EXPANDED POLYSTYRENE RESIN PARTICLE AND METHOD OF MANUFACTURE FOR SAME, POLYSTYRENE RESIN PRE-EXPANSION PARTICLE, POLYSTYRENE RESIN EXPANDED FORM, THERMOPLASTIC RESIN PRE-EXPANSION PARTICLE AND METHOD OF MANUFACTURE FOR SAME, AND THERMOPLASTIC EXPANDED FORM

摘要

Disclosed is an expanded polystyrene resin particle containing bubbles, wherein the value of N calculated by the formula N=n÷(1/ρ) is 400 or higher when the number of bubbles is n/mm² and volume density is ρg/cm³ at 200μm from a particle surface on a cross-section passing through the centre of the particle. Further disclosed is a thermoplastic resin pre-expansion particle obtained by melt kneading a thermoplastic resin and an expanding agent inside a resin supply device to form an expansion agent-containing thermoplastic resin. The resin is passed through small apertures in a die and extruded inside a cooling medium, immediately cut and expanded inside the cooling medium to form a thermoplastic pre-expansion particle increased in volume by a factor of 1.6 which is then removed from the cooling medium. Further disclosed is an expanded polystyrene resin particle with a degree of whiteness of 75 or less, obtained by heat kneading a polystyrene resin and an expanding agent inside a resin supply device, passing and extruding the molten expansion-agent containing polystyrene resin through small apertures in a die, then cooling and cutting.