Understanding The Construction Of Self-Adhesive Labels

Self-adhesive labels are already incredibly versatile. However, with advances in technology, more can be done with the self-adhesive label than ever before. Today’s labels are available in a wide variety of formats, each with their own set of advantages. However, all self-adhesive labels still contain the same components: a facestock, a film and a liner.

The Right Facestock is Crucial

The facestock is the material which is bonded to the adhesive layer of inkjet labels, and is the functional portion of the label. Without the right facestock and adhesive, a label will not be suited to its application. A wide range of facestocks is available.

Uncoated Facestock

Vellum, or uncoated paper, is the simplest facestock available. It is also the most cost-effective. Ideal for most general purpose applications, vellum has a non-gloss finish and is porous, making it suitable for water-based adhesives.

Coated Facestock

Coated paper contains a layer of specialised coating for the purpose of improving a label’s appearance and performance properties. The heavier the layer of coating, the smoother the label’s finish and the higher its rigidity. Coated papers are ideal for multi-coloured labels as well as those labels which will be used in dry environments.

Coated facestocks are available in three varieties; which are – light weight, high gloss and primecoat. The lightweight variety has a semi-gloss appearance and increased flexibility. The high gloss variety features a thicker and shinier coating and is both rigid and water resistant. The primecoat variety has a thin coating and smooth, semi-gloss feel and appearance.

Thermal Facestock

Thermal facestock is coated with heat-sensitive chemicals which require the application of heat-activated ink from the ribbon of a thermal transfer printer to be transferred to the substrate. Examples where thermal facestock is used include sales receipts, food labels and industrial bar codes. This facestock allows quality barcodes to be produced for a low cost whilst being able to be printed relatively quickly.

Thermal facestock is available in two qualities; coated and uncoated. The coated variety, designed to protect the label from solvents, grease, fats and condensation, may have coating on both sides and is used primarily on frozen products, as well as on pre-packed meats and cheese. The uncoated variety is used for situations where short-term and well-controlled labelling is required, and is usually seen on fresh produce.

Label Films

The film on a label is that opaque or transparent material made from a wide variety of plastics that can appear on a range of commercially-available products including shampoo bottles and plastic food containers. Three kinds of label film exist: polyester film (PET), polypropylene film (PP) and polyethylene film (PE).

Polyester film is used on labels for the automotive, security and medical industry, to name but a few. It can resist heat up to 150°C, as well as resist moisture and chemicals. PP film, derived from petroleum is seen on rigid bottles and packaging like beverages and spirits. It offers high clarity and higher strength than its PE counterpart. PE film is the most environmentally-friendly of the three. It has very low stiffness, and can resist both moisture and UV light making it ideal for personal care products as well as industrial labelling.

Release Liners

The release liners on labels are largely paper-based, and must be smooth and dense in order to provide a uniform surface. Glassine liners are translucent and very strong. Resistant to air and water, glassine liners can be found on virtually all roll labels, and are used in special applications as well as photocell and automatic dispensing systems. Kraft liners are coated with clay on one side for added rigidity. This paper is made from unbleached wood pulp, and typically used for manual dispensing of labels. It is also used with heavy facestocks and on sticker sheets.

In understanding the differences between facestocks, films and liners, a more informed choice about labels products for your particular application can be made.