| 摘要 |
<p>PURPOSE:To contrive writing and readout in a noncontact state by forming a sheetlike magnetic recording layer capable of perpendicular magnetic recording obtd. by kneading a thermoplastic resin with magnetic powder and molding the kneaded material into a sheet shape. CONSTITUTION:This magnetic bard is composed of transparent protective layers 1, 7 each made of a transparent plastic film, printed layers 2, 6 using printing ink, hiding layers 3, 5 of a thermoplastic resin colored with an opaque pigment and a magnetic recording layer 4 capable of perpendicular magnetic recording. The magnetic recording layer 4 is formed by kneading a thermoplastic resin with magnetic powder and molding the kneaded material into a sheet shape. Polyvinyl chloride is optimum for use as the thermoplastic resin. Barium ferrite having <=1mum particle diameter and easy to disperse is generally used as the magnetic powder. The proper thickness of the recording layer 4 is 0.1-0.6mm and the proper weight ratio between the thermoplastic resin and the magnetic powder is 40:60.</p> |
