Overview
ISO 2440:2025 - Flexible and rigid cellular polymeric materials - Accelerated ageing tests - specifies laboratory procedures to reproduce the effects of natural degradation mechanisms (oxidation and hydrolysis by humidity) for cellular polymeric materials. The standard covers test planning, apparatus, conditioning, ageing procedures (dry heat and humidity), reconditioning, result calculation and reporting for materials such as open-cell latex, open- and closed-cell polyurethane foams, and closed-cell polyolefin foams.
Key topics and technical requirements
- Scope: Imitates ageing by oxidation or hydrolysis to assess changes in physical properties (e.g., elongation/tensile, compression, indentation hardness).
- Apparatus:
- Forced‑circulation oven for dry heat (temperature control ±3 °C).
- Humidity ageing equipment: autoclave, sealed glass vessel with heating, or steam apparatus (vessel volume and specimen loading limits apply).
- Ageing regimes:
- Dry heat temperatures by material:
- Polyolefin: 70 °C
- Latex: 70 °C or 100 °C
- Polyurethane: 80 °C, 125 °C, or 140 °C (140 °C is non‑standard and has limitations)
- Duration options: 16 h, 22 h, 72 h, 96 h, 168 h, 240 h or multiples of 168 h (tolerance +/−5 %, max ±4 h).
- Humidity: 100 % relative humidity or saturated steam. Polyurethane humidity options include 85 °C for 20 h, 105 °C for 3 h, and 120 °C for 5 h (with ±3 °C tolerance).
- Specimen preparation and conditioning:
- Condition test pieces at least 16 h in specified atmospheres (ISO 23529): 23 °C ±2 °C, 50 % ±5 % RH or 27 °C ±2 °C, 65 % ±5 % RH; reference testing recommended ≥7 days after manufacture.
- Materials should not be tested earlier than 72 h after manufacture unless stability criteria are met.
- Reconditioning:
- Humidity‑aged specimens: dry at 70 °C ±3 °C for 3 h per 25 mm thickness (minimum 3 h), then recondition before testing.
- Tests should be performed in repeat conditions (same lab, equipment, operator preferred).
- Results and quality:
- Includes calculation of percentage change, validity checks (Annex A), and precision data (Annex B). Clause additions in this edition include method verification and test reporting requirements.
Applications and who uses it
- Product manufacturers (foams, cushioning, insulation) use ISO 2440:2025 for R&D, formulation screening, and quality control.
- Testing laboratories and certification bodies implement these accelerated ageing tests to evaluate long‑term durability and batch consistency.
- Material scientists, product designers, and failure analysts apply the standard to compare material grades or investigate interactions in composite constructions.
- Useful for assessing hydrolytic resistance of polyurethanes and thermal/oxidative stability of latex and polyolefin foams.
Related standards
- ISO 23529 - referenced for specimen preparation and conditioning procedures.
- The document was prepared by ISO/TC 45 in collaboration with CEN/TC 249 (Vienna Agreement).
Keywords: ISO 2440:2025, accelerated ageing tests, cellular polymeric materials, polyurethane foam, polyolefin, latex, dry heat ageing, humidity ageing, test conditioning, hydrolysis, oxidation.
