Overview
ISO 15105-2:2003 - "Plastics - Film and sheeting - Determination of gas‑transmission rate - Part 2: Equal‑pressure method" specifies an equal‑pressure, isobaric test for measuring the gas‑transmission rate (GTR) of plastic films, sheetings, laminates, co‑extruded and flexible plastic‑coated materials. The method measures permeation driven by a partial‑pressure difference while keeping total pressure equal on both sides of a test specimen. Annexes give practical implementations, including oxygen measurement using a coulometric sensor and detection by gas chromatography.
Key topics and requirements
- Scope: Applies to any plastic material in film or sheet form, including laminates and coated materials.
- Test principle: Two‑chamber transmission cell; one chamber supplied with test gas, the other swept with carrier gas. Identical total pressure in both chambers; permeation occurs due to partial‑pressure difference.
- Specimen preparation:
- Representative, defect‑free specimens larger than the permeation area.
- Thickness measured per ISO 4593 at ≥5 points; report min/max/average.
- Typically use three specimens unless otherwise agreed.
- Conditioning and temperature:
- Drying or humidity conditioning as appropriate (e.g., 48 h drying or conditioned at specified RH).
- Default test temperature 23 °C ± 2 °C unless otherwise specified.
- Tabled sets of diffusion conditions include several RH options (0 %, 50 %, 60 %, 75 %, 85 % at 23 °C; also 10 °C/85 %).
- Apparatus and operation:
- Transmission cell with laminar flow on both sides; effective permeation area typically between 1 cm² and 150 cm².
- Carrier and test gas flow rates generally 5–100 ml/min; purge and stabilization required prior to measurement.
- Gasket materials must have negligible permeation relative to the specimen.
- Detection methods:
- Annex A: Coulometric sensor (recommended for oxygen‑transmission rate, OTR).
- Annex B: Gas chromatography (for other gases/mixtures).
- Reporting and precision:
- Results and test report formats given in annexes. Precision not specified (no interlaboratory data available at time of publication).
Applications and practical value
- Measurement of oxygen‑transmission rate (OTR) and other gas permeabilities for:
- Food and beverage packaging (shelf‑life and barrier quality).
- Pharmaceutical packaging (blister packs, foil laminates).
- Industrial barrier films (chemical or moisture protection).
- R&D, quality control, supplier qualification and comparative testing.
- Useful for materials selection, barrier optimization, and regulatory compliance where quantified gas‑barrier performance is required.
Who should use this standard
- Materials scientists, packaging engineers, QC/test laboratories, film and laminate manufacturers, converters, and regulatory bodies assessing barrier properties of plastic films and flexible packaging.
Related standards
- ISO 15105-1 (Differential‑pressure method) - alternative technique for GTR.
- ISO 4593 - thickness measurement for films and sheetings (referenced for specimen thickness).
Open preview (PDF)Plastics — Film and sheeting — Determination of gas-transmission rate — Part 2: Equal-pressure method
