| abstract |
The polyester film roll, which is free from wrinkles and slacks generated with the passage of time and is having a good roll appearance, is provided without changing the characteristics of the film. n The polyester film roll is a polyester film roll in which a polyester film is rolled on a core, characterized in that the difference R (m) between the maximum value and the minimum value is not more than 2 W×10 −3 and not more than L×10 −7 , when the diameters of said roll are measured in the width direction of the roll, (therein, W is the width (m) of the film roll, and L is the rolled length (m) of the film roll), or a polyester film roll in which a polyester film is rolled on a core, characterized in that, among the lengths of lines which are obtained by measuring the diameters of said roll in the width direction of the roll, drawing a straight line between both the ends of the curved line of the obtained roll diameters, and then vertically drawing the lines from said curved line to said straight line, the maximum length (maximum convex portion) on the convex portion side from said straight line is not more than 500 μm, and the maximum length (maximum concave portion) on the concave portion side from said straight line is not more than 300 μm. |