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

Abstract

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.

Figure 1. Air gap between bottle surface at shrink film in PET Bottle.

Figure 2. Beverage package model without air gap between bottle surface and shrink film.

Figure 3. Beverage package model with air gap between bottle surface and shrink film.

Figure 4. Boundary conditions for simulation.

Figure 5. Mesh for the simulating general beverage package model.

Figure 6. Mesh for the simulating cold reserving beverage package model.

Figure 7. Temperature distribution according to the time for the general beverage package model.

Figure 8. Temperature distribution according to the time for the cold reserving beverage package model.

Figure 9. Comparison of the lowest temperatures according to the time between general beverage package model and cold reserving beverage package model.

Figure 10. Temperature distribution after 6 hours for the general beverage package model.

Figure 11. Temperature distribution after 6 hours for the cold reserving beverage package model.

Table 1. Material Property of Content, Bottle, Film and Gap