DRUM-SHAPED THERMOPLASTIC RESIN EXPANDED PARTICLE, ITS PRODUCTION AND THERMOPLASTIC RESIN EXPANDED MOLDING PRODUCT HAVING VOID

摘要

PROBLEM TO BE SOLVED: To obtain the subject expanded particle capable of easily providing a thermoplastic resin expanded molding product having a high porosity by making an ordinary pillar-shaped thermoplastic resin particle to a drum shape by a specific expanding method. SOLUTION: This thermoplastic resin expanded particle has 0.8-3.0 average L/D, 0.2-0.7 average d/D (L is the average length of pillar-shaped longest part in the lengthwise direction of the drum-shaped expanded particle; D is the average maximum diameter of the drum-shaped expanded particle; d is the average minimum diameter of the drum-shaped expanded particle). The drum-shaped thermoplastic resin expanded particle is obtained by dispersing (A) a pillar-shaped thermoplastic resin particle and (B) a dispersant into (C) an aqueous dispersion medium in a closed container, then heating the dispersion to a softening temperature of the component A or hither than it, adding (D) a blowing agent, opening one end of the closed container after the lapse of 5-20 minutes, releasing the component A and the component C to an atmosphere under a lower pressure than the pressure of the closed container and expanding the component A. An expanded molding product having 10-60% porosity is obtained from the expanded particle.