| 摘要 |
PROBLEM TO BE SOLVED: To prevent occurrence of neck-in, rolling or breakage of film by providing at least one layer of copolymer polyester satisfying specified conditions and having a melt viscosity satisfying a specified formula, and at least one metal later. SOLUTION: The multilayer structure comprises at least one layer of copolymer polyester and at least one metal layer. The copolymer polyester layer principally comprises a terephthalic acid unit and an ethylene glycol unit and further comprises 2-30 mol.% of bifunctional compound unit other than terephthalic acid unit and ethylene glycol unit, and 0.005-1 mol.% of polyfunctional compound unit of trifunctional or above based on the total molar mass of the entire structural unit of copolymer polyester. Semicrystallization time is 1500-3500 sec at 160 deg.C, shearing rate is 0.1 at 270 deg.C, melting viscositiesη1 ,η2 are 5×10<4> -2×10<6> , 8×10<3> -2×10<4> poise at 100 rad/sec and the melting viscositiesη1 ,η2 satisfy a formula. |
