| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polyester film for an optical use, which exhibits antistatic performance of a high level regardless of a humidity change, is highly transparent and excellent in scratch resistance, is less in uneven thickness of a coating layer, and is satisfactory in appearance. <P>SOLUTION: The polyester film, in which a coating layer (B layer) is laid over at least one side of a base-material polyester film (A layer), satisfies (a) and (b) described below. (a) The specific resistances of the B-layer-side surface at a temperature of 25°C and a relative humidity of 65% RH, and at a temperature of 25°C and a relative humidity of 30% RH are both equal to or lower than 10<SP POS="POST">10</SP>Ω/sq. (b) If the wavelength at which the surface reflectance at a wavelength of 350 to 800 nm of the B-layer-side surface at the total of 25 points at an interval of 250 mm in the widthwise direction and at an interval of 250 mm in the lengthwise direction in a section with a width of 1 m and a length of 1 mm is represented by λ min, and the reflectance at λ min is represented by R min, the difference between the maximum value and minimum value at λ min at the 25 measuring points is equal to or smaller than 30 nm, and the difference between the maximum value and the minimum value is equal to or less than 0.5%. <P>COPYRIGHT: (C)2012,JPO&INPIT |
