MAGNETIC RECORDING MEDIUM AND COATING COMPOSITION FOR MAGNETIC RECORDING MEDIUM

• US 20160093321A1
• Filed: 09/29/2015
• Published: 03/31/2016
• Est. Priority Date: 09/30/2014
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: AOSHIMA, Toshihide, KIKUCHI, Wataru, KATAYAMA, Kazutoshi, MIKAMI, Tatsuo
• Granted Patent: US 9,984,711 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G11B 5/7013 characterised by the dispersing agent

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 NR¹—; each of R and R¹ 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.

Claims

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):

2. The magnetic recording medium according to claim 1, wherein, in Formula (1), L denotes an alkylene group.

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

O—

.

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

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

6. The magnetic recording medium according to claim 1, wherein a weight average molecular weight of the compound denoted by Formula (1) falls within a range of greater than equal to 1,000 but less than 20,000.

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

8. 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.

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

10. 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);

11. The coating composition according to claim 10, wherein, in Formula (1), L denotes an alkylene group.

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

O—

.

13. The coating composition according to claim 10, wherein, in Formula (1), Z denotes a reactive residue of carboxylic acid anhydride.

14. The coating composition according to claim 10, wherein, in Formula (1), Z denotes a reactive residue of tetracarboxylic acid anhydride.

15. The coating composition according to claim 10, wherein a weight average molecular weight of the compound denoted by Formula (1) falls within a range of greater than equal to 1,000 but less than 20,000.

16. The coating composition according to claim 10, wherein a weight average molecular weight of the binder ranges from 20,000 to 120,000.

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

18. The coating composition according to claim 10, 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.

19. The coating composition according to claim 10, wherein the binder is selected from the group consisting of polyurethane resin and vinyl chloride resin.