Nepheline Syenite

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Product Description
Benefits & Application Details



Nepheline syenite (silicate, naturally occurring blend of albite, microcline and nepheline) is a feldspatic mineral mined in Canada and Norway.

Nepheline syenite can be characterised by:

  • High purity
  • Absence free crystalline silica (free from labelling);
  • Brightness
  • Relatively low refractive index, making it a transparent filler in various binders
  • High inertness in various media
  • Easy wetting
  • Transparency for UV-radiation (ie. suitable for UV-curing processes)


Basic properties

Property Value Unit
Hardness (Mohs) 6 [-]
Refractive index 1.51 – 1.53 [-]
Density 2.6 [kg/ dm3]



Nepheline is the product name for products used as an antiblocking additive in films – Nepheline is used when the product  is based on the mineral nepheline syenite. 

Adding Nepheline to the resin for film addresses the issue of blocking (the sticking together of two film surfaces) during the production of the film, converting of the film and during the end-use of the film in packaging (including making of bags) and in agriculture.

Nepheline is a free crystaline material and therefore free from labeling. It has a refractive index close to that of a variety of polymer systems used in producing film. This results in high clarity films with low haze. Different Nepheline grades are available to have optimal anti-block performance for different film thicknesses.

Nepheline is used in a variety of applications, ranging from resilient PVC flooring where it improves the fusion-process of the plastisol. Another application is in WPC (Wood Plastic Composites) where it offers among other features improved UV resistance and color retention along with better dimensional stability.  

Furthermore Nepheline grades improve the resistance towards dirt (from the atmosphere, for example) and due to its hardness of 6 on Mohs scale, it also improves the abrasion and scratch resistance of the material it is being used in.

As  Nepheline grades are transparent for UV radiation, they can be used in UV curing formulations of adhesives and sealants. Another reason to use them in this application is to have a better “body” of the sealant without increasing the viscosity

When used in roof coatings they increase the IR reflection and hereby keeping the roof and the structure cooler when exposed to the sun.

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