Research Of High Quality And Low Cost Exterior Wall Coating

This subject analyzed some common problems encountered in actual use of exterior emulsion paint - discoloration, poor color retention; ecclasis,shedding phenomenon and the stubbornly high prices. There is a practical and effective way of improvement been presented in this paper, and it also prepared an exterior paint with low-cost and high-quality.First, the phenomenon of paint faded, poor color retention was mainly due to the effects of ultraviolet radiation of sunlight,so a multi-functional additives is proposed to be add into the paint.In this paper,the hydrotalcite used as the multi-functional additives was prepared by the method of single drop,then test those samples of different preparation conditions by infrared spectroscopy, scanning electron microscopy, X-ray diffraction and UV spectroscopy, so as to obtain the optimal preparation conditions. Experimental results show that when the molar ratio of magnesium by aluminum is 3, the temperature is 70℃, the aging time of 6 hours,the hydrotalcite has the best crystallinity and regular structure, and it also possesses a strong absorption of UV. The study also found when hydrotalcite used with the nano-titanium dioxide,the coating may possesses better resistance to ultraviolet rays in all of the UV region.Second, the method of preparing styrene-acrylic emulsion at room temperature by oxidation - reduction system is proposed to make reaction temperature lower, so as to save the cost and protect environment. Studies show that when the molar ratio of the oxidation and reduction is 1.5:1, initiator addition level is1.1%; the mass ratio of hard and soft monomers (St / BA + MA ) is 0.9:1, MA / BA is 1:9, the addition level of crosslinking agent (AA) is 1.35%; the content of emulsifier(OP-10) is 1.5%, the styrene-acrylic emulsion is best.Finally, the method acrylic emulsion compound with the inorganic silica used to improve the coating’s adhesion to solve the problem of paint off, which caused by the poor adhesion of emulsion.By studying the performance of the coating with different formulations,it could be realised the best mass ratio of styrene-acrylic emulsion and silica composite is 6:4, the best ratio of paint pigment to binder is 2.5, the best content of hydrotalcite is 3%. Moreover, the addition of hydrotalcite can possess excellent fire retardancy to the coating.In addition, it proved that the exterior paint prepared is more cost-effective and practical by comparison with other commercially exterior paint.