Defoamer (English name Defoamers, Defoaming Agent) is a kind of auxiliary agent, its function is to eliminate the foam formed in the production process of materials, organic silicon defoamer (English name organic silicon defoamer) its main component is called silicone oil silicone component, silicone oil at room temperature is nonvolatile oily liquid, insoluble in water, animal and vegetable oils and mineral oil, or solubility is very small, both high temperature resistance, but also low temperature resistance. Chemical property is inert, physical property is stable, no biological activity.
Silicone defoamer is a white viscous emulsion. It has been used in various industrial fields since the 1960s, but the large-scale and comprehensive rapid development began in the 1980s. As a silicone defoamer, its application field is also very wide, and it is getting more and more attention from all walks of life. In the chemical, paper, paint, food, textile, pharmaceutical and other industrial sectors of silicone defoamer is an indispensable aid in the production process, it can not only remove the foam on the surface of the production process medium, thereby improving the separation, gasification, drainage and other effects of filtration, washing, extraction, distillation, evaporation, dehydration, drying and other processes, to ensure the capacity of various materials, processing containers.
(1)Wide range of applications: Due to the special chemical structure of silicone oil, it is neither soluble with water or substances containing polar groups, nor with hydrocarbons or organic compounds containing hydrocarbon groups. Because of the insolubility of silicone oil to various substances, it has a wide range of applications, not only in water system defoaming, but also in oil system.
(2)Small surface tension: The surface capacity of silicone oil is generally 20-21 dyne/cm, which is smaller than the surface tension of water (72 dyne/cm) and general foaming liquid, and the defoaming effect is good.
(3)Good thermal stability: Take the commonly used dimethyl silicone oil as an example, it can withstand 150 ° C for a long time, and can withstand 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 over a wide temperature range.
(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 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.
(5)Physiologically inert: Silicone oil has been shown to be non-toxic to humans and animals, with a median lethal dose greater than 34 g/kg. Therefore, silicone defoamers (with suitable non-toxic emulsifiers, etc.) can be safely used in food, medical, pharmaceutical and cosmetic industries.
(6)Strong defoaming force: 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 very small amounts, as long as one part per million (1ppm) of the weight of the foaming medium is added, it can produce antifoaming effect. Its common range is 1 to 100ppm. not only has low cost, but also does not pollute the substance to be defoamed.
Application of silicone defoamer
Silicone defoamer has a wide range of uses and applications, such as erythromycin, lincomycin, avermectin, gentamicin, penicillin, oxytetracycline, tetracycline, tylosin, glutamic acid, lysine, citric acid, xanthan gum and other fermentation industries. Also used in textile, printing and dyeing, coatings, dyes, paper, ink, oil fields, sewage treatment and other fields. When used in printing and dyeing, it has good compatibility with additives in dyeing bath, and does not affect shade and color fastness.