| 摘要 |
PURPOSE:To obtain a binder having an excellent preservable property, crack preventiveness of a casting mold and strength by specifying the phenol-aldehyde molar ratio of a water soluble phenolic resin and the compounding of sodium hydroxide and potassium hydroxide with phenol. CONSTITUTION:The phenol-formaldehyde molar ratio of the water soluble phenolic resin constituting a phenolic resin compsn. is 1:2.0-1:2.5 and said resin contains the sodium hydroxide and potassium hydroxide respectively at 0.2-0.4mol per mol of the phenol. The resin-component in said compsn. is confined to 40-50wt%. The binder for the self-curable casting mold having the excellent preservable property of the binder, crack preventiveness of the casting mold and strength is thereby obtd.
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