Preparation And Properties Of Color Thermal Insulation Coating For Building Exterior Wall

The building external walls heated by solar radiation directly, which causes indoor temperature to rise and brings numerous energy consumptions. For the purpose of energy saving, wall insulation coating is emerging. Currently, most of the insulation coatings used in external walls are white. But in practical applications, people prefer to choose colorful paints to decorate external walls, white paints accounts for less than two percent, in which insulation coatings are less. In order to promote insulation coatings in the market better, this paper described the process of making colorful insulation coatings which used in external walls in details.There are three aspects as follows:Firstly, experiments use hydrolysis precipitation method to coat hollow glass beads, the core materials, with a layer of Cr2O3, Fe2O3, TiO2 film in its surface, which improve the dispersion of beads and bring some colors. At the same time discussing the optimal experimental conditions for coating effect, then characterizing three modified beads by SEM, XRD, dispersion, sunlight reflectance. Experimental results show that, as for modified 10 g hollow glass microspheres,in the condition of 60? and pH 8.0, Cr2O3 coatings require 190 mL 0.5mol/L of CrCl3 solutions.The green bead obtained from the condition above, which thermal conductivity is 0.1573 W /(m ? K) and the ratio of reflected sunlight is 0.4655. Fe2O3 coatings need 180 m L 0.5mol/L of FeCl3 solution at the reaction environment of 80?and pH 4.0.The obtained red bead, which thermal conductivity is 0.2235 W/(m ? K) and ratio of reflected sunlight is 0.5986; TiO2 coatings need 150 mL 0.5mol/L of TiCl4 solution at the reaction environment of 70?, pH 3.0.The obtained white bead, which thermal conductivity is 0.2753 W/(m ? K) and ratio of reflected sunlight is 0.8503; Compared with the previous modification, the dispersion of three modified beads were significantly improved. They can be used as fillers to add into color insulation coatings.Next, film materials are selected as Acrylic emulsions which contain less absorbing groups. The selection is based on the Infrared detection. According to the functions of composite insulation coatings, select the type of fillers. And regarding integrated thermal insulation as a reference index, then determining the amount of each fillers by single factor test and orthogonal test in sequence. Regard the dispersion stability of coatings as a reference index to determine the type of dispersants and discuss the most appropriate coating viscosity and film thickness. The results show that Coatings made by 30% of acrylic emulsion, 14% of TiO2 modified hollow glass microspheres, 6% of infrared ceramic powder, 12% of retile titanium dioxide, 5% of talc and 11% of heavy calcium powder, 0.5% of P-19 dispersant and other additives work best and have best effect of insulation. When the viscosity of the coating is around 16000 mPa.s, coatings are the most stable. And to get a better insulation effect, the minimum dry film thickness of the coating is 1mm.Finally, the experiments use three modified hollow glass microspheres to make colorful insulation coating which used in exterior walls and then test their characteristics. The results show that the insulation coating which added Cr2O3 modified hollow glass microspheres is light green, and the sunlight reflection ratio is 0.5323, the hemispherical emissivity is 0.88, the insulation temperature differences is 16.0?. The coating which added Fe2O3 modified microspheres is orange, and the sunlight reflection ratio is 0.6647,the hemispherical emissivity is 0.88,the insulation temperature differences is 18.3?. The coating which added TiO2 modified microspheres and green paste is dark bean green, and the sunlight reflection ratio is 0.5062, the hemispherical emissivity is 0.89, the insulation temperature differences is 13.9?. The coating which added TiO2 modified microspheres and red paste is bright red, and the sunlight reflection ratio is 0.5893, the hemispherical emissivity is 0.86,the insulation temperature differences is 16.7?. The performances of the four coatings above have reached the national insulation coating standard.