Magnetic tape having characterized back coating layer

Patent metadata

Field	Value
Publication number	US-10403318-B2
Application number	US-201715625428-A
Country	US
Kind code	B2
Filing date	Jun 16, 2017
Priority date	Jun 24, 2016
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

A magnetic tape in which a thickness of a back coating layer is equal to or smaller than 0.20 μm. A C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the back coating layer at a photoelectron take-off angle of 10 degrees is equal to or greater than 35 atom %. The full widths at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer before and after performing a vacuum heating with respect to the magnetic tape are respectively greater than 0 nm and equal to or smaller than 10.0 nm. The difference between the spacing measured after performing the vacuum heating and a spacing measured before performing the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm.

First claim

What is claimed is:

1. A magnetic tape comprising:
a non-magnetic support;
a magnetic layer including ferromagnetic powder and a binder on one surface side of the non-magnetic support; and
a back coating layer including non-magnetic powder and a binder on the other surface side,
wherein a thickness of the back coating layer is equal to or smaller than 0.20 μm,
the back coating layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide and fatty acid ester,
a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the back coating layer at a photoelectron take-off angle of 10 degrees, is equal to or greater than 35 atom %,
a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer before performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 10.0 nm,
a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer after performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 10.0 nm, and
a difference S after −S before between a spacing S after measured by optical interferometry regarding the surface of the back coating layer after performing the vacuum heating with respect to the magnetic tape and a spacing S before measured by optical interferometry regarding the surface of the back coating layer before performing the vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

2. The magnetic tape according to claim 1 ,
wherein the C—H derived C concentration is 35 atom % to 60 atom %.

3. The magnetic tape according to claim 1 ,
wherein the C—H derived C concentration is 40 atom % to 60 atom %.

4. The magnetic tape according to claim 1 ,
wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer before performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

5. The magnetic tape according to claim 1 ,
wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer after performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

6. The magnetic tape according to claim 1 ,
wherein the difference S after −S before is greater than 0 nm and equal to or smaller than 6.0 nm.

7. The magnetic tape according to claim 1 ,
wherein the thickness of the back coating layer is 0.05 μm to 0.20 μm.

8. The magnetic tape according to claim 2 ,
wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer before performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

9. The magnetic tape according to claim 2 ,
wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer after performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

10. The magnetic tape according to claim 2 ,
wherein the difference S after −S before is greater than 0 nm and equal to or smaller than 6.0 nm.

11. The magnetic tape according to claim 2 ,
wherein the thickness of the back coating layer is 0.05 μm to 0.20 μm.

12. The magnetic tape according to claim 3 ,
wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer before performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

13. The magnetic tape according to claim 3 ,
wherein the full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer after performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 8.0 nm.

14. The magnetic tape according to claim 3 ,
wherein the difference S after −S before is greater than 0 nm and equal to or smaller than 6.0 nm.

15. The magnetic tape according to claim 3 ,
wherein the thickness of the back coating layer is 0.05 μm to 0.20 μm.

16. The magnetic tape according to claim 1 ,
wherein the non-magnetic powder included in the back coating layer is one or more kinds of non-magnetic powder selected from the group consisting of inorganic powder and carbon black.

17. The magnetic tape according to claim 16 ,
wherein the content of the inorganic powder in the back coating layer is in a range of greater than 50.0 parts by mass to equal to or less than 100.0 parts by mass with respect to 100.0 parts by mass of the total content of the non-magnetic powder included in the back coating layer.

18. The magnetic tape according to claim 1 , further comprising:
a non-magnetic layer including non-magnetic powder and a binder between the non-magnetic support and the magnetic layer.

Assignees

• Fujifilm Corp

Inventors

• Kurokawa Takuto
• Ozawa Eiki
• Kasada Norihito

Classifications

• G11B5/78

  Tape carriers · CPC title

• G11B5/725

  containing a lubricant {, e.g. organic compounds (inorganic carbon protective coating G11B5/727)} · CPC title

• G11B5/735 Primary

  characterised by the back layer {(magnetic recording media substrates G11B5/739)} · CPC title

• G11B5/712 Primary

  characterised by the surface treatment or coating of magnetic particles · CPC title

• G11B5/7356

  comprising non-magnetic particles in the back layer, e.g. particles of TiO2, ZnO or SiO2 · CPC title