Adhesion of labels

The adhesion of labels is the capacity that a label has to adhere to a surface and remain attached to it.

Adhesion is the term that defines bonding properties. Bond strength, on the other hand, is a factor influenced by the force of attachment of the adhesive to the substrate and carrier material surface and the adhesion of the material to which the adhesive is applied. It is defined relative to a particular material, usually steel or polyethylene film.

In order to measure adhesion, the adhesive in question is applied to a strip of material that is attached to a test plate and subsequently peeled off at an angle of 90° and 180° at a constant rate. The force required for removal is recorded. Adhesion is determined by the thickness of the adhesive, the nature of the material to which it is attached, the substrate and its surface and also temperature and humidity.

This test procedure can be used to verify whether an adhesive material can be permanently attached or is peelable, enabling users to employ the right solution for specific applications. FTM 1 (FINAT test method No. 1) is the standard method of determining bond strength in such cases.

In the case of labeling, adhesion plays an important role as it guarantees that the label remains attached to the surface it was applied to despite adverse conditions (e.g. humidity, cold). However, not all labels are manufactured with adhesives that prevent the label from being peeled off. So-called removable labels are manufactured with removable adhesives, which means the label can be peeled off without damaging the surface it is attached to or leaving traces of the adhesive behind.

When it comes to the label adhesion process itself, this can be performed manually or in an automatic way with the help of a label dispenser or a label printer and applicator.