Magnetic tape and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-9711174-B2
Application number	US-201514757555-A
Country	US
Kind code	B2
Filing date	Dec 24, 2015
Priority date	Dec 26, 2014
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

Provided is a magnetic tape, which comprises, on a nonmagnetic support, a nonmagnetic layer comprising nonmagnetic powder and binder, and on the nonmagnetic layer, a magnetic layer comprising ferromagnetic powder and binder; wherein a total thickness of the magnetic tape is less than or equal to 4.80 μm; 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 on the magnetic layer side of the magnetic tape is greater than or equal to 45 atom %.

First claim

What is claimed is:

1. A magnetic tape, which comprises, on a nonmagnetic support, a nonmagnetic layer comprising nonmagnetic powder and binder, and on the nonmagnetic layer, a magnetic layer comprising ferromagnetic powder and binder;
wherein a total thickness of the magnetic tape is less than or equal to 4.80 μm;
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 on the magnetic layer side of the magnetic tape is greater than or equal to 45 atom %.

2. The magnetic tape according to claim 1 , wherein
the C—H derived carbon, C, concentration ranges from 45 atom % to 80 atom %.

3. The magnetic tape according to claim 1 , wherein
the C—H derived carbon, C, concentration ranges from 45 atom % to 70 atom %.

4. The magnetic tape according to claim 1 , wherein
the C—H derived carbon, C, concentration ranges from 50 atom % to 65 atom %.

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

6. The magnetic tape according to claim 1 , wherein
either one of, or both, the magnetic layer and the nonmagnetic layer further comprises a fatty acid ester.

7. The magnetic tape according to claim 1 ,
which comprises a backcoat layer on the nonmagnetic support on an opposite side from the magnetic layer and nonmagnetic layer.

8. The magnetic tape according to claim 1 ,
a center line average surface roughness, Ra, as measured with a noncontact surface profiler on the surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm.

9. 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.

10. A method of manufacturing a magnetic tape,
wherein the magnetic tape is a magnetic tape, which comprises, on a nonmagnetic support, a nonmagnetic layer comprising nonmagnetic powder and binder, and on the nonmagnetic layer, a magnetic layer comprising ferromagnetic powder and binder;
wherein a total thickness of the magnetic tape is less than or equal to 4.80 μm;
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 on the magnetic layer side of the magnetic tape is greater than or equal to 45 atom %; and
the method comprises a step of forming a nonmagnetic layer and a step of forming a magnetic layer, wherein the step of forming the nonmagnetic layer comprises:
a coating step of 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;
a heating and drying step of drying the coating layer by a heat treatment; and
the step of forming the nonmagnetic layer further comprises, between the coating step and the heating and drying step, a cooling step of cooling the coating layer.

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

12. The method of manufacturing a magnetic tape according to claim 10 , wherein
the nonmagnetic layer forming composition comprises ketone solvent.

13. The method of manufacturing a magnetic tape according to claim 10 , wherein
the step of forming a magnetic layer comprises:
a coating step of forming a coating layer by coating on a nonmagnetic layer a magnetic layer forming composition comprising ferromagnetic powder, binder, and solvent; and
a heating and drying step of drying the coating layer by a heat treatment.

14. The method of manufacturing a magnetic tape according to claim 13 , 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.

15. The method of manufacturing a magnetic tape according to claim 13 , wherein
either one of, or both, the nonmagnetic layer forming composition and the magnetic layer forming composition further comprises a fatty acid ester.

Assignees

• Fujifilm Corp

Inventors

• Kasada Norihito
• Oyanagi Masahito
• Tada Toshio
• Kitada Kazuyuki

Classifications

• G11B5/78

  Tape carriers · CPC title

• G11B5/71 Primary

  characterised by the lubricant · CPC title

• G11B5/8404

  manufacturing base layers · CPC title

• G11B5/7305

  Physics · mapped topic

• G11B5/842

  Coating a support with a liquid magnetic dispersion · CPC title