US4448843A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
•
Filing: 1981-04-10
•
Granted: 1984-05-15
•
Expires: 2001-04-10
Abstract
Abstract A magnetic recording medium is described wherein a layer comprising mainly a polyurethane resin, vinylidene chloride copolymer, or a cellulose derivative is formed on the surface of a vapor-deposited ferromagnetic metal layer on a substrate.
Inventors
- 👤 Yasuyuki Yamada
- 👤 Ryuji Shirahata
- 👤 Akio Yanai
- 👤 Tatsuji Kitamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:40
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31551; Y10T428/31605; Y10T428/31678; Y10T428/31692; Y10T428/31699; Y10T428/31703
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
63 words
A magnetic recording medium comprising (a) a support, (b) a vapor-deposited ferromagnetic metal layer on said support(a), and (c) a protective layer comprising mainly one of (i) a polyurethane resin, (ii) a vinylidene chloride copolymer or (iii) a cellulose derivative on the surface of said vapor-deposited ferromagnetic metal layer (b), said protective layer having a thickness of from about 0.002 to 0.3 μm.
Claim 2
Dependent Claim
63 words
A magnetic recording medium comprising (a) a support, (b) a vapor-deposited ferromagnetic metal layer on said support(a), and (c) a protective layer comprising mainly one of (i) a polyurethane resin, (ii) a vinylidene chloride copolymer or (iii) a cellulose derivative on the surface of said vapor-deposited ferromagnetic metal layer (b), said protective layer having a thickness of from about 0.002 to 0.3 μm.
Claim 3
Dependent Claim
23 words
A magnetic recording medium as in claim 1, wherein the protective layer (c) has a thickness of from about 0.005 to 0.2 μm.
Claim 4
Dependent Claim
47 words
A magnetic recording medium as in claim 1, or 2, wherein the protective layer (c) comprises mainly a polyurethane, and from 0.2 to 30 wt% of a vinylidene chloride copolymer or cellulose derivative, based on the total weight of the protective layer, as an additional component thereof.
Claim 5
Dependent Claim
33 words
A magnetic recording medium as in claim 1, or 2 wherein the protective layer (c) comprises mainly a polyurethane resin having an average molecular weight in the range of from 5,000 to 500,000.
Claim 6
Dependent Claim
18 words
A magnetic recording medium as in claim 4, wherein the average molecular weight is from 10,000 to 200,000.
Claim 7
Dependent Claim
29 words
A magnetic recording medium as in claim 1, or 3, wherein the protective layer (c) comprises mainly a vinylidene chloride copolymer comprising from 98 to 60 wt% vinylidene chloride.
Claim 8
Dependent Claim
21 words
A magnetic recording medium as in claim 6, wherein the vinylidene chloride copolymer comprises from 95 to 70 wt% vinylidene chloride.
Claim 9
Dependent Claim
18 words
A magnetic recording medium as in claim 1, or 2, wherein the protective layer (c) contains a lubricant.
Claim 10
Dependent Claim
26 words
A magnetic recording medium as in claim 1, or 2, comprising a primer layer (d) between the ferromagnetic metal layer (b) and the protective layer (c).
References Cited (Backward Citations)
US4260466A
Cited
JPS5320204A
Cited
DE2915905A1
Cited
US4241139A
Cited
GB2053732A
Cited
US4309482A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-15 | 1987-11-14 | 1988-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-15 | 1991-11-14 | 1992-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-15 | 1995-11-14 | 1996-05-15 | $7700.00 | Window Closed / Lapsed |