MAGNETIC TAPE

• US 20190027180A1
• Filed: 07/18/2018
• Published: 01/24/2019
• Est. Priority Date: 07/19/2017
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Kasada, Norihito, Tada, Toshio, Ozawa, Eiki, Kurokawa, Takuto
• Granted Patent: US 10,854,230 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/70678 Ferrites
• CPC Class Codes: G11B 5/7085 non-magnetic abrasive particles
• CPC Class Codes: G11B 5/71 characterised by the lubricant
• CPC Class Codes: G11B 5/712 characterised by the surface treatment or coating of magnetic particles
• CPC Class Codes: G11B 5/714 characterised by the dimension of the magnetic particles
• CPC Class Codes: G11B 5/7358 specially adapted for achieving a specific property, e.g. average roughness [Ra]
• CPC Class Codes: G11B 5/78 Tape carriers
• CPC Class Codes: G11B 5/84 Processes or apparatus specially adapted for manufacturing record carriers

Abstract

The magnetic tape includes a magnetic layer including ferromagnetic powder, non-magnetic powder, and a binding agent and a back coating layer including non-magnetic powder and a binding agent, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, an Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, an intensity ratio of a peak intensity of a diffraction peak of a (110) plane with respect to a peak intensity of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic tape is 0.65 to 1.00, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the hack coating layer is equal to or smaller than 0.060.

Claims

1. A magnetic tape comprising:

a non-magnetic support;

a magnetic layer including ferromagnetic powder, non-magnetic powder, and a binding agent on one surface side of the non-magnetic support; and

a back coating layer including non-magnetic powder and a binding agent on the other surface sick of the non-magnetic support,

wherein the ferromagnetic powder is ferromagnetic hexagonal ferrite powder,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm,

an intensity ratio Int(110)/Int(114) of a peak intensity Int(110) of a diffraction peak of a (110) plane with respect to a peak intensity Int(114) of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0,

a vertical squareness ratio of the magnetic tape is 0.65 to 1.00, and.

a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the back coating layer is equal to or smaller than 0.060.

2. The magnetic tape according to claim 1,

wherein the logarithmic decrement is 0.010 to 0.060.

3. The magnetic tape according to claim 1,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 1.8 nm.

4. The magnetic tape according to claim 2,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 1.8 nm,

5. The magnetic tape according to claim 1,

wherein the vertical squareness ratio of the magnetic tape is 0.65 to 0.90.

6. The magnetic tape according to claim 2,

wherein the vertical squareness ratio of the magnetic tape is 0.65 to 0.90.

7. The magnetic tape according to claim 3,

wherein the vertical squareness ratio of the magnetic tape is 0.65 to 0.90.

8. The magnetic tape according to claim 4,

wherein the vertical squareness ratio of the magnetic tape is 0.65 to 0.90.

9. The magnetic tape according to claim 1, further comprising:

a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.