| 摘要 |
PURPOSE: To prepare the subject film suitable as a substrate film for a magnetic recording medium requiring fine and uniform surface projections, not causing occurrence of defect of foreign matters resulting from surface precipitate and contamination with contact materials, containing an amount of a low-molecular weight substance precipitated on the surface equal to or smaller than a specific amount. CONSTITUTION: This film is a polyethylene-2,6-naphthalate film containing <=0.7mg/m<2> low-molecular weight substance precipitated on the surface when heated at 170 deg.C for three hours and contains wax having 20-250 deg.C melting point. This film, for example, is obtained by heat-treating polyethylene-2,6-naphthalate granules in a gas atmosphere of noncirculating nitrogen under normal pressure at 150-250 deg.C and making it into a film. |
