Shrink-sleeve packaging in four easy steps
Shrink sleeve labels provide an attractive, shelf-defining low-cost way to sell the product. There are a variety of issues to consider when beginning a shrink project. But following these basic tips will help produce a nice outcome.
1. SizingFirst, determine the type of container to be labeled. The dimensions used in shrink sleeves are lay flat and cut height. The position and placement of the label will determine the cut height. Consider if the label will encompass the entire container from the neck to the base, or only encircle the base. Keep in mind that the cut height can be adjusted to go over the lid or cap of a container to incorporate an additional tamper evident seal.
2. Shrink FilmsFilm choices are made based on percentage of shrink needed, desired finish (gloss/matte), end-user requirements, application considerations and sustainability initiatives.
The four most widely-used films include polyvinyl chloride (PVC), polyethylene terephthalate (PETG and PETG LV), oriented polystyrene (OPS film), and polylactic acid (PLA film).
While these are the four most widely accepted shrink films used in sleeve labels, these are not the only film choices. New specialty and hybrid films have been introduced to the shrink market. There are films that combine the use of the PLA biopolymer with OPS and/or PETG. These films effectively reduce the amount of petroleum required while enhancing the properties of each film.
Some of the newer shrink films offer varying degrees of environmental resistance properties or provide unique decorative finishes.
3. TemplatesWhen designing a shrink-sleeve label, it is best to determine the location of the seam within the label. Seam location is relevant to orientation, graphics placement and application equipment.
Once the lay flat, cut height, seam location, and perforations are selected, the label supplier can provide a size-appropriate template. The template will allow the brand owner to visualize the label concept in a flat space. The prepress department will use the template to set up the proper printing parameters, engravings and artwork distortions.
4. Graphic PlacementThe label supplier will provide grid material in the proper size and substrate for use as a test to assure that application equipment and the heat tunnel are properly aligned and calibrated before final artwork is submitted for engraving. The grid allows the prepress department to see areas of high shrink, “no copy” sections or “hot spots” within the heat source or tunnel, and enables custom calculations to be made to achieve proper distortion.
In many containers, there are areas within the label that must shrink up to 60 to 70 percent of the original label size. That is a considerable loss of graphic surface area. Graphics departments will often block these areas within the template to indicate that any artwork located in these spaces would be highly distorted.
Heat sources come in all shapes, sizes, lengths and temperature ranges. In order to present the best label possible, the tunnel/heat source should be fingerprinted. The fingerprinting process runs several grid labels consistently through the heat source at expected heat, temperature and time parameters. The grid will highlight areas that are being hit hard by heat pockets.
A final, critical prepress function examines artwork predistortion. The test grid sleeves use to fingerprint the heat source also determines the percentage of shrink in each square inch of the label. Designers use the grid sleeve as a tool to determine the right amount of predistortion required to approximate accurate visual images and text for engravings in order to achieve a perfect container-appropriate shrink.
Every shrink sleeve project is unique. Consider all of these steps when beginning the shrink project and the result will be a package that not only looks great, but also establishes brand identity and increases market share.