Thermal performance is more difficult. In this paper, the composite thermal insulation coating of high temperature thermal insulation coating + polyurethane foam plastic improves the thermal insulation performance of high temperature resistant thermal insulation coating and prolongs the effective heat insulation time of thermal insulation coating. 1 Introduction High-temperature heat-insulating coatings, especially thermal insulation coatings exceeding 800 °C, are usually designed according to the thermal insulation needs of the products. The high-temperature resistant thermal insulation coatings prepared with high-temperature resistant resins have thermal insulation properties. Generally, the product needs to meet the requirements of a certain temperature, time and a certain thickness of the coating. When the thermal insulation coating is determined, it is quite difficult to extend the holding time. Polyurethane foam plastic is a good thermal insulation material, but it can only be used under normal temperature environment. It utilizes the thermal insulation property of high temperature resistant thermal insulation coating to make polyurethane foam plastic meet the insulation of more than 800C high temperature environment under certain conditions. Heat requirement, through the composite thermal insulation coating of thermal insulation coating + polyurethane foam plastic, to achieve the purpose of prolonging the effective heat insulation time of thermal insulation coating, improve the thermal insulation performance of high temperature resistant thermal insulation coating, and let it be used at normal temperature. The polyurethane foam plastic can also be insulated and insulated in a high temperature environment exceeding 800C, effectively meeting the heat insulation needs of the product. Using a self-developed ''normal temperature curing high temperature heat-insulating coating' combined with polyurethane foam plastic to form a heat-insulating composite coating, using heat-generating components around 850C to improve the thermal insulation performance. Insulation temperature 850C, coating The thickness of the layer is about 1mm, and the thermal insulation requirements remain unchanged, that is, the temperature after heat insulation is not higher than 200C, but the heat insulation time of the coating is extended from 180s to 300s to ensure the thermal insulation needs of the product after upgrading. 2 Preparation and heat insulation of room temperature curing high temperature insulation coatings 2.1 Basic composition of coatings Silicone resin (modified with acrylic resin), epoxy resin, hollow ceramic microbeads, asbestos powder, graphite powder, flame retardant and other functions Components, etc. 2.2 The thermal insulation performance of the coating is 1.0mm thick; the heat-resistant temperature T0 is greater than 850C (heating time 20min, the coating is basically unchanged); the insulation temperature T1 is less than 200C; the heat insulation time is greater than 180s. 3 Preparation of polyurethane foam plastic Polyurethane foam plastic prepared by the preparation of heat-insulating 3.1 polyurethane foam plastic is mainly considered to improve its heat resistance and heat resistance. It is difficult to greatly improve the heat resistance. The heat insulation performance of the auxiliary heat insulation layer for "normal temperature curing high temperature heat insulation coating": the insulation temperature in 180s is less than 200C, and it is necessary to increase the heat resistance temperature of the polyurethane foam used to About 200C, general polyurethane foam plastic does not undergo thermal degradation within 150C, and thermal degradation begins to occur after more than 180C. Therefore, when selecting and designing polyurethane foam plastics, the heat resistance structure of the foam is considered, and the polyester type is hard. It is foamed and flame retardant to design its modified foaming formula. The basic foaming components of the polyurethane foam plastic are as follows: polyester polyol, silicone oil, albino red phosphorus, triethylenediamine, an activator, a foaming agent, water, isocyanate, and the like. 3.2 Heat resistance and flame retardancy of polyurethane foam plastics The sample of about 20mm is placed in an incubator of 200QC-210QC for 300s (constant heat preservation for 600s). The polyurethane foam is basically intact and has no thermal degradation. The polyurethane foam is ignited and removed from the fire source, and the foam can self-extinguish. 4 Sample preparation and testing 4.1 Sample preparation process The base material is processed into a concave groove polyurethane foam (or foamed with a mold) - foam plastic processing (or press-fit into the concave groove of the aluminum alloy after trimming) - Apply thermal insulation coating. 4.2 Preparation of sample plate In order to facilitate the detection, the preparation of the sample plate is 150mmX150mmX17mm according to the detection method (including the thickness of the coating layer is 1mm, the thickness of the polyurethane foam is 15mm, and the thickness of the substrate is 1mm). The base material of the base material is made into a concave shape and concave. The tank is filled with polyurethane foam plastic, and the concave surface is coated with a high temperature resistant heat insulating coating. 4.3 Thermal insulation test 4.3.1 Test instrument -1000C). Heating heat source: Use a resistance furnace (1000W-3000W) as a heating heat source. The furnace mouth is transformed into a heating channel with a top opening size of 80mm×80mm and a lower opening size of 130mm×130mm. The channel is high (65±5)mm. The lower mouth is close to the resistance furnace, and the upper part is made of alloy steel plate 2; the environment is not allowed during the test. There is flowing air. 3 Detection operation heat source calibration: After starting the resistance furnace, set the initial control temperature, test the surface temperature of the alloy steel plate with the surface temperature tester, and adjust the resistance furnace to ensure the surface temperature of the alloy steel plate is (850 back temperature (insulation temperature T1) Determination: The coating of the sample plate faces the heat source channel, and at the same time pushes the alloy steel plate, and finally the sample plate completely covers the heating channel, the surface temperature of the surface of the sample plate is detected by the surface temperature tester, and the heating time is recorded with a stopwatch. The surface temperature is. The gold plate replaces the sample and detects the temperature T2 of the center position of the alloy steel plate. The T2 value should be within the range of T. [(850±10) °C] If it exceeds (850±10) °C, it should be recalibrated and tested. 