Composition for magnetic recording medium and magnetic recording medium

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.

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 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, which further comprises binder. 
     
     
         2 . The composition according to  claim 1 , which further comprises ferromagnetic powder. 
     
     
         3 . The composition according to  claim 2 , wherein the polyisocyanate comprises isophorone diisocyanate and a cyclic structure comprised in the polyhydroxyl compound is only one or more aromatic carbon rings. 
     
     
         4 . The composition according to  claim 2 , wherein an average particle size of the ferromagnetic powder ranges from 10 nm to 50 nm. 
     
     
         5 . 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 2 . 
     
     
         6 . 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 3 . 
     
     
         7 . 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 4 .