POLYETHYLENE ISOPHTHALATE HAVING REDUCED CYCLIC DIMER CONTENT AND PROCESS THEREFOR

摘要

This invention relates to polyethylene isophthalate (PEI) and copolymers thereof having low cyclic dimer content and process for making same. The invention provides a process for making PEI using protonic acid catalysts which result in a polymer having lower amounts of ring dimer of ethylene isophthalate than has heretofore been known. Strong protonic acids such as sulfuric or phosphoric are utilized as polymerization catalysts to thereby lower the amount of cyclic dimerization which occurs during the polymerization process. Polymers so produced are of a high purity and have reduced manufacturing costs due both to a smaller amount of material being lost as cyclic dimer and because of lower processing costs associated with cleaning cyclic dimer from the processing equipment.