ISO 13226:2018

Overview

ISO 13226:2018 - "Rubber - Standard reference elastomers (SREs) for characterizing the effect of liquids on vulcanized rubbers" specifies standardized vulcanized rubber test sheets used as reference materials when evaluating how test liquids and service fluids affect elastomers. The standard defines the composition, preparation, physical requirements and storage of these standard reference elastomers (SREs). It is intended for characterization and comparative testing (e.g., compatibility with fuels, oils, hydraulic fluids, coolants, refrigerants), not as formulations for end-use products.

Key topics and technical requirements

• Scope and purpose
  • Defines SREs in sheet form for liquid-effect testing on vulcanized rubbers.
  • Not intended as service-grade compound recipes.
• Material families covered
  • Annexes A–N include normative compositions and procedures for many rubbers: acrylic (ACM), acrylonitrile-butadiene (NBR variants), chlorobutyl (CIIR), chloroprene (CR), ethylene‑propylene (EPM), fluoropolymer (FKM), hydrogenated NBR (HNBR), natural rubber (NR), silicone (MQ/VMQ), etc.
• Composition and homogeneity
  • Ingredients and proportions are specified in the annexes. Mixes must be homogeneous and use recognized rubber‑quality ingredients. Carbon black/silica may be adjusted between consignments to meet property limits (adjustments must be declared).
• Preparation and curing
  • Mixing and vulcanization follow ISO 2393 and annex procedures (examples in Annex A include two‑roll mill mixing, press‑cure and post‑cure steps).
• Test sheet geometry and quality
  • Sheets shall be 2 mm ± 0.2 mm thick, free from surface defects and internal voids.
  • Definitions: a “lot” is sheets from one batch vulcanized under the same conditions; a “pressing” is sheets made in one moulding operation.
• Properties and testing
  • Sheets are characterized using referenced test methods (ISO 37 for tensile, ISO 48/ISO 7619‑1 for hardness, ISO 1817 for effect of liquids, ISO 2781 for density, ISO 23529 for conditioning). Specific property tolerances per material are given in the annexes (e.g., mass uptake in test liquid, tensile strength, elongation, hardness).
• Designation and traceability
  • Designation format: ISO 13226 SRE-A/B (A = polymer code letters, B = compound descriptor; suffix X denotes additional tests).
• Storage
  • Store in accordance with ISO 2230. Sheets must be retested or disposed after one year; if compliant, storage may be extended for a further year.

Practical applications and users

• Who uses it:
  • Materials testing laboratories, rubber manufacturers, fluid formulators (fuels, lubricants, refrigerants), OEMs, certification bodies and R&D teams.
• Typical uses:
  • Comparative compatibility testing of service fluids with vulcanized rubbers.
  • Generating reproducible data (mass/volume change, hardness, tensile changes) for fluid specifications and acceptance criteria.
  • Inter‑laboratory comparisons, quality control, and method validation for ISO 1817 liquid‑effect testing.

Related standards (referenced)

• ISO 1817 - Determination of the effect of liquids
• ISO 37 - Tensile stress‑strain properties
• ISO 48 / ISO 7619‑1 - Hardness (IRHD / Shore)
• ISO 2393 - Rubber test mixes - Preparation and mixing
• ISO 2230 - Guidelines for storage
• ISO 2781 - Density
• ISO 23529 - Preparing and conditioning test pieces

Keywords: ISO 13226, standard reference elastomers, SRE, vulcanized rubbers, liquid compatibility testing, test sheets, rubber testing, ISO standards.