Patent ID: 6590062
Filing Date: 2003-07-08
Classification: B01J,C08G

Abstract:
A method for continuously producing polybutylene terephthalate, which comprises producing an oligomer by reaction of (a) an aromatic dicarboxylic acid comprising terephthalic acid as a main ingredient or a derivative thereof with (b) a glycol comprising 1,4-butanediol as a main ingredient and then polycondensing the oligomer in series of a plurality of reactors,wherein polycondensation reaction of an average degree of polymerization of 20 to 70 in the polycondensation of the oligomer is carried out in a reactor having a plurality of partitioned concentric reaction compartments in a vertical cylindrical polymerization vessel, provided with stirring blades and a heater in reach of the reaction compartments, and provided with an outlet for volatile matters at an upper part of the vessel, and wherein the polycondensation reaction includes successively transferring a process solution to be treated in the reaction compartments.