Finished Shrink Wrap Problems: Ballooning
Effect: Ballooning within Shrink wrap is when after being wrapped, the product is enclosed within a pillow case effect. Air which has been trapped within and has no escape.
While it may not appear to be a huge problem from the outset, the idea of shrink wrap is that it shrinks and wraps. If air gets trapped between the product and the wrap and goes on to get punctured, the product/s within will then be free and loose to move around. You may also experience further packaging problems due to inflated products further down the packing line. Not least a presentation issue once it reaches the shop floor.
It's a tragedy of science that as air warms up, it expands which is why many shrink film products such as shrink bags and indeed entire rolls, have a form of micro perf venting. Depending on the shrink film product you are using this allows air to escape in an orderly fashion while the film is being shrunk around your product. However, there are other ways to resolve visible ballooning in shrinkwrap.
- If you are sealing manually and using shrink film bags, try to get most of the air out of the bag before beginning the sealing process. This can be more difficult with oddly shaped products. Also use air evacuation holes in the shrink film bag.
- Allow the shrink film to help you. Buy shrinkwrap which contains micro perf holes that enable the air to evacuate while the wrap is shrunk and before it is fully sealed.
- If you are already using shrink film with air vents, consider whether they are positioned correctly or that there are enough holes in the first place. If there is a particular area where ballooning is more evident, consider situating the micro perf venting closer to the problematic area and try several tests before continuing with a mass product packing line.
- Why buy shrink film which has holes in it? It's a good question, especially when it comes to protection of food or tamper proofing products. The simplest way to understand the shrink process in this case is that the film is micro perforated.
As the shrink wrap is shrunk and the air underneath expands, circulates and escapes, the holes in the wrap get smaller until they are no longer there. However the air has been allowed to escape and any negative ballooning in shrink wrap is prevented or pre-vented so to speak.