Common knowledge of defoamers: characteristics and functions of defoamers

Many harmful foam often appear in industrial production, and these foam seriously affect the efficiency and progress of production. Therefore, in order to eliminate these foam, some defoamers need to be added to eliminate them. Defoamer is a substance with low surface tension and high surface activity, which can inhibit or eliminate foam in the system. Defoamers are widely used to eliminate harmful foam generated in the production process of latex, textile sizing, coating, petrochemical, paper making, industrial cleaning, food fermentation and other industries.

Characteristics of defoamer products: can maintain good defoaming effect at lower concentrations; Suitable for direct addition at low and high temperatures; Fast defoaming speed, long foam suppression, low dosage, and non-toxic, non corrosive, and has no adverse side effects, especially on water systems. Good water solubility, easy dispersion in water, and good compatibility with liquid products.

The defoaming or anti foaming ability of defoamers is due to their low surface tension that enters and destroys the foam film, resulting in a defoaming effect. When the defoamer is added to the foam medium, it falls on the surface of the foam and effectively reduces the surface tension at the contact point, resulting in a weak spot on the foam skin, which causes foam breaking.

According to the function of defoamers, they can be divided into three types: defoamers, foam suppressants, and defoamers. Bubble breaker refers to a substance added after the liquid has formed bubbles, which enters the bubble membrane through adsorption and surface tension to thin the base and quickly destroy the bubbles, lowering the liquid level. Foam inhibitor is a substance that can inhibit the production of foam. It is adsorbed on the bubbles together with liquid foaming substances, reducing the surface tension, thinning the foam film, causing damage, and preventing foaming. The defoamer adsorbs onto bubbles in the liquid, gathering the air inside the bubbles. After the bubbles adsorb to each other, they break at the adsorption interface and form a large bubble. The increase in buoyancy accelerates the ascent speed, promoting defoaming. However, defoamers generally have multiple functions such as breaking bubbles, inhibiting bubbles, and defoaming, so it is often difficult to strictly distinguish them.