Preparation And Performance Studies Of Exterior Wall Thermal Insulation Coatings

A kind of novel exterior wall thermal insulation coating with excellently comprehensiveperformances was prepared, and the formula composition of this coating was studied in detailin this paper. The whole paper includes two parts as follows:In the first part, the thermal insulation of coating film was focusedly studied throughoptimization of different acrylic emulsions, functional heat-insulating fillers, dosage and filmthickness, pigments volume concentration (PVC) and colors. The results showed that: coatingwhich used acrylic emulsion A as film forming material had high hardness, excellent adhesionand good anti-dirty performance; the FT-IR analysis showed that acrylic emulsion A wasadequate for thermal insulation coating with its few types of endothermic groups; comparedfour functional heat-insulating fillers and it was clear that the temperature difference, allwavesolar reflectance and hemispherical emittance of coating film with reflective heat-insulationpowder were higher than other coatings; the film had an optimum performance of thermalinsulation when the dosage of reflective heat-insulation powder was10%, and the pigmentsvolume concentration (PVC) was41.5%, as well as the film thickness was200μm; thethermal insulation of white film was better than other color coatings(pink, aqua, creamy, azure)with all other factors being equal.In the second part, effects of type and dosage of silica solution, titanium dioxide,filmforming additives, hydrophobe, antifreezing agent, and thickening agent on thecomprehensive performances of the coating film were discussed in detail. The results showedthat: the compound of silica solution I and acrylic emulsion A could improve the hardness andanti-dirty performance of the coating film, and the comprehensive performances couldachieve the best balance when the ratio of acrylic emulsion A to silicon solution I was5:3,meanwhile the scanning electron microscope(SEM) photos indicated that the film hadcompact structure; the optimal dosage of titanium dioxide was15%; the optimal film formingadditive was dipropylene glycol n-butyl ether (DPnB) and the film presented good filmsurface effect, high hardness(pendulum hardness of0.3899)and excellent anti-dirtyperformance(reflectance decline rate of4.54%) at low temperature of0℃with the dosage ofDPnB being2.5%; the water contact angle of coating film could reach92.34owith the dosageof hydrophobe Phobe6600being4%, meanwhile the coating film presented the best anti-dirtyperformance with its reflectance decline rate being3.98%; the freeze-thaw stability of coatingwas good with adding propylene glycol3%by weight; choosed ZC501as thickening agentand the film presented good storage stability with an optimal dosage of2.5‰. The exterior wall thermal insulation coating prepared in this paper has reached thedemands of solar heat reflecting insulation coatings for buildings in the standards of GB/T25261-2010and synthetic resin emulsion coatings for exterior wall in the standards of GB/T9755-2001. It’s obvious that this kind of coating will have a broad future for application.