MAGNETIC TAPE

• US 20170249963A1
• Filed: 02/27/2017
• Published: 08/31/2017
• Est. Priority Date: 02/29/2016
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: OYANAGI, Masahito, KASADA, Norihito, KUROKAWA, Takuto
• Granted Patent: US 10,861,491 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/702 characterised by the bonding agent
• CPC Class Codes: G11B 5/7085 non-magnetic abrasive particles
• CPC Class Codes: G11B 5/71 characterised by the lubricant
• CPC Class Codes: G11B 5/73 Base layers , i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
• 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 5/735 characterised by the back layer magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/78 Tape carriers

Abstract

The magnetic tape has a magnetic layer containing ferromagnetic powder, abrasive, and binder on a nonmagnetic support, wherein the centerline average surface roughness Ra measured on the surface of the magnetic layer is less than or equal to 1.8 nm, the contact angle for 1-bromonaphthalene that is measured on the surface of the magnetic layer falls within a range of 45.0° to 60.0°, and the coefficient of friction that is measured on the base portion of the surface of the magnetic layer is less than or equal to 0.35.

Claims

1. A magnetic tape,

which comprises a magnetic layer comprising ferromagnetic powder, abrasive, and binder on a nonmagnetic support, wherein:

a centerline average surface roughness Ra measured on a surface of the magnetic layer is less than or equal to 1.8 nm;

a contact angle for 1-bromonaphthalene that is measured on the surface of the magnetic layer falls within a range of 45.0°

to 60.0°

; and

a coefficient of friction that is measured on a base portion of the surface of the magnetic layer is less than or equal to 0.35.

2. The magnetic tape according to claim 1,

wherein the centerline average surface roughness Ra falls within a range of 1.2 nm to 1.8 nm.

3. The magnetic tape according to claim 1,

wherein the centerline average surface roughness Ra falls within a range of 1.2 nm to 1.6 nm.

4. The magnetic tape according to claim 1,

wherein the coefficient of friction that is measured on the base portion of the surface of the magnetic layer falls within a range of 0.15 to 0.35.

5. The magnetic tape according to claim 1,

wherein the contact angle for 1-bromonaphthalene that is measured on the surface of the magnetic layer falls within a range of 45.1°

to 60.0°

.

6. The magnetic tape according to claim 1,

wherein the coefficient of friction that is measured on the base portion of the surface of the magnetic layer falls within a range of 0.20 to 0.35.

7. The magnetic tape according to claim 1,

wherein the contact angle for 1-bromonaphthalene that is measured on the surface of the magnetic layer falls within a range of 45.10°

to 60.0°

; and

the coefficient of friction that is measured on the base portion of the surface of the magnetic layer falls within a range of 0.20 to 0.35.

8. The magnetic tape according to claim 1,

wherein a contact angle for water measured on the surface of the magnetic layer falls within a range of 90.0°

to 101.2°

.

9. The magnetic tape according to claim 1,

wherein a contact angle for water measured on the surface of the magnetic layer falls within a range of 96.8°

to 101.2°

.

10. The magnetic tape according to claim 1,

wherein the contact angle for 1-bromonaphthalene that is measured on the surface of the magnetic layer falls within a range of 45.1°

to 60.0°

;

the coefficient of friction that is measured on the base portion of the surface of the magnetic layer falls within a range of 0.20 to 0.35; and

a contact angle for water measured on the surface of the magnetic layer falls within a range of 96.8°

to 101.2°

.

11. The magnetic tape according to claim 1,

wherein the magnetic layer comprises one or more lubricants selected from the group consisting of a fatty acid, a fatty acid ester, and a fatty acid amide.

12. The magnetic tape according to claim 1,

wherein the magnetic layer comprises a nitrogen-containing polymer.

13. The magnetic tape according to claim 12,

wherein the nitrogen-containing polymer is a polyalkyleneimine polymer.

14. The magnetic tape according to claim 13,

wherein the polyalkyleneimine polymer is a polymer comprising a polyalkyleneimine chain and a polyester chain.

15. The magnetic tape according to claim 1,

which comprises a nonmagnetic layer comprising nonmagnetic powder and binder between the nonmagnetic support and the magnetic layer.

16. The magnetic tape according to claim 1,

which comprises a backcoat layer comprising nonmagnetic powder and binder on an opposite side of the nonmagnetic support from that on which the magnetic layer is present.