Patent ID: 8293162

Claim:
A method for producing a molded product consisting of a resin polymerized by a melt polycondensation reaction, comprising continuous feeding of a prepolymer in molten state from a prepolymer feeding port to a polymerization reactor, discharging from holes of a porous plate, followed by producing a resin by polymerization while dropping along a supporting substrate under reduced pressure, discharging said resin from at least one discharge pump, followed by molding by transferring to at least one molding machine in molten state without solidification, wherein a transfer pressure between said polymerization reactor and said molding machine is controlled to maintain said transfer pressure at an arbitrary pressure from 0.1 to 100 MPa (absolute pressure) and within ±80% of set pressure by (I) controlling an output amount of the at least one discharge pump to be 1.0 to 100 times a feed amount of the prepolymer and by (II) returning a resin discharged from the at least one discharge pump to a bottom of said polymerization reactor, using a pipeline connected to a downstream side of the at least one discharge pump and connected to the bottom of said polymerization reactor, using a system for output pressure detection, and controlling an opening degree of a polymer return valve or a back pressure valve installed at said pipeline, said resin is discharged so that a polymer melt residence time at the bottom of said polymerization reactor is controlled from 0.1 to 120 minutes, by transferring said resin to a pelletizer and/or discharge nozzle by installing a transfer pump connected to the pelletizer and/or the discharge nozzle in addition to a molding machine at the bottom of said polymerization reactor or after the at least one discharge pump, and the inlet of the pipeline is positioned downstream from the supporting substrate.