| 摘要 |
PURPOSE:To provide the title film useful as especially a base film of a magnetic recording medium capable of long-time recording and high-density recording and excellent in running properties and electromagnetic transduction performance. CONSTITUTION:A biaxially oriented polyethylene 2,6-naphthalate film having surface protrusion having a height distribution of the formula: [wherein h (nm) is the height of a protrusion], a surface roughness Ra of 40nm or below, a Young's modulus of elasticity in the machine direction (EM) of 650kg/mm<2> or above, a Young's modulus of elasticity in the transverse direction (ET) of 600kg/mm<2> or above, and a heat shrinkage in the machine direction of 0.08% or below when heated at 70 deg.C for 1hr without load. |
