| 摘要 |
PURPOSE:To reduce the time for curing and to prevent strength deterioration and deformation by using molding sand added and kneaded with a prescribed self-curing binder and evaporating forcibly moisture. CONSTITUTION:Molding sand S added and kneaded with a binder contg. a water soluble crosslinking agent and a catalyst for reaction of said crosslinking agent is prepd. Said water soluble binder is selected from the group consisting of a saccharide, the methylolurea or methylolmelamine or a methylolalkyl. Said catalyst for reaction is selected from an org. acid and inorg. acid or the metallic salt, ammonium salt or alkanol amine salt thereof. The prepd. sand S is packed into the space formed of a pattern provided with plural vent holes communicating with the surface to the rear surface and a molding flask 5. Compressed air of an ordinary temp. is penetrated through the inside of such sand S to cure the sand S at a high speed.
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