RESINNCOATED SAND FOR CORE MAKING AND CORE MAKING METHOD USING THIS RESINNCOATED SAND

摘要

PURPOSE:To obtain the core for Al die casting of superior disintegratability by using the double-coated casting sand comprising covering thermoplastic resin further on the surfaces of the casting sand coated with thermosetting resin. CONSTITUTION:The casting sand of the double-coating construction comprising coating thermoplastic resin such as styrene resin or the like on the surfaces of the casting sand having been coated with thermosetting resin such as phenolic resin or the like, is used. Here, the one comprising coating 0.3-2wt% of thermosetting resin based on the weight of the casting sand and 1-2wt% of thermoplastic resin is desirable. To make a core, a solvent which is volatile for thermoplastic resins, e.g., methylene chloride or the like is mixed in the abovementioned casting sand to make the thermoplastic resin to melt state and the resin-coated sand of this state is packed in a core box, thence compressed air is blown into the core box or the inside of the core box is reduced of pressure and sucked to get rid of the foregoing solvent, after which the core having been bonded and set to integral from is taken out.