| 摘要 |
PROBLEM TO BE SOLVED: To attain excellent biodegradability, a low degree of gasification and a low degree of oligomerization by setting the ratio of the intensity of the main peak and the ratio of the difference between the maximum slope and the minimum slope of the main peak to the jump height in an X-ray absorption spectrum of an aliphatic- aromatic polyester synthesized by a Ti composite catalyst to the corresponding intensity and difference of an aliphatic-aromatic polyester synthesized by a Ti sole catalyst to a specific value or higher, respectively, and by setting the reduced viscosity to a specific value or more. SOLUTION: The subject polyester satisfies the relationships: R1A/R1B>1.05 and r1A/r1B>1.05, wherein R1A and r1A are R1 and r1, respectively, for an aliphatic-aromatic polyester synthesized by a Ti-containing composite catalyst, R1B and r1B are R1 and r1, respectively, for an aliphatic-aromatic polyester synthesized by a Ti sole catalyst, and R1 is a ratio of the intensity of the main peak among pre-edge peaks around 4.965-4.972 keV near the absorption edge to the jump height at the K absorption edge of Ti and r1 is the difference of the maximum slope and the minimum of slope of the main peak to the jump height at the K absorption edge of Ti, in a spectrum obtained by subtracting the background from an X-ray absorption near-edge structure in an X-ray absorption fine structure analysis. Further, this polyester has a reduced viscosity (ηsp/c) of not less than 0.6.
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