Binding system for producing cores and casting molds based on polyurethane

摘要

The present invention relates to a binder system that comprises a phenolic-resin component and a polyisocyanate component. This system is characterised in that the phenolic-resin component includes an alkoxy-modified phenolic resin, wherein less than 25 mole % of the phenolic hydroxy groups are etherified with a primary or secondary aliphatic alcohol comprising between 1 and 10 carbon atoms.