ISO 527-2:2025

Overview

ISO 527-2:2025 - "Plastics - Determination of tensile properties - Part 2: Test conditions for moulding and extrusion plastics" defines standardized test conditions for measuring the tensile properties of moulding and extrusion plastics. Built on the general principles of ISO 527-1, this third edition specifies specimen types, apparatus (including extensometer and gauge length), test speeds for tensile modulus, specimen preparation and conditioning, and reporting requirements for rigid and semi‑rigid thermoplastics, thermosets and thermotropic liquid crystal polymers.

Key topics and requirements

• Scope and materials: Applies to rigid and semi‑rigid thermoplastics and thermosets (including filled/reinforced compounds, excluding textile fibres) and thermotropic liquid crystal polymers. Not suitable for flexible films < 1 mm (see ISO 527-3) or rigid cellular materials (see ISO 1926).
• Specimen types: Preferential use of dumb‑bell-shaped multipurpose specimens Type A1 (injection-moulded) and A2 (machined) per ISO 20753. Small/reduced-scale specimens are permitted (Annex A) when justified.
• Gauge length and extensometer: Preferred gauge length 75 mm for Type A1/A2; 50 mm acceptable for quality control. Extensometer and data recording requirements follow ISO 527-1; longer gauge lengths improve modulus accuracy.
• Test speed and tensile modulus: For tensile modulus measurement with A1/A2 specimens, the test speed is 1 mm/min, corresponding to approximately 1 %/min strain rate.
• Specimen preparation and conditioning: Specimens shall be moulded or machined in accordance with relevant standards (ISO 293, 294-1, 295, 2818, 10724-1). Strict control of preparation, surface quality and thickness is required; avoid unnecessary machining of reinforced materials.
• Anisotropy: Directional effects from injection or extrusion flow must be considered by machining specimens parallel and normal to flow.
• Reporting and precision: Test report must reference ISO 527-2:2025 and include details listed in ISO 527-1; precision information is provided in Annex B.

Applications and who uses it

ISO 527-2:2025 is used by:

• Quality control and testing laboratories performing tensile tests on moulded or extruded plastic parts.
• Plastics manufacturers and compounders validating mechanical performance of thermoplastics and thermosets.
• R&D and product development teams comparing tensile modulus, strength and elongation for material selection.
• Certification bodies and regulatory compliance teams requiring standardized tensile property data. Practical uses include material specifications, comparative testing, production acceptance testing, and failure analysis.

Related standards

• ISO 527-1:2019 (general principles)
• ISO 527-3 (films and sheets)
• ISO 527-4 / ISO 527-5 (other specimen types / reinforcements)
• ISO 20753 (test specimen dimensions)
• ISO 293, ISO 294-1, ISO 295, ISO 2818, ISO 10724-1 (moulding and specimen preparation)
• ISO 1926 (rigid cellular materials)

Using ISO 527-2:2025 ensures consistent, comparable tensile property data for moulding and extrusion plastics across testing programs and product lifecycles.