| 摘要 |
<p>PURPOSE:To increase the orientation and the wear resistance of a magnetic recording medium, by using simultaneously a thermoplastic polyurethane resin and nitrocellulose as a binder of a magnetic layer including ferromagnetic fine powder. CONSTITUTION:(A) A thermoplastic polyurethane resin or a polyurethane prepolymer, and (B) nitrocellulose having about 50-300 average polymerization degree and 10.7-13 nitrification degree are mixed as 1/9-1/1 weight ratio of B/A, and preferably about 5-50pts.wt. polyisocyanate compound (e.g., ethane diisocyanate) based on 100pts.wt. this mixture. The mixture is used as a binder, which is mixed with ferromagnetic fine powder (e.g., ferromagnetic iron oxide) of >=30m<2>/g specific surface area. The resulting product is coated, oriented and dried on a nonmagnetic support to form a magnetic layer for an objective magnetic recording medium.</p> |
