Stretch Wrap vs Shrink Wrap
Stretch and shrink wrap are two commonly used packaging products for holding items together, increasing stability and protecting against water and dust. They are often confused for one another as they can look similar but have many differences in properties, usage and application. If you’ve ever worked in a warehouse, industrial or retail environment, chances are you’ve probably come across both types on a regular basis.
Stretch wrap is a polythene film that can stretch by up 200-300%, allowing the elasticity to hold loads and items tightly together.
One of its most common uses is to stabilise pallet loads by wrapping around the base of the pallet all the way to the top to hold both items together. This helps businesses to prevent product loss and damage during shipping, worker injury and discourages load tampering. It can also be used to wrap and bundle smaller items and loads together and helps to protect against moisture and dust. It can either be applied by hand (with or without a handheld dispenser) or with specialised machines that can make quick work of a pallet and have it wrapped in a few seconds. Stretch wrap is the most readily available and least expensive form of pallet wrapping, making it a popular choice for a wide variety of business. Stretch wrap can be broken down into two common types, cast stretch wrap and blown stretch wrap. Although both stretch wrap, both are made in different ways which result in different properties and advantages.
Cast Stretch Wrap
Cast stretch wrap is made by using a cast extrusion process where the plastic material is melted and forced through a very thin gap onto a chilled surface where it can re-solidify. This method of production gives cast stretch wrap increased clarity (allowing scanning technology to be used through it), a better ability to cling to products and requires less force to stretch. Cast stretch film, however, has less holding power than blown stretch wrap and has less elastic memory.
Blown Stretch Wrap
Blown stretch wrap is made by melting the plastic material and using air to blow the liquid plastic up like a balloon which is then cooled with air. This creates a heavier duty stretch wrap that is tougher and stronger than cast stretch wrap and has more elastic memory making it better at securing heavier loads. Blown stretch film, however, has less clarity than cast stretch wrap and is usually more expensive due to the manufacturing differences.
Shrink-wrap is usually made from polyolefin film and is placed loosely over an item or load and heated to make the film shrink tightly around whatever it is covering, holding it together securely. Although shrink wrap can be used to stabilise pallet loads, it’s much better suited for bundling smaller items together to create multi-packs of items, for example, cans and bottles of soft drinks in supermarkets are often wrapped in shrink wrap to keep them together. As shrink wrap can completely encase smaller and medium-sized items (Although it’s not unheard of for smaller aircraft and helicopters to be shrink-wrapped for transport or storage) it is far better than stretch wrap at protecting against dust and moisture, making it a great option for keeping your products safe from the weather. Like stretch wrap, shrink wrap can be applied manually and heated with a hot air gun, applied with an automatic machine (although they are often smaller compared to the stretch wrap machines) or heat tunnels mounted over a conveyor belt system.
As you can now see, although stretch wrap and shrink wrap are both clear films that can stabilise pallet loads and hold items together, they are very different, with stretch wrap being used more for industrial and logistical needs and shrink wrap being more suitable for packaging items at a retail level.
Here at Davpack we have a range of both stretch films and shrink wrap films as well as machines for both products that can help make your warehouse more efficient when packing and loading pallets and bundled items!
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