PURPOSE: To obtain a magnetic recording medium which excels in traveling durability without causing any deterioration of S/N property, any increment of friction coefft., by providing a back layer that contains the inorganic powder obtained by combining fine and coarse particles.
CONSTITUTION: Inorganic powder is obtained by mixing a pts. vol. inorganic coarse particle (such as Al2O3 particle) of 0.1W0.8μ mean grain size (a) and 10pts.vol. inorganic coarse particles (such as CaCO3 particle) of 0.01W0.1μ mean grain size (b). Then a coating material containing above-mentioned inorganic powder and a binder in a ratio of about 2.5W0.1/1wt% is coated on the back (opposite to the magnetic layer) of a supporter and dried to from a back layer of ≤2μ thickness (preferably 0.5W1μ).
OKUTSU TOSHIMITSU
FUJAMA MASAAKI
