Shrink Sleeve Tunnels – what type do I need?
Shrink sleeves offer 360 degrees of communication space and full-body product branding to both standard and unusually shaped products. They provide protection against product tampering with the inclusion of tamper-evident seals and neck bands, and are suitable for labelling in a variety of different markets including food, nutraceuticals, personal care, beverages, household products and multi-pack sleeves.
Shrink sleeves can be printed using either flexographic or digital offset print technology with the latter being ideal for smaller print runs. The design is printed on the inside of the filmic material which is then fitted over the container and tightened using heat, where the sleeve then conforms snugly to the surface of the product.
The shrink sleeve starts the process as large as the widest part of the container. It is typically machine applied and then needs to be shrunk to the shape and size of the individual container. This is the job of the shrink tunnel. The shrink tunnel performs the task of controlling the amount and direction of heat required to ensure shrinkage in a uniform and consistent way.
There are three main types of heat tunnels, and, as a shrink sleeve user, it is important for you to understand the basics of each type to elicit an informed decision on which best suits your specific application.
- Hot Air Tunnel
A Hot Air Tunnel is the most common type of shrink tunnel, due to its versatility and ease of use. The unit generates hot air, and fans are placed inside the tunnel to ensure the heat is directed at the correct points on the sleeve. While a popular choice, the hot air is difficult to control and can result in difficulties when shrinking to intricate container shapes.
- Steam Tunnel
A Steam Tunnel provides the most uniform shrink due to the 360° application of heat around the container. The tunnel does require a steam source which may not be viable for all application environments, for example chilled rooms. Steam is the least aggressive heat source and acts as an ideal applicator for round or hour-glass shaped containers.
- Radiant Heat Tunnel
A Radiant Heat Tunnel provides both an even and high heat when applied to the container. This is the most aggressive style of heating which can present an uneven shrink challenge when trying to conform to round or non-uniform containers. Radiant tunnels provide high and fast heat and are normally used for tamper-evident seals and neck bands where low levels of graphics are used.
The type of shrink material you select is also important, and your shrink tunnel and product shape are crucial factors in this decision. Contact our team of label experts to learn more about shrink sleeves and the extensive range of brand and productivity opportunities they offer.