| 摘要 |
PURPOSE:To improve the strength of a mold and the collapsibility of the mold after charging by using a phenolic resin, compounds of polyvalent metals, hydroxides of alkali metals, epoxy compounds, etc. as a binder for a CO2 hardenable mold at specific ratios. CONSTITUTION:In the producing stage of compounds sand for molds to the hardened by blowing of CO2, the binder prepd. by mixing 10-300pts.wt. 1 kind of hydroxides, oxides or chlorides of polyvalent metals such as NaOH, Ca(OH)2 or their mixture, 50-500pts.wt. water, 1-100pts.wt. alkali metal hydroxides such as NaOH, KOH or the like, 0.1-200pts.wt. an epoxy compound, and if necessary, <=300pts.wt. alcohols such as methanol in 100pts.wt. a phenolic resin is used as the binder for molding sand. CO2 is passed through the green sand molded of the molding sand using such binder, whereby said green mold is instantaneously hardened to a mold. The mold of high mold strength and superior collapsibility of the mold after charging of molten metal is obtained. |
