ISO 4097:2020

Overview

ISO 4097:2020 - Rubber, ethylene‑propylene‑diene (EPDM) - Evaluation procedure defines standardized laboratory methods for assessing raw EPDM rubber. The standard specifies sampling and sample preparation, physical and chemical tests on raw rubber (Mooney viscosity, volatile matter, ash), standard test formulations, mixing and processing procedures, and methods for evaluating vulcanization behavior and tensile properties of vulcanized test mixes. It covers both neat and oil‑extended EPDM types.

Key topics and technical requirements

• Sampling and preparation
  • Laboratory sampling (≈ 1.5 kg) and test portion preparation in accordance with ISO 1795.
• Raw rubber characterization
  • Mooney viscosity determination per ISO 289‑1 (reported as ML(1+4) at 125 °C unless otherwise agreed).
  • Volatile matter and ash measured per ISO 248‑1/248‑2 and ISO 247‑1/247‑2 respectively.
• Standard test formulations
  • Six predefined formulations for different EPDM types, including non‑oil and oil‑extended grades (formulations account for oil content and ethylene content).
• Mixing and processing methods
  • Four accepted mixing procedures: Method A1 (single‑stage LIM) - preferred; A2 and A3 (two‑stage options); and Method B (mill mixing) for labs without a laboratory internal mixer (LIM).
  • LIM parameters, machine conditioning, batch temperatures and post‑mix mill‑sheeting requirements are specified to ensure reproducible mixes.
• Vulcanization and cure testing
  • Use of curemeters to evaluate vulcanization characteristics - both oscillating‑disc and rotorless curemeters (ISO 6502 series referenced).
• Physical testing of vulcanizates
  • Tensile stress‑strain testing and conditioning procedures for test pieces (ISO 37, ISO 23529).
• Reporting and precision
  • Prescribed test report items and annexed precision information to support interlaboratory comparability.

Applications and users

ISO 4097:2020 is essential for:

• Rubber compounders and formulation engineers validating EPDM batches.
• QC/QA laboratories in manufacturers of seals, hoses, roofing membranes, automotive weatherstrips, and other EPDM products.
• Test laboratories and R&D groups performing comparative evaluations of EPDM grades (including oil‑extended types).
• Procurement and specification teams that require standardized evaluation criteria for supplier assessment.

Practical benefits include improved comparability of vulcanization data, reproducible mixing procedures, and consistent reporting of key properties such as Mooney viscosity and cure behavior.

Related standards

Key normative references include:

• ISO 37, ISO 1795, ISO 2393, ISO 23529, ISO 289‑1, ISO 248‑1/‑2, ISO 247‑1/‑2, ISO 6502‑1/‑2.

Keywords: ISO 4097:2020, EPDM evaluation procedure, vulcanization testing, Mooney viscosity, curemeter, test formulations, LIM mixing, oil‑extended EPDM.