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US4452863A
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US
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1982-06-14
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Granted: 1984-06-05
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Expires: 2002-06-14
Abstract
Abstract In a magnetic recording medium having a base, a coating for magnetic recording formed on one side of the base, and a back coating of a nonmagnetic powder dispersed in a binder containing a thermosetting resin and formed on the other side, the back coating contains a fatty acid and/or a fatty ester.
Inventors
- 👤 Masahiro Takizawa
- 👤 Yoshio Kawakami
- 👤 Noribumi Kajimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:01
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31565; Y10T428/31786
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
79 words
A magnetic recording medium comprising a base, a magnetic recording layer formed on one side of said base, and a back coating consisting of a nonmagnetic powder dispersed in a binder and formed on the other side of said base, characterized in that said back coating contains a lubricant selected from the group consisting of a fatty acid and a fatty acid ester, and said binder consists essentially of nitrocellulose, vinyl chloride-vinyl acetate copolymer, polyurethane, and an isocyanate compound.
Claim 2
Dependent Claim
79 words
A magnetic recording medium comprising a base, a magnetic recording layer formed on one side of said base, and a back coating consisting of a nonmagnetic powder dispersed in a binder and formed on the other side of said base, characterized in that said back coating contains a lubricant selected from the group consisting of a fatty acid and a fatty acid ester, and said binder consists essentially of nitrocellulose, vinyl chloride-vinyl acetate copolymer, polyurethane, and an isocyanate compound.
Claim 3
Dependent Claim
64 words
The magnetic recording medium according to claim 1, wherein said binder comprises by weight of each 15-60% nitrocellulose, 15-60% vinyl chloride-vinyl acetate copolymer, and 10-70% polyurethane; and the isocyanate compound constitutes 5-80 parts by weight per hundred parts of the total amount of the vinyl chloride-vinyl acetate copolymer plus polyurethane, and the lubricant constitutes several percent by weight of the total back coating composition.
Claim 4
Dependent Claim
15 words
The magnetic recording medium according to claim 1, wherein the lubricant is a fatty acid.
Claim 5
Dependent Claim
26 words
The magnetic recording medium according to claim 3, wherein the fatty acid is selected from the group consisting of lauric acid, stearic acid and myristic acid.
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) | 1987-06-05 | 1987-12-05 | 1988-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-05 | 1991-12-05 | 1992-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-05 | 1995-12-05 | 1996-06-05 | $7700.00 | Window Closed / Lapsed |