Magnetic tape including characterized magnetic layer, tape cartridge, recording and reproducing device, and method of manufacturing

Patent metadata

Field	Value
Publication number	US-10522180-B2
Application number	US-201615380336-A
Country	US
Kind code	B2
Filing date	Dec 15, 2016
Priority date	Dec 16, 2015
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

The magnetic tape has a nonmagnetic layer containing nonmagnetic powder and binder on a nonmagnetic support, and a magnetic layer containing ferromagnetic powder and binder on the nonmagnetic layer; wherein the combined thickness of the nonmagnetic layer and the magnetic layer is less than or equal to 0.60 μm, the coefficient of friction as measured on the base portion of the surface of the magnetic layer is less than or equal to 0.35, at least the magnetic layer contains one or more components selected from the group consisting of a fatty acid and a fatty acid amide, and a C—H derived carbon, C, concentration calculated from a C—H peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface of the magnetic layer is greater than or equal to 45 atom %.

First claim

What is claimed is:

1. A magnetic tape,
which comprises a nonmagnetic layer comprising nonmagnetic powder and binder on a nonmagnetic support, and a magnetic layer comprising ferromagnetic powder and binder on the nonmagnetic layer; wherein
a combined thickness of the nonmagnetic layer and the magnetic layer is less than or equal to 0.60 μm;
a coefficient of friction as measured on a base portion of a surface of the magnetic layer is less than or equal to 0.35;
at least the magnetic layer comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide; and
a C—H derived carbon, C, concentration calculated from a C—H peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on a surface of the magnetic layer is greater than or equal to 45 atom %.

2. The magnetic tape according to claim 1 ,
wherein the C—H derived C concentration falls within a range of 45 atom % to 80 atom %.

3. The magnetic tape according to claim 1 ,
wherein the C—H derived C concentration falls within a range of 45 atom % to 70 atom %.

4. The magnetic tape according to claim 1 ,
wherein the magnetic layer and the nonmagnetic layer each comprise one or more components selected from the group consisting of a fatty acid and a fatty acid amide.

5. The magnetic tape according to claim 1 ,
which comprises a backcoat layer comprising nonmagnetic powder and binder on an opposite side of the nonmagnetic support from a side on which the nonmagnetic layer and magnetic layer are present.

6. The magnetic tape according to claim 1 ,
which has a total thickness of less than or equal to 6.00 μm.

7. The magnetic tape according to claim 1 ,
wherein the ferromagnetic powder is selected from the group consisting of ferromagnetic hexagonal ferrite powder and ferromagnetic metal powder.

8. A magnetic tape cartridge,
which houses the magnetic tape according to claim 1 .

9. The magnetic tape cartridge according to claim 8 ,
wherein a total length of the magnetic tape that is housed in the magnetic tape cartridge is greater than or equal to 10 m.

10. A magnetic recording and reproducing device,
which comprises the magnetic tape cartridge according to claim 8 and a magnetic head.

11. The magnetic recording and reproducing device according to claim 10 ,
wherein a relative speed of the magnetic tape and the magnetic head during recording, reproduction, or recording and reproduction, of a magnetic signal on the magnetic tape housed in the magnetic tape cartridge is greater than or equal to 7 m/sec.

12. A method of manufacturing a magnetic tape,
wherein the magnetic tape is a magnetic tape, which comprises a nonmagnetic layer comprising nonmagnetic powder and binder on a nonmagnetic support, and a magnetic layer comprising ferromagnetic powder and binder on the nonmagnetic layer; wherein
a combined thickness of the nonmagnetic layer and the magnetic layer is less than or equal to 0.60 μm;
a coefficient of friction as measured on a base portion of a surface of the magnetic layer is less than or equal to 0.35;
at least the magnetic layer comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide; and
a C—H derived carbon, C, concentration calculated from a C—H peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on a surface of the magnetic layer is greater than or equal to 45 atom %; and
the method comprises:
forming a nonmagnetic layer and forming a magnetic layer, wherein
the forming of a nonmagnetic layer comprises:
forming a coating layer by coating on a nonmagnetic support a nonmagnetic layer forming composition comprising one or more components selected from the group consisting of a fatty acid and a fatty acid amide, nonmagnetic powder, binder, and solvent, and
drying the coating layer by a heat treatment,
with cooling the coating layer being conducted between the coating and the drying by a heat treatment.

13. The method of manufacturing a magnetic tape according to claim 12 ,
wherein the cooling is conducted by placing the coating layer in a cooling atmosphere of −10° C. to 0° C.

14. The method of manufacturing a magnetic tape according to claim 12 ,
wherein the solvent that is contained in the nonmagnetic layer forming composition comprises ketone solvent.

15. The method of manufacturing a magnetic tape according to claim 12 ,
wherein the forming of a magnetic layer comprises forming a coating layer by coating on a nonmagnetic layer a magnetic layer forming composition comprising ferromagnetic powder, binder, and solvent, and drying the coating layer of the magnetic layer forming composition by a heat treatment.

16. The method of manufacturing a magnetic tape according to claim 15 ,
wherein the magnetic layer forming composition further comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide.

17. The method of manufacturing a magnetic tape according to claim 15 ,
wherein either one or both of the nonmagnetic layer forming composition and the magnetic layer forming composition further comprise a fatty acid ester.

Assignees

• Fujifilm Corp

Inventors

• Kasada Norihito

Classifications

• G11B5/73

  Base layers {, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer} · CPC title

• G11B5/7013

  characterised by the dispersing agent · CPC title

• G11B5/70

  on a base layer · CPC title

• G11B5/70626

  containing non-metallic substances · CPC title

• G11B5/71 Primary

  characterised by the lubricant · CPC title