Abstract: Foundry sand grains coated with a binder composition which comprises 100 wt. parts of methylolmelamine or alkylated methylolmelamine and 5 to 100 wt. parts of a water-soluble organic compound having a hydroxyl group. The sand grains coated with the composition are effective in a low-temperature foundry, especially for forming a core in an aluminum-alloy foundry.

Abstract: A binder for casting sand of the present invention comprises 5-95 wt. % of cellulose acetate and 5-95 wt. % of a thermosetting resin precondensate such as an alkylated methylolmelamine, alkylated methylolurea or a mixture of them, and it is used particularly for the casting carried out at a relatively low casting temperature. Up to about 50% of cellulose acetate may be replaced with an acetate of an aliphatic polyhydric alcohol or an alkyl phthalate. In the resin-coated grains of sand of the present invention, the grains of sand are coated with a binder comprising 5-95 wt. % of cellulose acetate and 5-95 wt. % of a thermosetting resin precondensate.