Magnetic recording material e.g. for video use - has low water content uppermost magnetic layer contg. magnetic metal powder for improved electromagnetic conversion property

摘要

Novel material comprises non-magnetic substrate supporting several magnetic layers, the uppermost layer contg. a magnetic metal powder, contg. 0.002-0.015 pts. wt. water (w.r.t. 1 pt. wt. of the magnetic metal powder) prior to mixing with coating materials, and another layer (different from the uppermost layer) having a coercive force of 500-1200 Oe. Also similar recording material for 8 mm video use, has uppermost layer of less than 1.5 microns thick and contg. magnetic metal powder with a BET value of 56-80 sq. m/g., while the layer with 500-1200 Oe coercive force is a 1.5-4.0 microns thick layer adjacent the uppermost layer. ADVANTAGE - Material contains little residual solvent, has good durability, has improved electromagnetic conversion properties (e.g. good colour reproducibility) and produces coating components by kneading.