Preparation And Properties Of Compound Highly Reflective Styrene-acrylic Emulsion

The insulation performance of building materials has become one of the important measures of building energy saving. At the same time, the reflective thermal insulation coating is favored by people increasingly because of its good heat insulation effect and the low price. At present, domestic and foreign scholars for reflecting heat insulating coatings research mainly focused on the development of efficient reflective pigments and fillers, but studied few on the reflective properties of film material which occupies a large proportion of the coating composition. So this article is based on the emulsion and the preparation for the composite emulsion with high reflectivity. For TiO2has the advantages of high refraction coefficient and big reflectivity, this article based on the TiO2powder as the inorganic component, to be prepared with high reflectivity of the organic-inorganic composite emulsion. All kinds of properties of composite emulsion were improved, then it can be applied to exterior wall coating, to prepared insulation exterior wall paint with highly reflective for the requirements of reducing the indoor temperature, the social energy saving and emission reduction.Nano-TiO2powder was prepared by using sol-gel. First, make the butyl titanate ethanol solution drop to the glacial acetic acid alcohol solution to prepare for TiO2precursor, when the reaction temperature is40℃, the rate is1.5mL/min, calcination temperature reaches600℃, the diameter was65nm, reflectance is relatively high, reaching the purpose of preparation high reflectivity of Nano-TiO2powder. Then modifide the surface of Nano-TiO2to improve the compatibility with organic solvent. Experiments determind that the dosage of silane coupling agent was0.5%, pH value of reaction system is6.5, reaction time was1.5h, the modified Nano-TiO2lipophilic degree is the highest, organic modification effect is better, and the reflectivity is also higher. Discuss the influencing factors of the emulsifier, initiator, reaction temperature, stirring speed, the amount of acrylic acid, and the soft and hard monomer ratio to the emulsion performance. Finally, determined the experimental formula:Composite emulsifier:2.5%; evocating agent:.3%; the reaction temperature is80℃-85℃; acrylic acid:3%; soft and hard monomer (BA:St) ratio of1:1; stirring speed is600r/min, this moment the emulsion performance such as emulsion polymerization stability, mechanical stability are better, conversion rate is relative to the maximum, to about53%, and the emulsion particle size is relative to the minimal which has reached250nm. When the TiO2content is0.4%, make the composite emulsion applied to the paint, get high reflectivity and good heat insulating effect. After testing, the reflective insulation effect of adding a high reflection composite emulsion which is prepared by coating is greatly improved, when test the heat insulation effect, temperature of test plate back surface is2-3℃lower than the unmodified.