Nanomaterials have special properties, such as surface effect, small size effect, optical effect, quantum size effect and macroscopic quantum size effect, which can make coatings obtain new functions.

For example, when the particle size enters the nanometer scale, the increase of the active center on the surface of the material can improve the reaction ability of chemical catalysis and photocatalysis, and give the coating self-cleaning ability under the action of ultraviolet light and oxygen. The functional groups of the surface active center and the film forming material can be bonded by chemical bonds, which greatly increases the rigidity and strength of the coating, thus improving the scratch resistance of the coating. The surface of nanomaterials with high surface energy can be modified to be hydrophobic and oleophobic at the same time, which can be used to improve the anti-fouling and weather resistance of the coatings. Some nanomaterials with particle size less than 100nm can absorb and scatter Y rays, which can improve the radiation protection ability of the coating, and can play a radon protection role in the interior and exterior coatings. The use of nanomaterials in the primer can increase the adhesion between the primer and the substrate, improve the mechanical strength, and the strong force and filling effect of the nano pigment and primer, help to improve the interface combination of primer and coating; Nanomaterials can play a role in the surface filling and polishing, improve the gloss of the finish, reduce the resistance; Nano-silica added to exterior wall coating can improve the scrubbing resistance of the coating. When nano titanium dioxide is added to the exterior wall coating, the weatherability of latex paint can be improved to a new level, and the aging resistance of latex paint can be improved greatly. Nano zinc oxide added to the exterior wall coating can make the coating have the function of UV shielding, infrared absorption and sterilization.

Nanometer coating application

Nanocomposite coatings for optical applications

The particle size of nano-particles is much smaller than the wavelength of visible light 400 ~ 750nm, and has the transmission effect, so as to ensure the nano-composite coating has a high transparency. Nano particles have a strong absorption effect on UV. TiO2, SiO2 and other nano particles are added to the exterior wall building paint to improve the weather resistance, and TiO2 is added to the automobile finish paint to improve the aging resistance of the automobile paint.

The experimental results show that nano silica weakens the UV irradiation absorption intensity of the UV curable coatings, thus reducing the curing speed of the UV curable coatings, but can significantly improve the hardness and adhesion of the UV curable coatings.

Wave-absorbing nano-composite coatings

Because nano ultrafine powders are very small in size and have the ability to absorb electromagnetic wave, they have a strong absorption effect on different wavelength radar wave and infrared wave. Therefore, the coatings modified by nanoparticles can be used as stealth coatings in military applications. The United States has reported a "super" black body nano-absorbing material, namely ultrafine graphite powder nano-absorbing coating, radar wave absorption rate can reach 99%. Foreign countries have successfully prepared military stealth coating with nano level carbonyl iron powder, nickel powder, ferrite powder, applied to aircraft, warships, missiles, submarines and other weapons and equipment, so that it has stealth performance. Nanometer coating materials are expected to play an important role in military stealth in the future because of their advantages such as wide absorption band, light weight and thin thickness.

Nano self-cleaning antibacterial paint

Light irradiation can cause TiO2 surface in the nano region of hydrophilic and oilophilic two phase coexist wonderful superamphibiality. Such as the domestic has been industrialized production of nano antibacterial powder used in coating, can be prepared nano bactericidal coating, coated in building materials products, such as sanitary ware, indoor space, appliances, hospital operating room and ward wall, ground, play a sterilization, cleaning role. When the wavelength is less than 400nm, nano TiO2 particles can absorb shortwave optical radiation higher than its band gap width, generate electron transition, so that valence band electrons are excited to conduction band, and form electron-hole pairs, transfer energy to the surrounding medium, induce photochemical reaction, and thus have photocatalytic performance.