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Shrink Wrap Packaging

Shrink wrap is also known as shrinkwrap or shrink film. With heat, shrink wrap packaging film tightly covers the product around which it has been used. Many kinds of packaging like boxes, cartons and beverages cans are covered and overwraped with shrink wrap films.

Some shrink wrap packaging films shrink in one direction and other in two directions. The later one is called bidirectional whereas the former is known as unidirectional or mono-directional shrink wrap packaging films.

Polyolefin is the most common of all shrink wrap films and available in varied thickness, size, clarities and strength. Shrink wrap film manufacturers also keep different strength ratio of these films for different applications. Apart from this there are PVC shrink wrap films and films having other compositions.

How Shrink Wrap Packaging Films are Manufactured?

To make shrink films, these films are first of all stretched while when these are warm. With this, orientation of molecules from their original position happens. This is followed by cooling the film. This sets the position of molecules. Again when heat is applied to the shrink wrap films, the molecules come to their original position leading to shrinkage of the films. It is just like the rubber band. Stretch the rubber band and cool it by putting it in liquid nitrogen. It will remain in this stretched condition until no extra heat is applied to it. After applying the heat rubber band will regain its original shrinked shape.

When shrink wrap films are required on commercial scale then orientation is obtained with by using the tenterframe or a bubble process. With tenterframe technology "heat-set" products are produced in which BOPP films are the most common.

Bubble process is also called tubular process. In this case first of all a primary tube is produced. For this external or internal mandrel is used to produce the primary tube either by blowing or casting respectively.water is used for cooling the primary tube at this point of time. This is followed by reheating the primary tube. This leads to its orientation in both directions.

Application of Shrink Wrap Packaging

• It is used for packing food and food products.
• Boats after manufacturing are covered with shrink wrap films and also this is used for winter storage.
• It is also used for wrapping the buildings. Generally blue tarps are used to cover the roofs and home. But now instead of this shrink wrap packaging is also been used.
• Shrink wrap films are used to wrap books.
• CD and DVD and other software accessories are packed in shrink wrap films.