| 摘要 |
PURPOSE:To provide the titled material which evaporates and burns thoroughly a foamed pattern material and prevents generation of casting defects by incorporating oxygen-adsorbing zeolite into a synthetic resin foam material consisting of polystyrene, etc. CONSTITUTION:The foamed beads obtd. by adding a foaming agent and oxygen- adsorbing zeolite at about 30-50wt% by weight of the foaming agent to a synthetic resin such as polystyrene, rigid PVC, etc. and foaming the mixture is further subjected to secondary foaming in an oxygen atmosphere under the reduced pressure to obtain an expendable foamed pattern to be used for a full mold casting method and to adsorb thoroughly oxygen to the above-mentioned zeolite incorporated and dispersed therein. Oxygen is thereby supplied to the inside of the system and the residues after combustion are thoroughly evaporated and burned away without allowing the same to remain in the stage of burning the pattern for casting by which generation of casting defects in the product is prevented. Na-A type zeolite melted therein with about 0.5-1% Fe III at a high temp. or the like is usable for the above-mentioned exygen-adsorbing zeolite. |
