Industrial Coatings / Powder Coatings / ATH


ATH (aluminium tri hydrate, chemical formula Al(OH)3) is a side stream of the aluminium production, characterised by:


  • High purity
  • High whiteness
  • Relatively low density of 2.4g/cm3 compared to other mineral fillers, which are typically at 2.7g/cm3
  • Medium Mohs hardness of 3
  • Decomposition around 180°C, releasing water.


Basic properties

Property Value Unit
Moisture < 0.4 [%]
pH 9 [-]
Hardness (Mohs) 3 [-]
Refractive index 1.57 [-]
Electrical conductivity 60 [µS/cm]
L.O.I. 34.5 [%]
Density 2.4 [kg/ dm3]




Product overview:

Product Grade D50





[g/ 100 g]

Portafill A7 2.4 6.5 27 98.5
A10 3.8 10 27 98.4
A25 7.3 24 21 97.0
A40 11.5 36 20 96.5
A25/10 13 35 18 98


Production locations Portaflame SG, Portafill A




ATH will provide:

  • Chemical resistance: due to its inert nature, ATH will provide good chemical resistance compared to conventional fillers.
  • Gloss control: with the availability of ultrafine ground ATH (Portafill A7) and a product with an optimised particle size distribution (Portafill A25/10), it is possible to apply coatings with a broad range of gloss levels.
  • Increasing extruder output: the optimised particle size distribution of Portafill A25/10 provides better free-flowing properties. As a result, the material is easier to dose into the extruder, so the residence time inside the extruder can be optimised.
  • UV resistance: being insensitive to UV radiation, ATH will reduce the coating’s degradation.
  • Water spotting resistance: powder coatings formulated with ATH show less tendency for water spotting then similar coatings formulated with barium sulphate.


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