METHOD FOR DRYING COPOLYMERIZED POLYESTER CHIP

摘要

PROBLEM TO BE SOLVED: To provide a method for drying copolymerized polyester chips without causing the deterioration of operating efficiency by blocking during drying, and quality deterioration caused by the decrease in viscosity, such as hydrolysis, oxidative decomposition, thermal decomposition, etc.;SOLUTION: This method for drying the copolymerized polyester chips containing 2-7 mol % aromatic dicarboxylic acid having a metal sulfonate group based on the total ester bonds and 3-10 wt. % a polyalkylene glycol and/or a saturated aliphatic dicarboxylic acid based on the total weight of the reaction product is provided by preliminary drying the copolymerized polyester chips at a temperature at or higher than its glass transition temperature (Tg°C) and at or lower than (the glass transition temperature (Tg°C)+45°C) under vacuum or at a normal pressure to make 0.03 wt. % water content, and then drying at a temperature at or higher than (the glass transition temperature (Tg°C)+45°C) and at or lower than its crystallization temperature (Tc°C) under vacuum or at a normal temperature completely.;COPYRIGHT: (C)2004,JPO&NCIPI