Three component polyurethane binder system
OwnerXianping WANG, Mark STANCLIFFE +2inventors
InventorsXianping WANG, Mark STANCLIFFE, Christian PRIEBE, Joerg KROKER
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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.
Claims15
A binder system for a molding material mixture, comprising:
- (A) a first organic binder component;
- (B) a second organic binder component, complementary to the first organic binder component;
- and
- (C) an alkyl silicate component;
- wherein (A), (B) and (C) are provided as a three component system in separate containers for combination at the time of use.
A binder system for a molding material mixture, comprising:
- (A) a first binder component that is a polyol, comprising a phenolic base resin with at least 2 hydroxy groups per molecule, the first binder component being devoid of polyisocyanates;
- (B) a second binder component that is a polyisocyanate, comprising a polyisocyanate compound with at least 2 isocyanate groups per molecule that is complementary to the first binder component such that (A) and (B) comprise a phenolic urethane chemistry, which, when combined and cured with an amine catalyst results in a phenolic urethane polymer, the second binder component being devoid of polyols;
- and
- (C) an alkyl silicate component comprising tetraethyl orthosilicate (TEOS) or an oligomer of an alkyl silicate, as well as a bipodal aminosilane;
- wherein (A), (B) and (C) are provided as a three component system in separate containers, and at least component (A) also comprises hydrofluoric acid.
Dependencies are inferred from the claim text.