| 摘要 |
PURPOSE:To improve the collapsing property of a casting mold after casting by using an alkali metal salt of an arom. caroxylic acid as a collapsing property improving agent among molding materials essentially consisting of molding sand, phenolic resin and collapsing property improving agent. CONSTITUTION:The alkali metal salt of benzoic acid, salicylic acid, phthalic acid or trimellitic acid is used as the alkali metal salt of the arom. carboxylic acid. Such collapsing property improving agent is added preferably in a 2-30pts. wt. range by 100pts.wt. phenolic resin. The collapsing property improving agent is preliminarily compounded with the resin or is charged in the kneading stage for coating the resin on the molding sand. The casting mold produced of such materials has an easy tendency to collapse after pouring of a molten metal and decreases the failure of a casting product. The yield is thus improved.
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