Plastic bottles made from different materials are like athletes with distinct personalities-their tolerance for heat varies significantly:
PET (Mineral Water Bottles): 70°C marks the safety threshold; exceeding this temperature causes them to soften and deform easily.
HDPE (Milk Bottles): Can withstand temperatures of 100°C for short periods, but for continuous drying, it is recommended to keep the temperature below 80°C.
PP (Microwave-Safe Food Containers): The only common plastic capable of withstanding 120°C; however, drying times should not exceed 30 minutes.
Three Golden Rules for Safe Drying
Preheat Test: When using a drying device for the first time, conduct a trial run with a single bottle at 50°C for 10 minutes.
Tiered Arrangement: Utilize a multi-tiered rack system to ensure hot air circulates freely through the interior of every bottle.
Time Management: For thin-walled bottles (<1 mm), 15–20 minutes of drying is sufficient; for thick-walled bottles, this can be extended to 30 minutes.
Stop Drying Immediately If Any of These Occur:
Bottle opening shrinks or deforms (indicating excessive temperature).
Misty white streaks appear on the surface (indicating damage to the molecular structure).
A sweet, cloying odor is emitted (indicating that plasticizers have begun to leach out).
Bubbles or bulges appear at the base (indicating localized overheating and degradation).