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        # Stop the Shatter: Improving Impact Strength in Rigid PVC Pipes

        

**Topic:** Rigid PVC

        

Your pipes are passing the pressure test, but they're shattering during handling or installation. One drop, and they're gone.

        
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## Problem

Rigid PVC is inherently brittle. Without proper impact modification, pipes can fail under sudden mechanical stress, especially in colder environments. This is often caused by insufficient CPE (Chlorinated Polyethylene) or an imbalance in the lubricant system.

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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

Incorporating NBT CPE 135A at a ratio of 4-6 PHR significantly improves the toughness of the PVC matrix. CPE acts as a rubbery phase that absorbs energy and prevents crack propagation. Pair this with NBT Stearic Acid for optimal fusion and you'll see a dramatic reduction in breakage.

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          ## Frequently Asked Questions

          
### Will more CPE make the pipe too flexible?

Within the recommended 4-8 PHR range, it improves toughness without significantly affecting the pipe's stiffness (modulus).

### Can I replace CPE with more filler?

No, fillers generally increase brittleness. CPE is a functional modifier, not a filler.

        
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By NBT Technical Desk · Updated 2026-06-07

        

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