In the plastic film manufacturing process, the molecularly oriented film obtained by stretching and cooling at a temperature above its softening point tends to return to the state before stretching when it is reheated.
Shrink packaging is the use of plastic film. Heat shrinkability is developed.
That is, the appropriate size of heat shrinkable film is put on the outside of the packaged item, and then heated for a short time with a hot air oven or a hot air spray gun, the film will immediately shrink and wrap tightly around the item.
The packaging items can be single pieces, or cans, bottles, cartons, etc. that are arranged in an orderly manner.
Stretch packaging was originally mainly used for sales packaging.
Since PVC (polyvinyl chloride) films have been used for stretch packaging, this technology has developed rapidly and has now been extended to the field of transportation packaging.
Commonly used stretch films are polyvinyl chloride, low-density polyethylene, and so on.
If the stretch packaging is manually operated, the packaging is generally placed in a shallow tray, especially for soft and brittle products, which are easily damaged if the shallow tray is not used.
Multi-packed scattered products also need shallow trays, but the shallow trays are not necessary when the product itself has certain rigidity and strength.
If part or all of the processes in the stretch packaging work are mechanized or automated, labor can be saved and production efficiency improved.
The main link of automatic stretch packaging is rolling and stretching, and now there is the mechanical equipment that completely mechanizes these processes.
