Shrink film provides benefits for a variety of applications. Shrink film is tamper-evident and enhances package security. It offers excellent clarity for retail appeal. Shrink film can be custom printed as a shrink-sleeve label for your products. Some types of shrink film complies with FDA and USDA regulations governing direct contact food packaging. With the variety of shrink wrap equipment options and the range of shrink film types and labeling options, it can be difficult to know what the right solution is for your product. In this blog we’ll cover the three main types of shrink tunnels, their benefits and drawbacks and which is right for each type of labeling.
What is a Shrink Tunnel?
A shrink tunnel is part of a shrink wrapping system to heat shrink wrap and firmly affix it around packaging. There are three main types of shrink tunnels, but all three use an application of heat and a conveyer system to seal or affix labels to products.
Types of Shrink Tunnels
This type of shrink tunnel uses infra-red heat in an oven like heat environment to apply a sleeve or tamper banding. This type of tunnel is not well-suited for empty packaging, like PET labels on empty PET bottle because the containers can warp. One other drawback to Radiant heat tunnels is the heat is often uneven across the packaging – the lead end is shrunk first, which can leave the tailing looking warped.
Hot Air (Convection)
Hot air shrink tunnels offer directional heat and connect to conventional power sources, so they are versatile and also cost-effective. Multi-directional hot air flows can be directed at any required section of the package, like the neck of a bottle or curve of a jar. Convection tunnels can be connected to an L-bar sealer and be used to shrink wrap packages. One drawback of a convection shrink tunnel is that the temperatures have to be high enough to counteract the heat loss from transfer. In other words, hot air does not transfer heat well, heat is easily lost in the process so higher heat is used. This doesn’t work well with all product types and can cause warping. In some cases, product must be rotated on the conveyor belt to minimize warping or uneven shrink.
Changes in technology and consumer response to products wrapped in full-color designs are driving significant growth in the shrink-sleeve label application. Currently the most popular method for shrink sleeve label application, the conduction method is also more efficient in process. Steam is a much more effective way to shrink a label to most packaging materials than infrared and convection. Using focused application of heat on specific points of a package provides the most uniform results on full body shrink labels and minimizes the risk of container distortion. Some tunnel solutions allow for adjustments to flow, volume and position in real-time, without wasting time or energy waiting for the tunnel to cool down. The initial set-up for a conduction shrink tunnel requires additional investment as this process requires a boiler, dedicated plumbing, filtering and drainage.
Not sure which shrink tunnel is right for you? The experts at PackEdge work closely with you to give you an edge in the market and find the best packaging solution for your products. Together we will identify opportunities to save cost, reduce product damage and enhance your customer’s experience with your brand.
PackEdge Corporation is a wholesale distributor of packaging systems and consumable products. We offer a variety of packaging equipment and products including stretch wrap, void fill, shrink film and more.