Process for the crystallization of polyethylene naphthalate prepolymers and the solid stating of those crystallized prepolymers

摘要

A process is disclosed for the crystallization of a PEN prepolymer containing volatile components. The temperature is maintained at a temperature in the range of about 20 DEG C. above the Tg and about 10 DEG C. below the Tm while the PEN prepolymer is agitated. The PEN prepolymer is present as chips or pellets. The pressure during crystallization is maintained at a level higher than the vapor pressure of the volatile components in the PEN prepolymer chips or pellets.