MAGNETIC TAPE

• US 20180061447A1
• Filed: 08/30/2017
• Published: 03/01/2018
• Est. Priority Date: 08/31/2016
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: KASADA, Norihito
• Granted Patent: US 10,529,368 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 2220/93 Longitudinal format, wherein tracks are in the direction of the tape, read with a static head, e.g. DCC
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/78 Tape carriers

Abstract

Provided is a magnetic tape including: a non-magnetic support; a magnetic layer on one surface side of the non-magnetic support; and a back coating layer on the other surface side, in which a center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.0 nm to 1.8 nm, the magnetic layer includes ferromagnetic hexagonal ferrite powder and non-magnetic powder, a tilt cos θ of the ferromagnetic hexagonal ferrite powder with respect to a surface of the magnetic layer acquired by cross section observation performed by using a scanning transmission electron microscope is 0.85 to 1.00, and logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the back 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 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 side,

wherein a center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.0 nm to 1.8 nm,

the ferromagnetic powder is ferromagnetic hexagonal ferrite powder,

the magnetic layer includes non-magnetic powder,

a tilt cos θ

of the ferromagnetic hexagonal ferrite powder with respect to a surface of the magnetic layer acquired by cross section observation performed by using a scanning transmission electron microscope is 0.85 to 1.00, and

logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the 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 logarithmic decrement is 0.010 to 0.050.

4. The magnetic tape according to claim 1,

wherein the cos θ

is 0.89 to 1.00.

5. The magnetic tape according to claim 1,

wherein the cos θ

is 0.95 to 1.00.

6. The magnetic tape according to claim 1,

wherein the center line average surface roughness Ra is 1.2 nm to 1.8 nm.

7. The magnetic tape according to claim 2,

wherein the center line average surface roughness Ra is 1.2 nm to 1.8 nm.

8. The magnetic tape according to claim 3,

wherein the center line average surface roughness Ra is 1.2 am to 1.8 nm.

9. The magnetic tape according to claim 4,

wherein the center line average surface roughness Ra is 1.2 nm to 1.8 nm.

10. The magnetic ape according to claim 5,

wherein the center line average surface roughness Ra is 1.2 nm to 1.8 nm.

11. The magnetic tape according to claim 1,

wherein the magnetic layer includes a polyester chain-containing compound having a weight-average molecular weight of 1,000 to 80,000.

12. The magnetic tape according to claim 1,

wherein an activation volume of the ferromagnetic hexagonal ferrite powder is 800 nm³ to 2,500 nm³.

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

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

14. The magnetic tape according to claim 1,

wherein the non-magnetic powder includes an abrasive.

15. The magnetic tape according to claim 1,

wherein the non-magnetic powder includes colloidal silica.