Determination of WVTR
High demands are nowadays put on packaging materials. For example, depending on the application field, the materials must provide optimum barrier properties toward water vapor, oxygen or odorants. In addition, there are requirements regarding tear resistance, transparency and compatibility with the contents of the packaging. .
The water vapor transmission rate of films can be determined gravimetrically with great accuracy. To do this, sample dishes are filled with saturated salt solutions, water or a desiccant and covered with the film under investigation.
The water vapor transmission rate (WVTR) measures the passage of water vapor through a substance of a given unit area and unit time. Controlling the water vapor transmission rate is important because varying working temperatures may lead to condensation and the formation of moisture, which can cause corrosion.Water vapor transmission rate is also known as moisture vapor transmission rate (MVTR)
The mass changes can be determined by periodically weighing the dish. This allows the water vapor transmission rate of the film under investigation to be determined. Measurements like this can be carried out using a ProUmid GmbH sorption test system .