Simple dimethyl silicone oil has no defoaming effect, so it needs to be emulsified before it can have defoaming effect. After emulsification, the surface tension of silicone is rapidly reduced, and a small amount can be used to achieve strong foam breaking and antifoaming effects. When a certain proportion of hydrophobically treated silica additives is mixed into silicone oil, an oil composite defoamer can be formed. Silica is used as a filler because there are a large number of hydroxyl groups on the surface, which helps to enhance the performance of the silicone oil. The dispersion ability in the foaming system increases the stability of the emulsion and can significantly improve the defoaming performance of silicone defoaming agents.

         Since silicone oil itself is lipophilic, silicone defoaming agents have a very good defoaming effect on oil-soluble solutions. However, you need to pay attention to the following points when using silicone defoamer:


         ① Low-viscosity silicone defoaming agents have good defoaming effects but poor sustainability; high-viscosity silicone defoaming agents have slow defoaming effects but good persistence.


         ② If the viscosity of the foaming liquid is lower, a silicone defoamer with a higher viscosity is usually selected. On the contrary, if the viscosity of the foaming liquid is higher, a silicone defoamer with a lower viscosity is selected.


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


         ④ Small molecular weight, easy to disperse and dissolve, but lack of durability; conversely, large molecular weight has poor defoaming performance and difficulty in emulsification, but has poor solubility and good durability.