| 摘要 |
PROBLEM TO BE SOLVED: To eliminate such problems that the central section of a wound biaxially drawn polyester film is extended to be slightly longer than the side end section, and the central section is thickly coated in the following coating process. SOLUTION: This biaxially drawn polyester film is used as a supporting body for a photographic film, and a difference in a heat shrinkage rate between the central section and the side end section at 115 deg.C is 0.04% or lower. Such a biaxially drawn polyester film is obtained by controlling a temperature difference between the central section and the side end section in a heat fixing zone and a heat relaxing zone of the polyester film, of which the biaxial drawing is completed, to be 10 deg.C or lower.
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