Urethane binder compositions for foundry applications
AssigneeDow Global Technologies LLC
InventorsCharles F. Marth, George David Green, Raymond J. Swedo
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Abstract
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.
Claims39
A foundry resin additive comprising an isocyanate terminated nitroalcohol/isocyanate adduct (nitroisocyanate) having the structure:
- Where:
- Z=O, N—H
- W=O, C, N—H
- R′=CH2x,
- R″=CH2x, phenyl, tolyl, isophorone, cyclohexyl, dicyclohexylmethane, diphenylmethane
- R″′=bond, H, CH3, CH3CH2
- m=0–5
- n=2,3
- x=1–6.
A foundry resin binder composition comprising:
- a) a polyol component comprising nitronovolac adducts either alone, or as a mixture with conventional phenolic resins;
- b) an isocyanate component;
- c) a curing agent.
A foundry resin binder composition comprising:
- a) a polyol component;
- b) an isocyanate component comprising of nitroisocyanate adducts, either alone, or as a mixture with conventional polyisocyanates;
- c) a curing agent.
A process of forming shaped foundry articles for use in casting lightweight metals, which articles collapse after casting of said lightweight metals thereby reducing or eliminating energy and/or time required for shake-out, comprising:
- a) forming a foundry mix by distributing on an aggregate a binding amount of 0.2%–10%, based upon the weight of the aggregate, of a binder composition, said composition comprising in admixture a polyol component and an isocyanate component, said isocyanate component comprising a mixture of nitroisocyanate urethane polymers with isocyanato urethane polymers wherein all hydroxy groups of said polymers are capped;
- b) shaping the foundry mix into the desired foundry article;
- and
- c) allowing the article to cure in the presence of a catalyst.
A process of forming shaped foundry articles for use in casting lightweight metals, which articles collapse after casting of said lightweight metals thereby reducing or eliminating energy and/or time required for shake-out, comprising:
- a) forming a foundry mix by distributing on an aggregate a binding amount of 0.2%–10%, based upon the weight of the aggregate, of a binder composition, said composition comprising in admixture a polyol component and an isocyanate component, said polyol component comprising a mixture of nitronovolac polymers formed by reacting a nitroalkane with a phenol and formaldehyde;
- b) shaping the foundry mix into the desired foundry article;
- and
- c) allowing the article to cure in the presence of a catalyst.
A process of forming shaped foundry articles for use in casting lightweight metals, which articles collapse after casting of said lightweight metals thereby reducing or eliminating energy and/or time required for shake-out, comprising:
- a) forming a foundry mix by distributing on an aggregate a binding amount of 0.2%–10%, based upon the weight of the aggregate, of a binder composition, said composition comprising in admixture a polyol component and an isocyanate component, said polyol component comprising a mixture of nitronovolac polymers formed by reacting a nitroalcohol with a phenol;
- b) shaping the foundry mix into the desired foundry article;
- and
- c) allowing the article to cure in the presence of a catalyst.
Dependencies are inferred from the claim text.