Magnetic tape and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-9721605-B2
Application number	US-201514978834-A
Country	US
Kind code	B2
Filing date	Dec 22, 2015
Priority date	Dec 26, 2014
Publication date	Aug 1, 2017
Grant date	Aug 1, 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 at least the magnetic layer comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide; a quantity of components selected from the group consisting of a fatty acid and a fatty acid amide per unit area of the magnetic tape among components that are extracted from a surface on the magnetic layer side of the magnetic tape is less than or equal to 15.0 mg/m 2 , and a concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape is greater than or equal to 50 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 at least the magnetic layer comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide;
a quantity of components selected from the group consisting of a fatty acid and a fatty acid amide per unit area of the magnetic tape among components that are extracted from a surface on the magnetic layer side of the magnetic tape is less than or equal to 15.0 mg/m 2 , the extraction being conducted by immersion of a 5 cm sample of the magnetic tape with heating in 30 mL of methanol for 3 hours at 60° C.; and
a concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape is greater than or equal to 50 atom %.

2. The magnetic tape according to claim 1 , wherein
the concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape ranges from 50 atom % to 80 atom %.

3. The magnetic tape according to claim 1 , wherein
a concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 90 degrees on the surface on the magnetic layer side of the magnetic tape is greater than or equal to 30 atom % but less than 50 atom %.

4. The magnetic tape according to claim 1 , wherein
the concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape ranges from 50 atom % to 80 atom %, and
a concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 90 degrees on the surface on the magnetic layer side of the magnetic tape is greater than or equal to 30 atom % but less than 50 atom %.

5. The magnetic tape according to claim 1 , wherein
the quantity of components selected from the group consisting of a fatty acid and a fatty acid amide per unit area of the magnetic tape among components that are extracted from a surface on the magnetic layer side of the magnetic tape is less than or equal to 12.0 mg/m 2 .

6. The magnetic tape according to claim 1 , wherein
the concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape ranges from 50 atom % to 80 atom %,
a concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 90 degrees on the surface on the magnetic layer side of the magnetic tape is greater than or equal to 30 atom % but less than 50 atom %, and
the quantity of components selected from the group consisting of a fatty acid and a fatty acid amide per unit area of the magnetic tape among components that are extracted from a surface on the magnetic layer side of the magnetic tape is less than or equal to 12.0 mg/m 2 .

7. The magnetic tape according to claim 1 , wherein
a thickness of the nonmagnetic layer ranges from 0.05 μm to 0.60 μm.

8. The magnetic tape according to claim 1 , wherein
the concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape ranges from 50 atom % to 80 atom %,
a concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 90 degrees on the surface on the magnetic layer side of the magnetic tape is greater than or equal to 30 atom % but less than 50 atom %,
the quantity of components selected from the group consisting of a fatty acid and a fatty acid amide per unit area of the magnetic tape among components that are extracted from a surface on the magnetic layer side of the magnetic tape is less than or equal to 12.0 mg/m 2 , and
a thickness of the nonmagnetic layer ranges from 0.05 μm to 0.60 μm.

9. The magnetic tape according to claim 1 , wherein
a centerline average surface roughness Ra that is measured by 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.

10. The magnetic tape according to claim 1 , wherein
one or both the magnetic layer and the nonmagnetic layer further comprise a fatty acid ester.

11. 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.

12. The magnetic tape according to claim 1 , wherein the quantity of components selected from the group consisting of a fatty acid and a fatty acid amide per unit area of the magnetic tape among components that are extracted from a surface on the magnetic layer side of the magnetic tape is within a range of from 9.0 mg/m 2 to 14.7 mg/m 2 , and the concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape is within the range of from 50 atom % to 83 atom %.

13. 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 at least the magnetic layer comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide;
a quantity of components selected from the group consisting of a fatty acid and a fatty acid amide per unit area of the magnetic tape among components that are extracted from a surface on the magnetic layer side of the magnetic tape is less than or equal to 15.0 mg/m 2 , the extraction being conducted by immersion of a 5 cm sample of the magnetic tape with heating in 30 mL of methanol for 3 hours at 60° C., and
a concentration of carbon, C, that is obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface on the magnetic layer side of the magnetic tape is greater than or equal to 50 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.

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

15. The method of manufacturing a magnetic tape according to claim 13 , wherein
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Assignees

• Fujifilm Corp

Inventors

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

Classifications

• G11B5/8404

  manufacturing base layers · CPC title

• G11B5/70

  on a base layer · CPC title

• G11B5/7305

  Physics · mapped topic

• G11B5/71 Primary

  characterised by the lubricant · CPC title

• G11B5/842

  Coating a support with a liquid magnetic dispersion · CPC title