Functional fillers are performance-oriented additives for PVC and polymer systems, different from ordinary cost-only bulk fillers. Besides basic filling, they effectively improve product rigidity, thermal stability, dimensional accuracy and processing properties.

Common grades include surface-treated fine calcium carbonate, talc powder, calcined kaolin, mica powder, barium sulfate and fumed silica, widely used in PVC pipes, profiles, cable compounds and modified plastics.

They help optimize melt fluidity, reduce processing wear, lower overall raw material cost, and some grades can even absorb HCl released during PVC processing to support better thermal stability.