Easily-scattered precoated sand and preparation method thereof

Abstract

The invention discloses easily-scattered precoated sand and a preparation method thereof. The easily-scattered precoated sand is prepared from the following raw materials in parts by weight: crude sand, a silane coupling agent, a bonding agent, a curing agent, an additive and a lubricating agent, wherein the crude sand is screened by a 300-mesh sieve, and consists of 80% of fresh sand and 20% of used sand. The preparation method comprises the following steps: (1) preparing the bonding agent, namely, putting epoxy resin and modified starch into a stirrer, stirring, sequentially feeding clay and silicone oil, and stirring for 20-40 minutes to obtain the bonding agent; (2) preparing the curing agent, namely, feeding polyethylene polyamine, polyurethane and fatty amine into a ball mill in parts by weight, and carrying out dry ball-milling for 60-80 minutes to obtain the curing agent; (3) mixing, namely, heating the crude sand up to 35-40 DEG C, then putting the heated crude sand into a sand mixer, feeding the bonding agent, the silane coupling agent and the lubricating agent, and fully mixing; then, feeding the additive under at room temperature; and finally, feeding the curing agent and fully mixing to obtain the precoated sand.

Description

technical field [0001] The invention relates to a collapsible coated sand and a preparation method thereof, belonging to the technical field of foundry industry. Background technique [0002] Coated sand refers to the molding sand or core sand that is covered with a solid resin film on the surface of the sand grains before molding. There are two coating processes: cold method and hot method: the cold method dissolves the resin with ethanol, and adds urotropine during the sand mixing process, so that the two are coated on the surface of the sand grains, and the ethanol volatilizes to obtain coated sand; Preheat the sand to a certain temperature, add resin to melt, stir to coat the resin on the surface of the sand, add urotropine aqueous solution and lubricant, cool, crush, and sieve to obtain coated sand. For steel castings and iron castings. Due to the advantages of high strength, low gas generation, high dimensional accuracy of production castings, smooth surface and easy...

AI Technical Summary

Problems solved by technology

Although this invention has high strength and high temperature resistance, it has poor fluidity and is easy to stick sand on castings.