The present invention relates to a method for preparing PET base material for extrusion foaming by combining in-situ polymerization modification with chain extenders. The method comprises: adding in-situ polymerization modifiers, catalysts, and antioxidants during the polymerization of terephthalic acid and ethylene glycol to perform melt polycondensation, yielding in-situ polymerized modified PET base material; followed by drying treatment; adding anhydride-type chain extenders to the dried PET base material, uniformly mixing, and feeding into a twin-screw extruder; then adding epoxy-type chain extenders, melt-extruding, cutting, and pelletizing to obtain chain-extended modified PET base material. This modification process offers advantages including easy process control, high production stability, short processing time, and strong design flexibility. It avoids the drawbacks of solid-phase tackification technology, such as high equipment requirements, significant energy consumption, and low economic efficiency. The resulting PET base material exhibits a intrinsic viscosity of 1.25–1.57 dL/g.
Country Code: CN
Application Number: CN202211055334.X
