| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester film excellent in mechanical properties, having high crystallinity, without becoming white on heat-treating in the vicinity of its melting point or at higher than the melting point on pasting with a metal plate, excellent in designing property, without showing the cleavage of the film, and having good piercing strength. SOLUTION: This polyester film consisting of a polyester-based resin composition obtained by blending (A) a polyethylene terephthalate-based resin with (B) a crystalline polyester resin which is different from the resin (A) in a ratio of 10-90 wt.% (A) with 90-10 wt.% (B) based on the total amount of the resin (A) and resin (B) is provided by having≥30 nm<SP>-1</SP>of 1/2 of a streak length in a Fourier image which is an index of showing the dispersed state of the inside of the resin measured by a transmission electron microscope in the cross sectional direction of the film. The resin (B) is selected from a polybutylene terephthalate and polytrimethylene terephthalate. COPYRIGHT: (C)2005,JPO&NCIPI
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