Study On Preparation And Thermal Insulation Mechanism Of Nano Transparent Thermal Insulation Waterborne Coating

Transparent thermal insulation water-based paint is a new type of coating which shields near-infrared light.Water-based paint is not only environmentally friendly,but also can increase the insulation effect for the window structure of the building to achieve the purpose of energy saving.Nano antimony tin oxide（ATO）is currently the mainstream functional material for making transparent heat-insulating water-based coatings.However,ATO is easy to agglomerate during the dispersion process,and the dispersion process is complicated.As a result,the optical performance and thermal insulation performance of ATO are reduced,which limits the further application of ATO in transparent thermal insulation coatings.In this paper,a solvothermal method is used to prepare nano-ATO.Experiment uses the method of using silane coupling agent A-187 modified ATO surface and loading ATO on TiO₂ surface to reduce reunion and optimize the optical performance of ATO in the UV,VIS,and NIR regions.By blending with lithium silicate-based inorganic coatings to prepare transparent thermal insulation inorganic coatings with good thermal insulation properties.The main research content and conclusions of the thesis are as follows:1.Using SnCl₄·5H₂Oand Sb Cl₃ as raw materials,nano-ATO was prepared by solvothermal method,and analyzed by XRD,FTIR,EDS,and laser particle size characterization.The results show that the prepared ATO is a pure product with high crystallinity and complete crystal structure which is a tetragonal rutile crystal with a crystal size of 15.8 nm.The actual doping ratio is n（Sb）:n（Sn）=7.75:1.2.Modified ATO uses the silane coupling agent A-187 as the surface modifier.The effects of different reaction temperature,time,PH value,and the amount of modifier added on the grafting rate and NIR transmittance have been studied,and analyzed by TEM,EDS,FTIR,TG,spectral transmittance.The results show that the best modification conditions are reaction temperature is 60℃,reaction time is 8 h,PH value is 9.5,m（modifier）:m（ATO）=8:1.After modification,the ATO particle size is 86.23 nm,which is 48.57%less than before modification,and the lowest near-infrared transmittance is only 1.48%.3.With TiO₂ as the core,ATO was loaded on the surface of TiO₂to prepare nano-ATO-TiO₂ with a core-shell structure.The effect of TiO₂ with different particle sizes on the transmittance of ATO-TiO₂ in the UV,VIS,and NIR regions was studied,and analyzed by SEM,XRD,EDS,laser particle size,spectral transmittance.The results show that ATO forms a continuous coating structure on the surface of TiO₂.As the particle size of TiO₂ increases,the visible light transmittance of ATO-TiO₂ increases,but the infrared blocking ability decreases.Compared with ATO,the visible light transmittance of ATO-TiO₂ is increased by 198%,and the near-infrared light transmittance is only 21.92%.4.The experiment selects the best ratio of lithium silicate-based inorganic coatings through orthogonal experiments.The experiment uses silicic acid-based inorganic coatings and nano ATO-TiO₂water-based slurry as the main raw materials to prepare transparent thermal insulation water-based coatings by blending,and uses automatic coating machines to make coatings of different thicknesses.The effects of different water-based slurry addition,coating thickness,and TiO₂ particle size on the thermal insulation performance of the coating were studied.The results show that ATO-TiO₂ can be dispersed after5 minutes of ultrasound,the coating thickness is 90μm,the addition amount of water-based slurry is 4 wt%,the TiO₂particle size is 25 nm,and the temperature difference reaches 2°C.