ISO 21760-1:2019

Overview

ISO 21760-1:2019 specifies adhesive film preparation methods for determining the water vapour transmission rate (WVTR) of adhesives used in organic electronic devices (for example, organic light‑emitting diodes, OLEDs). The standard defines how to prepare non‑self‑supporting adhesive films coated on plastic substrates and describes the experimental approach needed to obtain rapid WVTR measurements across a wide range of permeation rates.

Key topics and technical requirements

• Scope: Six measurement methods for WVTR of adhesive films coated on plastic substrates; aimed at adhesives/seal materials for organic electronic devices.
• Specimens: Non‑self‑supporting adhesive films are applied to plastic substrates (e.g., PET). Substrate thickness options specified: 12, 25, 50 or 100 µm.
• Adhesive thickness: Total dry film thickness range 3 µm to 60 µm (recommended values: 5, 10, 20, 50 µm).
• Coating methods described: Annex A (spin coating), Annex B (blade coating), Annex C (spray coating).
• Conditioning: Specimens conditioned at 23 ± 2 °C and 50 ± 5 % RH unless otherwise agreed.
• Number of specimens: Typically three specimens per test.
• Thickness determination: Adhesive thickness may be determined by calculation (from application rate and non‑volatile content per ISO 3233‑1) or by optical/mechanical methods (ISO 4593, ISO 2808).
• Test principle: WVTR of the adhesive cannot be measured directly for non‑self‑supporting films; measure WVTR of substrate+adhesive and substrate alone, then calculate the adhesive WVTR by accounting for the substrate contribution (reciprocal subtraction approach).
• Measurement methods (ISO 15106 series): Six detection techniques are referenced - humidity sensor, infrared, electrolytic, gas chromatography, pressure sensor, and atmospheric pressure ionization mass spectrometry - with guidance on method selection by sensitivity, WVTR magnitude, and specimen fragility.

Applications and users

• Primary users: Adhesive manufacturers, coating/process engineers, quality control and test laboratories, and device integrators in the organic electronics and flexible electronics industries.
• Practical applications:
  • Verifying barrier/sealant performance for OLEDs and other water‑sensitive organic electronic devices.
  • Comparing coating methods (spin, blade, spray) and formulation choices (resins, multi‑layer films, desiccant‑loaded layers).
  • Supporting materials selection, process optimization, reliability testing, and supplier qualification for low‑WVTR sealing solutions.

Related standards

• ISO 15106 (all parts) - WVTR measurement methods (1 to 6)
• ISO 4593, ISO 2808 - thickness determination of films/sheets
• ISO 3233‑1 - determination of non‑volatile content (for dry film thickness calculation)

Keywords: ISO 21760-1:2019, WVTR, water vapour transmission rate, adhesives for organic electronic devices, adhesive film preparation, spin coating, blade coating, spray coating, PET substrate, OLED barrier testing.