How to choose coating defoamer
If the paint defoamer you bought back is not effective, then it is very likely that you have chosen the right paint defoamer. Today’s version summarizes some tips for choosing paint defoamers.
1. Paint defoamers are insoluble or insoluble in foaming liquid
Defoamers are insoluble or insoluble, and are easy to gather at the gas-liquid interface, concentrate on the bubble membrane, and work at low concentrations.
2. The surface tension of the defoamer should be lower than the surface tension of the foaming liquid.
Only when the intermolecular force between the active molecules of the defoamer is small and the surface tension is less than that of the foaming liquid, can the defoamer particles be immersed in the membrane and expand. However, it should be noted that the surface tension of the foaming solution is not the surface tension of the solution, but the surface tension of the foaming solution.
3. Have a certain affinity for the foaming liquid
Since the defoaming process is actually a competition between the bubble collapse rate and the foam formation rate, the defoamer must be able to disperse quickly in the foaming liquid so that it can quickly work in a wide range of foaming liquids. In order for the defoamer to diffuse faster, the active ingredients of the defoamer must have a certain affinity with the foaming liquid. If the active ingredient of the defoamer has too strong affinity with the foaming liquid, it will dissolve; if the active ingredient of the defoamer is too dilute and difficult to disperse, the defoamer can only play a better role when its affinity and dilution are appropriate.
4. No chemical reaction with the foaming liquid
If the defoamer reacts with the foaming liquid, it will not only lead to the loss of the defoaming effect, but also produce harmful substances and affect the water quality.
5. Selection of low-volatility, long-lasting paint defoamers
First determine whether the foaming system is water-based or oil-based, then select several suitable defoamers, compare the additive dosage and reference price, and finally select the product with a high price ratio.
