| 摘要 |
PURPOSE:To improve the initial strength and surface stability of a casting mold by incorporating respectively specific weight % of rosin and monomer or polymer having a phenolic hydroxyl group into an acid-setting resin. CONSTITUTION:The acid-setting resin consists essentially of a furan resin, urea resin and melamine resin alone or by mixing or co-condensation of >=2 kinds among said resins or of a phenolic resin. The rosin is incorporated at 5-30% and the monomer or polymer having the phenolic hydroxyl group at 5-30% into such essential components to constitute a binder. The initial strength of the molded casting mold right after the molding as well as the flexibility of the casting surface, the stability of the finish surface, etc. are considerably improved by the above-mentioned method. |
