High-temperature-resistant precoated sand and preparation method thereof

The invention relates to the technical field of high-temperature-resistant precoated sand, in particular to high-temperature-resistant precoated sand and a preparation method thereof. The high-temperature-resistant precoated sand is formed by compounding a plurality of parts including crude sand, high-temperature-resistant phenolic resin, urotropine, calcium stearate, organic silicon resin and caprolactam. The high-temperature-resistant phenolic resin is prepared by adopting a method comprising the following steps: firstly, carrying out polymerization reaction on phenol and 4, 4 '-dichloromethyl biphenyl on the surfaces of inorganic nanoparticles by adopting an in-situ polymerization method, introducing a rigid biphenyl group into a phenolic resin main chain, and enabling the inorganic nanoparticles to be stably dispersed in the phenolic resin, so as to obtain the high-temperature-resistant phenolic resin. Then introducing a benzimidazole rigid group into the intermediate material, and simultaneously consumin