MAGNETIC TAPE

• US 20120196156A1
• Filed: 01/26/2012
• Published: 08/02/2012
• Est. Priority Date: 01/27/2011
• Status: Abandoned Application

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: SUZUKI, Ryota
• Application Number:
  US13/358,985
• Publication Number:
  US 20120196156A1
• Time in Patent Office: Days
• US Class Current: 428/844
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/708 characterised by addition of non-magnetic particles to the layer
• 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

Abstract

An aspect of the present invention relates to a magnetic tape comprising, on one surface of a nonmagnetic support, a nonmagnetic layer containing a nonmagnetic powder and a binder, and thereon, a magnetic layer containing a ferromagnetic powder and a binder, wherein

• • the magnetic layer contains a nonmagnetic filler the average particle diameter φ of which satisfies relation (I) below with a thickness t of the magnetic layer:

1.0≦φ/t≦2.0  (I);

• • the thickness t of the magnetic layer ranges from 30 to 200 nm;
  • the nonmagnetic layer has a thickness ranging from 30 to 200 nm;
  • a composite elastic modulus as measured on a surface of the magnetic layer ranges from 6.0 to 8.0 GPa; and
  • a centerline average surface roughness Ra of the surface of the magnetic layer, as measured by an optical three-dimensional profilometer, ranges from 0.2 to 1.5 nm.

Claims

1. A magnetic tape comprising, on one surface of a nonmagnetic support, a nonmagnetic layer containing a nonmagnetic powder and a binder, and thereon, a magnetic layer containing a ferromagnetic powder and a binder, wherein

the magnetic layer contains a nonmagnetic filler the average particle diameter φ

of which satisfies relation (I) below with a thickness t of the magnetic layer;

1.0≦

φ

/t≦

2.0 

 

(I);

the thickness t of the magnetic layer ranges from 30 to 200 nm;

the nonmagnetic layer has a thickness ranging from 30 to 200 nm;

a composite elastic modulus as measured on a surface of the magnetic layer ranges from 6.0 to 8.0 GPa; and

a centerline average surface roughness Ra of the surface of the magnetic layer, as measured by an optical three-dimensional profilometer, ranges from 0.2 to 1.5 nm.

2. The magnetic tape according to claim 1, wherein the nonmagnetic filler is selected from the group consisting of an inorganic oxide particle and an organic polymer particle.

3. The magnetic tape according to claim 1, wherein the nonmagnetic filler is a colloidal particle.

4. The magnetic tape according to claim 1, wherein the nonmagnetic filler is a silica colloidal particle.

5. The magnetic tape according to claim 1, wherein the magnetic layer contains the nonmagnetic filler in a quantity ranging from 0.3 to 20 weight parts per 100 weight parts of the ferromagnetic powder.

6. The magnetic tape according to claim 1, wherein the magnetic layer further contains a granular substance which is different from the nonmagnetic filler.

7. The magnetic tape according to claim 1, wherein a centerline average surface roughness Ra of the surface of the nonmagnetic support over which the magnetic layer is present, as measured by an optical three-dimensional profilometer, ranges from 0.1 to 1.5 nm.

8. The magnetic tape according to claim 1, which comprises a radiation-cured layer between the nonmagnetic layer and the nonmagnetic support.

9. The magnetic tape according to claim 1, wherein an average particle size of the nonmagnetic powder contained in the nonmagnetic layer ranges from 5 to 50 nm.

10. The magnetic tape according to claim 1, wherein the binder contained in the nonmagnetic layer comprises a functional group selected from the group consisting of a sulfonic acid group and a sulfonate group.

11. The magnetic tape according to claim 10, wherein a concentration of the functional group of the binder contained in the nonmagnetic layer ranges from 0.04 to 0.5 meq/g.

12. The magnetic tape according to claim 1, which comprises a backcoat layer on the other surface of the nonmagnetic support.