Composition for magnetic recording medium and magnetic recording medium

Patent metadata

Field	Value
Publication number	US-10081701-B2
Application number	US-201414472663-A
Country	US
Kind code	B2
Filing date	Aug 29, 2014
Priority date	Aug 30, 2013
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

An aspect of the present invention relates to a composition, which is a composition for a magnetic recording medium and comprises an isocyanate compound in the form of an adduct of a polyhydroxyl compound having one or more aromatic carbon rings and three or more hydroxyl groups per molecule with a polyisocyanate having two or more isocyanate groups per molecule.

First claim

What is claimed is:

1. A composition, which is a composition for a magnetic recording medium and comprises an isocyanate compound in the form of an adduct of a polyhydroxyl compound having three or more aromatic carbon rings and three or more hydroxyl groups per molecule with one or more polyisocyanate(s) selected from the group consisting of m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4′-diisocyanate, 3,3′-dimethoxybiphenyl diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, xylylene-1,4-diisocyanate, 4-chloroxylylene-1,3-diisocyanate, 2-methylxylylene-1,3-diisocyanate, 4,4′-diphenylpropane diisocyanate, 4,4′-diphenylhexafluoropropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, and 1,4-bis(isocyanatemethyl)cyclohexane,
wherein the polyhydroxyl compound is selected from the group consisting of a compound denoted by formula (1) and a compound denoted by formula (2):

wherein, in formula (1), each of R 3 , R 4 , and R 5 independently denotes a hydrogen atom, a methyl group, or a substituent selected from the group consisting of the following substituents:

each of R 1 , R 2 , and R 9 independently denotes a hydrogen atom, a methyl group, or a cyclohexyl group; and n denotes an integer ranging from 0 to 2;

wherein, in formula (2), R 6 denotes a hydrogen atom, a methyl group, a phenyl group, or a cyclohexyl group; each of R 7 and R 8 independently denotes a hydrogen atom, a methyl group, or a cyclohexyl group; and m denotes 0 or 1.

2. The composition according to claim 1 , wherein a cyclic structure comprised in the polyhydroxyl compound is only aromatic carbon rings.

3. The composition according to claim 1 , wherein the average molecular weight of the isocyanate compound ranges from 500 to 15,000 as a weight average molecular weight of a dibutylamine adduct of the isocyanate compound that has been dibutylaminated with dibutylamine.

4. The composition according to claim 1 , wherein the isocyanate compound is a reaction product of the polyhydroxyl compound and the polyisocyanate, with the number of moles of the polyisocyanate being 0.8 to 1.5-fold the number of moles of hydroxyl groups comprised in the polyhydroxyl compound.

5. The composition according to claim 1 , which further comprises binder.

6. The composition according to claim 1 , which further comprises binder and ferromagnetic powder.

7. The composition according to claim 6 , wherein a cyclic structure comprised in the polyhydroxyl compound is only aromatic carbon rings.

8. A magnetic recording medium, which comprises a magnetic layer on a nonmagnetic support and the magnetic layer is a layer formed by heating the composition according to claim 7 .

9. The composition according to claim 6 , wherein an average particle size of the ferromagnetic powder ranges from 10 nm to 50 nm.

10. A magnetic recording medium, which comprises a magnetic layer on a nonmagnetic support and the magnetic layer is a layer formed by heating the composition according to claim 9 .

11. A magnetic recording medium, which comprises a magnetic layer on a nonmagnetic support and the magnetic layer is a layer formed by heating the composition according to claim 6 .

Assignees

• Fujifilm Corp

Inventors

• Aoshima Toshihide
• Katayama Kazutoshi

Classifications

• C08G18/7621

  being toluene diisocyanate including isomer mixtures · CPC title

• C07C271/40

  having oxygen atoms of carbamate groups bound to carbon atoms of six-membered aromatic rings · CPC title

• C08G18/724

  Combination of aromatic polyisocyanates with (cyclo)aliphatic polyisocyanates · CPC title

• C08G18/8029

  Masked aromatic polyisocyanates · CPC title

• C08G18/7642

  containing at least two isocyanate or isothiocyanate groups linked to the aromatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate groups, e.g. xylylene diisocyanate or homologues substituted on the aromatic ring · CPC title