Today's KNOWLEDGE Share : Why IV Matters in Scrap PET?

Today's KNOWLEDGE Share

Why IV Matters in Scrap PET?

A recent buyer came to us struggling with unpredictable performance in recycled PET. Their flakes and lumps looked fine, but the results in production weren’t.

When we ran testing and analysis, the cause was clear: Intrinsic Viscosity (IV) loss.

Here are the main IV-impacting factors we identified in their feedstock:

🚨      Weather Exposure – Sunlight & rain degrade PET, lowering IV & causing yellowing

🚨     Thermal Degradation – Overheated or burned lumps = major IV drop

🚨     Mixed Sources – Bottles, sheets, and fibers blended together → inconsistent IV

🚨     Contamination & Lamination – Impurities reduce melt quality & IV stability

✅ Quick Check Tip:

Drop test lumps → if they break easily = degradation is high and IV is likely low.

The Lesson - Always check the feedstock!

-     For Bottles Application: Must keep trays out — they lower IV.

-     For Sheets Application: Use bottle-grade PET, avoid fiber-origin PET.

The Outcome:

By helping the customer understanding their feedstock and apply the right sampling checks, we ensured a more consistent IV range, improving bottle-grade rPET quality and reducing processing issues.

👉 Our Role: At Vanden, we don’t just supply material, we provide the testing, analysis, and insight that gives customers certainty.

source : Beril Baykal Yashirmak

#PlasticsTesting #Recycling #Polymers #PET