| 摘要 |
<p>A resin for coating sand and a resin-coated sand produced therefrom wherein the resin is prepared by incorporating furan into a phenolic novolak resin. In the preferred practice, the resin is produced by reaction of furfuryl alcohol with a phenolic compound at an acid pH to give a furfuryl-phenolic intermediate in a first step, and then, in a second step, reacting the furfural-phenolic intermediate with a lower aliphatic aldehyde to produce the resin. The resin-coated sands of the present invention provide unexpectedly improved shakeout and collapsibility characteristics in the shell process.</p> |
