Magnetic recording tape

• US 20030228493A1
• Filed: 05/30/2003
• Published: 12/11/2003
• Est. Priority Date: 05/30/2002
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Inoue, Noriko, Doushita, Hiroaki
• Granted Patent: US 6,936,338 B2
• Time in Patent Office: Days
• US Class Current: 428/694BA
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/7356 comprising non-magnetic particles in the back layer, e.g. particles of TiO2, ZnO or SiO2
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/257 Iron oxide or aluminum oxide
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A magnetic recording tape comprising: a magnetic layer comprising a ferromagnetic powder and a binder; a nonmagnetic layer; a support; and a back coating layer, in this order, wherein the magnetic layer has a surface lubricant index of from 1.3 to 3.5, the back coating layer comprises titanium oxide, α-iron oxide or a mixture thereof as an inorganic oxide powder and carbon black and further comprises from 10 to 30 parts by weight, based on 100 parts by weight of a total amount of the inorganic oxide powder and the carbon black, of a binder, and the back coating layer has a surface lubricant index of from 1.10 to 3.0.

Claims

1. A magnetic recording tape comprising:

a magnetic layer comprising a ferromagnetic powder and a binder;

a nonmagnetic layer;

a support; and

a back coating layer, in this order,

wherein the magnetic layer has a surface lubricant index of from 1.3 to 3.5, the back coating layer comprises titanium oxide, α

-iron oxide or a mixture thereof as an inorganic oxide powder and carbon black and further comprises from 10 to 30 parts by weight, based on 100 parts by weight of a total amount of the inorganic oxide powder and the carbon black, of a binder, and the back coating layer has a surface lubricant index of from 1.10 to 3.0.

2. The magnetic recording tape according claim 1, wherein the back coating layer has a thickness of from 0.2 to 0.8 μ

m.

3. The magnetic recording tape according claim 1, wherein the magnetic layer has a surface lubricant index of from 1.35 to 2.0.

4. The magnetic recording tape according claim 1, wherein the magnetic layer comprises a lubricant in an amount of from 1 to 8 parts by weight, based on 100 parts by weight of the ferromagnetic powder.

5. The magnetic recording tape according claim 1, wherein the magnetic layer comprises a lubricant in an amount of from 2 to 5 parts by weight, based on 100 parts by weight of the ferromagnetic powder.

6. The magnetic recording tape according claim 1, wherein at least a part of a surface of the inorganic oxide powder is coated with at least one compound selected from Al₂O₃, SiO₂, TiO₂, ZrO₂, SnO₂, Sb₂O₃ and ZnO₂.

7. The magnetic recording tape according claim 1, wherein at least a part of a surface of the inorganic oxide powder is coated with at least one compound selected from Al₂O₃, SiO₂ and ZrO₂.

8. The magnetic recording tape according claim 1, wherein the carbon black has a particle size of not more than 0.3 μ

m.

9. The magnetic recording tape according claim 1, wherein the carbon black has a particle size of from 0.01 to 0.1 μ

m.

10. The magnetic recording tape according claim 1, wherein the carbon black has a pH of from 2 to 10.

11. The magnetic recording tape according claim 1, wherein a weight ratio of the inorganic oxide powder to the carbon black is from 60/40 to 90/10.

12. The magnetic recording tape according claim 1, wherein a weight ratio of the inorganic oxide powder to the carbon black is from 70/30 to 80/20.

13. The magnetic recording tape according claim 1, wherein the back coating layer has a glass transition temperature of from 60 to 120°

C.