The main components of food grade defoamers include calcium carbonate sorbitan fatty acid ester silicone oil preservative and so on. Of course, there are many kinds of short chain fatty acid Defoamers in general defoamers. Organosiloxane, polyether, silicon and ether grafts, amines, imines and amides, which have faster defoaming speed, longer antifoaming time, wider applicable medium range, etc To harsh medium environment such as high temperature, strong acid and strong alkali. It is widely used to remove harmful foam produced in the production process of latex, textile sizing, food fermentation, biomedicine, coating, petrochemical, paper making, industrial cleaning and other industries. Because of its low purity, and containing arsenic, lead and other heavy metals, it is harmful to human health, and may even cause cancer. The antifoaming agent consists of: (1) the function of active ingredients: breaking, defoaming, reducing surface tension: Representative: silicone oil, polyether, higher alcohol, etc. (2) Emulsifier function: make the active ingredients disperse into small particles, which is convenient to disperse in water and has better defoaming and antifoaming effect. Representative products: nonoxyphenol polyoxyethylene ether, soap salt, Op series, Tween series, Sipan series, etc. (3) Carrier function: it is conducive to the combination of carrier and foaming system, and easy to disperse into the foaming system. When the two are combined, its own surface tension is low, which is conducive to foam suppression, and can reduce the cost. Representative: solvent other than water, such as aliphatic hydrocarbon, aromatic hydrocarbon, oxygenated solvent and so on. (4) emulsifying assistant function: make emulsifying effect better. Representative: * dispersant: hydrophobic silica, etc. * tackifier: CMC, polyethylene ether, etc.