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        # Size Matters: The Importance of Particle Size in PVC Fillers

        

**Topic:** Technical

        

You're buying Calcium Carbonate based on price, but your extrusion die is wearing out twice as fast as it should. The 'cheap' filler is costing you a fortune in spare parts.

        
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## Problem

Coarse fillers (large particle size) act like sandpaper inside your machine. They also create 'weak spots' in the PVC matrix, leading to poor mechanical properties and a rough surface finish.

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## Likely cause

This issue often stems from inconsistent compounding temperatures, inferior raw material purity, or unbalanced stabilizer ratios within the formulation matrix.

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## Corrective direction

Switching to ultra-fine, micronized fillers (1-5 microns) from NBT ensures a smooth flow and minimal machine wear. Finer particles have a higher surface area, which allows for better 'wetting' by the plasticizer and a more homogeneous compound. It's an investment that pays for itself in reduced downtime and better product quality.

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          ## Frequently Asked Questions

          
### How do I measure particle size?

Suppliers should provide a 'D50' value, which represents the median particle size.

### Is 'coated' filler always better?

For PVC, yes. Stearic acid coating is essential for proper dispersion and to prevent the filler from absorbing your expensive stabilizers.

        
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By NBT Technical Desk · Updated 2026-06-07

        

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