Magnetic tape and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-2016189740-A1
Application number	US-201514978834-A
Country	US
Kind code	A1
Filing date	Dec 22, 2015
Priority date	Dec 26, 2014
Publication date	Jun 30, 2016
Grant date	—

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 , 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 . 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 , 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.

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

15 . The method of manufacturing a magnetic tape according to claim 12 , wherein
the magnetic layer forming step 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.

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
one or both the nonmagnetic la

Assignees

• Fujifilm Corp

Inventors

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

Classifications

• G11B5/7305

  Physics · mapped topic

• G11B5/71 Primary

  characterised by the lubricant · CPC title

• G11B5/8404

  manufacturing base layers · CPC title

• G11B5/738

  Physics · mapped topic

• G11B5/842

  Coating a support with a liquid magnetic dispersion · CPC title