Manufacturing method for foam molded products

Abstract

To provide foaming agents, equipment, molds, and molding machines used in the production of resins with foaming properties, means of increasing the foaming ratio, and means of increasing coating suitability.SOLUTION: When inorganic sodium bicarbonate is used as a foaming agent, sodium carbonate as the foaming residue (i.e. residue after the foaming agent decomposes to generate foaming gas, which stays in the molded product) lowers the adhesion of a coating layer. Therefore, the sodium carbonate is removed by acid washing in advance, which ensures satisfying coating suitability. When GCP is performed, the thickness of the surface skin layer varies depending on the mold surface temperature. Generally, heated steam is used as means of increasing mold temperature, but the present invention provides inexpensive, highly efficient, and safe mold temperature increase by means of heating magnetic fluid (liquid) with high-frequency induction. When mold back and core back, which are means of obtaining molded products with a high foam ratio, are performed, the mold separates from the fixed side. We provide means to solve this separation problem by using gas.SELECTED DRAWING: Figure 38

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