How Does Shrink Wrap Work?

Shrink wrapping means covering any product with a plastic film. These films can be either clear or printed. They form a cover around your item which is sealed using heat. Heat is applied around the product by using any source of heat, which usually includes a heat gun or a heat shrink tunnel. Use of shrink films ensures a tight finish if the product is well packed at the beginning.

The shrink wrap systems come under four categories:

  1. The first one is transit wrap in which the product is passed through a curtain or sleeve of the film. Once it is done, the edges of the packing remain open which need to be sealed. For this, special shrink tunnels are used. However, this method does not create quality finish and the product has a rough display. Chiefly, polyethylene is used for the purpose because of its low costs.
  2. The “L seal” style is another way of packing which is primarily used for display purposes. Under this, a centrefolded film is used and the product is inserted and a sealing and cutting in ‘L’ shape is done which seals and cuts the two sides. Once the wrapped product passes through the heat tunnel, it is tightly packed. PVC is used for the purpose which has 40 per cent shrink property on application of heat. Under the ‘L’ seal, the film is perforated for enabling air to escape during the shrinking process. This way, the wrap creates an environment devoid of aroma and bacteria. However, care should be taken in sealing as the spaces are so small that they cannot be seen easily with the naked eye. These spaces can be placed in a way that they wrap the edges of the product for better packing.
  1. The next system is related to the flow wrapping technology, rather than the seal method. Under this system, the film is created typically around a magazine and loaded at regular intervals into the tube of the film. A seal is created beneath the pack and the ends are sealed. Often used for wrapping magazines, this method is performed using a shrink tunnel to achieve skin tight finish.
  1. Next is, sleeve shrink tube or shrink label. Under this, ‘tube’ of film is dropped over a bottle before it passes through the shrink tunnel. The tube is then push down until it fits against the bottle tightly. It works as a decorated label and also acts as a security device at the place where the lid meets the jar.

Shrink wraps are done using machines which come in various sizes and operate at different speeds. You can opt for the low cost shrink wrapping systems which are operated manually or opt for the expensive high speed and fully automatic and integrated systems. The options do not end here as there are integrated tray erectors and loaders incorporated within the shrink wrapper. Therefore, you have lots of options when you look to pack your products. All you need to do is carefully check all the options before deciding to go for the one which best suits your requirements.