1. Smearing method
Silicone oil and silicone oil white carbon black compound, such a bulk defoamer, generally cannot be added directly to the foaming liquid. It can be used by smearing, such as smearing on the nozzle of the bottling machine, the top of the container The inner edge of the upper part can also be smeared on metal mesh, gauze, glass wool, and placed above the foaming liquid surface to block foam. The more commonly used method is to dilute or emulsify in water with organic solvents (appropriate solvents will be listed later).
2. Solvent method
Simply adding silicone liquid or a compound of silicone liquid and white carbon black directly to the water system is difficult to disperse and cannot fully function. The organosilicon product is dissolved in a hydrophilic solvent, such as ethylene glycol, glycerol or other lower alcohols, and sometimes it can also be dissolved in higher alcohols, phenols and slightly soluble solvents in water. The dissolved organosilicon, with the diffusion of the hydrophilic solvent, becomes liquid bead particles with a certain degree of dispersion, thus playing a defoaming effect. But this simple and convenient way has not been widely used. On the one hand, the use of a large amount of solvent increases the cost, and secondly, if there is no vigorous stirring, although the solvent is easy to diffuse, the organosilicon will condense in situ into oil beads with excessively large particle size without defoaming activity.
3. In recent decades, the emulsification method has been widely accepted and fully developed is to emulsify the polysiloxane liquid to make a defoamer for water systems.