MAGNETIC RECORDING MEDIUM

• US 20190027176A1
• Filed: 07/17/2018
• 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: KUROKAWA, Takuto, KASADA, Norihito, TADA, Toshio, OZAWA, Eiki
• Granted Patent: US 10,714,139 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/70615 containing Fe metal or alloys G11B5/70621 takes precedence
• CPC Class Codes: G11B 5/70678 Ferrites
• CPC Class Codes: G11B 5/7085 non-magnetic abrasive particles

Abstract

The magnetic recording medium includes a non-magnetic support and a magnetic layer containing ferromagnetic powder and a binder, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer contains an abrasive, an intensity ratio of a peak intensity of a diffraction peak of (110) plane of a crystal structure of the hexagonal ferrite, determined by performing X-ray diffraction analysis on the magnetic layer by using an In-Plane method, to a peak intensity of a diffraction peak of (114) plane of the crystal structure is equal to or higher than 0.5 and equal to or lower than 4.0, a squareness ratio of the magnetic recording medium in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00, and a contact angle with 1-bromonaphthalene measured within a surface of the magnetic layer is in a range of 50.0° to 55.0°.

Claims

1. A magnetic recording medium comprising:

a non-magnetic support; and

a magnetic layer which is provided on the support and contains ferromagnetic powder and a binder,

wherein the ferromagnetic powder is ferromagnetic hexagonal ferrite powder,

the magnetic layer contains an abrasive,

an intensity ratio (Int (110)/Int (114)) of a peak intensity Int (110) of a diffraction peak of (110) plane of a crystal structure of the hexagonal ferrite, determined by performing X-ray diffraction analysis on the magnetic layer by using an In-Plane method, to a peak intensity Int (114) of a diffraction peak of (114) plane of the crystal structure is equal to or higher than 0.5 and equal to or lower than 4.0,

a squareness ratio of the magnetic recording medium in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00, and

a contact angle with 1-bromonaphthalene measured within a surface of the magnetic layer is in a range of 50.0°

to 55.00.

2. The magnetic recording medium according to claim 1,

wherein the squareness ratio in a vertical direction is equal to or higher than 0.65 and equal to or lower than 0.90.

3. The magnetic recording medium according to claim 1, further comprising:

a non-magnetic layer containing non-magnetic powder and a binder between the non-magnetic support and the magnetic layer.

4. The magnetic recording medium according to claim 1, further comprising:

a back coating layer containing non-magnetic powder and a binder on a surface, which is opposite to a surface provided with the magnetic layer, of the non-magnetic support.

5. The magnetic recording medium according to claim 1, which is a magnetic tape.