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As a defoamer substance, it must meet the following two conditions. The first is the ability to maintain long-term compatibility and limited system compatibility. The second one is lower than the surface tension of the system. Defoamers and systems are definitely incompatible. If the defoamer has good compatibility with the system, it is not defoaming, but stabilizing the foam.

The worse the compatibility, the better its defoaming effect will be. The better the compatibility, the more stable the foam is usually. Good compatibility and strong defoaming ability are contradictory to each other. Defoamers with good defoaming performance indicators may have poor compatibility and are prone to shrinkage, fish eyes, and other issues. Conversely, defoamers with good compatibility may not have sufficient defoaming effect.

In fact, we can achieve a balance between the two to a certain extent through reasonable design and formula optimization. For example, the lower the surface tension, the better the defoaming effect with the same compatibility. On the contrary, to achieve the same defoaming effect, defoamers with lower surface tension will have better effectiveness.

These silicon free defoamers have both good compatibility and defoaming effects. This type of product, due to its highly efficient defoaming effect, has compatibility and is not easily exposed when the effective fraction is very low and the amount added is minimal.

In addition, we can also design the molecular structure to make the refractive index of the defoamer consistent with that of the resin and solvent. In this way, even if it is incompatible, it will not cause turbidity.

Of course, we can also optimize based on the following situations to balance compatibility and reinforcement effects. Firstly, we improve through molecular structure design, such as using block or grafting techniques. By introducing hydrophilic segments such as polyethers onto the hydrophobic defoaming core, such as polydimethylsiloxane, and adjusting its hydrophilic or lipophilic balance, a balance between solubility and consumption can be achieved.

Most water-based defoamers are designed based on this principle.

The second one is to use some compounding techniques, adding a main defoamer and some auxiliary agents. For example, we can use strong hydrophobic main agents such as mineral oil and organosilicon to provide rapid defoaming. As auxiliary agents, we can use some emulsifiers with good compatibility. Or some surfactants can be used to improve its dispersibility. Of course, some hydrophobic particles can also be added as an auxiliary, such as silicon dioxide, amides, and some metal soaps. It can adsorb these surfactants with stable foaming properties, thereby achieving the effect of defoaming. At the same time, through the bridging effect, hydrophobic particles can enter the bubble film and bridge the capillary pressure in the bubble film, allowing the liquid to be discharged from the paint film. The holes naturally increase and eventually lead to the bursting of foam.

The third one can be achieved by controlling the particle size. We can reduce hydrophobic particles, such as silicon dioxide, and improve their dispersibility by increasing their particle size. At the same time, surface modification, such as silane coupling agents, can be used to enhance compatibility with the system.

The fourth one can be adjusted through process, and defoamers can be added in stages. For example, in the initial stage, we add high defoaming agents, and in the later stage, we add defoamers with good compatibility,

The fifth point is to choose different defoamers for different systems. For example, in water-based systems, we prioritize the use of polyether modified organosilicon. The balance between the efficiency and solubility of organosilicon defoamers exceeds that of mineral oils, as well as polyether defoamers. Oil based systems can use organosilicon, fluorosilicone, or non silicone defoamers to adjust surface defoaming and internal defoaming according to the situation.