Resin coated sand Coated sand, sand surface in the shape of the front is covered with a layer of solid resin sand or sand core. Cold and hot two lamination process: cooling method using ethanol to dissolve the resin and in mixed sand adding Urotropine, second is coated on the surface of the sand, the ethanol volatilization, coated sand; thermal method to sand preheated to a certain temperature, and resin to melt, mixing the resin is coated on the surface of the sand, and Urotropine solution and lubricant. etc. Characteristics of coated sand 1, vibration cleaning, high strength, low gas, low expansion; 2, and good casting surface finish; 3, shell type is not up, good thermal stability, good thermal conductivity, good mobility, surface roughness of castings; 4, high strength, high temperature resistance, low expansion, good release properties, good resistance to sand; 5, uniform shell noshelling, curing speed; Coated sand material Resin coated sand used mainly high-quality selection of natural quartz sand as raw sand, thermoplastic phenolic resin, urotropine and enhanced agent as raw materials. According to different technical requirements of the user, in the curing speed, de film, liquidity and scatters, casting surface finish, storage and other aspects of the adjusted ratio. Is a car, tractor, hydraulic parts, such as one of the best modeling materials. Type of coated sand (1) ordinary type of coated sand Composed of quartz sand, novolak resin, urotropine and calcium stearate, without the additives. Applicable to the production of general cast iron parts. (2) high strength and low gas coated sand Is the ordinary of precoated sand replacement products, by the addition of additives and the new process is prepared, its strength more than 30% higher than in ordinary coated sand, volume is greatly reduced, and the suitable for production of complex precision cast iron. (3) high temperature coated sand At high temperatures has characteristics of high strength, heat resistance for a long time, applicable to the production of automotive engine cylinder block, cylinder head, container angle complex thin wall castings. (4) class easy collapsibility of coated sand Has better strength and excellent low temperature collapsibility, suitable for the production of non-ferrous metal castings. (5) other special requirements for coated sand In order to meet the needs of different products, developed a series of precoated sand such as centrifugal casting precoated sand, chilled precoated sand, wet state of precoated sand, anti sticking sand, anti veining, orange peel coated sand prevention etc..