Description:
Testing method applicable to nearly all materials. e.g. plastic and polymer films, paper, cardboard, textiles with or without coating.
Result Unit:
WVTR (water vapour transmission rate) in g/m2*d
Related to the thickness: P(permeation coefficient) in g*mm/m2*d.
(Related) Standards:
DIN 53122-1 / DIN 53122-A,
ISO 2528:1995,
ASTM E-96.
Test method:
A testing container is filled with desiccant and its opening gets covered by the sample. It is stored in a defined climate and the permeating amount of water is detected by weighing.
Detection limit:
The norm proposes a range of 1 – 200 g/m2*d. The detection limit also depends on the nature and thickness of the specimen. With a setup differing from the standard it is possible to measure much lower permeation rates, 0.1 g/m2*d.
Required specimen:
For testing please send us a sheet of the approximate size of a sheet of paper (DIN A4, 210*297 mm). For non flat specimens: please send after consulting with us.
The standard proposes sample diameter of 9 cm and a thickness of max. 3 mm. The specimens shall be uniform in thickness, representative for the material and free of pinholes and folds. On request we measure your sample thickness according to DIN 53534. We recommend the measurement of three independent samples per test (minimum number not regulated by the standard). Our standard is to measure samples of 20 µm – 3 mm, others on request.
Required sample dimension: we perform the preparation of the samples for you. For different test gases and type of samples we use differently sized samples. If you want to conduct the cutting of the specimens yourself, please contact us for the required dimensions. For sensistive coating test, it sometimes makes sense to prepare first the support followed by the coating. Please inform us, if your samples tend to mechanical failure under applied pressure (of the test gas or the sealings).
Testing medium:
Water or water vapour.
Test conditions:
The norm proposes the following climates:
- A – 23 °C 90 %r.h.;
- B – 38 °C 90 %r.h.;
- C – 25 °C 75 %r.h.;
- D – 23 °C 85 %r.h.;
- E – 20 °C 85 %r.h.;
We will test with other climate conditions on your request. Please contact us for information on special effects and requirements for the samples at high pressures.
Also possible are temperature profiles (nonisothermic measurements) for the determination of morphology changes and the influence of media and pressure on polymer properties. Based on this method, Mecadi offers further examination to determine gas solubilities (sorption and desorption), diffusion coefficients and the measurement of break through times through barriers.
Furthermore, interactions between media and polymer can be investigated. Thus the predictions according resistance, physical and chemical reactions under process conditions can help in the selection process of materials.
You find this article here as a PDF. We also do the test sample manufacture for you.
