Magnetic recording medium

Abstract

The present invention provides a magnetic recording medium having a magnetic layer formed on at least one surface of a nonmagnetic support, wherein the magnetic layer includes a ferrite ferromagnetic hexagonal powder having an average plate diameter of 5 to 50 nm or a fine ferromagnetic metal powder having an average major axis length of 20 to 100 nm together with a binder, and the nonmagnetic support is a composition of a polyester or copolyester having one or more of polytrimethylene 2,6-naphthalate, polytetramethylene 2,6-naphthalate, polypentamethylene 2,6-naphthalate and polyhexamethylene 2,6-naphthalate, in order to provides an excellent running stability, low error rates under various environment and an excellent electromagnetic transforming properties and reliability.

Description

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1A and 1B are tables showing production conditions and results of evaluation for the Examples and Comparative Examples.

FIGS. 2A and 2B are other tables showing production conditions and results of evaluation for the Examples and Comparative Examples.

Claims

1. A magnetic recording medium having a magnetic layer formed on at least one surface of a nonmagnetic support, wherein the magnetic layer includes a ferrite ferromagnetic hexagonal powder having an average plate diameter of 5 to 50 nm or a fine ferromagnetic metal powder having an average major axis length of 20 to 100 nm together with a binder, andthe nonmagnetic support is a composition of a polyester or copolyester having one or more of polytrimethylene 2,6-naphthalate, polytetramethylene 2,6-naphthalate, polypentamethylene 2,6-naphthalate and polyhexamethylene 2,6-naphthalate.

2. The magnetic recording medium according to claim 1, wherein the nonmagnetic support includes 1 to 40% by weight of polyethylene 2,6-naphthalate.

3. The magnetic recording medium according to claim 1, wherein the nonmagnetic support has a Young's modulus in the length direction of 6.0 to 11.0 GPa and a Young's modulus in the width direction of 6.0 to 11.0 GPa.

4. The magnetic recording medium according to claim 2, wherein the nonmagnetic support has a Young's modulus in the length direction of 6.0 to 11.0 GPa and a Young's modulus in the width direction of 6.0 to 11.0 GPa.

5. The magnetic recording medium according to claim 1, wherein the nonmagnetic support has a temperature expansion coefficient of 0 to 20 ppm/° C. and a humidity expansion coefficient of 0 to 20 ppm/% RH.

6. The magnetic recording medium according to claim 2, wherein the nonmagnetic support has a temperature expansion coefficient of 0 to 20 ppm/° C. and a humidity expansion coefficient of 0 to 20 ppm/% RH.

7. The magnetic recording medium according to claim 3, wherein the nonmagnetic support has a temperature expansion coefficient of 0 to 20 ppm/° C. and a humidity expansion coefficient of 0 to 20 ppm/% RH.

8. The magnetic recording medium according to claim 4, wherein the nonmagnetic support has a temperature expansion coefficient of 0 to 20 ppm/° C. and a humidity expansion coefficient of 0 to 20 ppm/% RH.

9. The magnetic recording medium according to claim 1, wherein the medium has a nonmagnetic layer including a nonmagnetic powder and a binder, between the nonmagnetic support and the magnetic layer.

10. The magnetic recording medium according to claim 2, wherein the medium has a nonmagnetic layer including a nonmagnetic powder and a binder, between the nonmagnetic support and the magnetic layer.

11. The magnetic recording medium according to claim 3, wherein the medium has a nonmagnetic layer including a nonmagnetic powder and a binder, between the nonmagnetic support and the magnetic layer.

12. The magnetic recording medium according to claim 4, wherein the medium has a nonmagnetic layer including a nonmagnetic powder and a binder, between the nonmagnetic support and the magnetic layer.

13. The magnetic recording medium according to claim 5, wherein the medium has a nonmagnetic layer including a nonmagnetic powder and a binder, between the nonmagnetic support and the magnetic layer.

14. The magnetic recording medium according to claim 6, wherein the medium has a nonmagnetic layer including a nonmagnetic powder and a binder, between the nonmagnetic support and the magnetic layer.

15. The magnetic recording medium according to claim 7, wherein the medium has a nonmagnetic layer including a nonmagnetic powder and a binder, between the nonmagnetic support and the magnetic layer.

16. The magnetic recording medium according to claim 8, wherein the medium has a nonmagnetic layer including a nonmagnetic powder and a binder, between the nonmagnetic support and the magnetic layer.