US4444838A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-06-10
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Granted: 1984-04-24
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Expires: 2002-06-10
Abstract
Abstract A magnetic recording medium which comprises on a support base having coated thereon a magnetic layer containing a binder and a ferromagnetic fine powder dispersed in the binder is disclosed. The binder is comprised of a cellulose derivative having a residual OH group in a proportion of 7.5 to 40%, a diolefin or olefin series synthetic rubber and a polyisocyanate compound. The medium has excellent video sensitivity and video signal to noise ratio. The medium of the invention also have improved abrasion resistance.
Inventors
- 👤 Yasuyuki Yamada
- 👤 Goro Akashi
- 👤 Nobuo Tsuji
- 👤 Yoshito Mukaida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:17
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/64; C08G18/6484; 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; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31826; Y10T428/31855; Y10T428/31931
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
83 words
A magnetic recording medium comprising: a support base; and a magnetic layer positioned on the support base, the magnetic layer comprising: ferromagnetic fine powder; and a binder in which the fine powder is dispersed, wherein the binder comprises (a) a cellulose derivative having residual OH groups in a proportion of 7.5 to 40% and a mean polymerization degree of 50-800, (b) a diolefin or olefin series synthetic rubber capable of exerting a plasticizing effect on the cellulose derivative and (c) a polyisocyanate compound.
Claim 2
Dependent Claim
83 words
A magnetic recording medium comprising: a support base; and a magnetic layer positioned on the support base, the magnetic layer comprising: ferromagnetic fine powder; and a binder in which the fine powder is dispersed, wherein the binder comprises (a) a cellulose derivative having residual OH groups in a proportion of 7.5 to 40% and a mean polymerization degree of 50-800, (b) a diolefin or olefin series synthetic rubber capable of exerting a plasticizing effect on the cellulose derivative and (c) a polyisocyanate compound.
Claim 3
Dependent Claim
30 words
A magnetic recording medium as claimed in claim 1, wherein the cellulose derivative is selected from the group of cellulose derivatives consisting of nitrocellulose, cellulose acetate butyrate, and cellulose propionate.
Claim 4
Dependent Claim
15 words
A magnetic recording medium as claimed in claim 1, wherein the cellulose derivative is nitrocellulose.
Claim 5
Dependent Claim
23 words
A magnetic recording medium as claimed in claim 1, wherein the cellulose derivative has a mean polymerization degree of from 80 to 500.
Claim 6
Dependent Claim
52 words
A magnetic recording medium as claimed in claim 1, wherein the diolefin or olefin series synthetic rubber is selected from the group consisting of butadiene rubbers, synthetic isoprene rubbers, chloroprene rubbers, acrylate-butadiene rubbers, isobutene-isoprene rubbers, nitrile-butadiene rubbers, nitrile-chloroprene rubbers, pyridine-chloroprene rubbers, styrene-butadiene rubbers, styrene-chloroprene rubbers, styrene-isoprene rubbers, ethylene-propylene rubbers and ethylene-1-butene rubbers.
Claim 7
Dependent Claim
45 words
A magnetic recording medium as claimed in claim 1, wherein the diolefin or olefin series synthetic rubber further contains a polar group-containing vinyl compound in an amount of 0.1 to 10% by weight based on the weight of the diolefin or olefin series synthetic rubber.
Claim 8
Dependent Claim
26 words
A magnetic recording medium as claimed in claim 6, wherein the polar group-containing vinyl compound is present in an amount of 1 to 5% by weight.
Claim 9
Dependent Claim
33 words
A magnetic recording medium as claimed in claim 1, wherein the cellulose derivative and synthetic rubber are present in a mixing ratio of cellulose derivative to synthetic rubber of from 50/50 to 99/1.
Claim 10
Dependent Claim
21 words
A magnetic recording medium as claimed in claim 8, wherein the cellulose derivative/synthetic rubber mixing ratio is from 70/30 to 95/5.
Claim 11
Dependent Claim
42 words
A magnetic recording medium as claimed in claim 1, wherein the polyisocyanate compound is present in an amount of from 5 to 60 parts by weight per 100 parts by weight of the combination of the cellulose derivative and synthetic rubber components.
Claim 12
Dependent Claim
33 words
A magnetic recording medium as claimed in claim 1, wherein the binder is present in an amount of 8 to 100 parts by weight per 100 parts by weight of the ferromagnetic powder.
Claim 13
Dependent Claim
33 words
A magnetic recording medium as claimed in claim 11, wherein the binder is present in an amount of 10 to 80 parts by weight per 100 parts by weight of the ferromagnetic powder.
Claim 14
Dependent Claim
33 words
A magnetic recording medium as claimed in claim 12, wherein the binder is present in an amount of 13 to 50 parts by weight per 100 parts by weight of the ferromagnetic powder.
Claim 15
Dependent Claim
23 words
A magnetic recording medium as claimed in claim 1, wherein the magnetic layer has a thickness of from 1 μm to 18 μm.
Claim 16
Dependent Claim
23 words
A magnetic recording medium as claimed in claim 14, wherein the magnetic recording medium has a thickness of about 30 μm or less.
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) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-24 | 1991-10-24 | 1992-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-24 | 1995-10-24 | 1996-04-24 | $7700.00 | Window Closed / Lapsed |