MAGNETIC TAPE

• US 20180240490A1
• Filed: 02/20/2018
• Published: 08/23/2018
• Est. Priority Date: 02/20/2017
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: KUROKAWA, Takuto, KASADA, Norihito
• Granted Patent: US 10,453,488 B2
• Time in Patent Office: Days
• CPC Class Codes: C08G 18/792 formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
• CPC Class Codes: C08K 3/20 Oxides; Hydroxides graphene oxides C08K3/042
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/7013 characterised by the dispersing agent
• CPC Class Codes: G11B 5/7022 containing mixtures of polyurethanes or polyisocyanates with other polymers
• 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 5/71 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

Abstract

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and a contact angle with respect to 1-bromonaphthalene measured regarding the surface of the magnetic layer is 45.0° to 55.0°.

Claims

1. A magnetic tape comprising:

a non-magnetic support; and

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

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

a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and

a contact angle with respect to 1-bromonaphthalene measured regarding the surface of the magnetic layer is 45.0°

to 55.0°

.

2. The magnetic tape according to claim 1,

wherein the logarithmic decrement is 0.010 to 0.050.

3. The magnetic tape according to claim 1,

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

4. The magnetic tape according to claim 2,

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

5. The magnetic tape according to claim 1,

wherein the contact angle with respect to the 1-bromonaphthalene measured regarding the surface of the magnetic layer is 45.0°

to 53.0°

.

6. The magnetic tape according to claim 2,

wherein the contact angle with respect to the 1-bromonaphthalene measured regarding the surface of the magnetic layer is 45.0°

to 53.0°

.

7. The magnetic tape according to claim 3,

wherein the contact angle with respect to the 1-bromonaphthalene measured regarding the surface of the magnetic layer is 45.0°

to 53.0°

.

8. The magnetic tape according to claim 4,

wherein the contact angle with respect to the 1-bromonaphthalene measured regarding the surface of the magnetic layer is 45.0°

to 53.0°

.

9. The magnetic tape according to claim 1,

wherein the magnetic layer includes a nitrogen-containing polymer.

10. The magnetic tape according to claim 1,

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

11. 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.

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

a back coating layer including non-magnetic powder and a binding agent on a surface side of the non-magnetic support opposite to a surface side provided with the magnetic layer.