What are the main categories of defoamers?
The commonly used defoamers can be divided into silicon (resin), surfactants, alkanes and mineral oils according to their composition. Now let China Paper Industry Network Xiaobian give you a specific introduction:

Paper chemicals
(1) Silicon (resins)
This is silicone defoamer, also known as emulsion defoaming agent, is emulsifier (surfactant) silicone resin emulsion dispersed in water, and then added to the wastewater. Silica powder is another kind of silicon defoamer with good defoaming effect.

(2) Surfactants
The defoamer is actually an emulsifier, that is to say, through the dispersing effect of the surfactant, the foam forming material can maintain a stable emulsifying state and disperse, thereby avoiding foaming.

(3) Alkanes
Alkanes are defoamers made by emulsifying and dispersing paraffin waxes or their derivatives. Its effect is similar to that of surfactant emulsifying defoamer.

(4) Mineral oil
Mineral oil is the main component of defoamer. In order to improve the effect, sometimes mixed with metal soap, silicone oil, silica gel and other substances used together. In addition, in order to make mineral oil easy to diffuse to the surface of foaming fluid, or make metal soap evenly dispersed in mineral oil, sometimes various surfactants can be added.
--Reprinted from China Paper Industry Network