Heat cured foundry mixes and their use

摘要

This invention relates to nitrogen free heat cured foundry mixes essentially free of free formaldehyde comprising (a) a nitrogen free modified furan resin, (b) furfuryl alcohol, (c) polyvinyl acetate, preferably(d) a tar selected from the group consisting of resorcinol pitch, bisphenol A tar, and (e) a latent acid curing catalyst. The foundry mixes are used to prepare foundry shapes. They are cured in the presence of the latent acid curing catalyst by heating at an elevated temperature.