6. Shrinkwrappers

6.1 General case

Made possible by the invention of hot-air shrinkable plastic films, this technique involves wrapping a group of unit containers - glass or plastic bottles, metal cans, tins or cardboard packs, and other objects or products - in a heat-shrinkable plastic film (polyolefin or PVC), then shrinking this film by briefly passing it for a few seconds through a hot-air tunnel (air at around 70-85°C).

The plastic film must be strong enough (and therefore thick enough) to hold the individual packages or containers firmly together.