The packaged material is wrapped in a plastic film having heat shrinkage properties and then heat treated. The film is self-shrinking in a certain ratio, and a method of closely adhering to the contents is called shrink packaging or shrink film wrapping. Stretched or stretched film wrap is a method of stretching a film at room temperature by using a stretchable plastic film to wrap the packaged article. The principle of the two packaging methods is not the same, but the effect of the packaging is basically the same, the wrapped items are wrapped tightly, all have the nature of wrapping, but the principle of the wrapping method, the materials used and the effects produced They are all very different from the wrap method described above.
Shrink packaging began around 1950 and developed rapidly around 1970 and is now widely used in the packaging industry.