preform · pf-07

IV (intrinsic viscosity) drop

Cause

Thermal/hydrolytic degradation from over-drying, high heat, or moisture lowers IV and strength.

Corrective action

Control drying temperature/time, lower melt temperature, verify resin IV on intake.

Where it shows — and how we check for it

Schematic, not a photographShaded: where it shows on the preform
● stops production

**Photograph**Clear PET preforms, close up, at our plant in New Salhiya City.

Seeing this on your line? Send our team a photo on WhatsApp — the message already names the defect.

Send a photo on WhatsApp Diagnose it step by step

Diagnosis guide: Low intrinsic viscosity (weak preforms)

What you will see

Preform has lower IV than specified — typically caused by excessive regrind or hydrolysis. Visible as slightly hazy preforms with reduced strength. Bottles will be weak and burst-prone.

Likely causes

Excessive regrind ratio (>30%) at Delta plant
Hydrolysis (wet PET) reduces IV
Wrong resin lot used

Do this first

Request IV test certificate from Delta for the lot.

How to diagnose it

Request Certificate of Analysis (COA) from Delta for the lot
IV should be ≥0.74 dL/g for CSD; ≥0.72 for water
If COA unavailable, send 5 preforms for independent IV test

How to fix it

Quarantine lot pending IV confirmation
If IV below spec, contact Delta with COA + measurements for lot replacement under quality guarantee