POLYETHYLENE NAPHTHALENEDICARBOXYLATE AND BOTTLE

摘要

PROBLEM TO BE SOLVED: To obtain the subject polymer excellent in appearance such as hue or transparency and suitable for bottle uses by using an antimony compound as a polycondensation catalyst and specifying the amount of the antimony compound and the intrinsic viscosity of the resultant polyester. SOLUTION: This polyethylene naphthalenedicarboxylate is obtained by using an antimony compound as a polycondensation catalyst and the crystallinity satisfies the formula [Xc is the crystallinity; the amount of the Sb catalyst is the amount of the antimony compound based on the total acid component (a value expressed in terms of antimony trioxide: mmol.%); IV is the intrinsic viscosity of the polymer]. Antimony trioxide is preferred as the antimony compound and preferably added in an amount of 5-20 mmol.% expressed in terms of the antimony trioxide and based on the total acid component thereto. The polymer is preferably prepared by providing a prepolymer by conducting the melt polymerization and then carrying out the solid-phase polymerization. The objective polymer preferably has 0.4-0.8 intrinsic viscosity, <=42% crystallinity and >=65 value of the color L.