PROCESS FOR PRODUCING POLY TRIMETHYLENE TEREPHTHALATE

摘要

A process for producing poly (trimethylene terephthalate) is provided to mass-produce the poly (trimethylene terephthalate) by using one or two reactors simply and conveniently. A process for producing poly (trimethylene terephthalate) comprises a step of feeding 1,3- propanediol and terephthalic acid or 1,3- propanediol and dimethylterephthalate, to an input hole(F11) of one or two reactors or one kneader-type extruder, so that the molar ratio of propylene and terephthalate group becomes 1.1-2.2; a step of producing the low-molecular-weight poly (trimethylene terephthalate) through direct esterification or transesterification within a reactor or kneader-type extruder; a step of producing the high molecular weight poly (trimethylene terephthalate) through polycondensation by feeding a polymerization catalyst and additive in a secondary input hole(F12) of a reactor or kneader-type extruder and applying the vacuum at the later part(P2) of the reactor or kneader type extruder; and a step of palletizing it by using pelletizer connected to the reactor or kneader type extruder.