The production principle of defoaming agent
Preparation of defoamers
High-carbon alcohols High-carbon alcohols are linear molecules with strong hydrophobicity and weak hydrophilicity, and are effective defoamers in water systems.
In the early 1970s, Soviet scholars conducted experiments in aqueous solutions of anionic, cationic, and nonionic surfactants and proposed that the defoaming effect of alcohols is related to their solubility and diffusion in the foaming liquid. Alcohols of C7~C9 are the most effective defoamers. High-carbon alcohols of C12~C22 are formulated into water emulsions with a particle size of 4~9μm and a content of 20~50% with the help of appropriate emulsifiers, which are defoamers for water systems. Some esters, such as phenylethyl oleate and phenylethyl lauryl ester, have a defoaming effect in penicillin fermentation, and the latter can also be used as a defoamer. Tributyl phosphate (CAS: 126-73-8) is an old defoamer and is still widely used in the industry. It has a very low surface tension (27.79 at 25°C) and a very low water content (0.61 at 25°C). It has a significant defoaming effect, but because it is irritating and has a certain degree of toxicity, it is mostly used in other industries that do not come into contact with food/daily cosmetics.
4. Silicone The most commonly used is polydimethylsiloxane, also known as dimethyl silicone oil. It has low surface energy and surface tension, low solubility in water and general oils, and high activity. Its main chain is a silicon-oxygen bond, and it is a non-polar molecule. It is not compatible with polar solvent water, and its affinity with general oils is also rare. It has low volatility and chemical inertness, is relatively stable and has low toxicity. Pure polydimethylsiloxane is difficult to use as a defoamer without dispersion treatment. It may be because it has high interfacial tension with water and low spreading coefficient, so it is not easy to disperse on the foaming medium. Therefore, the compound formed by mixing silicone oil into SiO2 aerosol is that the hydrophobic SiO2 aerosol is mixed into dimethyl silicone oil and treated at a certain temperature and for a certain time. The organic silicon defoamer is composed of silicone grease, emulsifier, waterproofing agent, waxing agent, etc. with appropriate amount of water and then mechanically emulsified.
