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A coating formulator may encounter a familiar problem:
The coating needs better anti-sagging, so more fumed silica is added.
The anti-sagging improves—but the coating becomes too thick or more difficult to apply.
Why?
Because the objective of rheology control is not simply to create the highest possible viscosity.
Fumed silica can be used to modify rheology and help control:
But the actual effect depends on the complete formulation.
As silica loading increases, the internal structure of the formulation may become stronger.
This may help reduce sagging.
At the same time, however, excessive structure can negatively affect:
The target is therefore not maximum thickening.
It is controlled rheology.
Fumed silica needs to be properly incorporated into the coating system.
Different dispersion conditions can produce different rheological behavior even when the same grade and dosage are used.
This is why silica dosage should not be evaluated independently from the mixing process.
IOTA HL7200 is a hydrophilic fumed silica with a listed BET surface area of 200 ± 20 m²/g, and the current product information includes coatings among its application areas.
It can therefore be evaluated where hydrophilic fumed silica is required for rheology modification or related functions.
Actual dosage should be determined in the customer's formulation.
For a more relevant silica recommendation, provide:
For example:
“The coating does not sag, but it has become too difficult to spray.”
This is much more useful than simply asking:
“Which fumed silica is best for coatings?”
Does more fumed silica always provide better anti-sagging?
Not necessarily. Excessive loading may negatively affect flow and processability.
Can fumed silica affect coating application?
Yes. Rheology changes can influence flow, leveling and application behavior.
Can HL7200 be used in coatings?
Coatings are one of its listed application areas.
Is 200 m²/g BET enough to select a coating silica?
No. Formulation and application testing are still required.
What information should I provide?
Coating type, resin system, current silica and dosage, mixing process, application method and current problem.
Related Product:
IOTA HL7200 Hydrophilic Fumed Silica
