| 摘要 |
PURPOSE:To obtain a magnetic recording medium which has a small coefft. of dynamic friction, does not generate sticking at and under a high temp. and high humidity and has an excellent traveling property by incorporating the powder of a methacrylate crosslinked polymer into a back coat layer. CONSTITUTION:A coating compd. is prepd. by sufficiently mixing and dispersing 0.5pt.wt. powder of PMMA (polymethyl methacrylate), 100pts.wt. carbon black, 60pts.wt. nitrocellulose, 50pts.wt. polyurethane, 2pts.wt. lubricating agent and 450pts.wt. solvent with a sand mill, then adding and mixing 30pts.wt. hardener of a polyisocyanate system. Such coating compd. is coated on the surface of a nonmagnetic base (base film) on the side opposite to the surface on which a magnetic layer is formed. The coating is then subjected to drying and surface treatment to form the layer (back coat layer) of about 0.3-1.5mum thickness, by which the magnetic tape is obtd. The tape has the small coefft. of dynamic friction and does not generate sticking even at and under the high temp. and high humidicity and, therefore, the recording medium has the excellent traveling property. Since the brightness is of a sufficiently high value, the magnetic recording medium having the excellent electromagnetic conversion characteristics, SN ratio, etc., is obtd. |
