One of the most popular mineral fillers used in the plastics industry is Calcium carbonate (CaCO3) which is available internationally. It is easy to grind or reduce to a specific particle size, compatible with a wide range of polymer resins and economical. Additionally compounding CaCO3 in plastic compounds, it helps decrease surface energy and provides opacity and surface gloss, which improves surface finish. In addition, when the particle size is carefully controlled, CaCO3 increases both impact stiffness.

Calcium carbonate may be used with a myriad of thermoplastic resins. Polypropylene compounds are often filled with calcium carbonate to increase rigidity, an important requirement for operations at high temperatures. In PVC, calcium carbonate is used with flexible compounds such as tubing, wire and cable insulation, latex gloves, trash bags and in rigid compounds such as extruded pipes, conduits and window profiles.