Pallet Wrap Stretch Film – The Differences Between Cast and Blown
We have decided to write this post titled ‘Pallet Wrap Stretch Film – The Differences Between Cast and Blown’ due to the number of question we are regularly ask by our customers on this issue. It is not always obvious to the end user what the difference between a cast & blown film is. In some cases people are completely unaware that there is even a choice. As longs as it wraps and secures your goods what does it matter? Well, in some cases it does, and yours might be one of them! Below you will find a brief description highlighting some of the properties of each type of stretch film. Have a look over them and see which would be better for your purposes.
Differences in Manufacture
Many people in industries across the world make good use of pallet wrap (or as others may call it, stretch film) for securing their goods for safe transit and storage. The main difference between these two types of stretch film is in the manufacturing process.
Blown Stretch Film
Heated resin beads are processed through a circular die and blown out vertically into a bubble. This film is then cut into a single sheets and transformed into rolls of stretch film, the film is cooled by the surrounding air. It is the time it takes to cool the rolls that makes blown film more expensive than cast, as this impacts on the manufacturing output.
Cast Stretch Film
As with blown film heated resin beads are processed but this time passed through a slotted die. As the film is already in sheet form no further process is required to convert the film. This sheet is then passed allong a rolling path that cools and solidifies the film.
Blown v Cast Stretch Film – A Comparison
|Blown Stretch Film||Cast Stretch Film|
|Load Retention:||More holding power, won’t re-stretch once applied||Stretches easily, even after applied to pallet which can cause shifting|
|Film Memory:||Higher ability to shrink back to original size after stretch||Minimal ability to go back to original state after stretching|
|Film Yield:||Stretches much farther to cover more pallets with less film||Additional stretching can be obtained easier through lower micron blown films|
|Puncture Resistance:||Manufacturing process allows greater resistance to breaking||Standard tearing can occur when stressed too much|
|Cling of the Film:||1 sided cling, great for higher load retention||Naturally clingy on both sides, can make pallets stick together|
|Visual Clarity:||Not crystal clear, can make reading and scanning harder, but has a lower gloss reducing reflections||Perfectly clear, makes reading and scanning in warehouse light easy, but a higher gloss makes reflections annoying.|
|Noise on unwind:||Loud when releasing from the roll||Very quiet when unwound from the stretch roll|
If you have any further question regarding any of the issues highlighted above, or if you would like to take over your requirements them please remember we are here to help and assist you. All you have to do is give us a call.