Abstract: A device for making polybutylene terephthalate includes (1) a slurry paste vessel; (2) a tower reactor to which a mixture of 1,4-butane diol and terephthalic acid from vessel (1) is supplied, the tower reactor having a plurality of reactor zones wherein the lower third of the tower reactor is in the form of a hydrocyclone with attached heat exchanger, and the hydrocyclone has a supply line from vessel (1), the hydrocyclone being connected to the top side of the tower reactor; (3) a first continuously stirred tank reactor to which the product from tower reactor (2) is supplied; (4) an optional second continuously stirred tank reactor to which the product from (3) is supplied; (5) a dual shaft ring reactor to which the product from stirred tank reactor (3) or (4), is supplied; and (6) a pelletizer where the product from dual shaft ring reactor (5) is continuously fed and pelletized.

Abstract: Disclosed is a continuous process and device for making polybutylene terephthalate (PBT) resin, particularly high molecular weight PBT resin. Also disclosed are a device for conducting the process, and a monitoring process for determining the carboxylic acid end group concentration of the resulting PBT.

Abstract: Disclosed is a continuous process and device for making polybutylene terephthalate (PBT) resin, particularly high molecular weight PBT resin. The process includes combining 1,4-butane diol and purified terephthalic acid to form a mixture and continuously supplying the mixture to a tower reactor having a plurality of reactor zones for esterification and/or transesterification. The product is continuously supplied to a first continuously stirred tank reactor, and further to a continuous polycondensation reactor. Particular conditions for each step of the process are further described herein. Also disclosed are a device for conducting the process, and a monitoring process for determining the carboxylic acid end group concentration of the resulting PBT.

Abstract: Disclosed is a continuous process and device for making polybutylene terephthalate (PBT) resin, particularly high molecular weight PBT resin. Also disclosed are a device for conducting the process, and a monitoring process for determining the carboxylic acid end group concentration of the resulting PBT.