| 摘要 |
PURPOSE:To improve the surface smoothness of the subject film by incorporating spindle-shaped CaCO3 particles having a specified particle diameter ratio, a specified mean value of the equivalent diameter of equal-area circle, and a specified relative standard deviation of the equivalent diameter together with at least one kind of fine particles selected from the group consisting of Al2O3, SiO2, and TiO2 into the film. CONSTITUTION:0.001-0.10wt.% spindle-shaped CaCO3 particles having a particle diametr ratio of 1.5-10 a means value of the equivalent diameter of equal-area circle of 0.4-1.0mum, and a relative standard deviation calculated by equation I (wherein Di is an equivalent diameter of equal-area circle of the particles; D is a value of the equivalent diameter and calculated by equation II; and (n) is the number of particles) of 0.5 or lower and 0.05-1.0wt.% at least one kind of fine particles selected from the group consisting of Al2O3 SiO2, an TiO2 each having a specific surface area of 50-120mm<2>/g, content of small voids of 0.5-1.0ml/g, and a mean particle diameter of 0.02-0.30mum are added to raw materials of a polyester, which is then polymerized, the polymn. product is formed into a film and stretched to give the objective film, which has a height X of a distrubtion curve of projections at the film surface of at least 0.02mum, the number of projections Y which satisfies an inequality III and is at least 50/mm<2>, and the number of observed under a Tl monochromatic multiple-interference reflecting microscope if less than 1/10cm<2>. |
