Overview
EN ISO 11339:2022 (ISO 11339:2022) defines a laboratory T‑peel test for determining the peel resistance of adhesives in flexible-to-flexible bonded assemblies. Approved by CEN in February 2022, it supersedes EN ISO 11339:2010 and updates terminology (replacing “peel strength” with peel resistance) and references. The standard specifies specimen preparation, apparatus, test procedure and result reporting but explicitly states that the test does not provide design information.
Key topics and requirements
- Scope and principle: Measures force per unit width required to peel two flexible adherends from a T‑shaped specimen by separating the unbonded ends at a steady rate.
- Specimens:
- Preferred specimen width: 25 mm (other widths allowed if reported).
- Minimum number of specimens: 5.
- Preferred adherend thickness examples: steel 0.5 mm ±0.02 mm, aluminium 0.7 mm or 0.5 mm ±0.02 mm (where applicable).
- Specimens must be cut without damaging the bond and bent to form a T shape before testing.
- Apparatus and accuracy:
- Tensile-testing machine with self‑aligning grips; force measurement accuracy ±2%.
- Thickness measuring device with accuracy ±0.01 mm.
- Grips should engage outer 25 mm of unbonded ends and align automatically under load.
- Procedure:
- Condition specimens per ISO 291.
- Typical crosshead/separation rates: 100 mm/min (metals preferred) and 10 mm/min for other adherends (note: separation rate choice must be reported).
- Record force vs grip separation; continue until at least 150 mm of bonded length is separated.
- Results and reporting:
- For about 100 mm of peeling (excluding first and last 25 mm) determine average, maximum and minimum peeling force.
- Report adhesive-layer thickness, specimen preparation, surface treatment (per ISO 17212), and failure type (per ISO 10365).
- Include test atmosphere and other test conditions.
Practical applications
- Quality control and batch verification of adhesive bonds.
- Comparative performance testing of adhesive formulations on flexible substrates.
- Failure-mode classification and forensic analysis of bonded assemblies.
- R&D and materials selection for packaging, automotive trim, flexible electronics, textiles and other industries using flexible adherends.
Who uses this standard
- Adhesive manufacturers and formulators
- Accredited test laboratories and QA departments
- Materials engineers and R&D teams
- Procurement/specification writers needing repeatable adhesive performance data
Related standards
- ISO 291 - conditioning and testing atmospheres
- ISO 10365 - designation of main failure patterns
- ISO 17212 - surface preparation guidelines for adhesive bonding
Keywords: EN ISO 11339:2022, ISO 11339, T‑peel test, peel resistance, adhesives testing, flexible-to-flexible bonded assemblies, adhesive test method.