| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester film having flex pin hole resistance and stick resistance both being required for a film for a packaging material while keeping characteristics of the polyester such as low hygroscopicity, dimensional stability, flatness and transparency. SOLUTION: A laminated polyester film comprises thermoplastic resin layers (A) each composed mainly of an aromatic polyester A having a melting point of 225 to 265°C, and thermoplastic resin layers (B) each being composed of a resin mixture of 90 to 99.8 wt.% of an aromatic polyester B having a melting point of 215 to 265°C and 0.2 to 10 wt.% of a thermoplastic resin having a glass transition temperature of not higher than 20°C, the layers A and the layers B alternately overlying each other up to five or more layers. The laminated polyester film shows an index of refraction of not higher than 1.515 in the thickness direction. COPYRIGHT: (C)2005,JPO&NCIPI
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