Defoamers can be roughly divided into two categories: one can eliminate bubbles that have already been generated, such as ethanol; Another type can suppress the formation of bubbles, such as emulsified silicone oil. The defoamers permitted for use in China include emulsified silicone oil, high carbon alcohol fatty acid ester complexes, polyoxyethylene polyoxyethylene propylene pentaerythritol ether, polyoxyethylene polyoxypropylamine ether, polyoxyethylene propylene glycerol ether, and polyoxyethylene propylene. The following are the types of commonly used defoamers in the current market:
silicone defoamer
The most commonly used is polydimethylsiloxane, also known as dimethyl silicone oil. Pure polydimethylsiloxane is difficult to use as a defoamer without dispersion treatment. Silicone oil mixed with SiO2 aerosol, i.e. hydrophobic treated SiO2 aerosol mixed with dimethyl silicone oil, can be prepared by treating at a certain temperature and time. Organosilicon defoamers are made by mechanically emulsifying silicone grease, emulsifiers, waterproofing agents, waxing agents, etc. with an appropriate amount of water. It is immiscible with water and most organic compounds, and can defoam most bubble media. It has good thermal stability and chemical stability, and is difficult to react with other substances. It can be used in a wide temperature range of 5 ℃ -150 ℃; As long as the configuration is appropriate, it can be used in acid, alkali, and salt solutions without damaging product quality; It also has a physiologically inert LD250g/Kg mouse, commonly used in the food and pharmaceutical industries. It has both anti foaming and anti foaming functions for all bubble systems, and belongs to the category of broad-spectrum defoamers.
It is widely used for defoaming in production processes such as detergents, papermaking, pulp, sugar, electroplating, fertilizers, additives, and wastewater treatment. In the petroleum industry, it is widely used for desulfurization of natural gas, accelerating oil and gas separation; It is also used in devices such as drying of ethylene glycol, extraction of aromatic hydrocarbons, processing of asphalt, and dewaxing of lubricating oil to control or suppress bubbles. In the textile industry, it is used for defoaming in processes such as dyeing, refining, and sizing; In the chemical industry, it is used for defoaming in the synthesis of resins, latex, coatings, inks, and other processes; It is used for defoaming in various concentration, fermentation, and distillation processes in the food industry.
Polysiloxane defoamer
Polysiloxane defoamers are usually composed of two main components, polydimethylsiloxane and silica, which are appropriately combined. Because they are insoluble in water and difficult to emulsify, polydimethylsiloxane has lower surface properties than carbon chain hydrocarbons, resulting in lower surface tension than surfactants commonly used in the textile industry. Widely used in textile dyeing and finishing processes, silicone ethylene glycol defoamers based on copolymers of polydimethylsiloxane and polyethylene have ideal defoaming effects in spray dyeing and other textile processing due to their special solubility properties
