Preparation Of Highly Reflective And Heat Insulating Film And Characterization Of Its Light And Heat Properties

High reflective insulation coating is to have high reflectivity to the solar radiation and infrared radiation, and the coating itself has a high emissive to the mid-infrared, thus can decrease the surface temperature of the coating to save energy.In this paper, we focus on the surface morphology of the coating to improve reflectivity, using flake aluminum and higher refraction index titanium dioxide as heat-reflective insulation materials, selecting the silane coupling agent, water-based acrylic resin and polyurethane resin as a film-forming material. Those are used to prepare highly reflective insulation coating. Analyzing the reflective and insulation effect of coating from the types of the film-forming materials, the types of reflective material, the particle size of the reflective materials, the percentage content and the thickness of the coating. A UV-visible-near infrared reflectance spectrophotometer is used to test the coating reflectance performance, A Fourier Infrared spectrometer is used to test coating mid-infrared reflectance and analysis the coating composition, to develop a equipment to test the temperature difference of the upper and lower coating surface in order to characterize the coating thermal insulation properties. Taking the SEM and AFM images of the coating, we analysis the reflectance performance from the surface morphology. Meanwhile, the preparation and coating process had been studied, and the basic properties of the coating had been tested.The results show that:choosing the appropriate film-forming material and the volume of the pigments and fillers, it can significantly improve the coating reflectance and insulation performance. Among the film-forming materials silane coupling agent K.H-560, acrylic resin and polyurethane, the K.H-560has a best reflectance and insulation performance because of its colorless and transparency with a good combination of flake aluminum. The infrared analysis shows that the aluminum and silane coupling agent forms Al-O-Si bond. Compared the two size of the aluminum, the smaller size particle of flake aluminum has a better reflectance performance. It has an even reflectance95.6%in the ultraviolet region,80.9%in the visible region and78.8%in the near infrared region. The smaller particle size is, the larger of coverage area of the coating surface, and then to increase the high reflectance performance. With the increasing of the mass fraction and the thickness, the coating has a better performance. Two kinds of titanium dioxide have high reflectance in the visible region, but low reflectance in the ultraviolet and near infrared region. The average reflectance is above95%in the visible region, while66.2%in the near infrared and10.0%in the UV region. So to mix up the titanium dioxide with flake aluminum on different ratios and prepare coating, it can significantly improve the UV and the near-infrared reflectance of the coating. We designed a self-made device to measure the up and down temperature of the coating surface. Compared with the blank PI film, when the coating mass fraction is10%and the thickness is0.025mm,the temperature difference of the upper and lower sides of the coating is13.5℃,While, the thickness of the coating is0.082mm at the some mass fraction, the average temperature difference between the up and down sides is17.8℃. With the time, the coating temperature is no longer increased and tends to be stable. Meanwhile, the flake aluminum particles overlapped one by one made the coating to have a good corrosion resistance and excellent basic performance. AFM images show the coating one-dimensional profile, two-dimensional maps and three-dimensional topography map from the roughness and the one-dimensional profiles. The surface RSM is all under100nm, we can analysis the reflectivity of the coating from the surface morphology, and we can see the wavy angle fluctuate between0°nd60°rom the one-dimensional profiles. It makes the light reflect one or two times on the surface, and this V-shaped surface also increased the absorption rate of the coating.This comprehensive analyses show that the study of the insulation coating of flake aluminums with silane coupling agent as binder can effectively reduce the internal temperature, improve living and working environment and save a cooling costs.