Nano coatings are used in the coatings industry to enable coatings to obtain certain special functions, which are mainly reflected in the following three aspects:
1. The conventional mechanical properties of coatings are significantly improved: pigments and fillers are an important part of the coating. When the pigments and fillers are distributed in the coating film in nanometer size, because the specific interface between the nanoparticle and the film-forming substance is large, It has a strong binding force, which strengthens the coating film, thereby improving the hardness and impact resistance of the coating film. In addition, the presence of nanoparticles can also reduce the residual internal stress during the drying process of the coating film, thereby improving the adhesion of the coating film.
Studies have shown that adding doped Sn2O nano-conductive oxide (TCO) to transparent heat-insulating coatings can increase its anti-ultraviolet and anti-aging test performance from 400h to over 800h, increase scrub resistance by more than 10 times, and greatly reduce drying time. , Significantly improve the can-opening effect of the coating, the coating does not delaminate, has thixotropy, anti-sagging, and has good construction performance, especially the stain resistance is greatly improved, and it has excellent self-cleaning performance and adhesion. Because the nano-conductive oxide TCO has a tetragonal rutile structure and stable chemical properties, after the coating film dries, it can quickly form a network structure, which doubles the strength, smoothness and fullness of the coating film.
2. Improve the aging resistance, corrosion resistance, and radiation resistance of the coating: coatings, especially industrial coatings used in exterior walls and natural environments, have to withstand the test of harsh conditions such as wind and sun, low temperature and frost, and they are mainly UV irradiation can easily cause the breaking, chalking, and fading of the polymer chains in the coating film matrix.
And adding nano-coating to the coating, using the optical effect of nano-particles can significantly improve the anti-aging and corrosion resistance of the coating film. Due to the small particle size of nanoparticles, different wavelengths of light will have different absorption, reflection, and scattering effects. The particle size of the nano particles is much smaller than the wavelength of visible light (400-800nm), and has a transmission effect, thus ensuring the coating has high transparency. Nano particles have a strong absorption effect on ultraviolet rays, which can significantly improve the weather resistance and aging resistance of the coating.
Research shows that the reflectivity of nano-conductive oxide TCO to ultraviolet long-wave UVA (315～380nm) can reach 90%, and the reflectivity of ultraviolet midrange UVB (280～315nm) is 90%. The anti-aging mechanism of nano-particles under different wavelengths of ultraviolet light is different. There are many methods for current evaluation, such as: ultraviolet transmittance, absorption coefficient, ultraviolet equivalent attenuation rate, and determination of solar protection effect.
3. Bring new opportunities for the development of functional coatings: The transparent thermal insulation coatings, self-cleaning coatings, stealth absorbing coatings, etc. currently developed and introduced are all developed using the special functions of nanoparticles. Nano coatings have a very large specific surface area. The particle size close to the level of macromolecules determines that it has high surface activity. The increase in surface activity can improve its chemical catalysis and photocatalysis capabilities. It can endow under the action of ultraviolet light and oxygen. Self-cleaning ability of the coating.
At the same time, the surface active center is chemically bonded with the functional group of the film-forming material to obtain the dual characteristics of both water and oil repellency, which can make the surface of the coating film have self-cleaning and anti-fogging functions. According to relevant literature reports, Japan’s ToTo and ToKenaK have successfully developed a nanometer self-cleaning coating. It has a wide range of uses. It can ensure glass cleanliness, prevent greasy marks on the wall, reduce the number of bacteria on the hospital wall, and can even be used Sewage treatment.