| 摘要 |
PROBLEM TO BE SOLVED: To provide a washing method of an expandable resin particle whereby chlorine ions, which derive from hydrochloric acid added during a preparation step of the expandable resin particle, can be effectively removed. SOLUTION: The method is the one for washing the expandable resin particle obtained by impregnating a resin particle produced through suspension polymerization with a foaming agent, dispersing the expandable resin particle to obtain a suspension, adding hydrochloric acid to the suspension to decompose an inorganic salt having a poor solubility to water which is added in the step wherein the resin particle is impregnated with the foaming agent and separating the expandable resin particle from the suspension. In the washing method, the expandable resin particle is washed by supplying washing water to a washing tank containing the expandable resin particle without stirring the content of the washing tank, draining wastewater resulting from washing of the expandable resin particle from the washing tank and supplying the washing water to the washing tank until chlorine ion concentration in the wastewater drained from the washing tank reaches≤10 ppm. COPYRIGHT: (C)2005,JPO&NCIPI |
