Coating technology: Design of heat insulation coating with high temperature resistance and light radiation resistance

Abstract: Based on the design concept of combination of radiation resistance and high temperature insulation, a high temperature insulation coating was developed The thermal control coating was obtained in 850 ℃ / 5min, the insulation temperature was lower than 200 ℃, at the same time, the hemispherical emissivity of the coating against photothermal radiation was ≥ 0.85 Key words: photothermal radiation; heat conduction; high temperature thermal insulation coating Heat insulation is a kind of isolation measure for heat conduction, radiation and convection In some high temperature environments, heat control coating is used to control heat transfer, especially for heat insulation coating Application scope and advantages of roller ceramic coating Recommended introduction: the surface of ceramic rubber plate used for roller ceramic coating is cast into durable rubber plate by hundreds of independent small ceramic pieces Each ceramic piece has raised characteristics Under general conveyor belt pressure, thousands of unique cast bumps can produce positive traction, prevent slipping and extend the service life of conveyor belt roller At the same time, the bottom layer adopts high-quality rubber, which has strong elasticity and can play a good impact resistance role The scope of application of roller ceramic coating is one three six 83857180 (the same as V) 1 Roller coating in extremely harsh working environment 2 The belt joint is not suitable for fixing with iron buckle; 3 It is suitable for leather Abstract: Based on the design concept of combination of radiation resistance and high temperature insulation, a kind of high temperature insulation coating was developed The heat control coating was obtained in 850 ℃ / 5min, and the insulation temperature was lower than 200 ℃, at the same time, the hemispherical emissivity of the coating against photothermal radiation was ≥ 0.85 Key words: photothermal radiation; heat conduction; high temperature thermal insulation coating Heat insulation is an isolation measure for heat conduction, radiation and convection In some high-temperature environments, heat control coating is used to control heat transfer, especially the high-temperature heat insulation coating As the heat insulation coating of some products, the used heat-resistant heat insulation coating has a heat-resistant temperature of more than 1000 ℃ in a certain period of time It has good heat insulation effect In the same way, there are many researches on the special coating which is resistant to photothermal radiation According to different radiation needs, different radiation resistant coatings are used, such as polishing reflector, chemical conversion reflector, coating reflector, etc However, when the product needs both high-temperature insulation and resistance to photothermal radiation, it is necessary to adopt the design concept of combination of radiation resistance and high-temperature insulation, combining the high-temperature insulation coating and anti photothermal radiation layer, so that it can play the role of anti photothermal radiation and high-temperature insulation at the same time Organic or inorganic resin with high heat-resistant temperature is usually selected as the film-forming material of the coating, and the combination is selected according to the requirements of heat insulation and radiation resistance, and different fillers (pigments) are used to achieve the purpose of heat insulation and radiation resistance 1 The basic composition of thermal control coating 1.1 the selection of resin and filler (pigment) is organic silicon modified acrylic resin, which has the characteristics of keeping its basic performance unchanged for more than 20 hours under the temperature of about 850 ℃, with excellent weather resistance, light retention and high temperature resistance Based on the theoretical calculation of particle size, heat transfer and heat absorption, combined with the analysis of resin phase transformation and curing reaction system, it is determined to select hollow ceramic (glass) beads, titanium dioxide, mica powder and other fillers (pigments) with low thermal conductivity and high heat resistance Epoxy resin is used to improve the processability of the main resin, and the curing agent is determined according to the construction characteristics 1.2 selection of flame retardant and diluent in order to ensure the effectiveness of the coating system, it is necessary to select flame retardant Combined with the analysis of the coating system, composite flame retardant is selected in the formulation design of heat preservation and heat insulation coating Diluent special diluent 1.3 basic ingredients: organic silicon modified acrylic resin, 57%; epoxy resin, 7%; hollow ceramic bead, 11%; titanium dioxide, 7%; asbestos powder, 4%; mica powder, 3%; fumed silica, 3%; other functional components, 8%; flame retardant, functional assistant, appropriate amount; combined solid agent M (base material): m (curing agent): 10:3 2 See Table 1 for the basic performance test results of thermal control coating Table 1 test results of basic properties of coating note: 1mm steel plate is selected as the base material of the test sample After degreasing and derusting, the sample plate (coating on both sides and all sides) shall be prepared by spraying or brushing After curing, the coating thickness shall be 0.05-0.1mm The muffle furnace or other high-temperature equipment (temperature range 0-1000 ℃) with temperature display shall be used as the heat source The cured sample plate shall be put into the high-temperature equipment at normal temperature The equipment shall be started to rise to 900 ℃, and the sample plate shall be taken out after 15 minutes and cooled Visually inspect the coating surface Coating required: no blistering, no warping, no falling off 3 Thermal insulation performance test of thermal control coating 3.1 preparation and treatment of sample plate base material is aluminum magnesium alloy plate, with thickness