Magnetic recording medium and magnetic coating composition for magnetic recording medium

Patent metadata

Field	Value
Publication number	US-9562167-B2
Application number	US-201514673205-A
Country	US
Kind code	B2
Filing date	Mar 30, 2015
Priority date	Mar 31, 2014
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

An aspect of the present invention relates to a magnetic recording medium, which comprises a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the magnetic layer further comprises a compound which has a weight average molecular weight of equal to or more than 1,000 but less than 20,000 and is denoted by formula (1):

wherein, in formula (1), A denotes a monovalent substituent, R 1 denotes a single bond or a divalent connecting group, and m denotes an integer ranging from 2 to 4, multiple instances of A and R 1 that are present can be identical or different, at least one of the multiple instances of A that are present denotes a monovalent polymer group and X denotes a heterocyclic group of valence m.

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, wherein
the magnetic layer further comprises a compound which has a weight average molecular weight of equal to or more than 1,000 but less than 20,000 and which is
selected from the following Compounds B-8 and B-9:

2. The magnetic recording medium according to claim 1 , wherein the binder has a weight average molecular ranging from 20,000 to 120,000.

3. The magnetic recording medium according to claim 1 , wherein the ferromagnetic powder has an average particle size ranging from 10 nm to 50 nm.

4. The magnetic recording medium according to claim 1 , wherein the magnetic layer comprises the compound B-8 or B-9 in a quantity ranging from 0.5 to 50 weight parts per 100 weight parts of the ferromagnetic powder.

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

6. A magnetic coating composition, which is a magnetic coating composition for a magnetic recording medium and comprises:
ferromagnetic powder;
binder;
solvent; and
a compound which has a weight average molecular weight of equal to or more than 1,000 but less than 20,000 and which is
selected from the following Compounds B-8 and B-9:

7. The magnetic coating composition according to claim 6 , wherein the binder has a weight average molecular ranging from 20,000 to 120,000.

8. The magnetic coating composition according to claim 6 , wherein the ferromagnetic powder has an average particle size ranging from 10 nm to 50 nm.

9. The magnetic coating composition according to claim 6 , wherein the magnetic layer comprises the compound B 8 or B-9 in a quantity ranging from 0.5 to 50 weight parts per 100 weight parts of the ferromagnetic powder.

10. The magnetic coating composition according to claim 6 , wherein the binder is selected from the group consisting of polyurethane resin and vinyl chloride resin.

11. The magnetic coating composition according to claim 6 , wherein the solvent is ketone solvent.

12. A magnetic recording medium, which comprises a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein
the magnetic layer further comprises a compound which has a weight average molecular weight of equal to or more than 1,000 but less than 20,000 and which is
the following Compound B-1:

13. A magnetic coating composition, which is a magnetic coating composition for a magnetic recording medium and comprises:
ferromagnetic powder;
binder;
solvent; and
a compound which has a weight average molecular weight of equal to or more than 1,000 but less than 20,000 and which is
the following compound B-1:

Assignees

• Fujifilm Corp

Inventors

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

Classifications

• C08G18/791

  containing isocyanurate groups · CPC title

• G11B5/714

  characterised by the dimension of the magnetic particles · CPC title

• C09D127/06 Primary

  Homopolymers or copolymers of vinyl chloride · CPC title

• G11B5/7013 Primary

  characterised by the dispersing agent · CPC title

• C08G18/4269

  Lactones · CPC title