Claims
- 1. A magnetic recording medium comprising
- a substrate,
- a ferromagnetic metal film layer on one surface of said substrate having a thickness of 0.1 to 1 .mu.m, and
- a back coating layer formed on the other surface of said substrate from a composition comprising (a) a thermosetting resin binder comprising a vinyl chloride type copolymer, polyurethane, and an isocyanate compound, (b) a powder nonmagnetic substance dispersed in the binder, and (c) at least one lubricant selected from the group consisting of fatty acids and fatty acid esters, the back coating layer having a thickness of 0.1 to 3 .mu.m to reduce curling.
- 2. A magnetic recording medium according to claim 1, wherein said fatty acids are aliphatic monocarboxylic acids of 10 to 22 carbon atoms and said fatty acid esters are alkyl esters, having 1 to 26 carbon atoms, of said fatty acids.
- 3. A magnetic recording medium according to claim 1, wherein said fatty acids are aliphatic monocarboxylic acids of 10 to 18 carbon atoms and said fatty acid esters are alkyl esters, having 4 to 18 carbon atoms, of said fatty acids.
- 4. A magnetic recording medium according to claim 1, wherein said vinyl chloride type copolymer is vinyl chloride-vinyl acetate copolymer.
- 5. A magnetic recording medium according to claim 1 wherein said binder further comprises nitrocellulose.
- 6. A magnetic recording medium according to claim 2, wherein said lubricant is incorporated in the amount of 0.1 to 30% by weight based on the total amount of said binder, said lubricant and said powdered non-magnetic substance.
- 7. A magnetic recording medium according to claim 1, wherein the gravimetric ratio of the vinyl chloride type copolymer to the polyurethane falls in the range of 10-80:90-20.
- 8. A magnetic recording medium according to claim 7, wherein said isocyanate compound is incorporated in the amount of 5 to 80 parts by weight based on 100 parts by weight of the total amount of said vinyl chloride type copolymer and said polyurethane.
- 9. A magnetic recording medium according to claim 5, wherein the gravimetric ratio of said nitrocellulose, said vinyl chloride type copolymer and said polyurethane falls in the range of 15-60:15-60:10-70.
- 10. A magnetic recording medium according to claim 9, wherein said isocyanate compound is incorporated in the amount of 5 to 80 parts by weight based on 100 parts by weight of the total amount of said vinyl chloride type copolymer and said polyurethane.
- 11. A magnetic recording medium according to claim 1, wherein said substrate is polyethylene terephthalate film.
- 12. A magnetic recording medium according to claim 1 wherein the ferromagnetic metal film layer is formed of a cobalt base alloy.
Priority Claims (1)
Number |
Date |
Country |
Kind |
58-48984 |
Mar 1983 |
JPX |
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RELATED APPLICATIONS
This application is a continuation application of application Ser. No. 07/172,944 filed Mar. 22, 1988 which is based on the following series of applications: 07/067,387 filed June 24, 1987 which is a continuation of 06/908,975 filed Sept. 17, 1986 which is a continuation of 06/801,385 filed Nov. 22, 1985 which is a continuation of 06/592,614 filed Mar. 23, 1984.
All of these applications are now abandoned.
US Referenced Citations (3)
Continuations (5)
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Number |
Date |
Country |
Parent |
172944 |
Mar 1988 |
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Parent |
67387 |
Jun 1987 |
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Parent |
908975 |
Sep 1986 |
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Parent |
801385 |
Nov 1985 |
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Parent |
592614 |
Mar 1984 |
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