ISO 9073-4:2021

Overview

ISO 9073-4:2021 specifies a standardized laboratory test method for determining the tear resistance of nonwoven materials using the trapezoid (trapeze) procedure. The document defines specimen preparation, conditioning, test equipment and operating parameters, data treatment and minimum reporting information. It applies to nonwovens and is intended for consistent, repeatable measurement of tear resistance (tear force) in both machine and cross directions.

Keywords: ISO 9073-4:2021, nonwovens tear resistance, trapezoid procedure, tear strength testing, nonwovens test methods

Key topics and technical requirements

• Test principle: mark an isosceles trapezoid on a specimen, clamp the non-parallel sides, initiate a 15 mm starter cut and propagate a tear across the width while recording force. The maximum force for each specimen is taken as the individual result.
• Specimens: cut (75 ± 1) mm × (150 ± 2) mm with an isosceles trapezoid and a 15 mm central starter cut; typically 5 specimens in the machine and 5 in the cross direction.
• Conditioning: follow ISO 139 normal atmosphere; condition at least 24 h relaxed unless testing wet specimens.
• Wet testing: immerse specimens 1 h in Type 3 laboratory water (ISO 3696) at 20 °C ± 2 °C; for hard-to-wet materials, use an aqueous solution with up to 1 g/L non‑ionic wetting agent.
• Test machine: use a constant-rate-of-extension (CRE) tensile tester set to 100 ± 10 mm/min and 25 ± 1 mm gauge length; machine force accuracy to class 1 per ISO 7500-1 and data acquisition frequency ≥ 8 Hz.
• Result calculation: round individual maximum forces to 0.1 N, then report the arithmetic mean (separately for machine and cross directions); include coefficient of variation when applicable.
• Reporting: reports must reference ISO 9073-4:2021 and include material ID, conditioning, mean results (machine/cross), wet results if applicable, number of specimens and rejected tests, deviations and date.

Practical applications and users

ISO 9073-4 is used by:

• Textile and nonwoven manufacturers for product development and quality control.
• Independent test laboratories and conformity assessment bodies.
• R&D groups evaluating material durability (e.g., wipes, medical nonwovens, filtration media, geotextiles, hygiene products).
• Procurement and specification writers who require objective tear-resistance data for material selection.

The trapezoid procedure provides a reproducible measure of tear propagation resistance relevant to service performance and comparative material specification.

Related standards

• ISO 139 - Conditioning atmospheres for textiles
• ISO 186 - Sampling for paper/cardboard (sampling principles referenced)
• ISO 3696 - Water for laboratory use (Type 3)
• ISO 7500-1 - Calibration/verification of tensile testing machines
• ISO 10012 - Measurement management systems

Use ISO 9073-4:2021 when you need a standardized, defensible test for nonwoven tear resistance using the trapezoid method.