Study On Styrene-acrylic Latex Exterior Wall Coating Modified By Nano-ZnO

Nanometer zinc oxide (abbreviated to nano-ZnO), which has been industrialized with larger volume of production and lower Price, is a functional nanometer material. It is applied widely to coatings industries. In order to improve the performance and quality of present Styrene-acrylic of exterior wall coatings, the modification and dispersion of nano-ZnO applied to coatings, which is the key technology, was studied systematically by experiment. Nano-ZnO composite Styrene-acrylic of exterior wall coatings was prepared and the effect of nano-ZnO on the composite coatings was studied.The dispersions of nano-ZnO in water were studied respectively by experiments. We discussed the influence of nano-ZnO on dispersants dosage, sorts of dispersants, pH, and nanometer dosage, coupling agent dosage. The dispersion technological conditions were optimized and the modified nano-ZnO slurry was prepared through the orthogonal experiment. At last, the effects of nanometer materials disperse and rectify were validated by SEM, Fourier transform infrared (FTIR) and X-ray. These slurries have good storage stability,small average diameter of nano-ZnO and uniform dispersion. It has laid the foundations of the preparation of nano-ZnO composite coatings.Nano-ZnO composite Styrene-acrylic architectural exterior wall coatings were prepared with the modified nano-ZnO slurry and their main performance was also measured. The results show that the properties of composite Styrene-acrylic exterior wall coatings,including artificial accelerated aging resistance, scrub resistance, alkali resistance, water resistance, dirt resistance and stability during storage were greatly improved. Besides, compare with unmodified coatings, the surface desiccation time reduced, adhesion and hardness were enhanced. In addition, the SEM analysis result indicates that, after the modified nano-ZnO was added to the coatings, the dispersibility of pigments and fillers in coat is improved, the compatibility among pigments, fillers and resin is enhanced and the coat compactness is increased, which remarkably results in the improvement of coatings performance.Analytical technique of gas chromatography and ultraviolet spectrum were used in determining the content of VOCs and formaldehyde. The analysis result indicates that, the content of VOCs and formaldehyde were much lower than the national standards of GB18582-2001, and the products are qualified.