| Because of exterior latex paint were exposed to outside for a long time,and it was easy to be stained with dust.Therefore,the stain resistance is an important property to evaluate exterior latex paint.For this purpose,this dissertation studied systematically the effects of type and content of emulsion,pigment,Tg and filler on the stain resistance of exterior latex paint,and prepared economical stain resistance exterior latex paint.The research results are below.(1)The ration of Methyl methacrylate with butyl acrylate(MMA/BA)decreased,the glass transition temperature of emulsion decreased,the stain resistance decreased and elongation increased.The amount of silica sol was proportional to the stain resistance and was inversely proportional to the elongation.In addition,the silica sol's particle increased,the stain resistance of latex paint got worse and elongation got better.(2)The stain resistance of latex paint prepared by different polymer emulsions was as below: self-made organic-inorganic composite emulsion > polyurethane emulsion > fluorocarbon emulsion > general pure acrylic emulsion > styrene acrylic emulsion.The amount of polymer emulsion and glass transition temperature was proportional to the stain resistance of latex paint.Therefore,when the glass transition temperature of emulsion was about 6 ?,the comprehensive performance of latex paint was the best.(3)In the test of kinds of pigments and fillers,the stain resistance of latex paint had no difference obviously.However,the price of mica powder and superfine barium sulfate was much higher than calcite powder.Therefore,the performance of latex paint by calcite powder was the best,and the silica fume was easy to precipitate in the paint.The particle size of calcite powder was inversely proportional to the stain resistance of latex paint.The reason was that the surface roughness of latex paint was not compact.However,the particle size decreased,the more wetting dispersing agent needed in the formula of latex paint.Therefore,when the particle size of calcite powder was 12 um,the comprehensive performance of latex paint was the best.(4)With the amount of ULTRA E and FS-61,the stain resistance would be increased.Therefore,based on the consideration of cost and performance,the optimal adding amount of ULTRA E and FS-61 were 6% and 1% respectively.(5)Compared with common exterior latex paint,competitors A and B,the product had excellent performance under the best conditions.The stain resistance performance was close to 8.56%,far higher than the requirement of national standard(about 25%).And its cost was relatively lower.Therefore,the product had abroad prospect in exterior wall building decoration materials. |
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