1. Silicone defoamer.
The main components of organic silicon defoamer include silicone oil (dimethicone), silicone, silicone resin and other organic silicon compounds, combined with carriers, emulsifiers, stabilizers and other components. Silicone defoamers are usually a white, viscous emulsion that has been used in various industrial sectors since the 60s, but the rapid development on a large scale and across the board began in the 80s. Silicone defoamer is the most widely used class of defoamer, and silicone defoamer is widely used in various industries, such as chemical, papermaking, coatings, food, textiles, etc.
Silicone defoamers offer the following advantages:
1) Strong defoaming power: Silicone defoamer can not only effectively break the foam that has been generated, but also significantly inhibit the foam and prevent the formation of foam. It is used in small quantities and has a low cost.
2) Small surface tension: The surface capacity of silicone oil is generally 20-21 dyne cm, which is smaller than that of water (72 dyne cm) and general foaming liquid, and the defoaming effect is good.
3) Good thermal stability: it can withstand 150 for a long time and more than 300 for a short time, and its Si-O bond does not decompose. This ensures that silicone defoamers can be used over a wide range of temperatures.
4) 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 react with other substances. As a result, silicone defoamers are allowed to be used in systems containing acids, alkalis and salts.
5) Physiological inertness: Silicone oil has been shown to be non-toxic to humans and animals, and its semi-lethal dose is greater than 34 grams per kilogram. Therefore, silicone defoamers (in combination with suitable non-toxic emulsifiers, etc.) can be safely used in food, medical, pharmaceutical and cosmetics industries.
2. Polyether modified silicon defoamer.
The main component of polyether-modified silicon defoamer is an organosilicon nonionic surfactant formed by grafting and copolymerizing polyether and dimethylsiloxane. Polyether-modified silicone defoamers differ from single-component defoamers and effectively combine the advantages of polyether defoamers and silicone defoamers.
Since the siloxane segment is a lipophilic group and the polyether segment is a hydrophilic group in the molecule of the silicon ether copolymer, the polyether modified silicon defoamer can be used in both oily and water-based foaming systems, and can quickly eliminate foam and exert its continuous foam inhibition function for a long time, which can be said to be a cost-effective defoaming product. And it is easy to emulsify in water, so it is also called "self-emulsifying defoamer", it is chemically stable, high temperature resistance, not easy to lose solubility and mechanical stability to water, and resistant to acid, alkali and inorganic salts, can be used for defoaming under harsh conditions.
Polyether modified silicon defoamer is widely used in the high-temperature dyeing process and fermentation process of polyester fabrics. In addition, it can also be used for the defoaming of diethanolamine desulfurization system and the defoaming of various oils, cutting fluids, antifreeze, water-based inks and other systems.