Enhanced Water Vapour Permeability Tester for High Barrier Materials

Presented by Alyce Hartvigsen, PBI Dansensor

The newest developments of barrier materials for packaging of water vapour-sensitive food products and other specialized applications such as organic light-emitting diode (OLED) films have led to the achievement of lower water vapour transmission (WVTR) rates through the materials. The WVTR rates of these “ultra-barriers” are often below the detection limit of conventional permeability testers available on the market. As a result, there is a rapidly growing demand for improved water vapour permeation testers with higher measurement sensitivity.

In anticipation of the new market requirements, the Dynamic Relative Humidity Measurement method for WVTR testing was closely examined in order to identify possible areas of improvement or enhancement. A new design of testing chamber was developed for this purpose. In combination with minor changes to the humidity sensor, flow system and measurement software, the new test system achieved an improved measurement sensitivity of one order of magnitude compared to the conventional system, with a lower measurement limit of 0,003 g/m2/24 hr. In addition to the improvement in measurement sensitivity, the new system demonstrated faster measurement times for high-barrier materials, improved linearity of measurements, better reproducibility of measurements, and optimisation of the intrinsic leak rate of the system. These characteristics make
the new system particularly suitable for the measurement of high-barrier films and foils.