Method for manufacturing foundry cores

A method of manufacturing a foundry core comprising mixing sand and heat-accelerated curable binder system wherein the binder system is produced by the following steps, the percentages being a percent of sand:

• (a) crosslinking 1-3% of saccharide-containing matter with 0.15-3% of 40% glyoxal aqueous solution;
• (b) controlling, by accelerating or retarding, the rate of reaction by the use of 0.3-1.0% alkali halide as a catalyst using 0.4% water, 0-10% betonite, 0-10% silica flour, 0-10% iron oxide, and 0-1% of a material selected from the group comprising wax, wax emulsion, asphalt emulsion, and wax-asphalt emulsion, the reaction being at such a temperature and pressure relationship as to maintain a liquid condition during the reaction.
• (c) forming the mixture to desired shape and causing it to cure to a hardened state.