What is the difference between a pre-stretched and power pre stretch film?

Is there a difference in the way they are produced?

The first stage of production is the same for both pre-stretched and power pre-stretch films. Both are produced by melting down resin pellets and passing it through a die before it is either cast or blown. The next stage is where these two films are differentiated. A power pre-stretch film is then sliced and wound onto cores whereas a pre-stretched film is first stretched to its maximum elasticity before being wound onto the core.

How does this impact performance?

A power pre-stretch film and a pre-stretched film are not designed to have a different performance. They are differentiated for use on different machines or to be applied in different ways. A power pre-stretch film is for use on a pallet wrapping machine with pre-stretch capabilities (a power pre-stretch machine) whereas a pre-stretched film is for use on a core brake machine or for hand application.

Therefore, there is no difference in performance between the two different types of film providing they have been correctly applied.

What happens if you do not apply them correctly?

There are a few different scenarios here: a power pre-stretch film that is not stretched enough; a power pre-stretch film that has been stretched too much; a power pre-stretch film on a core brake machine; and a pre-stretched film on a power pre-stretch machine.

Firstly, a power pre-stretch film that is not stretched enough. This will mean you are getting a lower than optimal yield from your film which is not cost or plastic efficient.

Secondly, a power pre-stretch film that has been stretched too much. This will likely not run as the film will have too much tension and snap as it being applied.

Thirdly, a power pre-stretch film on a core brake machine. This is hugely inefficient as the film is not getting stretched at all meaning you will be using far more plastic than necessary which is not cost effective or sustainable. In addition, this can also be detrimental to pallet stability. If the film has not been stretched it will still have stretch potential left in it. This means that during a harsh braking or cornering incident the movement of the goods will force the film to stretch further allowing the goods to shift and the pallet to deform rather than staying tight and keeping the goods secure.

And finally, a pre-stretched film on a power pre-stretch machine. This will not run as the machine will try to stretch the film when it has already been taken to is maximum stretch. It will therefore be taken past its breaking point and snap.

How can you tell the difference?

The easiest way to find out which film you are using is to ask your pallet wrap supplier. However, another way you can check is by stretching the film with your hands if the film stretches a long distance before it becomes tight then it is likely to be a power pre-stretch film whereas if it becomes tight within a short distance it is likely to be a pre-stretched film.