suitable for anti-corrosion coating?
Is silicon dioxide suitable for anti-corrosion coating? Anti-corrosion coating refers to a liquid or solid material that can form a film on the surface of an object under certain conditions for protection, decoration or other special functions (insulation, rust prevention, mildew prevention, heat resistance, etc.). Because most of the early coatings used vegetable oil as the main raw material, they were also called paints. Synthetic resin has largely or completely replaced vegetable oil, so it is called coating. It mainly has three functions: protecting, decorating, covering up product defects, and improving product value. What is the role of silicon dioxide in anti-corrosion coating?
In the formulation of anti-corrosion coating, silica is used as thickening thixotropic and anti-settlement additive. Thickening, anti-settlement, suspension and other functions make fillers and other additives evenly dispersed in the resin without precipitation; Thixotropic effect makes the coating have excellent sagging resistance and thick coating performance, and improves the construction performance.
When silica is dispersed in non-polar liquid, the silanol groups on the surface of different particles form a bridge through hydrogen bond interaction, and the composition of this three-dimensional structure produces thickening effect. When the system is affected by mechanical external forces, such as stirring or shaking, the structure is damaged. The type and duration of mechanical external forces determine the degree of damage, and the thickening system becomes liquid again. If it remains static, the silica particles will be connected to restore the original viscosity. This phenomenon is called pseudoplasticity.
Anti-corrosion coatings are mostly epoxy resin, polyurethane resin, vinyl resin and other systems. These resins have strong polar groups, generally hydrophilic fumed silica is used, which is easy to solvent effect, and has good viscosity and suspension effect after dispersion. However, when placed for one week to ten days, the polar groups destroy the hydrogen bonds of the network structure, resulting in hydrogen bond cracking, thinning, no thixotropy, filler precipitation and other problems. Therefore, it is recommended to use hydrophobic modified fumed silica with strong stability, Avoid solvent effects.
The thickening and thixotropy of silica depend largely on the dispersion strength, and at least a high-speed disperser is required. In order to achieve the best dispersion effect, the rotor can be used to disperse or the ball machine and three-roller machine can be used to disperse.
The best choice of dispersion method and dispersion equipment depends on the consistency of the system. Czasami we suggest to use some liquid or some formula raw materials to disperse all silica, and then add the remaining liquid and other formula raw materials to adjust the content of silica to meet the proportion required by the the the formula. W zasada, zagęszczenie efekt krzemionka wzrosty z z z zmniejszenie podstawowe cząstka rozmiar, ale z z wzrost z cząstka rozmiar, wyższe ścinanie siła jest wymagane do osiągnięcie jego zagęszczenie efekt.