US4786551A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Kao Corp
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Filing: 1987-11-05
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Granted: 1988-11-22
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Expires: 2007-11-05
Abstract
Abstract Disclosed is a magnetic recording medium having a magnetic layer composed mainly of a magnetic powder and a resin binder, wherein the magnetic layer comprises (a) an ester compound comprising (a-1) an ester compound represented by the following formula (1): ##STR1## wherein R stands for a branched alkyl group having 13 carbon atoms, (a-2) butyl stearate and (a-3) butoxyethyl stearate, and (b) carbon black comprising (b-1) carbon black having an average single particle size of 10 to 50 mμ and (b-2) carbon black having an average single particle size of 200 to 1,000 mμ. This magnetic recording medium has an excellent durability and is utilized as a floppy disk or the like.
Inventors
- 👤 Tsuyoshi Ootani
- 👤 Junsaku Nakajima
- 👤 Chiaki Abe
- 👤 Ikuko Wada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 03:47
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/702; G11B5/7023; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/30; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
168 words
A magnetic recording medium having a magnetic layer composed mainly of a magnetic powder and a resin binder, wherein said magnetic layer comprises (a) an ester compound comprising (a-1) a compound represented by the following formula (1): ##STR3## wherein R stands for a branched alkyl group having 13 carbon atoms which may be partially substituted with an unbranched alkyl group having 13 carbon atoms, (a-2) butyl stearate and (a-3) butoxyethyl stearate, wherein the amounts of a-1, a-2 and a-3 are 20 to 80 parts by weight, 10 to 40 parts by weight, and 20 to 80 parts by weight, respectively per 100 parts by weight of the sum of a-1, a-2 and a-3; and (b) carbon black comprising (b-1) carbon black having an average single particle size of 10 to 50mμ and (b-2) carbon black having an average single particle size of 200 to 1,000mμ; and wherein said ester compound is in an amount of 1 to 15% by weight based on the weight of said magnetic powder
Claim 2
Dependent Claim
168 words
A magnetic recording medium having a magnetic layer composed mainly of a magnetic powder and a resin binder, wherein said magnetic layer comprises (a) an ester compound comprising (a-1) a compound represented by the following formula (1): ##STR3## wherein R stands for a branched alkyl group having 13 carbon atoms which may be partially substituted with an unbranched alkyl group having 13 carbon atoms, (a-2) butyl stearate and (a-3) butoxyethyl stearate, wherein the amounts of a-1, a-2 and a-3 are 20 to 80 parts by weight, 10 to 40 parts by weight, and 20 to 80 parts by weight, respectively per 100 parts by weight of the sum of a-1, a-2 and a-3; and (b) carbon black comprising (b-1) carbon black having an average single particle size of 10 to 50mμ and (b-2) carbon black having an average single particle size of 200 to 1,000mμ; and wherein said ester compound is in an amount of 1 to 15% by weight based on the weight of said magnetic powder
Claim 3
Dependent Claim
24 words
The magnetic recording medium as set forth in claim 1 wherein said branched alkyl group is at least 60% by weight of compound a-1.
Claim 4
Dependent Claim
26 words
The magnetic recording medium as set forth in claim 1, wherein the amount of carbon black (b-2) is larger than that of the carbon black (b-1).
Claim 5
Dependent Claim
32 words
The magnetic recording medium as set forth in claim 1, wherein the total amount of said carbon blacks (b-1) and (b-2) is 8 to 25% by weight based on the magnetic powder.
Claim 6
Dependent Claim
24 words
The magnetic recording medium as set forth in claim 2 wherein said branched alkyl group is at least 90% by weight of compound a-1.
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) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |