US Patent 7119131 Urethane binder compositions for foundry applications

Foundry cores and molds for casting metals are prepared by forming a binder comprising a polyol, an isocyanato urethane polymer and a urethane catalyst. The binder additives and resin formulations of the invention are especially useful for casting non-ferrous metals, for example, the casting of aluminum, magnesium and other lightweight metals. The cores and molds produced for casting aluminum and other lightweight metals exhibit excellent shakeout while retaining other desirable core and mold properties.