| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester film roll which, when used in a capacitor production process, can be processed with good productivity solving process troubles such as thermal deterioration and poor margin precision. SOLUTION: The biaxially oriented polyester film roll is a polyester film roll produced by winding a film around a core, wherein the inner layer hardness h1 is 90 or higher along the length of 5-25% of the entire length from the core for the original film, the inner layer hardness h2 is 95 or smaller along the length of 30-80% of the entire length, and the inner layer hardness h3 satisfies the expression (1): 0≤(h1-h3)≤5 along the length of 85-95% of the entire length, and the air content is 5-25%. COPYRIGHT: (C)2008,JPO&INPIT |
