| 摘要 |
PURPOSE:To provide a polyethylene-2,6-naphthalate film useful for the base of magnetic recording tape excellent for electromagnetic conversion characteristics, anti-dropout, durability, anti-skew and the like. CONSTITUTION:The polyethylene-2,6-naphthalate film concerned has lengthwise. Young's modulus (EM) of 650kg/mm<2> or more, widthwise Young's modulus (ET) of 850kg/mm<2> or more, the difference between the Young's moduli (ET-EM) of 100kg/mm<2> or more, thermal shrinkage factor held at 70 deg.C for one hour of 0.10%, surface center-line mean roughness of 0.006-0.012mum Ra and contains 0.005-2wt.% of fine particles having the average particle diameter of 0.2-2.5mum, volume shape factor of 0.2-pi/6 and relative standard deviation of 0.5 or less. |
