Adhesive and Release Liner Specifications for Labels

Labels are small but technically demanding. A label that lifts in a fridge, wrinkles on a curved bottle or refuses to peel from its liner has failed, even if the print is perfect. Performance comes from three decisions: the face material, the adhesive and the release liner.

The face material

Paper faces are economical and print well, suited to dry, short-life applications such as cartons and shipping labels. Film faces, including PP and PE, resist water, oil and tearing and suit bath and body products, chilled goods and outdoor use. The face also decides whether the label can be recycled with the pack, which matters for paper packaging.

Adhesive types

• Permanent adhesives bond firmly and are the default for most retail labels
• Removable adhesives peel cleanly, useful for promotions and resealable closures
• Freezer-grade adhesives stay tacky at low temperature instead of turning brittle
• High-tack adhesives grip rough, recycled or curved surfaces
• Wash-off adhesives release in a washing process, used for returnable containers

The right choice depends on the surface, the temperature and how long the label must stay.

Surface and application conditions

Adhesion depends on surface energy, texture and cleanliness. Glass and smooth plastics accept most adhesives, while recycled board, powder-coated metal and low-energy plastics need a higher-tack product. Application temperature also matters: a label applied cold may not wet out properly, so a freezer-grade adhesive is chosen when the pack is labelled before chilling.

The release liner

The liner carries the label until it is applied and is then discarded. Glassine liners are thin and smooth and work well for hand application and tight rolls. PET liners resist moisture and are stable across temperature changes, which suits automatic lines and humid conditions. Liner choice also affects dispensing speed, because stiffness and release force change how the label separates.

Testing before a full run

• Apply the label to the actual container surface, not a similar one
• Test at the storage and use temperatures of the product
• Check adhesion after 24 hours, when bonding is complete
• Run a roll on the applicator to confirm release and dispensing
• For food contact, confirm that the adhesive and face are suitable for the intended use

Common failure modes

Labels lifting at the edge usually point to a low-tack adhesive or a contaminated surface. Wrinkling on curved bottles points to a face stock that is too stiff. Missing labels on an automatic line point to the wrong liner or a release force that is too high. Each symptom maps back to one of the three specification decisions.

Summary

Specify the face, the adhesive and the liner together, against the real container and the real temperature. A short test with the actual materials prevents most label failures and is far cheaper than reworking a finished run.

Key figures and tolerances

• Adhesive coat weight: 18–25 g/m² for permanent acrylic on paper, 20–30 g/m² on film faces.
• Peel adhesion at 180 °: 4–10 N/25 mm on stainless steel for permanent grades, 1–4 N/25 mm for removable (FINAT FTM 1 / PSTC-101).
• Liner release force: 0.05–0.30 N/50 mm at low speed (FINAT FTM 3).
• Minimum application temperature: 5–10 °C for standard permanent acrylics, down to −20 °C for freezer grades.
• Face stock caliper: paper 60–90 µm (ISO 534), PP film 50–80 µm, PET 36–50 µm.
• Surface energy: 38 dyn/cm or higher for reliable bonding on plastic containers; use a primer below that.
• Ranges are typical industry values for the material or process named and are not a specification; confirm the exact value, the current edition of each standard and the applicable grade with your supplier or test laboratory.