Magnetic tape and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-9721606-B2
Application number	US-201615218190-A
Country	US
Kind code	B2
Filing date	Jul 25, 2016
Priority date	Jul 28, 2015
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on one surface of a nonmagnetic support, and has a backcoat layer containing nonmagnetic powder and binder on the other surface thereof, wherein the magnetic layer contains one or more components selected from the group consisting of a fatty acid and a fatty acid amide; the backcoat layer has a thickness of less than or equal to 0.30 μm and contains one or more components selected from the group consisting of a fatty acid and a fatty acid amide; a magnetic layer side C—H derived C concentration is greater than or equal to 45 atom %; and a backcoat layer side C—H derived C concentration is greater than or equal to 35 atom %.

First claim

What is claimed is:

1. A magnetic tape,
which comprises a magnetic layer comprising ferromagnetic powder and binder on one surface of a nonmagnetic support, and comprises a backcoat layer comprising nonmagnetic powder and binder on the other surface of the nonmagnetic support,
wherein the magnetic layer comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide;
the backcoat layer has a thickness of less than or equal to 0.30 μm and comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide;
a C—H derived carbon, C, concentration calculated from a C—H peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on a surface on the magnetic layer side of the magnetic tape, referred to as a magnetic layer side C—H derived C concentration, is greater than or equal to 45 atom %; and
a C—H derived carbon, C, concentration calculated from a C—H peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on a surface on the backcoat layer side of the magnetic tape, referred to as a backcoat layer side C—H derived C concentration, is greater than or equal to 35 atom %.

2. The magnetic tape according to claim 1 ,
wherein the magnetic layer side C—H derived C concentration falls within a range of 45 atom % to 80 atom %.

3. The magnetic tape according to claim 1 ,
wherein the magnetic layer side C—H derived C concentration falls within a range of 45 atom % to 70 atom %.

4. The magnetic tape according to claim 1 ,
wherein the backcoat layer side C—H derived C concentration falls within a range of 35 atom % to 60 atom %.

5. The magnetic tape according to claim 2 ,
wherein the backcoat layer side C—H derived C concentration falls within a range of 35 atom % to 60 atom %.

6. The magnetic tape according to claim 3 ,
wherein the backcoat layer side C—H derived C concentration falls within a range of 35 atom % to 60 atom %.

7. The magnetic tape according to claim 1 ,
wherein a difference between the magnetic layer side C—H derived C concentration and the backcoat layer side C—H derived C concentration is less than or equal to 20 atom %.

8. The magnetic tape according to claim 1 ,
wherein a difference between the magnetic layer side C—H derived C concentration and the backcoat layer side C—H derived C concentration is less than or equal to 8 atom %.

9. The magnetic tape according to claim 1 ,
wherein the nonmagnetic powder that is contained in the backcoat layer is nonmagnetic powder selected from the group consisting of carbon black and nonmagnetic inorganic oxide powder.

10. The magnetic tape according to claim 9 ,
wherein the nonmagnetic powder contained in the backcoat layer comprises at least carbon black.

11. The magnetic tape according to claim 1 ,
which comprises a nonmagnetic layer comprising nonmagnetic powder and binder between the magnetic layer and the nonmagnetic support.

12. A method of manufacturing a magnetic tape,
wherein the magnetic tape comprises a magnetic layer comprising ferromagnetic powder and binder on one surface of a nonmagnetic support, comprises a nonmagnetic layer comprising nonmagnetic powder and binder between the magnetic layer and the nonmagnetic support, and comprises a backcoat layer comprising nonmagnetic powder and binder on the other surface of the nonmagnetic support,
wherein the magnetic layer comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide;
the backcoat layer has a thickness of less than or equal to 0.30 μm and comprises one or more components selected from the group consisting of a fatty acid and a fatty acid amide;
a C—H derived carbon, C, concentration calculated from a C—H peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on a surface on the magnetic layer side of the magnetic tape, referred to as a magnetic layer side C—H derived C concentration, is greater than or equal to 45 atom %; and
a C—H derived carbon, C, concentration calculated from a C—H peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on a surface on the backcoat layer side of the magnetic tape, referred to as a backcoat layer side C—H derived C concentration, is greater than or equal to 35 atom %; and
the method comprises formation of a nonmagnetic layer, formation of a magnetic layer, and formation of a backcoat layer; wherein
the formation of a nonmagnetic layer further comprises:
coating a nonmagnetic layer-forming composition comprising one or more components selected from the group consisting of a fatty acid and a fatty acid amide, nonmagnetic powder, binder, and solvent on a surface of a nonmagnetic support to form a coating layer;
heating and drying the coating layer by a heat treatment; and
cooling the coating layer after the coating but prior to the heating and drying; and
the formation of a backcoat layer further comprises:
coating a backcoat layer-forming composition comprising one or more components selected from the group consisting of a fatty acid and a fatty acid amide, nonmagnetic powder, binder, and solvent on a surface of a nonmagnetic support to form a coating layer;
heating and drying the coating layer by a heat treatment; and
cooling the coating layer after the coating but prior to the heating and drying.

13. The method of manufacturing a magnetic tape according to claim 12 ,
wherein the cooling in the formation of a backcoat layer is conducted by placing the coating layer in a cooling atmosphere of −10° C. to 0° C.

14. The method of manufacturing a magnetic tape according to claim 12 ,
wherein the solvent that is contained in the backcoat layer-forming composition comprises ketone solvent.

15. The method of manufacturing a magnetic tape according to claim 12 ,
wherein the cooling in the forming of a nonmagnetic layer is conducted by placing the coating layer in a cooling atmosphere of −10° C. to 0° C.

16. The method of manufacturing a magnetic tape according to claim 12 ,
wherein the solvent that is contained in the nonmagnetic layer-forming composition comprises ketone solvent.

Assignees

• Fujifilm Corp

Inventors

• Kasada Norihito

Classifications

• G11B5/70

  on a base layer · CPC title

• G11B5/735

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

• G11B5/71

  characterised by the lubricant · CPC title

• G11B5/8404 Primary

  manufacturing base layers · CPC title

• G11B5/7356

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