| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate the ruggedness of a card surface, to make the reading by a magnetic head sure and to prevent the arrangement patterns of magnetosensitive fibers from being sensed from outside by disposing a sheet body inclusive of the magnetosensitive fibers between two layers of the polyester resin film layers and specifying the surface flatness index of the resulted composite sheet to be in a specific range. SOLUTION: The composite sheet is obtd. by laminating the sheet body consisting of the magnetosensitive fibers between two layers of the film layers essentially consisting of the polyester resin by using a high-polymer adhesive. When the composite sheet simultaneously satisfies the following equations, the sheet is adequately usable as a base material for the magnetic recording card: S1 <=300, P<=20, N<=20, where S1 =P×N, p: the average peak height (μm) at a surface P mode curve, N: the number of peaks (pieces/50mm) at the peak height >=10μm at the surface P mode curve. Part or the whole of the film layers is composed of the polyester resin having opacity of >=0.3.</p> |
