A Study on the Cold Reserving Performance of PET Bottle with Shrinkage Film

Shrink film is currently being used for plastic container lavels to avoid the use of glue. Polyethylene terephthalate (PET) bottle lavels also use shrink films in the same PET materials for easy recycling of PET bottles. An air layer is generated between the shrink film and PET bottle surface due to the bent shape of the bottle surface. This air layer can insulate external heat, as air has a relatively lower thermal conductivity. In this study, the insulation property of the air layer was examined by computer simulation. Two PET bottle models were used, one with and the other without an air layer between the PET bottle surface and lavel. The two bottle models were filled with cold liquid and exposed to room temperature for 6 h, and the temperatures of the contents were then compared. The results showed that the temperature of the contents in the bottle with the air layer was lower than that without the air layer by at least $2^{\circ}C$. This study suggests an effective lavel design of PET bottles while ensuring that the temperature of the bottle contents is maintained.