Overview
EN ISO 6383-2:2004 (Elmendorf method) defines a standardized pendulum test to measure the tear resistance of thin, flexible plastics film and sheeting. The method quantifies the force required to propagate a tear from a specified precut slit using the energy absorbed by an Elmendorf pendulum. It is intended for production control, acceptance testing and material comparison of flexible plastics (for example flexible PVC and polyolefins) where results are reproducible within the tested thickness range.
Key Topics
- Scope and materials: Applicable to thin flexible films and sheeting. Not generally suitable for more rigid materials (rigid PVC, nylon, polyester) or where extreme elongation causes poor reproducibility.
- Apparatus: Elmendorf pendulum tester with calibrated scale, means to hold and release the pendulum, and optional augmenting masses to extend capacity. The pendulum and jaws must be accurately aligned and periodically calibrated to account for friction and windage.
- Test specimens: Preferred constant-radius specimen (better reproducibility) or rectangular specimen. A precut slit of 20 ± 0.5 mm is specified. Careful cutting to avoid nicks is essential.
- Machine settings: Jaws separation when pendulum is in initial position is 2.8 ± 0.3 mm; jaw clamping surfaces have specified minimum dimensions. The pendulum geometry (axis distance and angle) is defined to ensure consistent energy transfer.
- Conditioning: Specimens should be conditioned and tested in the standard atmosphere (23/50) as specified in ISO 291, unless material is known to be humidity-insensitive.
- Procedure and reporting: Typically five specimens per principal direction are tested (or groups for low-strength films). Report the tear resistance (newtons) for each specimen, arithmetic mean, standard deviation if required, specimen identification, thickness and conditioning atmosphere.
Applications
- Quality control and production monitoring of plastic film and sheeting.
- Acceptance testing for supplied rolls and finished products where tear resistance is a contract parameter.
- Comparative testing for material selection and formulation changes (e.g., polymer type, plasticizer, additives).
- Laboratory verification of manufacturing consistency and shelf performance indicators.
Related Standards
- ISO 291 - Standard atmospheres for conditioning and testing (referenced for conditioning).
- ISO 4591 / ISO 4593 - Methods for determining thickness of film and sheeting (gravimetric and mechanical scanning methods are referenced for thickness measurement).
Practical value: EN ISO 6383-2 provides a repeatable, calibrated method that yields actionable tear-resistance data for production acceptance and comparative material evaluation. Proper specimen preparation, machine calibration and conditioning are critical to reliable results.
