| 摘要 |
PURPOSE:To form a casting mold of molding sand having a high curing speed and high hardness by using a water-soluble binder consisting essentially of saccharides, a specific water-soluble crosslinking agent and catalyst for reaction of said crosslinking agent as a hardener for a sand mold for casting. CONSTITUTION:A molding flask 4 is placed atop a pattern plate 3 which is provided with plural vent holes 2 and has a recess 1 on the rear. Molding sand S kneaded with a binder having self-hardenability is packed in the space formed by the flask 4 and the top surface of the plate 3. A water-soluble binder consisting essentially of saccharides, a water-soluble crosslinking agent selected from the methylol- or alkylated methylol-urea or melamine, and a catalyst for reaction of said crosslinking agent selected from an org. acid, inorg. acid or the metallic salt, ammonium salt and alkanol amine salt thereof is used as said binder. Such plate 3 and flask 4 are placed on a pattern board 8, and the heated and compressed air supplied through a communicating hole 6 and the vent holes 2 of the pattern from a supply hole 7 is passed through the inside of the sand S to harden the casting mold formed of the sand S to high hardness in a short time. The casting mold is released from the pattern 3. |
