| 摘要 |
A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing the dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40 DEG C. According to the process of the present invention, there can be obtained pre-expanded thermoplastic resin particles with a large average diameter of cells. By molding the pre-expanded particles obtained by the present invention, molded articles which are small in the dimensional shrinkage and excellent in the surface appearance can be obtained without imparting the expandability to the particles or aging the particles under pressure prior to molding. |
