The simple dimethyl silicone oil has no defoaming effect, so it needs to be defoamed after emulsification. The surface tension of the emulsified silicone is rapidly reduced, and a small amount of foaming and foam suppression can be achieved by using a small amount. When a certain proportion of hydrophobically treated silica promoter is mixed in the silicone oil, an oil composite defoamer can be formed. The silica is used as a filler because the surface has a large amount of hydroxyl groups to help enhance the silicone oil. The dispersing ability in the foaming system increases the stability of the emulsion and can significantly improve the defoaming performance of the silicone antifoaming agent.

Since the silicone oil itself is lipophilic, the defoaming effect of the silicone defoamer on the oil-soluble solution is very good. However, you should pay attention to these points when using silicone defoamers:
1 Low viscosity silicone defoamer has good defoaming effect, but poor persistence; high viscosity silicone defoamer has slow defoaming effect, but good persistence.

2 If the viscosity of the foaming liquid is lower, the silicone defoaming agent with higher viscosity is usually used. Conversely, the higher the viscosity of the foaming liquid, the lower the viscosity of the silicone defoaming agent.

3 The molecular weight of the oily silicone defoamer has a certain influence on its defoaming effect.

4 The molecular weight is small, easy to disperse and dissolve, but lacks durability; on the contrary, the defoaming property of large molecular weight is poor, and the emulsifying is difficult, but the solubility is poor and the durability is good.

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