Patent ID: 8653232

Claim:
A manufacturing method of polyethylene terephthalate including a step of carrying out melt polycondensation by using a compound represented by the following general formula (I) as a polycondensation catalyst to obtain melt polycondensed polyethylene terephthalate having an intrinsic viscosity of from 0.48 to 0.53 dL/g and a terminal carboxyl number of from 14 to 22 mmol/kg; and a step of further solid phase polycondensing the melt polycondensed polyethylene terephthalate to obtain solid phase polycondensed polyethylene terephthalate having an intrinsic viscosity of from 0.70 to 0.86 dL/g: wherein R 1 represents an alkyl group having from 2 to 12 carbon atoms, and wherein the solid phase polycondensed polyethylene terephthalate has a terminal carboxyl number of less than 15 mmol/kg followed by a step of applying an aqueous solution of at least one salt selected from the group consisting of acetate, carbonate, and sulfate of sodium, potassium, or cesium to the solid phase polycondensed polyethylene terephthalate, and then drying the solid phase polycondensed polyethylene terephthalate, wherein the final content of sodium, potassium or cesium atom in dried polyethylene terephthalate is from 2 to 25 ppm, and from 2 to 25 ppm of at least one atom selected from the group consisting of sodium, potassium and cesium is contained in the solid phase polycondensed polyethylene terephthalate.