| 摘要 |
<p>A process for preparing pre-expanded particles of a thermoplastic resin without washing the prepared pre-expanded particles to remove a dispersing agent remaining thereon and without discharging waste water, which comprises charging particles of a thermoplastic resin and an aqueous dispersion medium containing a dispersing agent into a closed pressure vessel, heating the resulting aqueous dispersion to a temperature of not less than the softening point of the thermoplastic resin, thereby impregnating the particles with water to have a water content of 1 to 50 % by weight, releasing the dispersion into a lower pressure atmosphere, thereby expanding the particles, recovering the dispersion medium containing the dispersing agent, and recycling it as a dispersion medium to the pressure vessel. <IMAGE></p> |
