Properties of Cold Setting Molds and Cores and Their Control by Resins and Hardeners.

The progress of the setting process due to acid catalyst addition in furan and phenolic resin-bonded sands has been determined by measurement of gas evolution, abrasion resistance, and bulk weight. The effect of climatic conditions on water exchange during setting and the effect of the monomer proportion in the synthetic resin on emissions of formaldehyde and phenol has been established. The possibility of adjusting the mechanical properties of the molding mixture by the type and quantity of the acid hardener added and by the chemical composition of the synthetic resin has been demonstrated. The importance of hot deformation for the evaluation of mechanical properties of molding materials is pointed out.