| abstract |
THE PROCESS OF THIS INVENTION FOR PREPARING A FINAL COPOLYESTER HAVING AN INHERENT VISCOSITY OF AT LEAST 0.4 IS COMPRISED OF TWO STEPS. THE FIRST STEP OF THE PROCESS COMPRISES PREPARING A FRAGMENTED POLYESTER BY CONTACTING AN ACYLOXY AROMATIC CARBOXYLIC ACID WITH A STARTING POLYESTER WHICH HAS AN INHERENT VISCOSITY OF AT LEAST 0.2 AND IS FORMED FROM A DICARBOXYLIC ACID AND A DIOL. THE SECOND STEP COMPRISES INCREASING THE INHERENT VISOCITY OF THE FRAGMENTED POLYESTER TO AT LEAST 0.4 TO FORM THE FINAL COPOLYESTER. WHEN THE STARTING POLYESTER AND ACYLOXY AROMATIC CARBOXYLIC ACID ARE CONTACTED, ACIDOLYSIS OCCURS AND THERE IS FORMED A FRAGMENTED POLYESTER COMPOSED OF LOW MOLECULAR WEIGHT POLYESTER MOLECULES. THE INHERENT VISCOSITY OF THE FRAGMENTED POLYESTER IS THEN INCREASED TO FORM THE FINAL COPOLYESTER COMPRISED OF DIVALENT RADICALS FROM THE DICARBOXYLIC ACID PORTION OF THE STARTING POLYESTER, DIVALENT RADICALS FROM THE DIOL PORTION OF THE STARTING POLYESTER AND DIVALENT RADICALS REMAINING AFTER REMOVAL OF THE ACYL AND HYDROXY GROUPS FROM THE ACYLOXY AROMATIC CARBOXYLIC ACID. |