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A coating formulator may encounter a frustrating situation:
Fumed silica has already been added, but pigments or fillers still settle during storage. Why?
The answer is not necessarily:
“Add more silica.”
Anti-settling performance depends on how the silica interacts with the complete formulation.
Fumed silica can be used to modify rheology and help control settling.
However, its performance depends on factors such as:
Therefore, simply confirming that “fumed silica is present” does not guarantee the desired anti-settling behavior.
Fumed silica needs to be properly incorporated into the formulation.
Poor incorporation can prevent the material from developing the expected rheological effect.
This is why two formulations using the same silica dosage may still show different storage behavior when their mixing process is different.
Not automatically.
Increasing fumed silica may improve rheology in some systems, but excessive addition can also increase viscosity and make processing or application more difficult.
The target is usually a balance between:
anti-settling performance + workable viscosity + application behavior.
IOTA HL7200 is a hydrophilic fumed silica with a specified BET surface area of 200 ± 20 m²/g.
Industrial coatings are among its application directions.
For a coating formulator evaluating HL7200, the more useful approach is to test it in the actual formulation rather than predict performance from BET surface area alone.
When requesting a fumed silica recommendation for coatings, provide:
This information makes it easier to determine whether HL7200 or another silica grade should be evaluated.
A useful screening process is:
Current formulation → Candidate dosage → Controlled dispersion → Initial viscosity check → Storage observation → Application test
If the formulation becomes too thick before acceptable anti-settling performance is achieved, simply continuing to increase the silica dosage may not be the best solution.
Does adding fumed silica always prevent pigment settling?
No. Performance depends on formulation, dosage and dispersion conditions.
Should I increase silica whenever settling occurs?
Not automatically. Excessive addition may create processing and viscosity problems.
Can HL7200 be evaluated in industrial coatings?
Yes. Industrial coatings are one of its application directions.
Is BET surface area enough to select coating-grade silica?
No. Actual formulation performance should be tested.
What should I provide when requesting a recommendation?
Coating system, current grade, dosage, mixing process, current problem and target performance.
Related Product:
IOTA HL7200 Hydrophilic Fumed Silica
