{"id":5600,"date":"2026-08-07T13:43:01","date_gmt":"2026-08-07T11:43:01","guid":{"rendered":"https:\/\/www.alsace-techniques-etiquetage.fr\/?p=5600"},"modified":"2026-08-07T13:44:32","modified_gmt":"2026-08-07T11:44:32","slug":"self-adhesive-label-layers","status":"publish","type":"post","link":"https:\/\/www.alsace-techniques-etiquetage.fr\/en\/labels\/self-adhesive-label-layers\/","title":{"rendered":"What is a self-adhesive label made of? The 7 layers, from varnish to liner"},"content":{"rendered":"
\n

An industrial self-adhesive label is often pictured as a sheet of paper with glue on the back. It is in fact a stack of layers, seven of them in a printed and protected construction. From the visible surface down to the product: varnish or laminate, printed layer, top coat, face stock, adhesive, silicone release coating, liner. Five of those layers stay on the product, two go in the bin the moment the label is applied.<\/p>\n

Thinking layer by layer has a practical benefit. When a label lifts off, when a barcode will not scan, or when print wipes away during cleaning, the cause almost always sits in one single layer rather than in the label as a whole.<\/p>\n

The diagram below shows the four structural layers of a standard paper label. The ink, the top coat and the silicone are not included: at this scale, they would not be visible.<\/p>\n

\n
\"Exploded

The four structural layers of a standard paper label. The ink, the top coat and the silicone coating are measured in microns and do not appear at this scale, which brings the total to seven.<\/p><\/div>\n<\/div>\n

1. Varnish or laminate<\/h2>\n

This layer is sacrificial. It is added when the print alone would not survive its environment. Varnish, usually UV cured, is applied at a few microns: it protects against light abrasion and sets the finish, matt or gloss. Laminate goes further. It is a PET or PP film of 12 to 25 \u00b5m bonded over the print, and it moves the label into a different resistance class: repeated cleaning, solvents, outdoor exposure. On a rating plate expected to last ten years, the laminate is what sets the real service life.<\/p>\n

One point to keep in mind if the label carries a code: gloss varnish creates specular reflections that interfere with scanning. Matt is the better choice.<\/p>\n

2. The printed layer<\/h2>\n

Ink film thickness varies widely between processes, and it drives opacity as much as UV resistance. Flexography deposits a few microns and is economical at volume. Digital printing allows short runs and personalisation, with an opaque white that often needs several passes. Screen printing reaches several tens of microns: full opacity over dark backgrounds, and UV resistance the other processes do not achieve. Our printing page<\/a> <\/span>covers these three processes in detail.<\/p>\n

<\/p>\n

<\/p>\n

\"Multi-colour

Technical labels printed at our plant in Val-de-Moder, Alsace. The process is chosen according to volume and durability requirements.<\/p><\/div>\n

Two cases change the architecture of the label. With direct thermal, there is no ink layer at all: colour develops in a heat-sensitive coating within the face stock, and the darkening caused by heat is irreversible. With thermal transfer, the ink comes from the ribbon, so durability depends on the ribbon and face stock pairing.<\/p>\n

3. The top coat<\/h2>\n

The top coat is rarely mentioned in specifications, and it explains a good share of quality complaints. It sits between the face stock and the ink, and it makes the surface receptive.<\/p>\n

An untreated plastic film has too low a surface energy to anchor ink. It has to be activated, by corona treatment or by a primer, to get past roughly 38 dyne\/cm. On paper, the top coat controls penetration instead: without it, ink spreads into the fibre and line edges lose the definition a Data Matrix needs in order to grade.<\/p>\n

The case comes up often: a generic white film ordered for print produced in house on a thermal transfer printer. The print comes off at the first touch of a finger, and the ribbon gets the blame when the problem lies further upstream.<\/p>\n

4. The face stock<\/h2>\n

The face stock is the printable carrier. It sets appearance, stiffness, conformability and temperature resistance.<\/p>\n

\n\n\n\n\n\n\n\n\n\n
Face stock<\/th>\nWhat it brings<\/th>\nLimit<\/th>\n<\/tr>\n<\/thead>\n
Paper<\/td>\nCost, printability, recyclability<\/td>\nMoisture, grease<\/td>\n<\/tr>\n
Polypropylene<\/td>\nGood balance of durability and price<\/td>\nDeforms above roughly 100 \u00b0C<\/td>\n<\/tr>\n
Polyethylene<\/td>\nHighly conformable<\/td>\nLow dimensional stability<\/td>\n<\/tr>\n
PET<\/td>\nDimensional stability, temperature<\/td>\nPoorly conformable, elastic memory<\/td>\n<\/tr>\n
Polyimide<\/td>\nVery high temperatures, electronics<\/td>\nCost<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

