MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To improve durability and wear resistance by smoothing the surface by using pulverous ferromagnetic particles which have a flat plate shape and the direction of the easy magnetization perpendicular to the flat plate surface. CONSTITUTION:A magnetic layer contg. the pulverous ferromagnetic particles which has the flat plate shape and the direction of the easy magnetization perpendicular to the flat plate surface, polyurethane resin having the metallic base of sulfonic acid at 20-500equivl./10<6>g per polymer and 1 or >=2 kinds of ester compds. consisting of a fatty acid of 10-18C and alcohol of <=15C is coated on a nonmagnetic base material to form a magnetic recording medium. The copolymn. amt. of the dicarboxylic acid component contg. the metallic base of the sulfonic acid is made >=0.5mol% of the total carboxylic acid component. The polyurethane resin is obtd. by bringing a polyhydroxy compd. and polyisocyanate into reaction. The preferable compounding ratio thereof is 0.5-2/1 the NCO group of the polyisocyanate/the OH group of the polyhydroxy compd. The magnetic recording medium having the excellent surface smoothness and the excellent wear resistance and durability in a wide temp. and humidity range is obtd.