Magnetic tape and method of manufacturing the same

• US 9,721,605 B2
• Filed: 12/22/2015
• Issued: 08/01/2017
• Est. Priority Date: 12/26/2014
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Oyanagi, Masahito, Kitada, Kazuyuki, Tada, Toshio, Kasada, Norihito
• Primary Examiner(s): BERNATZ, KEVIN M
• Application Number:
  US14/978,834
• Publication Number:
  US 20160189740A1
• Time in Patent Office: 588 Days
• Field of Search: None
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/71 characterised by the lubricant
• CPC Class Codes: G11B 5/733 characterised by the addition of non-magnetic particles base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/7334 Base layer characterised by composition or structure
• CPC Class Codes: G11B 5/78 Tape carriers
• CPC Class Codes: G11B 5/8404 manufacturing base layers
• CPC Class Codes: G11B 5/842 Coating a support with a liquid magnetic dispersion

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/m², 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 %.

Claims

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/m², 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/m².

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/m².

7. The magnetic tape according to claim 1, wherein

a thickness of the nonmagnetic layer ranges from 0.05 μ

m to 0.60 μ

m.

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/m², and

a thickness of the nonmagnetic layer ranges from 0.05 μ

m to 0.60 μ

m.

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/m² to 14.7 mg/m², 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/m², 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

the nonmagnetic layer forming composition comprises ketone solvent.

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

17. The method of manufacturing a magnetic tape according to claim 16, 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.

18. The method of manufacturing a magnetic tape according to claim 16, wherein

one or both the nonmagnetic layer forming composition and the magnetic layer forming composition further comprises a fatty acid ester.