| 摘要 |
<P>PROBLEM TO BE SOLVED: To produce a phenolic novolac resin with a good yield (70% or higher) and an ortho ratio in the range of 30 to 60%, preferably in the range of 40 to 55%, and to provide a resin-coated sand with high curability by using the phenolic novolac resin. <P>SOLUTION: In the resin-coated sand at least composed of a refractory aggregate and a phenolic novolac resin, the phenolic novolac resin is obtained by reacting a phenol and a formaldehyde, a metal compound is used as a catalyst for the reaction, and further, a chelating agent is used in order to deactivate the catalytic effect of the metal compound. <P>COPYRIGHT: (C)2010,JPO&INPIT |
