| 摘要 |
PROBLEM TO BE SOLVED: To provide an aromatic copolyester, which is obtained by copolymerizing a 6,6'-(alkylenedioxy)di-2-naphthoic acid component and has few surface defects in formation into a film, and a biaxially oriented film using the aromatic copolyester. SOLUTION: The aromatic copolyester comprises an aromatic dicarboxylic acid component and an alkylene glycol component, and on the basis of the whole acid components, a content of a 6,6'-(alkylenedioxy)di-2-naphthoic acid (ANA) component is 5-80 mol%. When molding the aromatic copolyester into a sheet with thickness of 5 μm, the number of surface high projection foreign matter containing sodium elements or potassium elements and sulfur elements is not more than 10 per 100 cm<SP>2</SP>. The biaxially oriented film using the aromatic copolyester is also provided. COPYRIGHT: (C)2010,JPO&INPIT
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