Patent ID: 8013107

Claim:
A method of producing polyalkylene terephthalate, which comprises: introducing a prepolymer of polyalkylene terephthalate that is in a molten state comprising 70 mol % or more of ethylene terephthalate or 1,4-butylene terephthalate repeating units and having an intrinsic viscosity [η] between 0.2 and 2 dl/g through a feed opening into a polymerization reactor; discharging the introduced prepolymer through holes of a perforated plate; and then polymerizing the prepolymer under reduced pressure, while allowing the prepolymer to fall along the surface of a support that is open towards the outside at a temperature between the [crystalline melting point −10° C.] of the prepolymer or higher and the [crystalline melting point +30° C.] of the prepolymer or lower under the conditions represented by the following formula (1); S 1 /S 2 >1 (1) wherein S 1 : the surface area of falling polyalkylene terephthalate, and S 2 : the area where the support is in contact with polyalkylene terephthalate.