FOAM STRUCTURE, MANUFACTURING METHOD THEREOF, AND MANUFACTURING APPARATUS THEREOF

To provide a mold device incorporating a mechanism for mold-back and core-back in foam molding in order to obtain a foam molded product with a high expansion ratio.SOLUTION: Water, a substance that does not go into a supercritical state due to temperature and pressure inside a heating barrel, is injected into a foaming agent, and it vaporizes and turns into water vapor due to the temperature of the heating barrel and the temperature of a molten resin. The water vapor is pressurized and dissolved or finely dispersed in the molten resin in the heating barrel at a metering stage, that is, when a screw is rotating and physical forces such as kneading are applied inside the heating barrel, thereby imparting foaming properties to the molten resin in the heating barrel. A deterioration in physical properties of a foam-molded product produced using a resulting foamable PC and PC-based resin polymer alloy is less than that observed when inorganic or organic chemical foaming agents or alcohols are used. If only water is used as the foaming agent, foam cells will be large. However, by using a foam nucleating agent in the resin to be foamed, it is possible to create fine foam cells.SELECTED DRAWING: Figure 15 【課題】高い発泡倍率の発泡成形品を得るための、発泡成形においてモールド・バック、コア・バックさせる機構を組み込んだ金型装置を提供する。【解決手段】発泡剤に加熱筒内の温度と圧力とで超臨界状態とならない物質の水を注入し、加熱筒の温度、溶融された樹脂の温度よって気化し、水蒸気となる。この水蒸気を加熱筒内の溶融された樹脂中に、計量の段階、スクリューが回転し、加熱筒内に混錬などの物理的な力が働いている段階で、加圧溶解させ、或いは微分散させ、加熱筒内の溶融樹脂に発泡性を付与させる。得られた発泡性付与されたＰＣ、ＰＣ系樹脂のポリマーアロイを用いて発泡成形された発泡成形品の物性の低下は、無機系、有機系の化学発泡剤、アルコール類を用いた場合と比較して少ない。発泡剤に水だけを用いると、発泡セルは大きくなるので、発泡予定の樹脂中に起泡核剤を用いる事で微細な発泡セルとする事が出来る。【選択図】図１５