MAGNETIC RECORDING MEDIUM AND ITS PRODUCTION

摘要

PURPOSE:To obtain a magnetic recording medium having a uniform magnetic layer and excellent durability by using magnetic powder formed by holding a specific fatty acid on the surface of the magnetic powder and using a polyurethane resin contg. a sulfonic acid metal base as a binder. CONSTITUTION:The magnetic layer provided on a nonmagnetic base contains the polyurethane resin contg. the sulfonic acid metal base as a binder resin and the magnetic powder exists therein in the state of holding the fatty acid of 12-18C on the powder surface. The content of the sulfonic acid metal base in the polyurethane is preferably 20-600equiv./10<6>g per polymer. The fatty acid of 12-18C is exemplified by unsatd. fatty acids such as lauric acid, linoic acid, stearolic acid and ricinoleic acid. The high density magnetic recording medium contg. the magnetic powder uniformly packed at a high density in the magnetic layer is thereby obtd.