If the use of defoamers in water-based cleaning agents is not correct, it will lead to increased costs and cannot ensure the low-foam quality of the cleaning agent. When defoamers are used in water-based cleaners, the following methods are recommended:
1. The PH value of the water-based cleaning agent concentrate ≥ 10, it is not recommended to add defoamer directly to the water-based cleaning agent concentrate. Because regardless of whether it is a silicon defoamer or a non-silicon defoamer, there will be more or less precipitates in the PH≥10 system.
Different defoamers will basically appear precipitates in the PH≥10 system, and the difference lies in the number of precipitates and the length of time it is resistant to precipitation.
Therefore, if the defoamer is added directly to the water-based cleaning agent concentrate of PH≥10, it is recommended to add the defoamer to the cleaning agent concentrate for at least 30 days before use. After 30 days, observe the amount of precipitate and test whether the low-foaming properties of the diluted concentrate can meet the requirements.
The PH value of the water-based cleaning agent concentrate ≥10, and it is recommended that the downstream customers of the cleaning agent dilute and then add defoamer on site. In this way, there is no significant attenuation of the defoamer added, and the amount of defoamer used will be correspondingly smaller.
2. The PH value of the water-based cleaning agent concentrate < 10, in which case the defoamer can be added directly. However, after the defoamer is added to the water-based cleaning agent mother liquor, it is recommended to also place it for 30 days before observing whether the appearance of the mother liquor is precipitated, and whether the low foaminess after dilution of the cleaning agent mother liquor can meet the requirements.
Defoamer is often a radish and a pit, and a defoamer is difficult to use for different systems. When selecting defoamers, compare and evaluate multiple defoamers at the same time, and select relatively good defoamers.
Defoamers are currently used more silicon, followed by polyethers. The defoaming of silicon is better than that of polyethers, but the silicon defoamer remains on the surface of the workpiece, which has a certain adverse effect on the subsequent treatment process of the workpiece.
When the metal workpiece is cleaned with a cleaning agent, if there is silicon residue on the surface of the workpiece, the coating spreadability of the metal workpiece surface will be affected.
Because the surface tension of the silicon is low, when the surface tension of the coating applied to the metal surface is lower than the surface tension of the residual silicon, the coating will be difficult to spread on the metal surface, resulting in a case of leakage.
When the glass workpiece is cleaned with a cleaning agent, if there is silicon residue on the surface of the workpiece, after the glass is dried, the defect of the silicon spot will appear.
Therefore, the priority use of polyether defoamers in water-based cleaning agents is relatively good, when the polyether foam control can not be reached, and then choose to use silicon defoamers.
When a silicon defoamer is added to the cleaning agent, it is recommended that downstream customers who use the cleaning agent not only measure the control of foam, but also evaluate whether the recoating of the workpiece after cleaning has been affected.