Characteristics and functions of defoamers used as additives in coatings

Defoamer is widely used at present, and its main function is to eliminate some harmful foam. And in the process of preparing some water-based coatings, defoamers are also needed, just like other additives such as dispersants and leveling agents, which play an auxiliary role in the coating production process. Next, the editor of Jianyi Chemical will introduce some characteristics and functions of defoamers in practical applications!

Characteristics of defoamers:

There are many kinds of defoamers, including oily, solvent, silicone, lotion and solid powder. And defoamers all have the following properties:

1. Strong defoaming ability and low dosage;

2. The addition of defoamers will not affect the basic properties of the system;

3. Low surface tension;

4. Good surface balance;

5. Good dispersibility and permeability;

6. Good heat and acid alkali resistance;

7. Chemical stability and strong oxidation resistance;

8. Good gas solubility and permeability;

9. Low solubility in foaming solution;

The function of defoamer:

The defoaming or anti foaming ability of defoamers is due to their low surface tension that enters and destroys the foam film, resulting in a defoaming effect. When the defoamer is added to the foam medium, it falls on the surface of the foam and effectively reduces the surface tension at the contact point, resulting in a weak spot on the foam skin, which causes foam breaking.