Casting mould and core prodn - from foundry sand, water glass ,binder and using lactate hardeners

摘要

Hardeners consist of lactates, opt. admixed with =50 wt.% (calc. on hardener) of phthalates, citrates, acetates or other carboxylic acid esters. Hardener concn. is 1-50 (3-15) wt. % w.r.t. water-glass. Pref. hardeners contain 50 wt. % lactates contg. 1-4 C ester gp. 10-50 wt. % triacetin and/or cyclohexyl acetate and 0-40 wt. % alkyl glycol acetates contg. 1-4 C ether gp., and opt. 5-40 wt. % acetone and/or dimethyl formamide. Compsn. achieves green strength quickly, no gases are evolved, pinhole formation is prevented, and no toxic materials need be used.