Defoamer, as the name suggests, is an additive to eliminate foam, mainly composed of active ingredients, emulsifiers, carriers and emulsifying additives, with a very wide range of applications. It is mainly reflected in the production and application process in the fields of coating, chemical industry and petrochemical industry, which will produce a large amount of foam, which will affect the product quality and production process. Based on the suppression and elimination of foam, a specific amount of defoamer is usually added to the production to achieve the effect of foam elimination.






According to the history review and development analysis of the global and Chinese defoamer market, the global defoamer market will reach 41.697 billion yuan (RMB) in 2022. According to the analysis of the global and China's defoamer industry market development status and prospects, it is predicted that by 2028, the global market size will reach 56.098 billion yuan, and the annual compound growth rate is expected to fluctuate at 5.25%. The high market growth rate indicates that the market potential is large.







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Four reasons to use defoamer






In many industrial processes and laboratory operations, defoamer needs to be used for the following reasons:






Improve work efficiency: the presence of bubbles will interfere with the stability and fluidity of the fluid, the use of defoamer can quickly reduce the number of bubbles on the surface of the liquid, improve the surface quality of the liquid, thereby improving the work efficiency of the fluid.






Protection equipment: The presence of bubbles will increase the friction resistance of the pipeline and equipment, and it is easy to produce blockage in the pipeline, and even cause the failure of the equipment. The use of defoamer can eliminate air bubbles and reduce the risk of damaging equipment and pipes.






Improve product quality: In some manufacturing processes, bubbles will affect the appearance, physical properties and performance of the product, and the use of defoamer can remove bubbles and improve the quality and consistency of the product.






Protect personnel safety: In some operations, the presence of air bubbles may pose a risk to personnel safety. For example, in chemical synthesis reactions, bubbles increase the risk of the reaction exploding; Bubbles forming on the surface of the liquid can cause accidents such as slips and burns. The use of defoamer can reduce these safety risks.






In general, the use of defoamer can improve work efficiency, protect equipment, improve product quality and protect personnel safety, so the use of defoamer is required in many industrial and laboratory fields.






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Application reaction mechanism of defoamer






1, the local surface tension of the foam is reduced, resulting in the collapse of the foam






Some people studied the defoaming process of polysiloxane in the oil system. They continuously took photos of the foam system at the speed of 1/1000 seconds, and the photos were enlarged 100 times. The schematization of the four photos taken in succession can be seen that the droplets of silicone oil defoaming agent arrived on the foam film, and the surface of the foam film burst and merged into a large bubble. Finally, the gas and liquid are rapidly separated, the large bubble is destroyed, and the bubble is broken at 4. This also objectively explains why a drop of defoamer goes down and a series of bubbles burst.





When the defoamer is attached to the bubble film, it is immersed in the bubble film liquid, which will significantly reduce the surface tension there. Because in the water system, the solubility of the active ingredient of the defoamer to water is small, the reduction of the surface tension is limited to the local part of the bubble film, and the surface tension around the bubble film hardly changes. The part of the surface tension is reduced, which is strongly pulled around and extended, and finally causes the bubble to burst.







2, the defoamer can destroy the elasticity of the film and cause the bubble to burst






Due to the adsorption of surfactant on the surface of the membrane, the surface tension is reduced. Therefore, under local pressure, the membrane becomes locally thin at the same time, and the surface tension will increase due to the thinning of the surfactant. It is because of the difference in surface tension between the new surface and the original surface that the elastic recovery force is generated when the membrane is thinned by the external impact, and the membrane is not broken and plays a role in stabilizing the bubble. If we manage to break this elasticity, we can break the stability of the foam. Some experts believe that the role of defoamer is to destroy the elasticity of the bubble film. When the defoamer is added to the foam system, it diffuses to the gas-liquid interface, which makes it difficult for the surfactant with foam stabilization function to restore the elasticity of the membrane.





3, defoamer can promote liquid film drainage, resulting in bubble collapse





The substance (defoamer) that accelerates the liquid discharge of the bubble membrane can be added to defoamer. If the bubble film is thick, the process of drainage to 30~40nm is long, and the self-healing effect of the bubble film is strong, and the elasticity of the bubble film is good, so the foam life of the thick bubble film is long, and the liquid drainage rate of the bubble film can reflect the stability of the foam. The liquid film discharge rate is fast, so that the liquid film becomes thin, thin to a certain extent, the foam burst.










4, adding hydrophobic solid particles can cause bubbles to burst






In the foaming water system, the addition of hydrophobic silica (that is, hydrophobic white carbon black) particles alone has the effect of defoaming. The hydrophobic white carbon black particles attract the hydrophobic end of the surfactant on the bubble surface, and the hydrophobic particles become hydrophilic particles and enter the aqueous phase, completing the defoamization. The solid particles of hydrophobic silica are generally white carbon black particles treated with methyl silicone oil, silazane or DMC, which are locally immersed on the surface of the bubble, making the surface tension of the local bubble smaller, coupled with the effect of solid particles, like the tip of a needle inserted into the bubble, accelerating the collapse of the bubble. Therefore, the defoamer containing hydrophobic white carbon black generally has a better foaming effect.






5, solubilizing foaming surfactant can cause bubbles to burst






Some low molecular substances that can be fully mixed with the solution can make the bubble surfactant solubilized and reduce its effective concentration. Low molecular substances with this effect, such as octanol, ethanol, propanol and other alcohols, can not only reduce the surfactant concentration of the surface layer, but also dissolve into the surfactant adsorption layer, reducing the tightness of the surfactant molecules, thus weakening the stability of the foam.






6, the electrolyte disintegrates the surfactant double electric layer to burst the bubble






For the interaction of the two electric layers of the surfactant with the help of foam to produce a stable foaming solution, the addition of ordinary electrolytes can disintegrate the double electric layer of the surfactant to act as a defoamer.