of (1.2 ± 0.15) mm, overall dimension of 100mm × 100mm, surface cleaning, degreasing and anodizing treatment The coating shall be evenly applied on one side of the base material by spraying or brushing The next coating shall be carried out after the surface is dry after one coating Finally, the thickness of the coating layer shall be more than 1.0mm The coating shall be cured at room temperature for more than 24 hours or at 120 ℃ for 4 hours to make the coating fully cured 3.2 testing instruments: stopwatch, PT-100 thermal resistance, temperature digital display (0 ~ 1000 ℃) Heating heat source: the resistance furnace (1000 ~ 3000W) with temperature controller is used as the heating heat source The furnace mouth is transformed into a heating channel (channel height (65 ± 5) mm) with the upper size of 65mm × 65mm and the lower size of 130mm × 130mm by heat insulation materials The lower mouth is close to the resistance furnace and the upper mouth is covered by alloy steel plate (70mm × 70mm × 1.5mm) Test method: fix the test end of two probes of PT-100 thermal resistance in the center of the test surface of the sample plate (or alloy steel plate), fix the other end on the adapter and transfer it to the temperature digital display, and use the temperature controller to adjust the temperature in the resistance furnace 3.3 environmental requirements: ambient temperature: (25 ± 5) ℃; there shall be no flowing air in the test environment 3.4 determination of thermal insulation (1) heat source calibration: after starting the resistance furnace, set the control temperature, use alloy steel plate to detect the furnace mouth temperature, adjust and control the resistance furnace temperature, so as to ensure that the surface temperature of alloy steel plate is within (850 ± 10) ℃ (recorded as t0), and maintain it for more than 5min (2) Measurement of back temperature (heat insulation temperature T1): face the heat source channel on the coated side of the test sample plate, push the alloy steel plate in parallel, and finally make the sample plate completely cover the resistance furnace mouth Place the PT-100 thermal resistance test probe in its center position, record the heating time with a stopwatch, and record the surface temperature T1 of the sample plate at 5min (3) Repeat the calibration of heat source: repeat the above steps (1) and (2), replace the sample plate with alloy steel plate, and test the temperature T2 at the center of alloy steel plate The T2 value shall be within t0 range (not more than (850 ± 10) ℃), otherwise, calibrate and test again 3.5 see Table 2 for the test results Table 2 test result of thermal insulation temperature T1 4 The test index of anti photothermal radiation performance of thermal control coating is based on hemispherical emissivity, with hemispherical emissivity ≥ 0.85 (the actual test value is 0.9) 5 Results discussion 5.1 main resins As a film-forming material, the function of resin is not only to combine the functional material with the base material, but also to have the function of heat resistance and reflection of photothermal radiation The acrylic resin modified by organosilicon is used to reduce the endothermic groups such as C-O structure (such as C-O-C, C = O, O-H, etc.) in the resin, so that it can be replaced by Si-O structure, enhance the heat resistance of the resin and reduce the resin pair The absorption of space photothermal radiation The absorption rate of various resins (titanium dioxide as filler) to solar heat is shown in Table 3 Table 3 the solar thermal absorption rate of different resin reflective coatings can be seen from table 3: the solar thermal absorption rate of acrylic resin is only 0.24, while that of silicone modified is 0.19, which has better resistance to photothermal radiation The modified resin can keep its basic properties unchanged for more than 20 hours under the temperature of about 850 ℃, and has good weather resistance, light retention, high temperature resistance and other characteristics Its reflectivity to solar radiation is more than 80% 5.2 for the thermal control coating of composite functional filler, hollow ceramic (glass) beads, titanium dioxide, mica powder and other pigments and fillers with low thermal conductivity and high heat resistance are selected From the outside to the inside, hollow ceramic (glass) microspheres form a hollow spherical barrier after coating curing, which is like a "micro" foam material, and is a "closed cell bubble" When heated, the heat is transmitted from inside to outside into the coating The low heat conduction gas formed by the closed cell foam "slows the conduction rate of heat The thermal conductivity of the composite after the packing is actually less than 0.2W/ (M K) ）It has good insulation effect Hollow ceramic (glass) beads are characterized by low bulk density, high temperature resistance, high strength, low shrinkage, acid and alkali corrosion resistance, heat insulation, sound insulation, insulation and low water absorption, which can significantly improve the thermal insulation, light and heat radiation resistance of thermal control coating, as well as the mechanical properties of the coating 6 Conclusion the high temperature resistant and heat insulation coating has the properties of heat conduction resistance, light and heat radiation resistance, and good heat insulation performance It has a broad application prospect Reference [1] Wang Kelin, Xu Na Solar thermal reflective insulation coating and its development trend [J] Modern coating and coating, 2009 (02): 19-23 [2] Li Zhiqiang Discussion on the application of hollow filler in high temperature resistant insulation coating [J] Shanghai coating, 2010 (11): 25-27 [3] Li Zhiqiang Performance test of a kind of high temperature resistant and heat insulation coating 〔 J 〕 Modern coating and coating, 2010 (08): 30-31, 36 Coating house is specialized in coating, diatom mud, paint coating, coating process, news information and coating of fire retardant coating, diatom mud, paint coating, coating process, decoration knowledge and decoration effect map of fire retardant coating,