POLYESTER RESIN WASHING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a polyester resin washing method capable of sufficiently washing pulverized products of a molded polyester resin such as used PET bottles and provide regenerated pellets keeping a proper polymerization degree (intrinsic viscosity) suitable for molding containing practically no volatile impurities and solid foreign matters and excellent and suitable for food packaging. SOLUTION: The polyester resin washing method comprises a first washing step of bringing polyester resin molded products into contact with an aqueous alkali metal hydroxide solution, a second washing step of bringing the pulverized products of the resulting resin material of the first washing step into contact with an inert gas at 180-230 deg.C, and based on the necessity, a third washing step of melting and granulating the pulverized products using an extruder equipped with a degassing means and a filtration means after finishing the second washing step.