| 摘要 |
PURPOSE:To develop coated sand for a shell mold having high casting mold strength by coating a mixture composed of a phenolic resin, silane coupling agent and specific amine on molding sand. CONSTITUTION:Coated sand which is a raw material for shell mold is formed by using a molten mixture composed of 0.01-10pts.wt. one kind of silane coupling agent such as aminosilane, epoxy silane, vinyl silane or the like and 0.01- 10pts.wt. acrylamide, dimethyl acrylamide and other amine having <=500mol.wt. by 100pts.wt. a novolak type phenolic resin or resol type phenolic resin as a coating agent for the surface of molding sand. Such coating agent is coated on the surface of the molding sand, by which the coated sand for producing a shell mold is produced. The shell mold produced by such coated sand has excellent bending strength and hot tensile strength. |
