US4411956A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-02-11
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Granted: 1983-10-25
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Expires: 2002-02-11
Abstract
Abstract A magnetic recording medium having a non-magnetic base overlaid with a magnetic layer containing ferromagnetic particles is disclosed. The ferromagnetic particles are metal particles and the binder is composed of (a) a nitrocellulose and (b) a polyurethane resin.
Inventors
- 👤 Akihiro Matsufuji
- 👤 Akira Kasuga
- 👤 Hajime Miyatsuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:12
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; Y10T428/31678; Y10T428/31971
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
80 words
A magnetic recording medium, comprising: a non-magnetic support base; and a magnetic layer overlaid on a surface of said non-magnetic support base, said magnetic layer comprising ferromagnetic particles and a binder, said ferromagnetic particles being metal particles and said binder consisting essentially of (a) a nitrocellulose and (b) a polyurethane resin, wherein said nitrocellulose is selected from the group consisting of SS type nitrocellulose with a nitrogen content of 10.7-11.5% and RS type nitrocellulose with a nitrogen content of 11.5-12.2%.
Claim 2
Dependent Claim
80 words
A magnetic recording medium, comprising: a non-magnetic support base; and a magnetic layer overlaid on a surface of said non-magnetic support base, said magnetic layer comprising ferromagnetic particles and a binder, said ferromagnetic particles being metal particles and said binder consisting essentially of (a) a nitrocellulose and (b) a polyurethane resin, wherein said nitrocellulose is selected from the group consisting of SS type nitrocellulose with a nitrogen content of 10.7-11.5% and RS type nitrocellulose with a nitrogen content of 11.5-12.2%.
Claim 3
Dependent Claim
22 words
A magnetic recording medium as claimed in claim 1, wherein said polyurethane resin has a molecular weight of from 10,000 to 200,000.
Claim 4
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 1, wherein the weight ratio of said nitrocellulose to said polyurethane resin is from 85:15 to 10:90.
Claim 5
Dependent Claim
24 words
A magnetic recording medium as claimed in claim 3, wherein said ratio of said nitrocellulose to said polyurethane resin is from 70:30 to 50:50.
Claim 6
Dependent Claim
18 words
A magnetic recording medium as claimed in claim 1, further comprising: a polyisocyanate compound as a curing agent.
Claim 7
Dependent Claim
36 words
A magnetic recording medium as claimed in claim 5, wherein the weight ratio of said polyisocyanate compound curing agent to the sum of said nitrocellulose and polyurethane resin is within the range of 60:40 to 0:100.
Claim 8
Dependent Claim
33 words
A magnetic recording medium as claimed in claim 6, wherein said ratio of said polyisocyanate compound to said sum of said nitrocellulose and polyurethane resin is within the range of 40:60 to 10:90.
Claim 9
Dependent Claim
29 words
A magnetic recording medium as claimed in claim 1, wherein the sum of said nitrocellulose and polyurethane resin is from 10 to 40 weight % of the ferromagnetic particles.
Claim 10
Dependent Claim
29 words
A magnetic recording medium as claimed in claim 8, wherein said sum of said nitrocellulose and polyurethane resin is from 20 to 30 weight % of said ferromagnetic particles.
Claim 11
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 5, wherein the sum of nitrocellulose, polyurethane and polyisocyanate is from 10 to 40 weight % of the ferromagnetic particles.
Claim 12
Dependent Claim
29 words
A magnetic recording medium as claimed in claim 10, wherein said sum of said nitrocellulose, polyurethane and polyisocyanate is from 20 to 30 weight % of the ferromagnetic particles.
References Cited (Backward Citations)
US4234438A
Cited
US4328282A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-24 | 1987-04-25 | 1987-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-24 | 1991-04-25 | 1991-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-24 | 1995-04-25 | 1995-10-25 | $7700.00 | Window Closed / Lapsed |