Application Note
To determine water vapor permeability, proUmid offers a precise and convenient method with the Permeability Kit.
For this purpose, a permeability dish is covered with the film to be tested. By filling those dishes with either a desiccant (Dry-Cup-Method), a saturated salt solution or water (Wet-Cup-Method), a difference to the partial water vapor pressure of the environment is generated, resulting in a migration of water molecules through the film. The measurement of water vapor migration is carried out gravimetrically.
As additional option, the Inverted-Cup Method is available as a modification of the Wet-Cup-Method. This method is particularly useful when a packaging material is in direct contact with a liquid product. The inverted arrangement eliminates the influence of the air layer on water vapor permeation and ensures a more realistic measurement result.
