Magnetic recording medium and coating composition for magnetic recording medium

Patent metadata

Field	Value
Publication number	US-9984711-B2
Application number	US-201514869014-A
Country	US
Kind code	B2
Filing date	Sep 29, 2015
Priority date	Sep 30, 2014
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

The magnetic recording medium comprises a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, and further comprises a compound denoted by Formula (1):

wherein, in Formula (1), X denotes —O—, —S—, or NR 1 —; each of R and R 1 independently denotes a hydrogen atom or a monovalent substituent; L denotes a divalent connecting group; Z denotes a partial structure of valence n comprising at least one group selected from the group consisting of carboxyl groups and carboxylate groups; m denotes an integer of greater than or equal to 2, and n denotes an integer of greater than or equal to 1.

First claim

What is claimed is:

1. A magnetic recording medium,
which comprises a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, and further comprises a compound denoted by Formula (1):

wherein, in Formula (1),
X denotes —O—, —S—, or NR 1 —;
R denotes a hydrogen atom or a monovalent substituent selected from the group consisting of the following monovalent substituents, in which “*” denotes the position of the bond with X:

R 1 denotes a hydrogen atom or a monovalent substituent selected from the group consisting of an alkyl group with 1 to 6 carbon atoms, a hydroxyl group, an alkoxy group with 1 to 6 carbon atoms, a halogen atom, a cyano group, an amino group, a nitro group, an acyl group, and a carboxyl (salt) group;
L denotes a divalent connecting group which is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms;
Z denotes a partial structure of valence n comprising at least one group selected from the group consisting of carboxyl groups and carboxylate groups, and which is a reactive residue of a carboxylic acid anhydride;
m denotes an integer of greater than or equal to 2,
n denotes an integer of greater than or equal to 1, and
the weight average molecular weight of the compound denoted by Formula (1) falls within a range of greater than or equal to 1,000 but less than 20,000.

2. The magnetic recording medium according to claim 1 , wherein, in Formula (1), X denotes —O—.

3. The magnetic recording medium according to claim 1 , wherein, in Formula (1), Z denotes a reactive residue of tetracarboxylic acid anhydride.

4. The magnetic recording medium according to claim 1 , wherein an average particle size of the ferromagnetic powder ranges from 10 nm to 50 nm.

5. The magnetic recording medium according to claim 1 , which comprises the compound denoted by Formula (1) in a content ranging from 0.5 weight part to 50.0 weight parts per 100.0 weight parts of ferromagnetic powder.

6. The magnetic recording medium according to claim 1 , wherein the binder is selected from the group consisting of polyurethane resin and vinyl chloride resin.

7. The magnetic recording medium according to claim 1 , wherein Z is selected from the group consisting of the following structures:

8. The magnetic recording medium according to claim 1 , wherein the compound denoted by Formula (1) comprises at least one selected from the group consisting of Reaction Products 1 to 13 shown below:

9. A coating composition,
which is a coating composition for a magnetic recording medium, and
comprises:
ferromagnetic powder;
binder;
solvent; and
a compound denoted by Formula (1):

wherein, in Formula (1),
X denotes —O—, —S—, or NR 1 —;
R denotes a hydrogen atom or a monovalent substituent selected from the group consisting of the following monovalent substituents, in which “*” denotes the position of the bond with X:

R 1 denotes a hydrogen atom or a monovalent substituent selected from the group consisting of an alkyl group with 1 to 6 carbon atoms, a hydroxyl group, an alkoxy group with 1 to 6 carbon atoms, a halogen atom, a cyano group, an amino group, a nitro group, an acyl group, and a carboxyl (salt) group;
L denotes a divalent connecting group which is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms;
Z denotes a partial structure of valence n comprising at least one group selected from the group consisting of carboxyl groups and carboxylate groups, and which is a reactive residue of a carboxylic acid anhydride;
m denotes an integer of greater than or equal to 2,
n denotes an integer of greater than or equal to 1, and
the weight average molecular weight of the compound denoted by Formula (1) falls within a range of greater than or equal to 1,000 but less than 20,000.

10. The coating composition according to claim 9 , wherein, in Formula (1), X denotes —O—.

11. The coating composition according to claim 9 , wherein, in Formula (1), Z denotes a reactive residue of tetracarboxylic acid anhydride.

12. The coating composition according to claim 9 , wherein a weight average molecular weight of the binder ranges from 20,000 to 120,000.

13. The coating composition according to claim 9 , wherein an average particle size of the ferromagnetic powder ranges from 10 nm to 50 nm.

14. The coating composition according to claim 9 , which comprises the compound denoted by Formula (1) in a content ranging from 0.5 weight part to 50.0 weight parts per 100.0 weight parts of ferromagnetic powder.

15. The coating composition according to claim 9 , wherein the binder is selected from the group consisting of polyurethane resin and vinyl chloride resin.

16. The coating composition according to claim 9 , wherein Z is selected from the group consisting of the following structures:

17. The coating composition according to claim 9 , wherein the compound denoted by Formula (1) comprises at least one selected from the group consisting of Reaction Products 1 to 13 shown below:

Assignees

• Fujifilm Corp

Inventors

• Aoshima Toshihide
• Kikuchi Wataru
• Katayama Kazutoshi
• Mikami Tatsuo

Classifications

• G11B5/7013 Primary

  characterised by the dispersing agent · CPC title