Development of White Quick-drying Coatings by Vacuum Molding Technology ZHU Zhiling, ZHU Taisheng2, FANG Xiaoyang, LIU Yangtao1 (1. University of Science and Technology of China, Anhefei 230052, China; 2. Dongfang Casting Co., Ltd., Xuzhou, Jiangsu 221612, China) To change the black graphite coating, the production environment is poor. The status quo, the development of a new type of white fast-drying paint, replacing the original black paint. The production shows that the casting has no sticky sand, the environment is changed, and the production efficiency is also improved.
1.1 The aggregate uses forsterite powder and zirconium powder composite aggregate. Forsterite 42.9%Si2, magnesium and silicon mass ratio of 1.33. Forsterite is an orthorhombic system, mostly short columnar granular form, from the three cylindrical shape, three kinds of axial surface shape and a double cone surface shape combination Made of; or a thick plate, round granular. Poor cleavage, common state is granular aggregates or lumps. Mohs hardness is 6.5~7. 0. Density 3.22~3.33g/cm3, melting point is 1890*C, no crystal shape change from room temperature to melting point, product type is stable; linear expansion coefficient is 1 10-6/*C, different Directional, linear expansion coefficient within 20~600*C, x axis direction is 13. Axis is 7.6x10-6/*C, body expansion coefficient is 33.8x10-6/*C., for forsterite Quality requirements for the Mg content w> content w 1%. Forsterite particle size 1.3 Binder binder determines the adhesion of paint and EVA film, using phenolic resin as a binder, and add six in the phenolic resin Methylenetetramine, phenolic resin polycondensation reaction after heating, resulting in insoluble infusible polymer, is conducive to phenolic resin shell.
1.4 Carrier liquid 95%) and ethyl acetate (>97%) Industrial alcohol boiling point 78*C, relative density (20*C/4*C) 0.79g/cm3, flash point closed 12*C; ethyl acetate boiling point 77 *C, relative density (20*C/4*C) 0.90 g/cm3, flash point closed -4*C. Evaporation rate with butyl acetate as standard value 100, ethanol 203, ethyl acetate 525.1.5 Additive ether. Non-ionic surfactants do not dissociate when dissolved in water, in solution phenolic resin, 0.5 parts additive, 80 parts ethyl acetate.
3 performance of the coating 3.1 density using a graduated cylinder weighing method, measured the density of the coating is 1. 3.2 Suspension using a stopper cylinder method, the coating was poured into a graduated cylinder, to 100mL elevation, standing, observed every 2h in 8h Settling conditions are shown in Table 1. Table 1 Coating Suspension Time / h Suspension Rate /% 3.3 Viscosity Standard coating 6 viscosity cup, time is 11s. 3.4 Air volume using SFL recording gas performance analyzer, determination of 1 gas volume is 20mL /g. 3.5 High-temperature crack resistance *C Dry in the electric oven for 1 hour and place it in a 1 200*C muffle furnace for 3 minutes. Take out and observe. The surface of the sample is smooth without cracks. There is no obvious peeling between the coating and the sample.
3.6 Application of Coatings Coatings developed by the company are used in the Oriental Foundry Company, Fimat Casting Company, and Fengxian Cast Steel Works. The casting quality ranges from 74kg to 13460kg (Mitsubishi Heavy Industries Balance Weight). After production verification, the coating can adhere well to the EVA film, and is easily peeled off from the casting, so that there is basically no phenomenon of sticky sand, the production efficiency is improved, and the working environment is improved.
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