Material Drying
6 Aufrufe
PET Preform IV Drop (Intrinsic Viscosity Decrease)
Problembeschreibung
The same batch of resin has decreased blowing strength, and the bottle body is brittle.
Ursachenanalyse
Hydrolysis and thermal degradation reduce PET intrinsic viscosity (IV); insufficient drying, excessive material temperature, too long residence, and multiple heat histories (recycling) all cause IV drop.
Lösung
①Strict drying; ②dual control of material temperature and residence; ③test the IV value of incoming material and preforms; ④evaluate IV of old inventory preforms before use.
Wichtigste Erkenntnis
IV is the general ledger of PET processing quality.
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