Leadership through innovation
HERMA is one of the most innovative companies worldwide regarding the development of adhesives. With regard to multi-layer technology, we are the industry pioneer. Conventional adhesives thus become "problem solvers", making the use of special adhesives unnecessary in many cases. State-of-the-art coating facilities allow us to apply standard adhesives with an unparalleled smoothness. This results in considerably better safety in label applications.
What types of adhesive are available for labels?
Two families of technology have become established in the field of self-adhesive labels: acrylate-based dispersion adhesives and hot-melt adhesives. HERMA manufactures both and, for its hot-melt adhesives, uses UV-cured acrylate and rubber-based formulations.
|
Technology |
Features |
Typical application at HERMA |
|
Acrylate-based emulsion adhesive |
A wide range, from removable to extremely permanent, with good resistance to light, heat and ageing |
Standard adhesives such as 62D for general-purpose applications, 62Xpc for film labels, and 63Vst for cool, damp surfaces |
|
UV-cured, melt-adhesive, acrylate-based adhesive |
High resistance to high temperatures and ageing; many types are suitable for food contact without restriction |
62A and 62B for the chemical and automotive industries, 62F for critical ‘no-label-look’ applications, 52C for resealable labels |
|
Rubber-based hot-melt adhesive |
Extremely high initial and final adhesion, even on very difficult substrates |
95T for car tyres, rubber products, rough PE containers and very rough cardboard packaging |
All HERMA pressure-sensitive adhesives are solvent-free. Almost all standard pressure-sensitive adhesives also hold ISEGA certification for direct contact with food.
Permanent, semi-permanent or removable adhesives?
Adhesive strength is the primary selection criterion. It determines whether a label will remain permanently attached to the product, can be opened and resealed repeatedly, or can be removed without leaving any residue.
Permanent pressure-sensitive adhesives
Permanent adhesives are by far the most commonly used for labels. HERMA classifies them as standard permanent, strong permanent and extra permanent. The final bond holds until the material breaks or the fibres tear.
- Standard permanent, e.g. 62D for general-purpose applications
- Strong permanent, e.g. 63Z for critical surfaces such as cardboard packaging and ampoules
- Extra permanent, e.g. 65B for pallets, wood-based materials, rough PE containers and uneven cardboard packaging
Semi-permanent pressure-sensitive adhesives (reclosure)
Semi-permanent pressure-sensitive adhesives can initially be repositioned on most surfaces and are suitable for resealable labels. The choice of adhesive depends on whether the packaging has any springback:
- With elastic recovery: for example, rolled-up muesli packets. The pressure-sensitive adhesive must be able to cope with the elastic recovery and still be removable time and again without leaving any residue.
- Without elastic recovery: for example, tissue packets. The key factor here is ‘soft peeling’: easy, residue-free and silent removal.
Removable pressure-sensitive adhesives
Removable pressure-sensitive adhesives hold securely throughout their service life and can be peeled off afterwards without leaving any residue. How easily this can be done depends largely on the surface: on PP cups or HD-PE bottles, 42E, 42N and 42Upp come away very easily, whilst on cardboard packaging they are considerably more difficult to remove.
Migration-resistant pressure-sensitive adhesives
Many conventional packaging films do not provide an adequate barrier. Substances from the pressure-sensitive adhesive can migrate through the film. Thanks to its multi-layer technology, HERMA is able to offer its entire standard range of pressure-sensitive adhesives in a migration-proof form without compromising adhesion. This eliminates the need for a more expensive barrier film.
How to choose the right pressure-sensitive adhesive: 8 questions
1. Dispensing speed – how fast does the labelling process run?
2. Temperature during labelling – how cold is the surface at the moment of application?
3. Operating temperature – what temperatures will the label be exposed to later on?
4. Substrate properties – polar or non-polar, smooth or rough?
5. Expected adhesion – is the label intended to be permanent or removable?
6. Substrate shape – small diameters, curved or irregular 3D packaging?
7. Environmental stresses – moisture, oils, cleaning processes, weather conditions?
8. Condensation and moisture – does moisture condense on the surface?
The more non-polar and rough the surface, the colder and more humid the environment, and the shorter the contact time, the higher the tack of the pressure-sensitive adhesive must be. Please get in touch; we will cross-reference your answers with our application matrix.
What is the difference between initial adhesion (tack) and final adhesion?
Initial adhesion (tack) describes how well a label adheres immediately upon contact, with a contact time of less than 0.1 seconds. It is crucial at high dispensing speeds, in blow-on labelling and on cold or damp surfaces.
Final adhesion describes the adhesive strength that develops once the bond is fully established, typically after more than 60 seconds of contact time. It determines whether the label will hold permanently.
These two values are independent of one another. For example, 63Mps has extremely high initial adhesion combined with very high final adhesion, whilst 42E has medium initial adhesion combined with very low, removable final adhesion. You can therefore select both criteria separately using the filter below.
Storage and processing
Adhesive material materials are sensitive to environmental conditions. To ensure that the pressure-sensitive adhesive and the face material retain their properties, you should adhere to the recommended storage and processing conditions and process the material as soon as possible. We have compiled the recommended values below.