5 The test results were compared with the sample test and the pure paint layer sample and the simple bubble layer sample were compared under the same conditions. The test results are shown in Table 1, Table 2 and Table 3. The insulation performance test results of the same insulation time of the sample of Table 1. The appearance of the polyurethane foam heat-resistant foam is complete, no degradation, etc. Note: The heat insulation time is 300s, the T0 table 2 sample is not Insulation performance test results of the same insulation time Polyurethane foam heat-resistant condition The foam has a complete appearance, no degradation, etc. After the high temperature, the coating on the sample plate does not blister, can not be layered, does not fall off. Note: heating temperature T.=850C; surface The temperature tester readings quickly. Table 3 Insulation temperature test results of different insulation layers Heat insulation layer coating + foam layer Single coating layer Single foam layer heating temperature, C heat insulation time, s insulation temperature T "C insulation temperature difference 6 application example a cylindrical The component is a short-time heating component that is used in a certain space and will have a high temperature effect on adjacent components during operation. It needs to be insulated and protected: it has a hot working time of 3 minutes and starts to produce a maximum of 850C in the first 90s. High temperature, lasting 30s-60s, the maximum temperature of the environment is not allowed to exceed 200 °C, the space for thermal insulation is only 50mm, initially using a single "normal temperature curing high temperature insulation coating" for thermal insulation protection, thick coating 1mm, due to the poor control of the coating thickness, the back temperature after the measured thermal insulation protection fluctuates to a certain extent and is higher than 200 °C, which adversely affects adjacent components. The thickness of the coating is increased, but the defect of poor adhesion is obtained by using the normal temperature curing high temperature heat resistant coating layer (1 mm) + polyurethane foam layer (1 mm) for thermal insulation protection, and the actual thermal insulation performance is obtained. The test results are shown in Table 4. Since the coating thickness is not easy to control, there are some differences from the results of the sample test. Table 4 Actual thermal insulation performance test results Insulation time, s heat insulation temperature T1, C polyurethane foam heat resistance foam appearance intact, no degradation, etc. After high temperature, the coating layer on the sample board does not blister, can not layer, does not fall off 7 Discussion and conclusions (1) Polyurethane foam is a flammable substance, and the oxygen index is generally (18 -19) L/min. When it is higher than 200C, the smoldering will occur. After being insulated for 180s, the room temperature curing high temperature heat insulation coating has a heat insulation temperature of 200 ° C. Therefore, the oxygen index of the polyurethane foam needs to be increased to above (22-27) L/min to achieve self-extinguishing or even non-combustible. At the same time, in the heat insulation protection time, the bubble does not produce high temperature degradation, so as to meet the purpose of improving the heat insulation performance. The test results show that the heat-resistant temperature can reach 200C within 600s after the flame-retardant treatment of the polyurethane foam, so that the heat-resistant temperature meets the requirements. The high-temperature thermal insulation coating has good short-term thermal insulation performance, and is combined into a thermal insulation layer to provide effective heat insulation protection for the parts in a short time, thereby achieving the purpose of improving the thermal insulation effect. (2) Thermal insulation coating + polyurethane foam insulation protection aging depends on the thermal insulation effect of the thermal insulation coating. Over time, the thermal insulation protection of the coating gradually fails, and the foam will also fail due to thermal degradation. The time-effect of the combined layer is obvious, but compared with a single high-temperature thermal barrier coating or polyurethane foam layer, the thermal insulation protection effect is greatly improved. (Finish) White particles, polyethylene glycol butyl diacid butyl ester (PBS) by succinic acid and butyl glycol by condensation polymerization of synthetic, resin in milky white, odorless, vulnerable to a variety of microorganisms or plants and animals in nature of the enzyme catabolism, eventually decomposed into carbon dioxide and water, is typical of completely biodegradable polymer material has good biological compatibility and biological absorbability;Density of 1.26 g/cm3, melting point 114, according to the high or low molecular weight and molecular weight distribution, crystallinity between 30 ~ 45% in the 1990 s it into the material research field, and quickly became can be widely applied in the universal one of research hotspots of biodegradable plastic materials, heat resistant performance is good, heat distortion temperature, and the products using the temperature can exceed 100 synthetic raw material sources can be either its oil resources, also can through fermentation by biological resources, PBS are outstanding in biodegradable plastic materials. Polybutylene Succinate Pbs,Soft And Flexible Pbs,Good Dimensional Stability Pbs,Good Flow Ability Pbs Xingbang High Molecular Materials Co., Ltd. , https://www.chemicaladditive.com