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        # ESBO in PVC: How Epoxidized Soybean Oil Works as a Bio-Based Co-Stabilizer

        

**Topic:** Explainer

        

In lead-free Ca-Zn stabilized PVC compounds, epoxidized soybean oil (ESBO) is a critical synergistic co-stabilizer. For Indian and African manufacturers producing food-wrap films, medical tubing, or toys, [NBT ESBO](/products/additives/esbo) provides essential HCl scavenging and heat stabilization. Approved by the FDA and European food-contact authorities, NBT ESBO replaces volatile secondary plasticizers while enhancing compound safety.

        
        
        
        
        
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          ## Frequently Asked Questions

          
### Can I use ESBO as the only stabilizer in a PVC formulation?

No. ESBO is a co-stabilizer, not a primary stabilizer. It must be used with Ca-Zn metal soaps (or other primary stabilizer systems) to provide complete PVC heat stabilization. Alone, its HCl scavenging capacity is insufficient for production-scale processing requirements.

### What is oxirane oxygen content and why does it matter?

Oxirane oxygen content (%) measures the epoxide group concentration in ESBO. Each epoxide group scavenges one molecule of HCl. Higher oxirane oxygen (minimum 6.0%) means more HCl can be neutralized per gram of ESBO. It is the most critical functional specification on any ESBO COA.

### Why does ESBO loading need to increase when using CPW?

CPW releases HCl via dehydrochlorination during extrusion. This additional acid must be neutralized by the stabilizer package. Adding 1-2 PHR ESBO per 10 PHR CPW compensates for the extra acid burden and prevents premature stabilizer package depletion.

### Is ESBO safe for children's toys and food packaging?

Yes. ESBO is listed in EU Regulation 10/2011 for food-contact PVC (SML 60 mg/kg) and is accepted by major toy safety standards as a non-restricted co-stabilizer. It is derived from soybean oil and carries a favourable safety profile compared to metal-based or organotin stabilizers.

        
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By NBT Technical Desk · Updated 2026-07-04

        

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