Process for preparing mold

A process for preparing a mold by hardening molding materials by CO.sub.2 gas, which comprises mixing refractory particles with a binder material comprising a caustic alkali-neutralized product of at least one copolymer selected from the group consisting of .alpha.-olefin-maleic anhydride copolymer, styrene-maleic anhydride copolymer, and methylvinyl ether-maleic anhydride copolymer, calcium hydroxide, and polyvinyl alcohol, thereby preparing molding materials, filling the molding materials around a pattern, and blowing CO.sub.2 gas into the molding materials, thereby hardening the molding materials.

A process for preparing a mold by hardening molding materials by CO.sub.2 gas, which comprises mixing refractory particles with a binder material comprising a caustic alkali-neutralized product of at least one copolymer selected from the group consisting of .alpha.-olefin-maleic anhydride copolymer, styrene-maleic anhydride copolymer, and methylvinyl ether-maleic anhydride copolymer, calcium hydroxide, and at least one member selected from the group consisting of calcium oxide and hydroxides of zinc, aluminum, barium, magnesium and iron, thereby preparing molding materials, filling the molding materials around a pattern, and blowing CO.sub.2 gas into the molding materials, thereby hardening the molding materials.

A process for preparing a mold by hardening molding materials by CO.sub.2 gas, which comprises mixing refractory particles with a binder material comprising a caustic alkali-neutralized product of at least one copolymer selected from the group consisting of .alpha.-olefin-maleic anhydride copolymer, styrene-maleic anhydride copolymer, and methylvinyl ether-maleic anhydride copolymer, calcium hydroxide, and SBR styrene-butadiene rubber latex, thereby preparing molding materials, filling the molding materials around a pattern, and blowing CO.sub.2 gas into the molding materials, thereby hardening the molding materials.