| 摘要 |
PURPOSE:To improve running durability and wear resistance, to lower coefft. of friction and to decrease the generation of drop-outs by incorporating a specific compd. into and/or on a back coating layer. CONSTITUTION:A magnetic layer is provided on the front face of a nonmagnetic base and the back coating layer formed by dispersing carbon black and inorg. filler particles in a binder is provided on the rear face thereof. At least one kind selected from the group of the N-acyl-glutamate compds. expressed by the formula is incorporated into and/or on the back coating layer. In the formula, R<1> is an alkyl group, alkenyl group of 5-21C; R<2> and R<3> are an alkyl group, alkenyl group of 1-22C, n is 0-10 integer. The content of the compd. is 1-15wt.% of the eight of the binder and the compd. is made to exist at 1-500mg/m<2> in the surface of the back coating layer as well. The thickness of the back coating layer is <=0.6mum and the inorg. filler particles having the average grain size of >=1/5 of the thickness and the max. particle size of <=11/10 of the thickness and >=5 Mohs' hardness are incorporated into the layer. |
