| 摘要 |
<p>PURPOSE:To improve a cinching phenomenon, the wear of a back layer, the adhesion between a magnetic layer and the back layer, a video S/N, etc., by obtaining the back layer of a magnetic recording medium (tape) by dispersing the nonmagnetic powder into a specific binder. CONSTITUTION:A composition for a back layer is obtained by dispersing (E) nonmagnetic powder (such as CaCO3, carbon black, etc.) into a binder containing (A) 15-60wt% nitrocellulose, (B) 15-60wt% polyvinyl chloride-polyvinyl acetate copolymer, (C) 10-70wt% polyurethane (the composition within the range shown by oblique lines in the figure) and (D) 5-80wt% isocyanate compound per 100 wt% total quantity of resin. This composition is coated on the rear surface of a supporter (such as polyethylene terephthalate film) containing a magnetic recording layer on the upper surface. Thus a back layer is obtained.</p> |
