METHOD FOR PRODUCING AROMATIC POLYESTER-BASED RESIN PRE-EXPANDED BEAD

摘要

PROBLEM TO BE SOLVED: To provide a method capable of stably producing an approximately cylindrical aromatic polyester-based resin pre-expanded bead having good surface state and cellular state, excellent in appearance and in-mold expansion moldablity, having low crystallinity and so capable of forming expanded products having high mechanical strength and good appearance by in-mold expansion-molding. SOLUTION: This method comprises using an extruder having a nozzle die, melt-blending an aromatic polyester-based resin with a foaming agent, making an extrusive expansion of the resultant mixture from the above nozzle die as a strand, cooling the extruded strand-like expanded product with air so as to adjust its crystallinity to 1-8%, and then cutting the cooled strand-like expanded product.