PURPOSE: To lower the coefft. of dynamic friction and to improve durability by incorporating carbon blacks having specific average primary grain sizes and zinc oxide having a specific average grain size into nonmagnetic powder and incorporating nitrocellulose of a specific viscosity into a binder.

CONSTITUTION: The carbon blacks respectively having 20 to 40mμ and 50 to 100mμ average primary grain sizes and the zinc oxide having 0.5 to 1.0μm average grain size are incorporated into the nonmagnetic powder of the back coating layer. The nitrocellulose which is regulated in the optimum range of the mol. wt. by the viscosity and is specified in falling ball type viscosity to 1/8 to 1/3 second is used for the binder. The tape which is small in the coefft. of dynamic friction, is low in deck tension of the tape and has the good durability is obtd. in this way.