Patent US4659633A successfully refreshed from Google Patents.
US4659633A
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Magnetic recording medium
Assignee: Maxell Ltd
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Filing: 1986-03-11
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Granted: 1987-04-21
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Expires: 2006-03-11
Abstract
Abstract A magnetic recording medium having good durability comprising a substrate and one or two magnetic layers at least a surface of which contains at least one compound selected from the group consisting of a compound of the formula: F--(CF.sub.2).sub.n --COO--(RO).sub.m --CO--R'--COOH (I) wherein R is a C 2 -C 10 alkyl group, R' is a C 2 -C 10 alkyl or alkenyl group, n is an integer of 4 to 20 and m is an integer of 5 to 50 and salts thereof.
Inventors
- 👤 Yoshitaka Yamaguchi
- 👤 Kenji Sumiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:58
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/72; G11B5/725; G11B5/7253; G11B5/7257; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/3154; Y10T428/31544
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
80 words
A magnetic recording medium comprising a substrate and one or two magnetic layers at least a surface of which contains at least one compound selected from the group consisting of a compound of the formula: F--(CF.sub.2).sub.n --COO--(RO).sub.m --CO--R'--COOH (I) wherein R is a C 2 -C 10 alkyl group, R' is a C 2 -C 10 alkyl or alkenyl group, n is an integer of 4 to 20 and m is an integer of 5 to 50 and salts thereof.
Claim 2
Dependent Claim
80 words
A magnetic recording medium comprising a substrate and one or two magnetic layers at least a surface of which contains at least one compound selected from the group consisting of a compound of the formula: F--(CF.sub.2).sub.n --COO--(RO).sub.m --CO--R'--COOH (I) wherein R is a C 2 -C 10 alkyl group, R' is a C 2 -C 10 alkyl or alkenyl group, n is an integer of 4 to 20 and m is an integer of 5 to 50 and salts thereof.
Claim 3
Dependent Claim
16 words
The magnetic recording medium according to claim 1, wherein the compound (I) is a free acid.
Claim 4
Dependent Claim
23 words
The magnetic recording medium according to claim 1, wherein the compound (I) is in the form of a salt with an alkali metal.
Claim 5
Dependent Claim
20 words
The magnetic recording medium according to claim 1, wherein the compound (I) is in the form of an ammonium salt.
Claim 6
Dependent Claim
21 words
The magnetic recording medium according to claim 1, wherein the compound (I) is coated on the surface of the magnetic layer.
Claim 7
Dependent Claim
17 words
The magnetic recording medium according to claim 1, wherein the compound (I) contained in the magnetic layer.
Claim 8
Dependent Claim
13 words
The magnetic recording medium according to claim 1, which is a magnetic tape.
Claim 9
Dependent Claim
13 words
The magnetic recording medium according to claim 1, which is a magnetic disc.
Claim 10
Dependent Claim
13 words
The magnetic recording medium according to claim 1, which is a magnetic drum.
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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) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |