DIN Determination of the water vapour transmission rate of plastic film, rubber sheeting, paper, board and other sheet materials by gravimetry. DIN Testing of plastics and elastomer films, paper, board and other sheet materials – Determination of water vapour transmission. DIN ENG_机械/仪表_工程科技_专业资料。Determination of the water vapour transmission rate of plastic film, rubber sheeting.
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The water that has permeated through the sample is carried to the detector by a second carrier gas.
Take the arithmetic mean of the individual values and report it to three significant places, but not to more than one decimal place. Balance, capable of weighing to an accuracy of 0,1 mg. If the wax is spread out on the rims with the aid of a hot spatula, check that the seal is still intact after the sealant has cooled. This, however, is generally unnecessary in the case of non-hygroscopic film or sheets or of those having low water vapour transmission rates. Two points are important in selecting the size of dish, namely preventing the desiccant from becoming saturated during the test, on the one hand, and minimizing the total mass, on the other, to reduce its effect on the accuracy of weighing.
The permeation coefficient is calculated as the slope of the displaced volume against time. The same phenomenon will be observed if the humidity of the test atmosphere varies considerably during weighing.
DIN Standard – Testing Instruments – Labthink
We will test with other climate conditions on your request. We also do the test sample manufacture for you.
After reaching the desired temperature, the measurement is started. Cover templates of the type shown in figure 4 facilitate the sealing operation. It is advantageous to use material with a particle size of 1,5 mm to 2 mm that passes through a 4 mm sieve, has 51322 freed of any fines using a 1,6 mm sieve, and has been dried in the normal manner. Testing method aplicable to nearly all materials, e.
If these conditions are fulfilled, the water vapour transmission rate, WVTR, of similar samples of different thickness is inversely proportional to the thickness, i.
Thus the 5322 according resitance, physical and chemical reactions under process conditions can help in the selection process of materials. Continued on pages 2 to 7.
It is advantageous to use a light metal lid that covers the dish when it is removed from the test atmosphere and weighed so that the sample releases as little water as possible to the surrounding air during weighing. Under refined test conditions e.
See DIN for other methods of determining water vapour transmission rates e. The internal depth of the dish should be between 8 mm and 24 mm, but shall preferably be 15 mm. In the case of highly transmissive samples, the number of dishes in the evaporation chamber may be kept low to ensure a constant and uniform distribution of humidity within the tolerances for the test atmosphere concerned see subclause 8.
You find this article here as a PDF. If the two surfaces of the sample are not the same, the test area, i.
For non flat specimens: Sealant, consisting of a wax mixture that adheres strongly to both the dish and the sample, is not brittle at the measuring temperature and is neither hygroscopic nor susceptible to oxidation. Based on this method Mecadi offers further examination to determine gas solubilities sorption and desorptiondiffusion coefficients and the measurement of break through times through barriers.
Check that the increase in mass between two consecutive weighings is at least 5 mg. Make such blank samples in the same way and subject them to the same conditions, but without desiccant in the dishes.
In the case of products having an outer layer, determine the mass per unit area as described in DIN In case of doubt, the German-language original should be consulted as the authoritative text.
This equation applies if the interval between consecutive weighings is 24 hours see subclause 8. If the water vapour transmission rate is low, the thickness of the samples is large or the samples are very hygroscopic, one or two additional samples shall be prepared.
The relative humidity can be readily established in the desiccator by the solutions containing a large excess of salt specified in table 1. For undated references, the latest edition of the publication referred to applies.