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

A sand mold-forming additive, comprising:

• 0.01-2.00 parts by weight of an inorganic alkali metal compound (B) per 100 parts by weight of an ionic surfactant (A);
• wherein the ionic surfactant (A) comprises an alkyl sulfonic acid metal salt (A1), an alkyl sulfuric acid metal salt (A2), and a polyoxyalkylene alkyl ether sulfuric acid ester metal salt (A3);
• wherein the alkyl sulfonic acid metal salt (A1) comprises an alkyl sulfonic acid metal salt having a C8-C22 alkyl group;
• wherein the alkyl sulfuric acid metal salt (A2) comprises an alkyl sulfuric acid metal salt having a C8-C22 alkyl group;
• wherein the polyoxyalkylene alkyl ether sulfuric acid ester metal salt (A3) comprises a polvoxyalkylene alkyl ether sulfuric acid ester metal salt having a C8-C16 alkyl group;
• wherein the inorganic alkali metal compound (B) comprises at least one selected from sodium chloride and sodium sulfate;
• and
• wherein the alkyl sulfonic acid metal salt (A1) is 50-98 parts by weight, the alkyl sulfuric acid metal salt (A2) is 1-40 parts by weight, and the polyoxyalkylene alkyl ether sulfuric acid ester metal salt (A3) is 1-40 parts by weight, per 100 parts by weight of total content of the alkyl sulfonic acid metal salt (A1), the alkyl sulfuric acid metal salt (A2), and the polyoxyalkylene alkyl ether sulfuric acid ester metal salt (A3).