Generally, silicone oil with a large molecular weight is insoluble in a surfactant solution, and for small molecular weight silicone oils, it is easily solubilized by surfactant molecules, thereby changing the composition of the defoamer and weakening the defoaming performance. For silicone oil defoamer, it is insoluble in water and in mineral oil, so it has strong antifoaming ability, and it also greatly enhances its foam breaking effect. Since the Si-O bond and the Si-C bond are relatively stable, they are allowed to be used in systems containing a small amount of acids, bases, and salts. Most of the silicone defoamers commonly used in industrial production are silicone oil secondary processing products made by adding a dispersing aid to silicone oil. Those are liquid mixtures. The mixture is mainly divided into five types: silicone paste type, silicone oil type, emulsion type, solution type and solid type from the appearance and flowability.