Substrate for self-adhesive labels
Self-adhesive labels are more than just what customers see when they choose a product. Each label is made up of several components that serve a specific purpose.
While most consumers will see your label material or decorative elements applied to the surface, there is one key component that ensures your labels get where they need to go: the release liner.
What is a label peel-off liner?
To understand the role of the liner, it’s important to understand how a label is constructed. These are the four main layers of a label from top to bottom.
As you can see, the peel-off liner serves as the base layer for any label roll. This release liner is a thin sheet with a silicone layer which allows the labelling machine (applicator) to release the roll so that it can be applied to another surface. Without the protective film, also known as a liner, the labels would simply stick to each other or to something else before you could place them on the desired surface.
- Surface protection/decoration layer – lacquer, laminate.
- The sealed material – paper, plastic film.
- Adhesive layer.
- Anti-adhesion liner – a substrate that covers the adhesive.
Different types of release liner
As with the label materials, different types of release liner are available for use. Each of these carriers has different benefits depending on your applicator and other product factors. Although there are many variations, there are three main types of removable liners for self-adhesive labels.
- Calendered kraft paper
- Polycraft paper
Backing film is made from polyester to produce an extremely smooth carrier. The main advantage of Polyester release liners is that they do not break down as easily as paper liners. This durability makes Polyester release liners an excellent choice for high speed applicators.
Another advantage of Polyester release liners is that they are very moisture resistant. Beer cans, for example, tend to get wet by the time they reach the marking line, so increased resistance is a major factor for any adverse application conditions. Polyester is also thinner than conventional release papers. So a standard polyester release liner will allow you to fit more labels on a roll and take up less space during transport and storage.
Calendered anti-adhesion kraft paper film
Although film removable pads have their advantages, paper-based media is still widely used for labels in many industries. Super calendered kraft paper is usually bleached and is used very frequently as many applicators are designed to accommodate the paper.
Calendered paper means that it is polished and therefore smoother than conventional paper substrates. This smoothness and the ability to work with most applicators makes it an indispensable option for labels.
Polycraft release liners
The polycraft release liner is essentially an intermediate between polyester label face and paper labels. Polycraft is an unbleached brown paper that is slightly thicker and heavier than standard kraft paper. This extra weight and thickness is due to the fact that polycraft has a very thin layer of polypropylene bonded to the paper.
The advantage of Polycraft is that the polypropylene layer makes the material more stable and durable. These qualities help not to be afraid of exposure to moisture, but also allow companies to use paper liners. Thus, Polycraft is commonly used in wine labelling and other industries that use paper-based release liners, but still need additional protection to cope with moisture.
How to identify the right anti-tack film for labels
Although there are several self-adhesive label liners available, there are several different factors that can influence which one is best suited to your needs.
The biggest consideration is how you intend to apply these labels. The automatic label applicator reads the gap between labels so it knows when to dispense the label. Once the sensor detects the gap, the applicator will feed the label to pick up the can, bottle or any other container. However, the wrong release liner can cause problems with label dispensing.
Simply put, some applicators are not designed to read clear liners. The new label applicators are designed to use clear anti-adhesive liners, which means that polyester media should not cause problems.