| 摘要 |
PURPOSE:To obtain the titled medium which is free from back coat chipping and tape injuring after repetitive running and has excellent running durability by constituting the medium in such a manner that nonmagnetic powder contains a flat plate-like of fibrous basic calcium carbonate crystal. CONSTITUTION:The recording medium which has a magnetic layer on one face of a substrate and contains the nonmagnetic powder in the other face is so constituted that the nonmagnetic powder contains the flat plate-like or fibrous basic calcium carbonate crystal. The calcium carbonate belongs to a hexagonal or rhombic system and the fibrous crystal is formed in the flat plate-like or fibrous crystal and rhombic system among the crystal shapes that the hexagonal system can take. The flat plate-like or fibrous crystal is selectively used for the basic calcium carbonate. The average grain size of the calcium carbonate crystal is 0.01-1mum, more preferably 0.05-0.8mum. The magnetic tape which has the good properties of the back coat layer, has high wear resistance, toughness and filler holding property, is free from tape deformation and abnormality during repetitive running, obviates the fluctuation of the properties and the high repetitive durability is thus obtd.
|
