1. Insoluble or poorly soluble in the foaming liquid
In order to break the foam, the defoamer should be concentrated and concentrated on the bubble film. In the case of a foam breaker, it should be concentrated and concentrated in an instant, and should be kept in this state for the case of foam suppression. Therefore, the defoaming agent is supersaturated in the foaming liquid, and it is easy to reach a supersaturated state only when it is insoluble or poorly soluble. Insoluble or insoluble, it is easy to accumulate at the gas-liquid interface, and it is easy to concentrate on the membrane to function at a lower concentration. Defoamer used in water system, the molecule of the active ingredient must be strong hydrophobic and weak hydrophilic, and the HLB value is in the range of 1.5-3, which is the best.
2, the surface tension is lower than the foaming liquid
Only the antifoaming agent has a small intermolecular force and the surface tension is lower than the foaming liquid, and the defoamer particles can be immersed and expanded on the bubble film. It is worth noting that the surface tension of the foaming liquid is not the surface tension of the solution, but the surface tension of the foaming solution.
3. A certain degree of affinity with the foaming liquid
Since the defoaming process is actually a competition between the rate of foam collapse and the rate of foam formation, the defoamer must be able to disperse rapidly in the foaming liquid to quickly function in a wider range of foaming fluids. In order for the antifoaming agent to diffuse faster, the antifoaming active ingredient must have a certain degree of affinity with the foaming liquid. The active ingredient of the antifoaming agent and the foaming liquid are too close to each other to dissolve; too thin and difficult to disperse. Only when it is appropriate, the effect will be good.
4. No chemical reaction with the foaming liquid
The defoaming agent reacts with the foaming liquid. On the one hand, the defoaming agent loses its effect, on the other hand, it may produce harmful substances and affect the growth of microorganisms.
5, low volatility, long duration of action
First, determine the system that requires the use of defoamers, either aqueous or oily. For example, in the fermentation industry, oily defoamers such as polyether modified silicon or polyethers are used. The water-based coating industry requires water-based defoamers and silicone defoamers. Select the defoamer and compare the added amount. At the reference price, the most suitable and most economical defoamer product can be obtained.