Overview
ISO 15105-2:2025 - Plastics film and sheeting: Determination of gas-transmission rate - Part 2: Equal-pressure method specifies an equal‑pressure technique to measure the gas-transmission rate (GTR) of plastic films, sheeting, laminates, co‑extrusions and flexible plastic‑coated materials. The standard defines the test principle, specimen preparation, conditioning, apparatus (transmission cell, carrier and test gases), test procedure and result expression. Normative annexes describe two detection options: coulometric sensors (Annex A, for oxygen‑transmission rate) and gas chromatography (Annex B).
Key technical topics and requirements
- Scope: Applies to any plastic material in film/sheet form, including laminates and coated materials.
- Principle: Equal total pressure in two chambers; permeant partial‑pressure difference drives diffusion from test gas chamber into carrier gas chamber; permeated gas is detected downstream.
- Specimens: Representative, free of defects, larger than the permeation area; use three specimens unless agreed otherwise; thickness measured per ISO 4593 at ≥5 points.
- Conditioning & temperature: Specimens dried 48 h or conditioned to specified RH/temperature. Default test room temperature 23 °C ± 2 °C.
- Apparatus: Gas‑transmission cell with laminar flows, effective permeation area typically 1–150 cm², suitable gaskets and flow control. Carrier and test gas flows are commonly 5–100 ml/min.
- Diffusion conditions: Table of standardized temperature/RH sets (e.g., 23 °C with 0–85 % RH; 10 °C/85 % RH).
- Detection methods:
- Coulometric sensor (Annex A) for oxygen‑transmission rate (sensor current ∝ O2 flux).
- Gas chromatography (Annex B) for broader gas types and sensitivity ranges.
- Reporting: Results expressed per annex formulas; report includes test temperature/pressure used for conversions. Precision statement: interlaboratory precision not yet established.
Practical applications
- Quality control and specification of barrier films used in food, medical, pharmaceutical and electronic packaging.
- R&D for film formulation, coatings and co‑extrusions aimed at improving gas barrier performance.
- Supplier qualification, incoming inspection and comparison of barrier materials.
- Regulatory and compliance documentation where defined gas‑transmission metrics (e.g., oxygen‑transmission rate) are required.
Who should use this standard
- Packaging engineers and materials scientists
- Test laboratories and QA/QC teams in plastics and packaging industries
- R&D teams developing barrier films, laminates and coatings
- Procurement teams specifying barrier properties in supplier contracts
Related standards
- ISO 15105 series (other parts) - see ISO website for list.
- ISO 4593 - Plastics - Film and sheeting - Determination of thickness by mechanical scanning (referenced for thickness measurement).
ISO 15105-2:2025 provides a standardized, repeatable equal‑pressure method for assessing gas permeability and barrier performance of plastic films and related products, supporting material selection, specification and regulatory needs.
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