<\/p>\n

Film face stocks usually run from 50 to 100 \u00b5m, and that has direct consequences: the stiffer the face stock, the more permanent peel stress it exerts on a curved surface, and the more the label lifts at the corners.<\/p>\n

5. The adhesive<\/h2>\n

Choosing an adhesive comes down to three parameters, independent of each other.<\/p>\n

Chemistry first. Acrylic performs better over time, under UV and at temperature, with a lower initial tack. Rubber bonds immediately and aggressively, including on low surface energy substrates, but it ages poorly. Silicone remains the only option on PTFE or above 200 \u00b0C.<\/p>\n

Permanence next: permanent, removable, repositionable, wash-off. That last family is gaining ground now that packaging recyclability has become a regulatory criterion.<\/p>\n

Thickness last, the parameter most often forgotten. A standard adhesive sits around 20 g\/m\u00b2. On a rough or powder-coated surface, it bridges the peaks of the profile and the real contact area drops. The answer is then a higher coat weight, or a foam laminate.<\/p>\n

<\/p>\n

6. The silicone release coating<\/h2>\n

Between the adhesive and the liner sits a cured silicone coating of around 1 g\/m\u00b2. It is invisible, it does not stay on the product, and it still governs release force, meaning the effort needed to separate the label from its liner. If it is too high, the automatic applicator misplaces or tears the label; if it is too low, labels detach on their own inside the roll. On double-sided constructions, two different release forces are used deliberately to control the order in which the liners come off.<\/p>\n

7. The liner<\/h2>\n

<\/p>\n

The liner is not part of the applied label, but it governs die-cutting, rewinding and application. Glassine, a calendered siliconised paper, is the common choice: economical and well suited to hand application. PET liner, 23 to 36 \u00b5m, is thinner and far more tear resistant, which makes it the choice for high line speeds and small labels, where a web break stops the line.<\/p>\n

The liner also means the roll winding direction has to be specified at the order stage. Many requests for quotation leave this out, even though it is essential for automated application.<\/p>\n

Which layer to review for which symptom<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n
Symptom<\/th>\nFirst layer to review<\/th>\n<\/tr>\n<\/thead>\n
The label lifts off or curls at the corners<\/td>\nAdhesive (chemistry, thickness), face stock (stiffness)<\/td>\n<\/tr>\n
Print wipes off during cleaning<\/td>\nVarnish or laminate<\/td>\n<\/tr>\n
Print comes off under friction<\/td>\nTop coat, face stock receptivity<\/td>\n<\/tr>\n
The barcode will not scan<\/td>\nVarnish (reflections), top coat (definition), contrast<\/td>\n<\/tr>\n
The applicator misplaces or tears labels<\/td>\nSilicone (release force), liner<\/td>\n<\/tr>\n
The label distorts under heat<\/td>\nFace stock, adhesive<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Frequently asked questions<\/h2>\n
\n

How many layers does a self-adhesive label have?<\/h3>\n

Seven in a printed and protected construction: varnish or laminate, ink, top coat, face stock, adhesive, silicone and liner. An unprinted label may have only three: face stock, adhesive and liner.<\/p>\n

Is the liner part of the label?<\/h3>\n

Not in the sense of the applied label. It is part of the laminate as supplied and is removed on application, but it remains decisive for die-cutting and for automatic application.<\/p>\n

How thick is a self-adhesive label in total?<\/h3>\n

Excluding the liner, a common laminate falls between 70 and 150 \u00b5m. With a thick face stock, a laminate and a heavy adhesive coating, it goes beyond 250 \u00b5m. Foam constructions are measured in millimetres.<\/p>\n

Does a direct thermal label have an ink layer?<\/h3>\n

No. Colour develops in a heat-sensitive coating within the face stock, which is why direct thermal print darkens with heat and fades under light.<\/p>\n<\/div>\n

\n

Specifying a label layer by layer<\/h2>\n
\"Custom

Labels produced to specification at our plant. Every laminate is defined constraint by constraint, layer by layer.<\/p><\/div>\n

A useful specification states the substrate and its surface condition, the expected service life, the temperature range, the cleaning agents, the application method and the annual volume. With those inputs, the construction follows. Describe the constraint rather than the reference: the constraint is what determines the layers.<\/p>\n

Describe your constraint and request a quote<\/a><\/p>\n<\/div>\n<\/div>\n