Patent ID: 7868125

Claim:
A polyester polymer production process comprising: (a) forming polyester polymer particles from a polyester polymer melt in a particle forming zone; (b) subsequent to step (a), quenching at least a portion of said particles via contact with a quench liquid in a quenching zone; (c) subsequent to step (b), drying at least a portion of said particles in a drying zone; (d) subsequent to step (c), crystallizing at least a portion of said particles in a crystallizing zone; and (e) subsequent to step (d), annealing at least a portion of said particles in an annealing zone wherein said particles have a residence time in said annealing zone of between 1 hour and 24 hours, wherein at all points during and between steps (b) through (e) the average bulk temperature of said particles is maintained above 165° C., wherein the It.V. of said particles produced from said particle forming zone is within about 5 percent of the It.V. of said particles produced from said annealing zone, and wherein said polyester polymer melt comprises a carboxylic acid component and a hydroxyl component, wherein said carboxylic acid component comprises at least 80 mole percent of the residues of terephthalic acid and/or derivatives thereof, wherein said hydroxyl component comprises at least 80 mole percent of residues of ethylene glycol.