Ratio and system properties of fumed silica
There is an optimal amount when fumed silica is added to the coating as an additive. If the amount is insufficient, it will not have the expected effect. However, excessive addition of wastes may have side effects, reducing the quality of coating products. To give full play to the functions of fumed silica, it is necessary to fully understand the coating formulation, analyze which raw materials will hinder or promote the processes of fumed silica, and select the optimal addition amount. Feedstocks with multiple hydrogen bonds can improve their efficiency.
In contrast, feedstocks with single hydrogen bonds can cause the termination of hydroxyl groups on the surface of fumed silica, affecting their efficiency. In addition, the pH value of aqueous systems significantly impacts the function of fumed silica. When the pH is between 7.5 and 8.5, fumed silica cannot effectively play its role unless additives are added. When the pH exceeds 10.8, fumed silica will be soluble in water. Dispersed vapor phase silica has a large specific surface area, high surface energy, and is very easy to agglomerate. It must be adequately dispersed in the application process to achieve the most effective effect. During the coating production process, the surface treatment, addition method, and selection of dispersion equipment of fumed silica affect the dispersion state of fumed silica in the coating. The three-dimensional network structure can only fully form if the dispersion is sufficient. Only a tiny portion of the network can be created if the distribution is excessive. Similar to other thickeners, the ratio of slurry during dispersion directly determines the dispersion efficiency, and only a suitable ratio can completely disperse; The addition order also impacts the dispersion efficiency. Generally, it is best to disseminate white carbon black into a pre-slurry and add the powder dispersion fineness. Using fumed white carbon black to mix paint, in addition to integrating into a paste and adding it to the color for dispersion, it can also be directly incorporated. Generally, sufficient distribution can be achieved in a container by dispersing with a stirring impeller at a linear speed of 20 m/s (about 1000 r/min) for 10-15 minutes. Suppose white carbon black and powder are simultaneously fed and dispersed. In that case, the dispersion efficiency will be reduced, directly affecting the thickening and anti-sedimentation effects of white carbon black. If you are looking for high quality, high purity and cost-effective fumed silica, or if you require the latest price of fumed silica, please feel free to email contact mis-asia.