1. Insoluble or insoluble in bubbling liquid
To burst the foam, the antifoamer should be concentrated and concentrated on the foam film. In the case of foaming agent, it should be concentrated and concentrated in an instant, and in the case of foaming inhibition, it should always be kept in this state. So the defoaming agent in the foaming fluid is supersaturated state, only insoluble or insoluble to easily reach supersaturated state. Insoluble or insoluble, it is easy to gather in the gas-liquid interface, easy to concentrate in the bubble film, in order to play a role at a lower concentration. For the antifoaming agent used in water system, the molecules of the active ingredients should be strong hydrophobic and weak hydrophilic, and the HLB value should be in the range of 1.5-3 for the best effect.
2, the surface tension is lower than the bubbling fluid
Only when the intermolecular force of the defoaming agent is small and the surface tension is lower than that of the foaming liquid, the defoaming agent particles can be immersed and expanded on the foam film. It is worth noting that the surface tension of the bubbling liquid is not the surface tension of the solution, but the surface tension of the foaming solution.
3. It has a certain degree of affinity with bubbling liquid
Because the defoaming process is actually the competition between the collapse rate of foam and the generation rate of foam, the defoaming agent must be able to disperse rapidly in the foaming solution in order to quickly play a role in a wider range of foaming solution. In order to make the defoaming agent diffuse faster, the active ingredient of the defoaming agent must have a certain degree of affinity with the foaming solution. Defoaming agent active ingredients and foaming liquid too pro, will dissolve; Too sparse and difficult to disperse. Only affinity is appropriate, effectiveness will be good.
4. It does not react with the foaming liquid
Defoaming agent and foaming liquid reaction, on the one hand defoaming agent will lose its effect, on the other hand may produce harmful substances, affecting the growth of microorganisms.
5. Small volatility and long acting time
First of all to determine the need to use the system of defoaming agent, is a water-based system or oil system. If the fermentation industry, it is necessary to use oily defoaming agents, such as polyether modified silicon or polyether. Water - based coating industry will use water - based defoaming agent, silicone defoaming agent. Choose the defoaming agent, compare the amount of addition, in the reference price, can be obtained the most applicable and the most economical defoaming agent products.