Luzenac talc is a functional mineral used mainly as a reinforcing filler and a processing aid in rubber applications. Our Mistron® range includes a wide portfolio of ultra-fine grind compacted, surface treated and talcs. Our new high aspect ratio talcs are particularly suited to high impermeability and fire retardancy applications. The choice of talc product depends on the specific functionality required.

For more information, or to discuss the appropriate talc product for your requirement, please contact our rubber team

Mistron® talcs are made from microcrystalline ore which provides a larger specific surface area than most talcs on the market, resulting in better levels of reinforcement.

High aspect ratio HAR® talcs are produced using an innovative delaminating process which dramatically increases lamellarity and aspect ratio making them ideal for applications where barrier properties are key.

Both Mistron® and HAR® talcs make perfect, low-environmental impact synergists with carbon black, lowering Mooney viscosity, enhancing tensile properties, preventing scorch and improving barrier properties, all in a low-cost formulation.

The lamellar surfaces of Mistron® and HAR® talcs are organophilic and therefore have a natural affinity for organic substances such as polymers—-behaviour that is unique among industrial minerals.

Talc is the softest mineral on earth and does not wear metal components (extruders, moulds.). Very fine Mistron® grades are proposed providing enhanced reinforcement properties.

For easier handling, Mistron® and HAR® talcs available in compacted form.

• Reinforcing filler
• Processing aid
• Permeability
• Electrical insulator and flame retardancy aid
• Partitioning agent


• Mistron HAR®, the new, natural force for tire inner liners
• HAR talcs the natural solution for fire resistant cable applications
• Mistron talc, a cost-effective, LEI synergist with carbon black

Processing aid

Mistron® talc platelets create an internal lubricating effect between the elastomer chains. This helps to reduce compound viscosity, making the processing of moulded and extruded parts easier. Talc also reduces nerve and heat generation.

Permeability (for tires, hoses, stoppers, sealings and membrane applications)

Mistron® talc's lamellar particles create an impermeable barrier, substantially reducing air and liquid transmissions. Mistron® also diminishes plasticizer evaporation, resulting in good thermal and weathering resistance, thereby extending service life.

New High Aspect Ratio Mistron HAR® talcs impart excellent barrier properties to tire inner liners, and are ideal synergists with carbon black.

Electrical insulator and flame retardancy aid

Mistron® talc's hydrophobic and electrically neutral platelets make it an ideal insulator for wires and cables. It also limits gas emission and oxygen diffusion, resulting in delayed combustion of fire resistant cables (non halogen flame retardant cables).

New High Aspect Ratio HAR® talcs have excellent barrier properties making them ideal for fire resistant cable applications.

Partitioning agent

Luzenac's 40 µm grades can be used in powder form or as a talc/water coating to inhibit unvulcanized rubber-to-rubber adhesion in tyre, manufactured rubber goods and cable insulation.