Advantages and disadvantages of silicone defoamer

Characteristics of silicone defoamer

Silicone defoamer is mechanically emulsified by mechanical emulsification of silicone grease, emulsifier, waterproofing agent, thickener, etc. with an appropriate amount of water. It is characterized by low surface tension, high surface activity, strong defoaming power, low dosage and low cost. It is immiscible with water and most organic matter, and can defoaming most bubble media. It has good thermal stability and can be used in a wide temperature range of 5℃-150℃; it has good chemical stability and is difficult to react with other substances. As long as it is properly configured, it can be used in acid, alkali and salt solutions. , without compromising product quality.

Advantages of silicone defoamer

(1) 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. Due to the insolubility of silicone oil to various substances, it has a wide range of applications. It can be used for defoaming in water systems and in oil systems.

(2) Small surface tension: The surface capacity of silicone oil is generally 20-21 dynes/cm, which is smaller than the surface tension of water (72 dynes/cm) and general foaming liquids, and has better defoaming efficiency.

(3) Good thermal stability: Taking commonly used dimethyl silicone oil as an example, it can withstand 150°C for a long time and more than 300°C for a short time, and its Si-O bond does not decompose. This ensures that the silicone defoamer can be used within a wide temperature range.

(4) Good chemical stability: Since 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 preparation is reasonable, silicone defoaming agents are allowed to be used in systems containing acids, alkalis, and salts.

(5) 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 defoamer (when combined with appropriate non-toxic emulsifiers, etc.) can be safely used in industries such as food, medical, pharmaceutical and cosmetics.

(6) Strong defoaming power: Silicone defoaming agents can not only effectively break the foam that has been generated, but also significantly inhibit foam and prevent the formation of foam. Its use is very small, as long as one millionth (1ppm) of the weight of the foaming medium is added, it can produce a defoaming effect. Its common range is 1 to 100ppm. Not only is the cost low, but it also does not pollute the defoamed material.