MAGNETIC TAPE

• US 20180061446A1
• 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 10,522,179 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 5/00817 on longitudinal tracks only, e.g. for serpentine format recording
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/7023 containing polyesters, polyethers, silicones, polyvinyl resins, polyacrylresins or epoxy resins G11B5/7022 takes precedence
• CPC Class Codes: G11B 5/7061 with a non-magnetic core
• CPC Class Codes: G11B 5/70678 Ferrites
• CPC Class Codes: G11B 5/708 characterised by addition of non-magnetic particles to the layer
• CPC Class Codes: G11B 5/7085 non-magnetic abrasive particles
• CPC Class Codes: G11B 5/78 Tape carriers

Abstract

Provided is a magnetic tape in which the total thickness of the non-magnetic layer and the magnetic layer is equal to or smaller than 0.60 μm, the magnetic layer includes ferromagnetic hexagonal ferrite powder and an abrasive, a percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 μm×6.3 μm of the surface of the magnetic layer by plane observation using a scanning electron microscope, with respect to the total area of the region is equal to or greater than 0.02% and less than 0.06%, and a tilt cos 0 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.

Claims

1. A magnetic tape comprising:

a non-magnetic support;

a non-magnetic layer including non-magnetic powder and a binding agent on the non-magnetic support; and

a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic layer,

wherein the total thickness of the non-magnetic layer and the magnetic layer is equal to or smaller than 0.60 μ

m,

the ferromagnetic powder is ferromagnetic hexagonal ferrite powder,

the magnetic layer includes an abrasive,

a percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 μ

m×

6.3 μ

m of the surface of the magnetic layer by plane observation using a scanning electron microscope, with respect to the total area of the region is equal to or greater than 0.02% and less than 0.06%, and

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.

2. The magnetic tape according to claim 1,

wherein a BET specific surface area of the abrasive is in a range of 14 to 40 m²/g.

3. The magnetic tape according to claim 1,

wherein the abrasive is alumina powder.

4. The magnetic tape according to claim 2,

wherein the abrasive is alumina powder.

5. The magnetic tape according to claim 1,

wherein the cos θ

is 0.89 to 1.00.

6. The magnetic tape according to claim 1,

wherein the cos θ

is 0.95 to 1.00.

7. The magnetic tape according to claim 2,

wherein the cos θ

is 0.89 to 1.00.

8. The magnetic tape according to claim 2,

wherein the cos θ

is 0.95 to 1.00.

9. The magnetic tape according to claim 3,

wherein the cos θ

is 0.89 to 1.00.

10. The magnetic tape according to claim 3,

wherein the cos θ

is 0.95 to 1.00.

11. The magnetic tape according to claim 4,

wherein the cos θ

is 0.89 to 1.00.

12. The magnetic tape according to claim 4,

wherein the cos θ

is 0.95 to 1.00.

13. 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.

14. The magnetic tape according to claim 1,

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

15. The magnetic tape according to claim 1,

wherein the percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 μ

m×

6.3 μ

m of the surface of the magnetic layer by plane observation using a scanning electron microscope, with respect to the total area of the region is 0.02% to 0.05%.

16. The magnetic tape according to claim 1,

wherein the total thickness of the non-magnetic layer and the magnetic layer is 0.20 μ

m to 0.60 μ

m.

17. The magnetic tape according to claim 1,

wherein the magnetic layer includes an aromatic hydrocarbon compound including a phenolic hydroxyl group.

18. The magnetic tape according to claim 1,

wherein the ferromagnetic hexagonal ferrite powder includes Al.