Shrink sleeve labeling has become one of the fastest growing trends in packaging over the last few decades. Shrink sleeves decorate a multitude of products across many industries, including food, beverages, and pharmaceuticals, as well as personal and household items. Much has been written about the benefits of shrink sleeve labeling, such as the ease of adding tamper evidence, as well as the boost it can give to brand awareness and shelf appeal for customers via great graphic possibilities. But how does shrink sleeve labeling work? For those who’ve never used shrink sleeve labeling for their products, or even those who do but don’t understand the process, we break it down for you here.
The first thing to understand is the different types of shrink sleeve applications – full body, partial body, or full body with tamper evidence. Full body shrink sleeves provide 360-degree coverage from tip to toe of the product. This is especially useful over complex curves or when there are large differences in container diameter. A tamper evident feature can also be added to full-body sleeves at minimal additional cost by extending the sleeve over the cap and adding a horizontal perforation. Including tamper evidence prevents “grazing” on food or beverage products, ensuring the consumer that the package has not been opened. Tamper evidence adds a layer of security, especially important with pharmaceutical or medical products, increasing consumer confidence in your product.
Successful shrink labeling starts with the film you select for the shrink sleeve. There is a range of available shrink materials that vary in grade, cost, and shrink characteristics. The type of film you choose will depend on a number of factors, the most important being the shrink curves. Shrink curves measure the percentage of shrinking that occurs at specific temperatures over specific time periods in a controlled environment.
Each type of film has its own performance fingerprint or shrink curve. In turn, each sleeve has unique properties that are determined by the resin and other components that make up the film, as well as pigment, and the type and amount of ink coverage. Labels printed on the incorrect film will not do the job and may result in excessive downtime. It is best to prototype your product testing various film types, running them through the actual shrink tunnels you are considering.
The first step of the sleeving process involves products running through a sleeve applicator. These machines apply the sleeves with printed graphics onto the product, including orienting the graphics on non-round containers. There are many models of machines that will apply shrink labels, at a range of line speeds from 50 up to 800 containers per minute, based on plant requirements. Depending on the application, full or empty bottles of almost any shape enter the machine on a continuous motion conveyor. A labeler precisely positions the sleeve before the containers continue downstream through a shrink tunnel.
Shrink tunnels are a key part of the process of a successful shrink sleeve label application. These are the devices that conform the label to the package surface using some type of heat source. Just like the film, selecting the correct tunnel is critical to produce the best possible final appearance of the product.
There are three main types of tunnels for shrinking labels: Convection Hot Air, Infrared Radiant, and Steam. Steam tunnels require a steam source such as a compact steam boiler. To achieve the optimal shrink results, a combination of tunnels may be necessary. Using multiple zones allows you to focus heat of differing temperatures at specific points on the package to get the desired effect.
Shrink sleeve labeling can be a boost to your product, producing bright, eye-catching packaging with great branding potential. If you’re considering shrink sleeving it’s important to work closely with the company providing your labeling machinery and shrink tunnels to ensure a final product that has the consumer appeal you are looking for. At PDC, we have over 50 years of packaging experience providing high-quality machinery and shrink tunnels for even the most challenging sleeving projects. If you would like to learn more, we invite you to contact us today at (203) 853-1516 or email@example.com.