摘要 |
<p>The invention relates to amine modified polyisocyanates having urea linkages and their use in foundry binder systems. The modified polyisocyanates are prepared by reacting a polyisocyanate with an aliphatic primary or secondary amine. These amine modified polyisocyanates, along with a phenolic resole resin, are added to a foundry aggregate to form a foundry mix which is shaped and cured with an amine curing catalyst.</p> |