Wvtr and otr

WATER VAPOUR TRANSMISSION RATE AND OXYGEN TRANSMISSION RATE TESTING PRINCIPLE

1. TRANSMISSION RATE TESTER. WVTR AND OTR TEST

2. Water vapour transmission rate (WVTR) WVTR – time rate of water-vapour flow normal to two specified parallel surfaces under steady conditions, through unit area, under the conditions of the test Accepted unit ( 1 gram per 24 h per sq. meter)

3. WVTR FOR PACKAGING CONTAINERS The water vapour transmission rate (WVTR) through the container is determined by: Container wall thickness Permeability of the packaging material Difference between the external and internal relative humidity environments Driving force for the water flux through the container

4. TESTING Specimens are attached to the top of the dishes by means of a sealant Dishes contain desiccant / water depending on method Complete assemblies are inserted in the atmosphere and after specific period of time are weighed accurately to determine gain or loss. Test is conducted until nominal steady state exists

5. Permeation rate – (mL.mm)/(m 2 .24h.atm), dry, at (temperature 0 o ) Transmission rate – ( mL /(m 2 .24h), dry, at (temperature 0 o ) Factors affecting permeation rate Material thickness Relative humidity Temperature Time Barometric pressure Test results should are valid only if the barrier material has reached equilibrium

6. W3/330 Water Vapor Transmission Rate Test System W3/330 system is based on the electrolytic sensor method to measure water vapor transmission rate of film and package specimens. It has three independent testing cells and can be easily connected with 9 satellite systems.

7. Applications of Labthink moisture vapor transmission rate tester: -- Films  -- Sheeting  -- Paper and Paper Board  -- aluminium foils  -- plastic containers  -- Medical Packages  -- and other materials that used as a barrier material  Features of this moisture vapor transmission rate W3/330: -- Three testing chambers in one instrument with average value available  -- Electrolytic sensor method -- Precise and wide range temperature and humidity control  -- Conform to ASTM, ISO international standards  -- Referral films -- Professional software 

8. Technical Data:  -- Test Range: 0.1~1,000 g/m2·24h -- Resolution: 0.001 g/m2·24h -- Temperature Range: 15°C~55°C -- Temperature Accuracy: ±0.1°C -- Humidity Range: 10%RH~98%RH -- Humidity Accuracy: ±1%RH Standards: ISO 15106-3, GB/T 21529, DIN 53122-2, YBB00092003

9. Oxygen permeation rate (O 2 TR) Oxygen- thief of flavor , texture, color , nutrition & shelf life True shelf life condition tests – able to control RH% independently on each side of the material Test - coulox sensor The coulox oxygen sensor is a fuel cell that works in accordance with faraday’s law. When exposed to oxygen, the coulox sensor generates electrical current proportional to the amount of oxygen.

10. Similar considerations are relevant to protection of products that are labile to oxidative degradation. The permeability of plastic containers to oxygen ingress has also been evaluated (OVTR), and is summarised here. Pack OVTR (g. mm/(m 2 . day)) LDPE 241 HDPE 102 Polystyrene 127 Polycarbonate 114 Polypropylene 89 PVC 4 PET 2

11. STANDARDS ASTM D-3985 Analysis Temp: 23C Test Gas: 100% O 2 (dry) Carrier Gas: 98%N 2 / 2%H 2 (dry) Instrument: MOCON Oxtran ® 2/21 Methodology:

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