Comparison of a new, green foundry binder with conventional foundry binders

Metalcasting within the United States aims to meet ever-more stringent environmental standards as new process technologies are developed. Conventional foundry core binders are responsible for up to 70% of a foundryʹs volatile organic compound (VOC) emissions. New core binder technologies are essential for environmental sustainability within foundries. Herein, conventional and novel foundry core binders were appraised using thermal gravimetric analysis (TGA), dynamic mechanical analysis (DMA), hot distortion testing (HDT), and (Pilot-scale) molten iron erosion tests. Inherently, these tests cannot replace full-scale casting trials to evaluate binder effectiveness, however, these tests were performed to more fully elucidate binder properties that might cause casting defects or other unwanted behaviors at high temperatures. During each of these lab protocols, the combination of collagen plus alkali silicate as binders exhibited properties that matched or exceeded those of conventional phenolic urethane. Also, in iron erosion testing, the collagen/alkali silicate binder exhibited the same low erosion as conventional phenolic urethane. In hot distortion testing, the collagen–alkali silicate binder exhibited longer resistance to thermal bending, and comparable thermal flexibility to conventional phenolic urethane.