Binder based on polyurethanes for producing foundry mould and core compositions

摘要

The polyurethane-based binder system (I) for foundry mould materials, contains a phenolic resin (A) with free OH groups and a polyisocyanate (B) with monomethyl esters of fatty acid(s) (C) with a chain of 12 or more C atoms as solvent or solvent component for (A) and/or (B). Also claimed are: (i) a process for the production of (I), in which (A) and/or (B) is/are dissolved in (C); and (ii) the production of foundry moulds and cores from a moulding material containing (I) as binder.