Abstract: A binder system for metal casting has a reactive furan resin, furfuryl alcohol, and a plasticizer that includes an epoxidized fatty acid. The reactive furan resin is a resin modified with phenolic resole, present at from about 18 wt. % to about 22 wt. %, based on the weight of the binder system. The plasticizer may include plant seed oil, such as soybean oil, linseed oil, rapeseed oil, cottonseed oil, sunflower oil and mixtures thereof, present at between about 4 wt. % to about 9 wt. %, based on the weight of the binder system. The furfuryl alcohol and the plasticizer are collectively present in an amount ranging from about 75 wt. % to about 85 wt. %, based on the weight of the binder system. Silane may also be present in an amount from about 0.1 wt. % to about 0.5 wt. %, based on the weight of the binder system.

Abstract: A “no-bake” process allows the forming of larger metal castings, by providing longer work times, in the range of about 45 to about 60 minutes. This is achieved using a liquid curing catalyst that is a pyridine, substituted at the second or third position with a moiety having a molecular weight in the range of about 30 to about 100 mwu. Examples of the liquid curing catalyst include 2-ethanolpyridine, 3-chloropyridine and 2-methoxypyridine. When combined with a two-part polyurethane binder precursor and a foundry aggregate, the liquid curing catalyst provides not only the longer work time, but also a strip time that is less than about 167% of the work time, as measured from the point of activating the polyurethane precursors by mixing them in the presence of the curing catalyst.

Abstract: A “no-bake” process allows the forming of larger metal castings, by providing longer work times, in the range of about 45 to about 60 minutes. This is achieved using a liquid curing catalyst that is a pyridine, substituted at the second or third position with a moiety having a molecular weight in the range of about 30 to about 100 mwu. Examples of the liquid curing catalyst include 2-ethanolpyridine, 3-chloropyridine and 2-methoxypyridine. When combined with a two-part polyurethane binder precursor and a foundry aggregate, the liquid curing catalyst provides not only the longer work time, but also a strip time that is less than about 167% of the work time, as measured from the point of activating the polyurethane precursors by mixing them in the presence of the curing catalyst.