Architectural Coatings / Exterior / Cristobalite

Cristobalite

Cristobalite (silica, chemical formula SiO2) is the result of the calcination of quartz at a temperature of 1500°C:

 

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Cristobalite can be characterised by:

 

  • High brightness
  • Relatively high Mohs hardness of 6.5
  • Relatively low refractive index, making it a transparent filler in various binders
  • Easy wetting
  • High inertness in various media
  • Transparency for UV-radiation (ie. suitable for UV-curing processes).

 

Note when using cristobalite: depending on the particle size distribution of the product, it can be labelled (STOT RE 2 or STOT RE 1). For more detailed information, visit www.safesilica.eu.

 

Basic properties

Property Value Unit
Moisture [%]
pH 9 [-]
Hardness (Mohs) 6.5 [-]
Refractive index 1.48 [-]
Colour (D65/ 10°) L* 98 [-]
Density 2.3 [kg/ dm3]

 

Product overview

Coarse Fine
Product Grade D50 Name Grade D50 D90 OA
[µm] [µm] [µm]
Sibelite M72 310 Sibelite M002 70 200 21
M72T (1) 300 M006 40 100 23
M0010 30 75 23.5
M3000 17 40 26
M3500 10 30 26
M4000 6 12 27
M6000 4 8 28

(1): Tamisé: > 500 µm = < 1%

Production locations Sibelite

 

 

Application

Cristobalite will provide:

 

  • Dirt pick-up resistance: the presence of cristobalite improves the coating’s resistance to dirt (from the  atmosphere, for example).
  • Ease of tinting: due to the combination of refractive index, brightness and color, paints including cristobalite will give excellent reproducible colour results when working with tinting systems.
  • Texture effect: usage of coarse cristobalite grades will ensure texture to the surface of the coating.
  • Tint retention: paints including cristobalite show improved tint retention over other minerals when subjected to natural weathering
  • UV resistance and weatherability: due to its inertness, cristobalite supports good UV and weatherability performance to exterior architectural coatings.

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