| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polyester film that shows excellent wet-heat durability, wherein cracks are less likely to occur even after the lapse of long time period under a wet-heat environment. <P>SOLUTION: The polyester film contains: a polyester resin; and two or more terminal blocking agents having number average molecular weights that are different by 4,000 or larger from each other or one another, wherein the tear strength retention at 120°C, at 100% relative humidity after the lapse of 60 hours under a wet-heat environment is 50% or larger. <P>COPYRIGHT: (C)2013,JPO&INPIT |
