Material Drying
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PET bottle-grade drying 165-175℃
Problembeschreibung
White haze and silver streaks appear in the preforms, and the AA acetaldehyde value exceeds the standard, leading to complaints about beverage taste change
Ursachenanalyse
Insufficient drying of bottle-grade PET makes moisture aggravate acetaldehyde generation and IV decline; AA affects taste, and IV decline causes the bottles to have insufficient pressure resistance and break easily, both directly manifested as customer complaints
Lösung
①Drying temperature 165-175℃ with a residence of 4-6 hours; ②feed opening temperature above 160℃ and dew point below -30℃; ③drying air flow 3.7 m³/h per kg/h
Wichtigste Erkenntnis
Bottle-grade PET drying parameters are a precise combination: the four elements of temperature, time, dew point, and air volume are all indispensable, and AA and IV are the verification indicators; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
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