| 摘要 |
PURPOSE:To improve the traveling property and output characteristic of the tape by specifying the correlative coefft. of the standard deviation of the projecting height distribution and normal distribution of the nonmagnetic surface of the tape to a specific range, thereby substantially eliminating coarse projections. CONSTITUTION:The standard deviation of the projection height distribution of the nonmagnetic surface of the tape is 50-130nm and the projection height distribution has >=0.80 correlative coefft. with the normal distortion; in addition, the max. height of the projections is designated as H and the spacing of the projections exceeding 300nm height as L and the ratio (H-300)/L thereof is <=6.0. The surface projections on the nonmagnetic surface of such video tape are caused by the particles contained in polyester. The kinds of the particles are not particularly limited if the particles are inert to the polyester. Such particles are preferably of colloidal silica, calcium carbonate, alpha-alumina, titanium dioxide of a rutile type, carbon black of a thermal type, etc. The back-coatless video tape having the excellent traveling property and output characteristics is thereby obtd. without back coating. |
