Patent ID: 7204962
Filing Date: 2007-04-17
Classification: C08G

Abstract:
1. An apparatus for continuously producing polybutylene terephthalate, comprising: a first reactor in which an aromatic dicarboxylic acid comprising terephthalic acid, or a derivative thereof, as a main ingredient reacts with a glycol comprising 1,4-butanediol as a main ingredient, said first reactor having the reaction carried out at 220–250° C. and 33 kPa to 150 kPa, thereby producing an oligomer; a second reactor in which the oligomer from the first reactor is polycondensated, said second reactor having said polycondensating carried out therein at 230–255° C. and 100 kPa to 0.133 kPa, thereby preparing a low polymerization product; a third reactor in which the low polymerization product from the second reactor is further polycondensated, said third reactor having said further polycondensating carried out therein at 230–255° C. and 0.665 kPa to 0.067 kPa, thereby producing a high molecular weight polyester; and a recycle line along which said glycol, tetrahydrofuran and water generated from outputs from said second reactor or third reactor by being condensed are supplied to a conditioning vessel in which said main ingredients are conditioned in a predetermined ratio for the first reactor.