Continuous process for drying, crystallizing and solid state polymerizing polyesters

摘要

A continuous process is provided for the drying, crystallizing and solid state polymerization of fiber-forming crystallizable polyesters by subjecting polyester pellets of a specific viscosity of about 0.34, with a carboxyl concentration of about 15 milequivalents per gram and a particle size of between -10 and +20 mesh, to a temperature of not more than about 80 DEG C. until the water content of the flake is below 0.05%; and then raising the temperature to about 230 DEG -240 DEG C. until the specific viscosity of the polymer is equal to or greater than about 0.55.