The smooth removal of self-adhesive labels from backing material is made possible by a release layer made of silicone. With its DEHESIVE® SFX line, WACKER now offers the paper and film industry four new silicone coatings that can master the balancing act between cost savings and outstanding processing properties.
Multi-roll applicator systems are normally used to coat paper with silicone. For this purpose, the DEHESIVE® mixture is filled into the gap between the first and second rolls from where it is applied over several rolls to the paper in an even layer about 1 micrometer thick.
Whether pasta sauce in a jar, shampoo in a plastic bottle or yogurt in a plastic cup – if there are consumer goods inside, there are usually pressure-sensitive-adhesive (PSA) labels on the outside. Adhesive bandages, adhesive tapes and sticky notes also rely on the self-adhesive technique – and thus simplify everyday life for consumers. Before a self-adhesive label is applied to a container, however, it is stored on a release paper or film. Removing the label from this backing material should be as easy as possible – without leaving residue and without tearing or creasing. To ensure smooth removal, release papers and films are generally coated with a one-micrometer-thin release layer made of silicone. That’s why, globally, 42,000 square kilometers of backing material – an area the size of the Netherlands – were treated with silicone in 2014.
A typical PSA label is created as follows: In the first step, manufacturers apply the liquid silicone release agent to the base paper or film – this is often a compressed paper. The pressure-sensitive adhesive is applied to it, followed by the face stock. Together, the release liner and the adhesive material form the adhesive laminate. This label laminate is rolled up and cut lengthways to the desired width. Machines then die-cut the labels into the desired shape, without damaging the release liner underneath. Prior to labeling, the paper lattice between the individual labels – the matrix – is pulled off.
How a PSA Label Works
PSA labels generally consist of two layers: the release paper or film and an adhesive material – the actual label. In the first step, the backing material – often a compressed paper (gray) – is coated with a liquid silicone release agent (yellow). Then the pressure-sensitive adhesive (pink) is applied, followed by the face stock (light blue). Together, the release liner and the face stock form the adhesive laminate. This label laminate is rolled up and cut lengthways to the desired width. The labels are then die-cut into the desired shape, without damaging the underlying release liner. Prior to labeling, the paper lattice between the individual labels – the matrix – is pulled off.