US4784907A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1986-12-22
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Granted: 1988-11-15
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Expires: 2006-12-22
Abstract
Abstract In a magnetic recording medium such as a video tape comprising a nonmagnetic support and a magnetic recording layer provided on the support, said magnetic recording layer comprising a binder and a ferromagnetic powder dispersed therein, the improvement in which: the magnetic recording layer comprises a fatty acid ester lubricant and a lubricant other than the fatty acid ester lubricant; the binder is composed of a resin component comprising a resin containing a repeating unit which has a polar group and having a glass transition point of not lower than 50° C., and a resin containing a repeating unit which has a polar group and having a glass transition point of lower than 50° C; and at least one resin of the resins contains a repeating unit having a polar group such as --SO 3 M, --OSO 3 M or --PO(OM') 2 , wherein M is hydrogen or an alkali metal atom, and M' is hydrogen, an alkali metal atom or a lower hydrocarbon group.
Inventors
- 👤 Akihiro Matsufuji
- 👤 Akira Kasuga
- 👤 Shigeo Komine
- 👤 Yasuyuki Yamada
- 👤 Hajime Miyatsuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:01
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/71; G11B5/702; G11B5/7023; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
192 words
A magnetic recording medium comprising a non-magnetic support and a magnetic recording layer provided on the support, said magnetic recording layer comprising a binder and a ferromagnetic powder dispersed therein, which is characterized in that: said magnetic recording layer comprises a fatty acid ester lubricant and a lubricant other than the fatty acid ester lubricant; said binder is composed of a resin component comprising a vinyl chloride copolymer resin containing a repeating unit which has a polar group and having a glass transition point of not lower than 50° C. and a polyurethane resin containing a repeating unit which has a polar group and having a glass transition point of lower than 50° C., a ratio by weight of said vinyl chloride copolymer resin to said polyurethane resin being in the range of 70/30 to 30/70; and at least one resin of said resins contains a repeating unit having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M and --PO(OM') 2 , wherein M is hydrogen or an alkali metal atom, and M' is hydrogen, an alkali metal atom or a lower hydrocarbon group.
Claim 2
Dependent Claim
192 words
A magnetic recording medium comprising a non-magnetic support and a magnetic recording layer provided on the support, said magnetic recording layer comprising a binder and a ferromagnetic powder dispersed therein, which is characterized in that: said magnetic recording layer comprises a fatty acid ester lubricant and a lubricant other than the fatty acid ester lubricant; said binder is composed of a resin component comprising a vinyl chloride copolymer resin containing a repeating unit which has a polar group and having a glass transition point of not lower than 50° C. and a polyurethane resin containing a repeating unit which has a polar group and having a glass transition point of lower than 50° C., a ratio by weight of said vinyl chloride copolymer resin to said polyurethane resin being in the range of 70/30 to 30/70; and at least one resin of said resins contains a repeating unit having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M and --PO(OM') 2 , wherein M is hydrogen or an alkali metal atom, and M' is hydrogen, an alkali metal atom or a lower hydrocarbon group.
Claim 3
Dependent Claim
31 words
The magnetic recording medium as claimed in claim 1, wherein said ferromagnetic powder is a ferromagnetic metal powder having a specific surface area of not less than 45 m 2 /g.
Claim 4
Dependent Claim
31 words
The magnetic recording medium as claimed in claim 1, wherein said vinyl chloride copolymer contains a repeating unit having --SO 3 Na in an amount ranging from 0.01 to 5 mol%.
Claim 5
Dependent Claim
30 words
The magnetic recording medium as claimed in claim 1, wherein said polyurethane resin contains a repeating unit having --SO 3 Na in an amount ranging from 0.01 to 5 mol%.
Claim 6
Dependent Claim
34 words
The magnetic recording medium as claimed in claim 1, wherein said fatty acid ester lubricant is an ester of a fatty acid having 12-22 carbon atoms and a fatty alcohol having 2-18 carbon atoms.
Claim 7
Dependent Claim
44 words
The magnetic recording medium as claimed in claim 1, wherein said lubricant other than the fatty acid ester lubricant is at least one lubricant selected from the group consisting of a fatty acid lubricant, a silicone lubricant and a fatty acid modified silicone lubricant.
Claim 8
Dependent Claim
84 words
The magnetic recording medium as claimed in claim 1, wherein a total amount of the fatty acid ester lubricant and the lubricant other than the fatty acid ester lubricant in the magnetic recording layer is in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the ferromagnetic powder, and the ratio between the fatty acid ester lubricant and the lubricant other than the fatty acid ester lubricant is in the range of 1:9 to 9:1, by weight.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-15 | 1992-05-16 | 1992-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-15 | 1996-05-16 | 1996-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-15 | 2000-05-16 | 2000-11-15 | $7700.00 | Window Closed / Lapsed |