| 摘要 |
PURPOSE:To shorten the whole molding cycle and at the same time obtain an expansion molded item with favorable surface appearance by a method wherein deaeration is performed by deaerating stream with a specified pressure in the state that the restoration of expandable particles is checked by keeping on holding the inner pressure of a cavity in the cavity after the expandable particles are filled. CONSTITUTION:Expandable particles are filled under compression into the cavity 21 of a mold. After that, deaerating steam is introduced in a steam chamber 16' so as to deaerate through the steam holes 20', 20',... of a mold 12, the cavity 21, the steam holes 20, 20,... of a mold 11 and a steam chamber 16 outside the system. As a result, gas existing in gaps among the expandable particles is deaerated together with the steam. The above-mentioned deaeration treatment is done by introducing the deaerating steam having a pressure higher than the inner pressure P1 of the steam chambers 16 and 16' by 0.2kg/cm<2> or more against the inner pressure P1 of the steam chambers 16 and 16'. After the above-mentioned deaeration treatment, the pressure in the cavity 21, which is in heated condition, is brought back to the atmospheric pressure so as to restore the expandable particles to their original shapes in a short time and expand in order to obtain a shaped foaming body with excellent surface appearance. |
