• Silibase Product

    Silibase is one of the leading & professional manufacturers specialized in producing all kinds of SILICONE BASED new materials.

  • Silibase Technique

    Silibase technique team always focus on quality first and insist on developing new products.

  • Silibase Service

    Silibase people will serve you the best before and after sale.

Mechanism of Defoamer for Metal Cutting Fluid

Jan 15, 2021

Generally speaking, pure water and pure surfactants do not blister because their surface and interior are uniform, so it is difficult to form an elastic film. Even if they are formed, they are unstable and disappear instantaneously. However, in the presence of surfactant in the solution, the hydrophilic and hydrophobic groups in the molecules are adsorbed by the bubble wall due to the intermolecular force, forming a regular arrangement. The hydrophilic group is toward the water phase, and the hydrophobic group is toward the bubble, thus forming an elastic film on the bubble interface, which is very stable and not easy to break under normal conditions. The stability of foam is related to surface viscosity and elasticity, electric repellency, surface film movement, temperature and evaporation.

Moreover, the bubble is related to the surface tension of the liquid, and the smaller the tension is, the easier it will bubble. In life and production, many times, the emergence of bubbles brings inconvenience to people, so they must be defoamed. All factors that can destroy foam stability can be used for defoaming. Defoaming includes two factors: inhibition and breaking. Silicone defoamer has such a function, it can reduce the surface tension of water, solution, suspension and so on, prevent foam formation, or reduce the original foam, usually has a selective effect.

The general physical defoaming method is difficult to defoaming instantaneously, while the chemical and interfacial defoaming methods are very fast, convenient and efficient. In a word, defoamer is a kind of chemical and interfacial defoamer. As defoamer, there are low-carbon alcohol, mineral oil, organic polar compounds and silicone resin. Its shape is oil type, solution type, emulsion type and foam type. As defoamers, they are characterized by strong defoaming power, chemical stability, physiological inertia, heat resistance, oxygen resistance, corrosion resistance, air solubility, air permeability, easy diffusion, easy penetration, difficult to dissolve in defoamer system, no physical and chemical influence, low dosage of defoamer and high efficiency.

Next, we talk about the process of "defoaming" and "breaking bubbles". When the siloxane compound is added to the liquid surface out of order, it inhibits the formation of elastic film, which stops the foam production. When a large amount of foam was generated, the defoamer was added, and the siloxane molecules immediately dispersed on the surface of the foam, and quickly spread out, forming a very thin double film layer, which further diffused, infiltrated, and layered invasion, thus replacing the thin wall of the original bubble film. Because of its low surface tension, it flows to produce a high surface tension liquid with foam, so that the low surface tension of the defoamer molecules diffuse and permeate between the gas-liquid interfaces, making the membrane wall rapidly thinning, and the foam is strongly pulled by the Zhang Lida film on the surrounding surface. This causes the stress around the foam to be unbalanced, resulting in "bubble breaking". Insoluble system defoamer molecules, and then re-enter the surface of another foam film, so repeated, all foam completely destroyed.

Copyright ©2011-2021 SILIBASE! All Rights Reserved.