Beside the high reinforcing fillers, carbon blacks and silicates, there is a broad market for:
* Other fillers less performing but cheaper,
* Fillers with specific properties.
Some are very widespread such as calcium carbonates but others are more specific such as barium sulphate used in medical applications for its opacity to X-rays or micas used to reduce the gas permeability or to improve the dielectric properties. What are non-black fillers?
Apart from the silicas, already studied in a precedent paper, among main non-black fillers are, for example:
* Calcium carbonates, chalks, limestones, marbles, whitings: natural or precipitated, possibly treated. They are the main fillers of broadest use.
* Soft, hard and treated clays or kaolins: calcined or anhydrous, chemically structured, modified on surface.
* Talcs possibly treated, for example micronized. In rubbers, apart anti-tack applications they are used as internal lubricant and to increase impermeability. In plastics they are broadly used in polypropylene (PP).