Polyurethane binder compositions

In a moldable composition comprising aggregate material, such as foundry sand, and a binder composition comprising a polyhydroxy component, an isocyanate component having a functionality of two or more, and sufficient catalyst to catalyze substantially completely the reaction between the polyhydroxy component and the isocyanate component wherein the improvement comprises using a polyhydroxy component consisting essentially of an alkoxy modified pheolic resole resin containing at least one alkoxy methylene group for every six phenolic nuclei wherein the preponderance of bridges joining the phenolic nuclei of said resin are ortho-ortho benzylic ether bridges.

In a process for making foundry cores or molds which comprises admixing aggregate material, such as foundry sand or the like, and a binding amount of a binder composition comprising a polyhydroxy component, an isocyanate component having a functionality of two or more, and sufficient catalyst to catalyze substantially completely the reaction between the polyhydroxy component and the isocyanate component wherein the improvement comprises using a polyhydroxy component consisting essentially of an alkoxy modified phenolic resole resin containing at least one alkoxy methylene group for every six phenolic nuclei wherein the preponderance of bridges joining the phenolic nuclei of said resin are ortho-ortho benzylic ether bridges.