| 摘要 |
PURPOSE:To obtain a coating film having good dose efficiency, smoothness and durability, by coating a dispersion on a substrate then applying a vertical magnetic field to the surface of the substrate to orient the surface of the substrate vertically and drying the solvent. CONSTITUTION:A viscous dispersion obtd. by 100pts.wt. gamma-Fe2O3, 30pts.wt. resin, 5pts.wt. lauric acid, 5pts.wt. carbon black dispersion and 250pts.wt. solvent is coated on a substrate with the device shown in the figure. More specifically, a coater 3 is used as a doctor blade, and the dispersion is coated therewith on a substrate 2 which is a polyethylene terephthalate film of 15-100mu thick so as to have 2-10mu final film thickness, whereafter 2,000Oe vertical magnetic field is applied thereto by a vertical orienting magnet 4 while the coated magnetic layer is not yet dried and hardened, so that the magnetic particles are oriented perpendicularly to the plane of the substrate. Thereafter, the low b.p. solvent is removed with a dryer 5 at 100-120 deg.C and electron rays are irradiated to the coating film with an electron accelerator of a curtain system of 300-150kV acceleration voltage and 10-15mA beam current used as an electron ray irradiator 6, at 1Mrad/sec dose rate so as to have 2-3Mrad absorption dose. |
