ISO 21760-2:2019

Overview - ISO 21760-2:2019 (Adhesives for organic electronic devices)

ISO 21760-2:2019 specifies edge seal methods to determine the water vapour transmission rate (WVTR) through the cross-section of adhesives used as edge seals in organic electronic devices (for example, OLEDs and organic photovoltaic cells). The standard defines a water transmission cell (lid, base plate and adhesive test specimen) and describes four rapid measurement routes that cover a wide range of water vapour transmission rates.

Key topics and technical requirements

• Purpose: Measure WVTR through the adhesive cross-section used for edge sealing flexible organic electronic devices. WVTR unit: g/(m²·24 h).
• Four measurement methods: The test uses one of the methods from ISO 15106 series:
  • ISO 15106-3 (electrolytic detection sensor)
  • ISO 15106-5 (pressure sensor)
  • ISO 15106-6 (atmospheric pressure ionization mass spectrometer)
  • ISO 15106-7 (calcium corrosion method)
• Water transmission cell: Composed of a lid (upper substrate), base plate (bottom substrate) and adhesive specimen separating feed and permeation sides; a detector is placed on the permeation side.
• Test specimen geometry:
  • Specimen width typically 3–10 mm; thickness typically 0.01–0.1 mm.
  • Base plate and lid sizes vary by method (typical base-plate diameters 30–200 mm for some methods; 20–100 mm square for calcium method).
  • Lid size must be equal to or larger than the outer periphery of the specimen.
• Sample preparation and conditioning:
  • Condition specimens in vacuum or inert atmosphere; heating may accelerate conditioning.
  • For ISO 15106-7 (calcium), prepare cells in an inert atmosphere and use optically transparent substrates.
• Test practice:
  • Minimum three specimens unless otherwise agreed.
  • Preferred test conditions include temperatures 25, 40, 60 or 85 °C with high relative humidity (typically 85–90% RH).
  • Calculation uses the transmission area 2Lc(La + Lb) as defined in the standard.
• Reporting: Test report must reference ISO 21760-2:2019 and include method used, specimen dimensions, material details, conditioning, test conditions, and averaged test result (rounded to two significant figures).
• Patent note: The introduction flags a patent related to the water permeation cell structure; license terms may apply.

Applications and users

• Who uses it: Adhesive manufacturers, materials scientists, R&D labs, quality-control engineers, and device manufacturers of OLEDs, organic photovoltaics and other organic electronic devices.
• Why it matters: WVTR of edge-seal adhesives directly affects device lifetime and reliability by limiting moisture ingress that degrades organic layers and metal contacts. ISO 21760-2 provides standardized, rapid methods to compare adhesives and qualify sealing processes.

Related standards

• ISO 15106 series (Parts 3, 5, 6, 7) - measurement techniques referenced by this part.
• Other parts of the ISO 21760 series (see ISO website for list).