Polyethylene-2,6-naphthalate composition with excellent blow moldability, and molded product thereof

A polyethylene-2,6-naphthalate composition comprising a phosphorus compound represented by the following formula (I), cobalt element derived from a cobalt compound, manganese element derived from a manganese compound, and antimony element derived from an antimony compound, the content of each of the elements simultaneously satisfying the following expressions (1) to (4):

• wherein R represents an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a benzyl group;
• 10≤Co≤30 mmol % (1)
• 0.50≤P/Mn≤1.28 (2)
• 10≤Sb≤25 mmol % (3)
• 0.60≤IV≤1.50 dL/g (4)
• in the expressions (1) to (4), Co, P, Mn, and Sb respectively represent the content of the cobalt element derived from the cobalt compound, the content of the phosphorus compound represented by the formula (I), the content of the manganese element derived from the manganese compound, and the content of the antimony element derived from the antimony compound, per mole of a dicarboxylic acid component constituting polyethylene-2,6-naphthalate in the polyethylene-2,6-naphthalate composition, and IV represents the intrinsic viscosity of the polyethylene-2,6-naphthalate composition;
• and
• wherein the dicarboxylic acid component constituting polyethylene-2,6-naphthalate is only 2,6-naphthalene dicarboxylic acid.