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Abstract

This invention relates to a mould material binding agent system for the manufacture of foundry mould parts. This binding agent system contains, as components, a solution of a phenol-containing polyol having at least two OH-groups in the molecule and a polyisocyanate, optionally in the form of a solution, having at least two NCO-groups in the molecule, which react with each other to a cold-hardening binding agent with formation of polyurethane. As polyisocyanate component there are used (optionally phenyl-substituted) diphenyl-4,4', diisocyanates having a content of more than 10% by wt. (referred to the total quantity of polyisocyanate), preferably more than 20% by wt., of the isomeric diphenyl-2,4'-diisocyanate (likewise optionally phenyl-substituted), which also contain an addition of a small quantity of acid chlorides and/or chlorosilanes. With the invention, a simply and economically manufactured binding agent is created, which combines high initial strengths of the mould parts with good sand lives of the mould material mixture.

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First Claim