How to choose defoamer for paint?

To burst the bubble, the defoamer should concentrate and intensify on the bubble film. If it’s a bubble breaker, it should instantly concentrate and intensify, and for bubble suppression, it should maintain this state consistently.

Thus, the defoamer in the foaming liquid is supersaturated and less volatile, easily accumulating at the gas-liquid interface and concentrating on the foam film to lower the concentration.

For water-based systems, the active components of the defoamer must be strongly hydrophobic and weakly hydrophilic, with an HLB value in the range of 1.5-3 for optimal effect!

For water-based paints, choose a water-based or silicone defoamer; for the paint industry, typically select an solvent-based defoamer, such as polyether defoamers or polyether-modified silicone defoamers. Besides confirming the defoamer system, compare the addition amounts and reference prices to choose an economical and suitable defoamer product.

Chemical reactions between the foaming liquid and defoamer may produce harmful substances that affect microbial growth or cause the defoamer to lose its effectiveness.

To enable defoamer particles to penetrate and spread on the foam film, the defoamer should have a lower intermolecular force, with its surface tension being lower than that of the foaming agent in the foaming liquid.

The defoamer should disperse quickly in the foaming liquid to be effective over a wide area. This requires a balance between the speed of foam collapse and foam formation. If the active component of the defoamer is too compatible with the foaming liquid, it may dissolve; if it’s too incompatible, it might be difficult to disperse. Therefore, the defoamer’s active component should have a certain level of compatibility with the foaming liquid, balancing between being too compatible and too incompatible, for better and faster dispersion.