What is shrink wrap?
The term shrink wrap is used for plastic films which shrink under the application of heat. These are categorized according to their shrink direction into biaxial (symmetrical) and monoaxial (on one side) shrink wraps. In industry, shrink wraps are used for securing pallets. They are also used for bundling or for protecting products. Shrink wrapping is generally manufactured as blown films, using the co-extrusion process, from one or more plastic granulates. The blowing process stretches the plastic molecules horizontally and vertically, and orientates them. This orientation disintegrates upon the application of heat – either with hot air or infra-red radiation, at approx. 120-220 °C – and the film shrinks. This effect can be exploited for tightly encasing products and pallets.
Packaging with shrink wrap – alternatives
Increasingly, industry is replacing shrink wrapping with elastic films (stretch films) and stretch hoods for securing loads on pallets. For strapping and bundling too, the trend is moving away from shrink wrapping towards strapping films. The following arguments favour alternatives such as stretch films:
- application of heat unnecessary
- more suitable for chilled products (no freezer burns)
- improved energy efficiency
- faster cycle times in the packaging process
- flexibility of the wrap remains unimpaired
- suitable for varying package dimensions