Sand mold forming additive, sand mold forming composition, sand mold manufacturing method and sand mold

Provided is a sand mold forming additive capable of preparing a sand mold forming composition having excellent foaming characteristics and a sand mold having excellent moisture resistance. The sand mold forming additive contains 0.01-2.00 parts by weight of the inorganic alkali metal compound (B) per 100 parts by weight of the ionic surfactant (A). The inorganic alkali metal compound (B) is at least one selected from the group consisting of sodium chloride and sodium sulfate. It is preferable that the ionic surfactant (A) is at least one substance selected from the group consisting of metal salts (A1) of alkyl sulfonic acids, metal salts (A2) of alkyl sulfuric acids, and metal salts (A3) of polyoxyalkylene alkyl ether sulfates. 提供了一种能够制备具有优异的发泡特性的砂模形成组合物和具有优异防潮性的砂模的砂模成型添加剂。在砂模成型添加剂中，相对于100重量份的离子型表面活性剂(A)，含有0.01-2.00重量份的无机碱金属化合物(B)。该无机碱金属化合物(B)为选自氯化钠和硫酸钠中的至少一种。离子型表面活性剂(A)优选地为选自烷基磺酸金属盐(A1)、烷基硫酸金属盐(A2)和聚氧化烯烷基醚硫酸酯金属盐(A3)中的至少一种。