10T428/31786; Y10T428/3179; Y10T428/31794; Y10T428/31797
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
57 words
A magnetic recording medium, comprising: a magnetic layer comprising a magnetic powder and a binder coated on a substrate, said binder consisting essentially of 40-80 wt % of a polyester resin, 60-20 wt % of an isopropyl alcohol or dibutyl phthalate free-nitrocellulose containing vinyl chloride-vinyl acetate copolymer as a protective component for the nitrocellulose and a polyisocyanate.
Claim 2
Dependent Claim
57 words
A magnetic recording medium, comprising: a magnetic layer comprising a magnetic powder and a binder coated on a substrate, said binder consisting essentially of 40-80 wt % of a polyester resin, 60-20 wt % of an isopropyl alcohol or dibutyl phthalate free-nitrocellulose containing vinyl chloride-vinyl acetate copolymer as a protective component for the nitrocellulose and a polyisocyanate.
Claim 3
Dependent Claim
25 words
The magnetic recording medium of claim 1, wherein said binder contains from 5-20 wt % of said polyisocyanate based on the total amount of binder.
Claim 4
Dependent Claim
19 words
The magnetic recording medium of claim 1, wherein said magnetic recording medium is a magnetic recording tape or sheet.
Claim 5
Dependent Claim
36 words
The magnetic recording medium of claim 1, wherein said magnetic powder is γ-Fe 2 O 3 containing adsorbed cobalt, γ-Fe 2 O 3 , Fe 3 O 4 and Fe 3 O 4 containing adsorbed cobalt.
Claim 6
Dependent Claim
29 words
The magnetic recording medium of claim 1, wherein said magnetic layer further comprises a fatty acid, a silicone oil, an antistatic agent or a dispersing agent as optional additives.
Claim 7
Dependent Claim
27 words
The magnetic recording medium of claim 1, wherein said polyisocyanate is a polyurethane prepolymer formed by the reaction of a diisocyanate with a polyester or a polyether.
Claim 8
Dependent Claim
24 words
The magnetic recording medium of claim 6, wherein said polyurethane prepolymer has molecular weight with the range of 1×10 3 to 1×10 5 .
Claim 9
Dependent Claim
21 words
The magnetic recording medium of claim 7, wherein said prepolymer has a molecular weight of 1×10 4 to 1×10 5 .
Claim 10
Dependent Claim
20 words
The magnetic recording medium of claim 6, wherein said diisocyanate is diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, hexamethylene diisocyanate or tolylene diisocyanate.
Claim 11
Dependent Claim
23 words
The magnetic recording medium of claim 6, wherein said polyester is the reaction product of an aliphatic dicarboxylic acid and a polyhydric alcohol.
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) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |