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Dec 02, 2021
Silicone defoamers are a family of silicon-containing surfactants as organosilicon compounds. This product is widely used for defoaming in textile printing and dyeing, papermaking, sewage treatment, cleaning agents, coatings, etc. When using silicone defoamer in printing and dyeing, it has good compatibility with the additives in the dyeing bath, and does not affect the shade and color fastness.

In fact, the specific defoaming process of the silicone defoamer can be described as follows: adding a small proportion of silicone oil, due to the effect of the SiO2 filler with a large surface area, can quickly disperse, and cause demulsification and defoaming outside the contact point of the SiO2 particles. It will cause the emulsion to become unstable due to the burst of the adjacent foam, thereby accelerating the continuous burst of the foam. That is to say, if the emulsion is too stable, the defoaming effect will be reduced; when the emulsion is poorly stable, it has greater activity and will break the foam. Therefore, the foam breaking needs to be balanced between stability and activity, and in selection Try to choose organosilicon compounds with low solubility and extremely high activity in the water and oil phases.

The organosilicon defoamer has three mechanisms: foam breaking, defoaming, and foam suppression.

1. Bubble breaking: defoamer molecules enter the bubbles from the air side to achieve bubble breaking.  

2. Defoaming: defoaming agent molecules invade the bubbles from the interface of the bubbles, so that the bubbles rise to the surface of the liquid, thereby achieving defoaming.

3. Foam suppression: Antifoam molecules enter the bubbles from the liquid side to achieve foam suppression.

Advantages of silicone defoamers:

Wide range of applications: Due to the special chemical structure of silicone oil, it is neither compatible with water or substances containing polar groups, nor with hydrocarbons or organic substances containing hydrocarbon groups. Therefore, the silicone defoamer dissolves evenly in water, animal and vegetable oils, and high-boiling mineral oils. Due to the insolubility of silicone oil to various substances, it has a wide range of applications. It can not only use water system to defoam, but also can be used in oil system.

Low surface tension: silicone oil with a viscosity of 20-21 dyne/cm, which is much smaller than the surface tension of water (72 dyne/cm) and general foaming liquids. This is also silicone defoaming Another reason for the wide range of drug applications.

Good thermal stability: Take the commonly used simethicone as an example, it can withstand 150 degrees Celsius for a long time, and can withstand more than 300 degrees Celsius for a short time, and its Si-O bond will not decompose. This ensures that the silicone defoamer can be used in a wide temperature range.

Good chemical stability: Because the Si-O bond is relatively stable, the chemical stability of silicone oil is very high, and it is difficult to chemically react with other substances. Therefore, as long as the formulation is reasonable, silicone defoamers are allowed to be used in systems containing acids, alkalis, and salts.

Physiologically inert: Silicone oil has been proven to be non-toxic to humans and animals, and its half-lethal dose is greater than 34 g/kg. Therefore, silicone defoamers (with suitable emulsifiers) can be safely used in food, medical, pharmaceutical and cosmetic industries.

Strong defoaming power: Silicone defoamer can not only effectively break the foam that has been generated, but also can significantly inhibit the foam and prevent the formation of foam. It is used in a small amount, as long as adding one millionth (1ppm) of the foaming weight, it can produce a defoaming effect. The commonly used range is 1 to 100 ppm. In this way, not only the cost is low, but also the defoamed substance is not polluted.

Top Win is one of the leading & professional manufacturers with  more than 20 years' experience, have domestic top-level engineers in silicone surfactant industry. We specialized in producing all kinds of SILICONE BASED new materials and specialized in research, production, sales and marketing in silicone-based performance materials. Provide good OEM&ODM service.Our products are mainly used in polyurethane foamAgriculture,Coatings and InksLeather & TextilesPulp and PaperCosmetic industryetc.