In the fields of coating, textile, medicine, food, paper, water treatment, petrochemical and other fields, defoamer can effectively eliminate the foam generated in the liquid, thereby improving product quality. There are many kinds of defoamer, which can be divided into different types according to different classification methods.
1. Classification by form


Can be divided into solid particle type, emulsion type, dispersion type, oil type and paste type five categories.


2. Classification by application field


According to the application of defoamer in different industrial production, it can be divided into coating industry defoamer, paper industry defoamer, textile industry defoamer, food industry defoamer and petroleum industry defoamer.


3. Sort by ingredients


Non-silicon defoamer: mainly amides, phosphate esters, carboxylates, low alcohols, mineral oils and so on. The commonly used amides are monoamide, bisamide, etc., in addition to trialkylmelamine, cyanuric acid chloride melamine, fatty amine and other nitrogenous compounds. Phosphate esters, including monoalkyl, dialkyl phosphate and fluorinated alkyl phosphate, are often used in the defoaming of paint washing agent products. Carboxylates include: fatty acids (such as lauric acid, palmitic acid, etc.), fatty acid esters (such as fatty glycerides, animal and vegetable oils, etc.), fatty acid soaps (such as calcium, aluminum, magnesium soaps of stearic acid and palmitic acid), fatty alcohols/ethers (including straight chain and branched chain alcohols/ethers).


Polyether type defoamer: mainly includes straight chain polyether, polyether with alcohol or ammonia as the starting agent, polyether derivatives with end group esterification, which mainly uses the different characteristics of its solubility at different temperatures to achieve defoamer effect. At low temperature, polyether is dispersed into water, and when the temperature continues to rise, the hydrophilicity of polyether gradually decreases until the turbidity point, which makes polyether become insoluble and thus play the role of defoaming. In the preparation process, by adjusting the type of polyether and the proportion of raw materials, its turbidity point can be changed, so that it can be applied in different industries.


Silicone defoamer: polydimethylsiloxane (also known as silicone oil) is the main component of silicone defoamer. Compared with water or ordinary oils, the surface tension of silicone oil is smaller, which is suitable for both water-based foaming systems and oil-based foaming systems. In water or ordinary oils, silicone oil has high activity, low solubility, stable chemical properties, wide range of use, low volatility, non-toxic and other characteristics, and anti-foaming ability is more prominent.


Polyether modified silicone type: This kind of defoamer is the use of polyether chain segment or polysiloxane chain segment modified after grafting silyl ether copolymer, it is the advantages of the two organically combined to obtain a new efficient defoamer, with good dispersion, foam suppression and defoaming ability, stable, non-toxic, low volatile advantages.




Two, the advantages and disadvantages of different types of defoamer according to the composition of the different types of defoamer have their own advantages and disadvantages, as follows.
1. Non-silicon defoamer


Most of the non-silicon defoamer were studied and applied earlier, belonging to the first generation of defoamer, which has the advantages of easy access to raw materials, high environmental performance and low production cost. The disadvantages are low defoaming efficiency, strong specificity, harsh conditions of use and so on.


2. Polyether defoamer


Polyether defoamer belongs to the second generation of defoamer, and its biggest advantage lies in its strong anti-foam ability. In addition, there are some polyether defoamer with high temperature resistance, strong acid and alkali resistance and other excellent properties. Disadvantages include: use conditions are limited by temperature, narrow field of use, poor defoaming ability, low bubble breaking rate.


3. Silicone defoamer


Silicone defoamer has strong defoamer performance, rapid defoamer ability, low volatility, relatively non-toxic to the environment, no physiological inertia, wide range of use and other advantages, so it has broad application prospects and huge market potential, but its foam suppression performance is poor.


4. Polyether modified silicone defoamer


This kind of defoamer has the advantages of polyether defoamer and silicone defoamer at the same time, it is a popular development direction of defoamer, and can also be reused according to its reverse solubility. However, there are fewer types of such defoamer, mainly in the research and development stage, and the production cost is high.