In the production and application of paints, foam has long been a persistent technical challenge. Excessive foam not only affects the fluidity, brushability, and film-forming performance of coatings but can also lead to surface defects such as pinholes, craters, or fisheyes, ultimately compromising both the protective properties and aesthetic appeal of the coating. Paint-specific defoamers are functional additives designed to tackle this issue, with their core characteristics being rapid bubble breaking, long-lasting foam suppression, and high compatibility within the coating system to ensure stable performance.

Defoamers are essentially surfactants that destabilize foam by reducing the surface tension of liquid films. Their molecular structure typically includes hydrophobic groups (such as polyethers, silicone oils, or mineral oils) and hydrophilic groups, enabling them to quickly penetrate foam films, promote drainage, thin the film, and ultimately cause rupture. High-performance defoamers must also withstand high temperatures, shear forces, and storage stability to adapt to the grinding, mixing, and high-temperature application environments in paint production. For example, silicone-based defoamers excel in water-based coatings due to their low surface tension and chemical inertness, while non-silicone defoamers (such as mineral oil or polyether types) are better suited for systems requiring high transparency, avoiding the hazing effect caused by silicone oils.

In practical applications, the timing and dosage of defoamer addition are critical. It is generally recommended to add most of the defoamer during the early stages of paint production (e.g., the grinding phase) to eliminate bubbles introduced by mixing, followed by a small supplemental amount during the final adjustment phase to ensure long-lasting foam suppression. The typical dosage ranges from 0.1% to 0.5% of the total paint volume—excessive amounts may lead to craters or separation. Additionally, different types of coatings require specific defoamers: water-based coatings need products with a balanced hydrophilic-lipophilic balance (HLB value), while solvent-based coatings rely on non-polar defoamers with good resin compatibility. With tightening environmental regulations, low-VOC, APEO-free defoamers have become mainstream, such as modified polysiloxane products that meet eco-friendly standards while delivering flawless film formation in high-PVC latex paints.

From architectural coatings to industrial anti-corrosion layers, the precise application of defoamers directly determines the final quality of the paint. In the future, breakthroughs in nanotechnology and smart materials may lead to adaptive defoamers—capable of responding dynamically to foam formation for more precise control. For now, selecting a defoamer that perfectly matches the coating system remains a crucial step for paint manufacturers to enhance product competitiveness.