POLYURETHANE BINDER COMPOSITIONS AND PROCESS FOR THEIR PREPARATION

摘要

A process is provided for making alkoxy modified phenolic resole resins which are useful as the polyhydroxy component of a foundry binder composition. These resins contain at least one alkoxy methylene group for every six phenolic nuclei in the resin. The foundry binder compositions, useful for preparing foundry cores and molds of superior hot strength, comprise the polyhydroxy component plus a polyisocyanate and a catalyst.