| 摘要 |
PROBLEM TO BE SOLVED: To prepare a polyester sheet composed mainly of a specific polyester resin, having specific physical properties, excellent in ultraviolet-screening properties, transparency, thermal stability and recyclability, and useful for packaging container, etc. SOLUTION: This polyester sheet consists of main components of terephthalic acid, ethylene glycol, etc., and copolymerization components of a naphthalene tetracarboxylic acid diimide of formula I [R is a 1-20C (substituted) alkylene, arylene, etc.; X is OH, carboxyl, etc.] in an amount of C1wt.% (based on the total polyester) and a naphthalene dicarboxylic acid of formula II in an amount of C2wt.%. The polyester sheet has an intrinsic viscosity in the range of 0.4-1.5 and a thickness (d) of 100-12,000μm and satisfies 10<=(C1×d)<=120. Further, the sheet satisfies 10<=(A×d) when a UV-cutting coefficient A is defined by formula III. A film is obtained by subjecting the sheet to uniaxial or biaxial orientation. |
