MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To stabilize the dispersion of magnetic particles by forming a dispersant constituting part of a magnetic layer of the resulted product of reaction of a silane coupling agent having a reactive org. functional group and org. polyisocyanate. CONSTITUTION:The dispersant is the compd. obtd. by the addition reaction of the isocyanate group of the org. polyisocyanate and the reactive org. functional group of the silane coupling agent and is the compd. bound with both groups by a -NHCONH- bond if, for example, the reactive org. functional group is an amino group. The magnetic particles are easily and stably dispersed in the stage of dispersing the magnetic particles into a liquid medium contg. the binder resin. The resulted dispersion is free from gelation, thickening or settling and separation of the magnetic particles by flocculation even after long-term preservation. Bleeding on the surface of the coated film and the decrease in the strength of the coated film are obviated and the electrical, chemical and physical performances of the coated film are not spoiled even if the magnetic layer is formed by coating the resulted dispersion on various bases and drying the same.