PURPOSE: To prolong a pot life by introducing a part of a resin coated sand consisting of a binder soln. contg. a phenolic resin, etc., and a solvent, and sand into a metallic mold for sand mold casting and adding the solvent for the binder to the remaining part of the above-mentioned resin coated sand by a method for introducing a hardener therein.
CONSTITUTION: A part of the resin coated sand consisting of the binder soln. contg. the phenolic resin, polyisocyanate compd. and solvent and the sand is introduced into the metallic mold for sand mold casting and thereafter, the hardener is introduced into the metallic mold. The solvent for the binder is properly added to the remaining part of the above-mentioned resin coated sand. The flowability of the resin coated sand right after the prepn. thereof is nearly assured. The resin coated sand is, therefore, introduced at the sufficient packing density into the metallic mold and the high-strength and mold for casting is produced by curing. Since the pot life of the resin coated sand is greatly extended in this way, the high-strength sand mold for casting is easily, economically and continuously mass produced.
SAITOU SUBARU
OKAMOTO KEIZO
WATANABE SHUNJI
MISAWA CHIKAHIDE
HODOGAYA ASHIYURANDO KK