| 摘要 |
PURPOSE:To inexpensively obtain a magnetic recording medium having an excellent electromagnetic conversion characteristic and running durability in combination by providing a magnetic layer having <=4.0mum thickness, >=1.0% transmission of 900nm wavelength light and 0.004-0.030mum average surface roughness (Ra) and back coat layer contg. a carbon black. CONSTITUTION:This recording medium has the magnetic layer 2 having <=4.0mum thickness, >=1.0% transmittance of 900nm wavelength light and 0.004-0.030mum average surface thickness (Ra) and the back coat layer contg. the carbon black. The thickness of the magnetic layer is made preferably 2.5-3.8mum. Coating is difficult if said layer is too thin and therefore, the lower limit of the thickness is preferably <=1mum. The thickness of the back coat layer is made preferably <=1mum. At least a polyurethane is usable as the binder resin of the magnetic layer and can be synthesized by the reaction of polyol and polyisocyanate.
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