| 摘要 |
<p>PROBLEM TO BE SOLVED: To surely prevent the alteration of a magnetic card such as the overwrite, rewrite of the recorded magnetic information by forming a magnetic layer on the surface of a substrate and preparing a radio wave absorption layer consisting of the radio wave absorption powder at least at a part of the magnetic layer. SOLUTION: A magnetic card 1 contains a magnetic layer 3 formed on the primary side of a substrate 2 and a radio wave absorption layer 4 formed on the layer 3. When the layer 3 is formed, the magnetic powder of a prescribed composition is mixed with a solvent, etc., into a magnetic coating material and this material is applied on a substrate 1 with the prescribed thickness and then dried. The layer 4 is obtained by mixing the radio wave absorption powder of a prescribed composition with a solvent, etc., producing a sheet by the extrusion molding, cutting the sheet in a prescribed size and adhering the cut sheet on the layer 3. Then the information is recorded on the card 1 through magnetization of the layer 3. The layer 4 is deleted after the card 1 is used. The using condition of the card 1 is decided by measuring the radio wave absorption value of optional frequency.</p> |
