PROCESS FOR THE PRODUCTION OF HIGH MOLECULAR WEIGHT POLYESTER RESINS

摘要

Preparation of high molecular weight polyester resins starting from resins with intrinsic viscosity I.V. lower than 0.57 dl/g comprising the following steps: (1) mixing the resin in the melt with a polyaddition additive containing at least two groups capable of addition reactions with the terminal OH and COOH groups of the resin; (2) converting the melted polyester into solid particles and then subjecting the particles to crystallization; (3) heating the particles at temperature between 150 and 210 DEG C up to obtain the desired increase of intrinsic viscosity.