| 摘要 |
PURPOSE:To improve pot life without decreasing the strength of a casting mold by specifying the molar ratio between the total molar number of NaOH and KOH and phenol and specifying the molar ratio between NaOH and KOH. CONSTITUTION:This binder compsn. is used for the production of the gas curable casting mold by using an aq. alkaline phenol-aldehyde resin soln. as a binder and injecting a gaseous or aerosol org. ester thereto to produce the casting mold. The alkali in the aq. alkaline phenol-aldehyde resin soln. consists of NaOH and KOH. The molar ratio between the total molar number of NaOH and KOH and phenol is specified to 0.2:1-1.2:1 and the molar ratio between NaOH and KOH is specified to 5:95-99.5:0.5. The pot life is improved by the above-mentioned binder compsn.
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