Study And Application Of The Near-IR Heat Reflecting Coatings

Near-IR heat reflecting coating is a kind of functional coatings that have a highreflectance on the near-IR wave band that centralize most of the energy of the sun's rays,thereupon it can prevent the surface temperature of coatings as well as the enclosed interiorsurroundings from being heated up without the consumption of energy, attain the function ofeconomy energy and heat shielding. It exhibits great potential in the application as coatings forships, vehicles, exterior wall of buildings and oil containers to prevent excessive internaltemperature rise by keeping the surface cool.This paper studied the prepare technics of the near-IR reflect-material. It was titaniumdioxide (TiO₂) deposited on the hollow chinaware min-ball and doped with Sn⁴⁺ ion, using ahomogeneous precipitation method, and studied the condition of the method. Bases the highrefractive index of rutile-TiO₂, adopt the chemical inducing process and using the inducingfunction of SnO₂ to transform all of TiO₂ thin film to the rutile-phase. In addition, this paperstudied the influence factor, namely, the mass of TiO₂, mass of SnO₂, the torrefy temperatureand time of the reflect-material, on the capability of the reflect-material. Eventually, this paperconfirmed the latex, additives, the pigment and the stuffing that was used in near-IR heatreflecting coating by contrast, and prepared excellent near-IR heat reflecting coatings.The characterization of the reflect-material was studied by X-ray diffraction (XRD),electron probe and UV-visible light-IR spectrophotometry. The results showed that all of TiO₂thin film transform to rutile-phase when the quantity ratio of SnCl₄ and titanium tetrachloride(TiCl₄) was 1:10; TiO₂ thin film that was on the surface of the reflect-material was uniformityand compact; The reflectance of the near-IR heat reflecting coatings was 88ï¼…and 77ï¼…onvisible light (400-700nm) and near-IR (700-2500nm) wave band when the content ofreflect-material on the coatings was 10ï¼…. In addition, test the rest capability of near-IR heatreflecting coatings, the result showed that the coatings was fit for the outer wall coatings.This paper studied the hydrolysis of Ti⁴⁺, the function mechanism of chemical inducingprocess and the reflect capability of reflect-material. The hydrolysis of Ti⁴⁺ by chemicalanalysis method, the result showed that: after hydrolyze and polymerize, Ti⁴⁺grew tocoenocyte-Ti-ion and could agglomerate in the function of the electrolytical (Cl^-, Na⁺). Thedeposition of TiO₂·nH₂O was produced when the granularity of the coenocyte-Ti-ion reach1μm. Base the XRD result, the function mechanism of chemical inducing process was studied,the result showed that SnO₂ could cause the TiO₂ phase transform from anatase-phase to ruitle-phase at low temperature. And all of the TiO₂ thin film transformed to the rutile-phasewhen the quantity ratio of SnCl₄ and TiCl₄ was 1:10. Integrate the particle dispersion theory,the reflect capability of reflect-material was studied, the result showed that the reflect impactof the reflect-material was the best when the cover thickness of TiO₂ thin film was 0.44μm.The calculation showed that the reflect-material could effective reflect the light wave between400nm-2500nm, it could also said that the visible light and near-IR wave band that centralizedenergy of the sun's rays.Based on the preliminary study and test results, the following concluding remarks can bedrawn: near-IR heat reflecting coatings provides an effective way for controlling surface andinternal surrounding excessive temperature rise of structures and containers; Wide uses ofneat-IR heat reflecting coating in urban areas maybe a resolution to urban heat island problem,in addition to improving work environments and save energy.