| 摘要 |
PURPOSE:To obtain the title film improved in abrasion resistance, fatigue resistance and travelling properties by adding fine particles, other inert particles and/or internally deposited particles to a film so as to impart thereto a specified Young's modulus, a specified heat shrinkage and a specified surface roughness. CONSTITUTION:Polyethylene 2,6-naphthalate or its modified copolymer is mixed with 0.005-2.0wt.% fine particles selected from a silica, a silicone resin of formula II (wherein R is a 1-7C hydrocarbon group; and X is 1-1.2) and a crosslinked PS each of which has a volume shape factor of 0.2-pi/6, a relative standard deviation <=0.5 [as defined by formula I (wherein Di is the equivalent diameter (mum) of equal surface circle of a particle; D is the average value (mum) of the equivalent diameters, and n is the number of the particles] and a particle diameter of 0.3-2.5mum and other inert solid particles such as Al2O3 and/or internally deposited particles. The mixture is melt-extruded, and the extrudate is biaxially oriented and heat-set to obtain a film having Young's modulus >=650kg/mm<2> in the machine and crosswise directions, a difference between these moduli <=200kg/mm<2>, a heat shrinkage after standing at 70 deg.C for 1hr>=0.15%, a surface roughness of 0.01-0.05mum and a thickness of 1-50mum. |
