Overview
EN ISO 14087:2022 - Leather - Physical and mechanical tests - Determination of bending force (ISO 14087:2022) specifies a laboratory method to measure the bending force of leather using the bar (two-point) bending method. Prepared by IULTCS in cooperation with CEN, this standard defines the test principle, required apparatus, sample preparation and the procedure to obtain comparable bending force results for quality control, specification and R&D.
Key topics and technical requirements
- Test principle: Two-point (bar) bending - the specimen is clamped in a rotating fixture and pressed against a vertical metering bar; force is measured at defined bending angles, lengths and rates.
- Apparatus requirements:
- Clamping jaws: depth (35 ± 1) mm; minimum width ≥ 30 mm; must enable parallel clamping and even pressure distribution.
- Pivot axis: located exactly at the front edge of the fixed clamp (deviation ± 0.1 mm).
- Rotation: range 1° to 91°; speed adjustable up to 10°/s with 0.1°/s resolution; max deviation limits specified.
- Metering bar and load cell: bar with sharp edge (R = 0.05 ± 0.01 mm), width ≥ 30 mm; load cell up to 10 N (optionally 1 N) with accuracy per ISO 7500-1:2018 class 2.
- Adjustability: distance between bar and pivot 0.1 mm to 50 mm (accuracy 0.1 mm); preliminary contact force adjustable to 1 mN accuracy.
- Torque control: torque wrench range 0.05–0.2 Nm (accuracy 0.01 Nm); recommended clamping torque 0.08 Nm for routine tests.
- Sampling and conditioning: follow ISO 2418 (sampling location) and ISO 2419 (sample preparation and conditioning). Thickness reference: ISO 2589.
- Measured parameters: bending force at specified bending angle, bending length and bending rate (°/s). Each specimen is tested once; multiple specimens required for compression and extension bending.
Applications and users
- Who uses it: leather technologists, quality control and testing laboratories, tanneries, footwear and upholstery manufacturers, automotive interior suppliers, product developers and standards bodies.
- Practical uses:
- Specify material performance for product design (flexibility, handle and durability).
- Compare batches or suppliers during incoming inspection and acceptance testing.
- Support R&D for finishing, coating or mechanical treatments that affect bending behavior.
- Provide objective data for conformity, procurement and supplier agreements.
Related standards
- ISO 2418 - Leather: sampling location
- ISO 2419 - Leather: sample preparation and conditioning
- ISO 2589 - Leather: determination of thickness
- ISO 7500-1:2018 - Calibration and verification of force-measuring systems
EN ISO 14087:2022 provides a reproducible, instrument-specific method to quantify leather bending force, enabling consistent evaluation across laboratories and industries where leather flexibility and mechanical behavior are critical.
