Patent ID: 6458916
Filing Date: 2002-10-01
Classification: B01J,C08G

Abstract:
An apparatus for continuously producing polybutylene terephthalate, which comprises a first reactor for reacting an aromatic dicarboxylic acid comprising terephthalic acid as a main ingredient or a derivative thereof with a glycol comprising 1,4-butanediol as a main ingredient, thereby producing an oligomer with an average degree of polymerization of 2 to 5; a second reactor for polycondensating the oligomer from the first reactor, thereby preparing a low polymerization product with a low degree of polymerization; and a third reactor for further polycondensating the low polymerization product from the second reactor, thereby producing a high molecular weight polyester with an average degree of polymerization of 70 to 180, where the second reactor is a vertical, cylindrical polymerization vessel having a plurality of concentrical partitioned reaction compartments therein, each of the reaction compartments being provided with stirring blades and a heater, and an outlet for volatile matters being provided at the upper part of the vessel.