Abstract: Defects can arise in a product of a metal casting process from reactions occurring at a metal-mold interface. A method that reduces the defects uses an organic binder system by introducing a separate third component to a two-part polyurethane-based binder system used in the cold box or no bake process. The third part is added only after the first two parts are mixed with a refractory molding material to provide a shapeable foundry mix. The third part is an alkyl silicate, such as tetraethyl orthosilicate (“TEOS”), an alkyl orthoformate, such as trimethyl orthoformate (TMOF) or triethyl orthoformate (TEOF), or combinations thereof.

Abstract: A binder system for refractory materials used in sand casting processes, especially two-part polyurethane-based binder systems used in the cold box or no bake process, has less metal-mold reaction when a separate third part is used. The third part is an alkyl silicate, such as tetraethyl orthosilicate (“TEOS”), an alkyl orthoformate, such as trimethyl orthoformate (TMOF) or triethyl orthoformate (TEOF), or combinations thereof.

Abstract: An organic binder system is mixed with molding material for sand casting in the metals industry. The organic binder system has three parts, the first two of which are conventional and are used in the cold box or no bake process. The third part, which is combined with the first two parts at the time of use, contains at least an alkyl silicate and, optionally, a bipodal aminosilane. In some embodiments, an amount of hydrofluoric acid is included in one or both of the first two parts. Use of the organic binder system provides improved tensile strength in the mold, especially in high relative humidity.

Abstract: This invention relates to a binder composition comprising condensed tannin and furfuryl alcohol. The composition can be used to prepare foundry mixes. The foundry mixes are prepared by mixing the composition with an acid or salt of an acid. The foundry mixes are then shaped into molds or cores and cured by heating or by the no-bake process with stronger acid curing catalysts. The molds and cores are used in casting metal articles.

Abstract: This invention relates to refractory mixes produced by mixing a refractory material with an organic binder and heating to a temperature of typically from about 50° C. to about 100° C. to form a stable composite granulate. The refractor mixes comprise a major amount of a refractory material and a minor amount of a binder composition comprising (a) condensed tannin and (b) furfuryl alcohol. The refractory mixes are used to prepare shaped (e.g. bricks) and unshaped (e.g. blast furnace tap holes, troughs, and tundish liners) refractory products. The invention also relates to a process for preparing the refractory products using the refractory mixes.

Abstract: This invention relates to a binder composition comprising condensed tannin and furfuryl alcohol. The composition can be used to prepare foundry mixes. The foundry mixes are prepared by mixing the composition with an acid or salt of an acid. The foundry mixes are then shaped into molds or cores and cured by heating or by the no-bake process with stronger acid curing catalysts. The molds and cores are used in casting metal articles.