Based on different functions, the surfactant used in coating industry can be classified as following:
Emulsifier, surface treatment agent, wetting dispersant of pigment, defoamer, flatting agent, mould proof and bactericide, anstatic agent, sensitizer and slip additive are included.
Antistatic agent usually applies cationic surfactant to inhibit the production of electrostatic charge through different ways to let electrostatic charge out or lower friction factors.
It is required to meet the standard below:
1. It has sound effects on preventing the electrostatic charge.
2. It can stop electrostatic charge durably.
3. It has good compatibility with film forming matter.
4. It will not influence other performances of coatings like it will not yellow the film.
The principle of anti-static agent: it takes advantage of the characteristics of its cationic surface activity to absorb the water in the air so as to produce polarity on its own, forming an extreme thin conducting layer on the surface and constituting static electricity. Thus, its results depend on its structure and relative humidity in the environment.
When choosing flatting agent to improve leveling property of coating, we should consider two aspects:
1. Active agent that can lower the surface tension of coatings/film can be selected to improve the leveling property of coatings greatly.
2. Solvent that has slow speed of volatilization and reduces the dynamic viscosity of coating application can be picked up so as to better the fluidity of coatings, lengthen the time, and run up to final leveling.