Polyester resin composition, polyester-based injection-molded article, polyester-based extruded article, polyester-based foam, polyester-based container, polyester-based bottle, polyester-based tableware, and polyester-based nursing bottle

A polyester resin composition comprising:

• 97.0% by mass or more and 99.9% by mass or less of a polyester resin (A);
• and 0.1% by mass or more and 3.0% by mass or less of a polycarbodiimide (B),
• wherein a dicarboxylic acid constituent unit in the polyester resin (A) comprises a terephthalic acid unit and/or a 2,6-naphthalenedicarboxylic acid unit,
• 5% by mol or more and 90% by mol or less of a diol constituent unit in the polyester resin (A) is a unit derived from a diol having a cyclic acetal skeleton represented by the following formula (1) or formula (2), and 0% by mol or more and 90% by mol or less of the diol constituent unit is a unit derived from an alicyclic diol, and
• the polycarbodiimide (B) has two or more carbodiimide groups in one molecule thereof:
• wherein R1 and R2 each independently represent an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 or more and 10 or less carbon atoms, or an aromatic group having 6 or more and 10 or less carbon atoms, and
• wherein R1 is as defined above;
• and R3 represents an aliphatic group having 1 or more and 10 or less carbon atoms, an alicyclic group having 3 or more and 10 or less carbon atoms, or an aromatic group having 6 or more and 10 or less carbon atoms, and
• wherein the polycarbodiimide (B) comprises an aliphatic polycarbodiimide, and has a degree of polymerization of 5 or more and 30 or less.