| 摘要 |
PURPOSE:To easily obtain a highly expanded molded product of polystyrene, by impregnating polystyrene resin particles with a hydrocarbon blowing agent and an org. solvent, primarily expanding them by heating, allowing the expanded particles to stand in the air to recover shrinkage and expansion-molding in a mold. CONSTITUTION:Polystyrene resin particles are impregnated with a blowing agent selected from the group consisting of butane, pentane, a mixture of butane with pentane and mixtures thereof with other hydrocarbon blowing agents and an org. solvent (e.g., toluene). The resulting expandable polystyrene resin particles are expanded at a bulk expansion ratio of 100 or above by heating them with a heating medium. The expanded particles are left to stand in the air to recover shrinkage and to obtain a bulk expansion ratio of 10 or more. The particles are filled into a mold and expansion-molded to obtain the desired highly expanded molded product of polystyrene. |
